Cov ToC + – ➭ ➮ A Intro How to Navigate the Magazine: At the bottom of each page, you will see a navigation bar with the following buttons: Arrows: Click on the right or left facing arrow to turn the page forward or backward. Introduction: Click on this icon to quickly turn to this page. Cover: Click on this icon to quickly turn to the front cover. Table of Contents: Click on this icon to quickly turn to the table of contents. Zoom In: Click on this magnifying glass icon to zoom in on the page. Zoom Out: Click on this magnifying glass icon to zoom out on the page. Find: Click on this icon to search the document. You can also use the standard Acrobat Reader tools to navigate through each magazine. Welcome to your Digital Edition of Medical Design Briefs August 2017 ➭ Intro Cov ToC + – A www.medicaldesignbriefs.com August 2017 From the Publishers of From the Publishers of Today’s Skin-Worn Wearables Designing Cybersecurity into Devices Magnesium for Medical Implants
Transcript
Cov ToC + – ➭
➮
AIntro
How to Navigate the Magazine:
At the bottom of each page, you will see a navigation bar with the following buttons:
Arrows: Click on the right or left facing arrow to turn the page forward or backward.
Introduction: Click on this icon to quickly turn to this page.
Cover: Click on this icon to quickly turn to the front cover.
Table of Contents: Click on this icon to quickly turn to the table of contents.
Zoom In: Click on this magnifying glass icon to zoom in on the page.
Zoom Out: Click on this magnifying glass icon to zoom out on the page.
Find: Click on this icon to search the document.
You can also use the standard Acrobat Reader tools to navigate through each magazine.
Mrs. Gillet began her career at Sterigenics 10 years ago as Quality Manager for the Petit-Rechain plant. She specializes in cycle design and development, process definition and performance qualification studies, PCD development, D-value determination & EO residues. Other areas of expertise include gas chromatography method validation and failure investigations.
Kevin is a Radiation Physicist with corporate responsibility for measurement and calculation of absorbed dose associated with the radiation treatment of product, such as sterilization of healthcare instruments. He is an applied computational physicist with almost 30 years of experience in radiation physics and radiation dosimetry within a highly technical industry. Kevin is actively involved in industry committees, task forces and working groups. As a Working Group member, Kevin represents Canada on ISO TC 198 WG 2 Radiation Sterilization.
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■ DEPARTMENTS
36 R&D Roundup
46 New Products & Services
49 Advertisers Index
50 Global Innovations
■ ON THE COVER
Concerns about relationships, wellness, illness, physicaldistance, time, and work are universal. People’s coreneeds for connectivity, especially in matters of the heartand health, are shared by all. Wearable medical devicesolutions to meet these needs are flowing swiftly intothe market. Some wearable medical devices store thedata on a patch throughout a prescribed wear period.Other skin-fixation devices transmit signals via wirelessnetworks, which connect the data to sophisticated real-time monitoringsoftware. To learn more about the critical decisions surrounding the devel-opment of skin-worn wearable technologies, read the article on page 8.
(Credit: Pronat Medical)
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MedAccred Makes Its MarkThe industry was buzzing when
Stryker announced in July that it wouldrequire its future suppliers of criticalmanufacturing processes to be accredit-ed by MedAccred, a medical supplychain oversight program formed in 2010by the Performance Review Institute.
The program is gaining traction asmore medtech OEMs are beginning torequire accreditation, but Stryker’s policymay force more suppliers to seek accredi-
tation sooner in order to stay competitive— especially if other medical device com-panies follow Stryker’s lead.
“MedAccred will be a game changerfor the industry,” says Connie Conboy,director of the program. “The compa-nies that really understand how [accred-itation] is going to impact them are try-ing to roll it out as quickly as they can.”
Accredited companies range in sizefrom privately owned companies like SolarAtmospheres and Global Technologies to
very large, multinational organizations likeFlex and Bodycote. Conboy says that thesupplier companies gaining accreditationare also leaders in the industry, noting thatthese companies are seeing opportunitiesfor new medical device business as theresult of their MedAccred accreditations.
“We have been having almost daily dis-cussions with new suppliers interested inlearning more about how to prepare forand achieve MedAccred accreditation.Because the program is still in its earlystages (MedAccred began conductingaudits in 2015),” she says, “there is anexcellent opportunity for suppliers whoachieve MedAccred accreditation to setthemselves apart from their competitorsand gain new business.”
Conboy says they expect to conductapproximately 60 audits this year aroundthe globe. Plants are already accreditedin six countries. So far, accreditations areoffered in eight critical processes: cableand wire harness, heat treating, plasticsextrusion, plastics injection molding,printed board, printed circuit boardassemblies, sterilization, and welding.The number of areas accredited willincrease based on input from industryand FDA.
“FDA’s CDRH has been very support-ive of the MedAccred program from thestart, and the agency continues to evalu-ate how they plan to utilize it in theiroversight of the industry,” says Conboy.
In addition to Stryker, other OEMsare also asking suppliers to gainMedAccred accreditation. Conboy notesthat industry support for the programcontinues to grow, and that major com-panies such as Philips, Johnson &Johnson, Baxter, Medtronic, GE HealthCare, BD, and Flex along with many oth-ers have been very active in the program.
Is MedAccred part of your future?
Sherrie TriggEditor and Director of Medical Content
TMBG, MDG Launch Medtech EventTech Briefs Media Group (TBMG)
and Medical Development Group(MDGBoston) have formed a partner-ship to benefit the medical technologycommunity. The two groups will jointlyproduce a full-day medical technologyconference next year in Boston. In addi-tion, MDGBoston will get national expo-sure through TBMG’s Medical DesignBriefs magazine and digital properties,and Medical Design Briefs will have a pres-ence at MDGBoston’s monthly Forums.
6 Medical Design Briefs, August 2017Free Info at http://info.hotims.com/65854-764
FROM THE EDITOR
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Medical Design Briefs, August 2017 www.medicaldesignbriefs.com 9
In the fast-expanding world of wearable medical devices, anentrepreneurial spirit is driving dreams of a digital healthfuture into reality. Collaboration on material selection andtesting early in the development cycle can help smooth theroad to innovation.
Imagine, if you will, a remote Chinese village. A small cottagesits far from the road surrounded by rice fields. Inside, anelderly woman and her husband enjoy a simple dinner, chattingabout their next trip to the city to visit their son’s family andnew grandchild. … A few hundred miles away, that very sameson and his wife are preparing dinner in their high-riseapartment, discussing some issues that came up at work andhis concerns about his mother’s recent fall. “We’re lucky Dadwas home,” he says. “But if it happens again, at least now wehave some peace of mind.” A quick glance at his smart phoneassures him his mother has been in stable health today.
An app receives continuous streams of data from a smallpatch his mother has worn since she tumbled in the gardenlast month and struggled to stand back up. Now the app’sdigital health algorithms send him an alert if something is awryso that he can immediately get in touch with his parents’nearest neighbor and the village nurse practitioner. … In theroom next door, a baby suddenly stirs, whimpers a bit, thenfalls back asleep. Again looking at his phone, the son, now alsoa concerned new father, sees that the child is running a low-grade fever. Thanks to a tiny monitoring device gently butsurely adhered to the infant’s tender skin for the past few days,the new parents don’t have to disturb their son to check histemperature. “If it doesn’t break by morning, I guess one of uswill need to take him to the clinic,” he says. “Yes,” says hiswife, “but why don’t I schedule a quick WeChat televisit tonightwith the on-call nurse to see if there’s something more we cando?” With a sigh of relief and a good plan of action, theyreturn to their meal preparations. …
10 www.medicaldesignbriefs.com Medical Design Briefs, August 2017
This hypothetical family could be any-where in the world. Their common
concerns about relationships, wellness,illness, physical distance, time, and workare universal. Their core needs for con-nectivity, especially in matters of theheart and health, are shared by all.
Wearable medical device solutions tomeet these needs are flowing swiftlyinto the market. Some of these wear-able medical devices store the data onthe patch throughout a prescribedwear period. Then the patient removesthe patch and mails it to the medicaldevice vendor for analysis. Other skin-fixation devices transmit signals viawireless networks, which connect theraw data feeds to sophisticated real-time monitoring software. Dependingon the application and the monitoredcondition, healthcare providers andother caregivers may be alerted in theevent of a medical problem, or theymight view or analyze the informationat regular intervals.
LifeWatch® Services, a company thatdevelops remote patient diagnostics,recently received FDA and CE approvalfor its Mobile Cardiac Telemetry Patch.This product utilizes a comfortable,hydrocolloid skin adhesive to providelong-term skin fixation for its sophisti-cated ECG sensor with mobile signalprocessing. The patch detects cardiacrhythms and wirelessly transmits theECG data in real time to LifeWatch foranalysis. The special choice of hydrocol-loid adhesives enables patients to contin-ue normal activities, including shower-ing, while wearing the patch for extend-ed periods.
The possibilities, applications, andconfigurations for wearable medicaldevices are virtually limitless. In thedisease prevention arena, cosmeticsgiant L’Oreal recently released its MyUV Patch, which alerts users about howmuch ultraviolet sunray exposure theyhave received so that they know whento apply protection. Among wellnessapplications, Kenzen is gainingmomentum with its body-worn patchthat measures athletes’ electrolyte lev-els in real time. In chronic diseasemanagement, researchers are workingsteadfastly on noninvasive ways tomeasure blood glucose levels with skin-worn monitors that analyze tinydroplets of sweat. In the future, thesewearables may not only monitor diabet-ic patients but they may also deliverlife-sustaining medication.
Wearables: An Expanding World ofOpportunity
While projections vary quite a bit, there is consensus among someleading market researchers that themedical wearables category is steadilyexpanding. Market Data Forecast esti-mates the global market for wearablemedical devices will reach $11.18 billion by 2020, growing at a com-pounded annual growth rate of over 19 percent.1
Market research firm Tractica expectsworldwide shipments of body sensors toincrease from 2.7 million units in 2015to 68 million units by 2021. “Healthcareis expected to be one of the biggest driv-ers for body sensors, particularly con-nected wearable patches,” the firm says.2
IDTechEx projects medical devicewearables will reach $31.6 billion by2026, with the potential to be a $100 bil-lion business over a longer term(beyond a decade). Lengthy product
Designed for long-term skin fixation, the LifeWatch Mobile Cardiac Telemetry Patch detects cardiacrhythms and wirelessly transmits the ECG data in real time to LifeWatch for analysis. The industrialdesigner for the Lifewatch patch was www.trim-id.com. (Credit: LifeWatch Services Inc.)
During medical wearable device converting, Pronat Medical uses an integrated pick-and-place robotand laser line in its cleanroom. (Credit: Pronat Medical)
12 www.medicaldesignbriefs.com Medical Design Briefs, August 2017
development cycles for medical wear-ables are a factor that has capped growthat a relatively modest pace so far, thefirm said in a 2016 webinar.3
Skin-Fixation Devices: Where Artand Science Merge
When it comes to wearable deviceproduct development, early decisionsabout material selection can make anenormous difference in launch time-lines, performance, and ultimately, thepatient experience. It’s beneficial towork with a material supplier, converter,and industrial designer with strongunderstanding of anatomy, medicaldevice quality standards, and the proper-ties and characteristics of diverse materi-al options.
During the initial stages of productdevelopment, there are big advantagesto keeping an open mind and detaileddialog going between partners aboutdevice parameters, desired functionali-ty, target price, size, and wear time. Adevice maker may have specific materi-als in mind, but a medical specialist con-verter may be able to recommend otheroptions that will offer equal or betterskin fixation, breathability, and con-formability. The device end use willdrive many of these decisions. Forinstance, device stability on the skin forvery short wear times can be mostimportant for patches used for somedrug-delivery applications. In this case,fast, secure adhesion is more importantthan breathability.
For other end uses, such as cardiacmonitors worn continuously over a two-week period, the ability to managesweat and bodily fluids is a muchgreater priority. Without a highlybreathable material, the patient may
not be able to tolerate the device,which could lead to serious skin sensi-tivity and irritation problems. Workingtogether with the device manufacturer,an experienced industrial designer,material manufacturer, and medicalspecialist converter can suggest bothskin-contact and construction materialsto manage varying levels of moisture —through allowing vapor transmission ormoisture absorption.
There is both art and science involvedin choosing the right materials, testingthem, and integrating them into a fullyfunctional wearable device. For exam-ple, the materials manufacturer, work-ing through the specialist converter, willbe able to provide biocompatibilityreports and documentation for eachmaterial used in a skin-contact adhesive.These will include results for cytotoxici-ty, irritation, and sensitivity according tomarket standards (ISO 10993). Thematerial data sheet will specify the adhe-sion strength and other key perform-ance characteristics. These are criticalscientific metrics.
However, there also is a need for agreat deal of qualitative analysis. Anexperienced wearable device convertershould be skilled in the art of wear-testexperimentation. How long does a mate-rial truly adhere under a variety of con-ditions? Will it stay on the skin for a weekwith regularly showering? How will ithandle intense movement and profuseperspiration from vigorous exercise?How does a patch feel on the skin overtime? How do these factors vary depend-ing on patch placement on differentparts of the body? How easy is it toremove from the skin? The answerscome from years of wear testing and trialruns — of putting oneself in the
patient’s skin, so to speak — to see howmaterials truly perform. And this can bemore art than science.
ConclusionProduct development of wearable
devices requires strong data to back upclaims for biocompatibility, wear time,and moisture management. But it alsobenefits from the softer skills, such as arefined sense for which design elementswill deliver the most effective perform-ance along with aesthetic appeal andcomfort. For without a good patientexperience, a wearable device isn’t likelyto be worn as prescribed, if at all.
References1. IDTechEx. (2016, July 14). Wearables: The
Next Big Thing or Next Big Disappoint -ment? Retrieved from http://www.idtechex.com/research/webinars/wearables-the-next-big-thing-or-the-next-big-disappointment-00077.asp
2. Market Data Forecast. (2016, December).Global Wearable Medical Device Market.Retrieved from http://www.marketdataforecast.com/market-reports/wearable-medical-devices-market-66/
3. Tractica. (2016). Smart Clothing and BodySensors. Retrieved from https://www.tractica.com/research/smart-clothing-and-body-sensors/
This article was written by Deepak Prakash,Thijs Janssens, and Paul Rosenstein. Prakashis Senior Director of Global Marketing andThijs Janssens is Technical Sales Engineer atVancive® Medical Technologies, an AveryDennison business. Prakash can be reached [email protected], andJanssens can be reached at [email protected]. Rosenstein is Managerat Pronat Medical, an Israel-based specialistmedical converter and turnkey manufacturerfor skin fixation solutions. Reach him [email protected]. For more information,visit http://info.hotims.com/65854-165.
These rotary converting machines in Pronat Medical’s cleanroom are used for mass production of wearable devices. (Credit: Pronat Medical)
14 www.medicaldesignbriefs.com Medical Design Briefs, August 2017
MAGNESIUM ALLOY
The use of medical devices has hit anall-time high, with the global industry
currently valued at $200 million andstrong growth predictions through to2023.1 These devices include surgicalimplants, which cover a broad range ofapplications such as artificial joints, lap-bands, stents, and pacemakers, with thegoal of supporting tissue regenerationand providing optimal healing, allowinga patient to return to full health in anacceptable time frame.
Within this industry, the use ofbioresorbable implants is increasing,competing with the more traditionaltitanium implants. Recent develop-ments within the bioresorbableimplants market includes magnesiumalloys, which offer new, revolutionarysolutions, demonstrating both biocom-patibility and biosafety. Magnesiumalloys present opportunities across themedical device market from orthope-dic implants to veterinary applications.Most recently the alloys have pro-gressed to use in cardiovascular stents,known as scaffolds. The alloys are nowbeing used in a commercially availableCE marked product (see the sidebar,“Developing the Magmaris MagnesiumScaffold”).
A New Opportunity: BioresorbableMaterials
Bioresorbable materials are advanta-geous for use throughout the medicaldevice market because they offer asteady resorption rate and can helpachieve optimum healing within thebody. Polymer materials have been usedas a bioresorbable option for a few years;however, magnesium alloys now offer animproved alternative. In comparison
with the relatively low strength of poly-mers, magnesium demonstrates a tensilestrength that is much closer to that ofnatural bone. This means that thesealloys are much more suited for use inload-bearing mechanical medicaldevices. Magnesium is also a naturallyoccurring element in the body, withproven biocompatibility.
Magnesium’s biocompatibility meansthat the body can remove magnesium
FOR MEDICAL IMPLANTS
THE BENEFITS OF
Top: The monolithic magnesium screws (a); the anodized magnesium screw (b), the PLLA screw (c).Bottom: the first two screws (d and e made from magnesium) stayed intact, whereas the PLLA (f)fractures at four weeks after implantation. (Credit: Marukawa et al. 2015).
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degradation products. Studies of bloodfollowing the use of magnesiumimplants within the body revealed thatresorption caused little change to thecomposition, with no disorder to theliver or kidneys.2 Furthermore, magne-sium is needed for effective heart, mus-cle, nerve, bone, and kidney functionand the World Health Organization(WHO) recommends that adults needbetween 280 and 300 mg of magne-sium per day.3
Magnesium alloys can be designed todegrade in a tailored manner to matchthe needs of specific implants in a rangeof applications. The advantage of thedegradation or resorption process of amagnesium implant is that it allows fornew bone to grow inward. This contrastswith other bioresorbable materials such aspolymers, which, as well as taking longerto degrade, have the potential to intakewater during degradation, leading to aloss in structural integrity as well as size.4
Magnesium Alloys for Use inMedical Devices
Medical implants can be used in arange of applications, such as vascularstents and bone repair. Traditional per-manent implants are common and typi-cally made from titanium or stainlesssteel; however, they often require a sec-ondary operation for removal.5 On theother hand, bioresorbable materials,including magnesium alloys, allow foroptimal healing before resorbing into
Developing the Magmaris Magnesium ScaffoldCardiovascular disease is thedeadliest, yet also the mostcommon disease in the world.Because of this, many rev -olutionary new procedures arebeing pioneered for its cure.Coronary angioplasties areknown as the most advancedsolution, and these involveminimally invasive insertion of a stent into the coronary artery.
Magnesium Elektron, a globaldeveloper of magnesium tech -nology, and Biotronik, a man -ufacturer of cardio medicaldevices, partnered to develop acardiovascular stent that resorbsover time. This bespoke newtechnology was launched fol -lowing a decade long researchprogram in which SynergMag®
410, a magnesium alloy system,was created as the criticalbackbone to Biotronik’s Mag marisscaffold. The Magmaris mag - nesium scaffold was launched inthe summer of 2016 by Biotronik,and it is now the world’s firstclinically proven magnesium-based resorbable scaffold toobtain a CE mark.
Patients have been treatedsuccessfully with Magmaris inGermany, Belgium, Denmark, theNetherlands, Switzerland, Spain,Brazil, New Zealand, and Sing -apore since its launch. The firstpatient in Australasia has re -cently been treated with theMagmaris stent, when it wasfound that the patient had 90percent of his heart vesselsblocked, causing ongoing anginaand chest pain.
During the development project, Magnesium Elektron invested $2.5 million in establishing a dedicated manufacturing facility, incorporatingstate-of-the-art laboratories, casting extrusion, and heat-treatment facilities. It achieved ISO 13485 certification for this purpose-builtSynerMag Technology Centre, which was used during the development of the SynerMag 410 alloy. The ISO 13485 certification means that thematerial produced is manufactured in line with international standards for biomedical use, which helps to increase the speed of medical deviceproduction for manufacturers by ultimately reducing time and costs associated with internally assessing materials brought in. This helps tosmooth out processes and simplify the device manufacturer’s role.
To read more about how Biotronik brought its product to market in partnership with Magnesium Elektron, access the case study athttps://www.magnesium-elektron.com/global-downloads.
16 www.medicaldesignbriefs.com Medical Design Briefs, August 2017
The SynerMag® Technology Centre.
The full Magmaris® scaffold created by Biotronik, which uses SynerMag® magnesium alloy as the key structuralbackbone of the scaffold.
the body as the surrounding tissuereplaces the implant. Bioresorbableimplants can also provide matchingresorption kinetics to the healing peri-od. This bioresorbability prevents theneed for secondary surgical procedures,which can be costly and stressful forpatients.
A recent study looked at the use ofmagnesium implants in osteosynthesis incomparison with PLLA polymers.6 Thisstudy, conducted by Marukawa et al.,was done in the tibia of beagles, usingMagnesium Elektron’s Syner Mag® alloyto evaluate the effectiveness. The studydiscovered that 100 percent of the PLLAscrews were broken within the timeframe. In comparison, only one in 24 ofthe SynerMag magnesium screws broke.It also found that four out of six PLLAscrews loosened within four weeks,whereas all magnesium screws remainedtight. This finding demonstrates boththe strength and obvious mechanicalbenefits of magnesium, which can beused in high-load-bearing areas. Thestudy also found magnesium to havegood biocompatibility.
ConclusionMagnesium is proven to be an advanta-
geous alternative to other bioresorbablematerials, suitable for use in many differ-ent applications. Not only is the elementnaturally occurring in the body, but mag-nesium alloys also have proven biocom-patibility. Furthermore, magnesium pro-motes new bone growth, and it does nottake on water, which would cause a lossin its integral shape during degradation.The success of magnesium in the med-ical device sector so far has led to it beingdeveloped for a number of differentapplications. It also shows great promisefor use in the pharmaceutical sector as adrug-delivery device.
Magnesium Elektron has successfullyproduced magnesium alloys for commer-cial applications. Its magnesium alloyproduct, SynerMag, which has alreadybeen used successfully as a platformmaterial in the healthcare sector, can bedesigned to resorb at different rates tosuit individual requirements.
References1. Anderson, A. Global Medical Implants
Market 2016: Industry Review, Research,
Statistics, and Growth to 2021. 2016(internet) https://www.linkedin.com/pulse/global-medical-implants-market-2016-industry-review-growth-anderson.
2. Zhang E, Xu L, Pan F, Yu G, Yang L, Yang K.In vitro and in vivo evaluation of the surfacebioactivity of a calcium phosphate coatedmagnesium alloy. 2009. Biomaterials, Volume30, Issue 8, Pages 1512–1523.
3. Institute of Medicine (IOM). Food andNutrition Board. Dietary Reference Intakes:Calcium, Phosphorus, Magnesium, Vitamin Dand Fluoride. Washington, DC: NationalAcademy Press, 1997.
4. Hofmann D, Entrialgo-Castano M, KratzK, and Lendlein A. Knowledge-basedapproach towards hydrolytic degradationof polymer-based biomaterials. 2009.Advanced Materials. 21, 3237–3245.
5. Bostman O.M. Osteoarthritis of theankle after foreign-body reaction toabsorbable pins and screws. The journalof bone and joint surgery. Vol 80-B No 2.March 1998.
6. Marukawa E, Masato T, Takahashi Y,Hatakeyama I, sata M, et al. Comparison ofmagnesium alloys and poly-l-lactide screwsas degradable implants in canine fracturemodel. J biomed Mater Res Part B. 2016.104B:1282–1289.
This article was written by Paul Lyon,Programmes Technology Manager atMagnesium Elektron, Manchester, UK. For moreinformation, visit http://info.hotims.com/65854-161.
18 Medical Design Briefs, August 2017Free Info at http://info.hotims.com/65854-770
Who we are / What we doWe are a non-profit professional organization that supports medical technology advances through our community of engineers, managers, clinicians, regulatory and others. Members improve their collaboration skills and knowledge across disciplines to innovate at levels they never imagined before whether as employees enhancing their value to their companies or as entrepreneurs commercializing their ideas and discoveries.
MDG Forums and VideosOur monthly forums cover all aspects of medical technology development with industry leading panelists and are held near Boston. Videos of these high-value presentations are available to members. Visit www.mdgboston.org to learn more.
“MDG Boston is an organization whose mission is to enhance the professional development of its members while also enhancing biomedical progress.”
Upcoming Dates TopicSept. 13, 2017 Nervous System Injury: Prevention, Detection and RecoveryOct. 4, 2017 Augmented Virtual Reality–Game Changing DevelopmentsNov. 1, 2017 Medical Device Single Use Disposables
Why MDG? “Industry trends become more clear, more quickly, and I have used specific knowledge points from meetings to make better decisions in my daily job.” – Member John O’Gara, PhD, Sr. R&D Program Manager, Hologic, Inc.
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Develop World Class Innovation SkillsIn Medical Technology
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20 www.medicaldesignbriefs.com Medical Design Briefs, August 2017
Cyber threats to health delivery organi-zations (HDOs) and the medical
device industry as a whole have hit a newlevel of maturity in the last year. A decadeago, the attack scene was dominated byacademic papers about theoretical attackson connected medical devices.1 Then westarted seeing data breaches on connectedmedical devices primarily as a means toaccess personal healthcare information.2
In the last year, however, at least two majorevents occurred where attackers directlymonetized attacks on medical devices. InAugust 2016, a short stock seller openlypublished video and de tails about cyber -security attacks on a medical devicemaker’s implantable cardiac devices.Predictably, the device manufac-turer’s stock fell.3 In May 2017, theWannaCry ransom ware compro-mised both hospital systems andmedical devices. While there aremul tiple reasons each attack suc - ceeded, it is clear that at tackers arebecoming bold er, and med icaldevices are not immune.
The U.S. government is takingsteps to address the issue. In 2012,the U.S. Con gress became con-cerned about safety impacts todevices and the U.S. GovernmentAc countability Office (GAO) sub-sequently recommended thatFDA “should expand its consideration ofinformation security for certain types ofdevices.”4 FDA provided premarket guid-ance in 2014 and postmarket guidance in2016. FDA continues to refine its cyber -security guidance and recently (May2017) hosted a large public workshop on“Cybersecurity of Medical Devices: ARegulatory Science Gap Analysis.”5
Government, security researchers in aca-demia, medical device companies, andHDOs participated to identify gaps andopportunities for improvement.
While FDA’s emphasis is on the impactcybersecurity has on safety, the U.S.Health and Human Services (HHS)emphasis is on protecting health informa-tion privacy and security, e.g., the HealthInsurance Portability and Ac countabilityAct (HIPAA) and Health InformationTechnology for Economic and ClinicalHealth (HITECH) rules. Cybersecurityalso affects non-health-related business
risk, where vulnerabilities in devices canbe exploited and those devices can thenbe used to attack other connected devicesor systems, not necessarily causing safetyor privacy issues. While not performed onmedical devices, this happened in anextreme way in the fall of 2016 with theMirai botnet.7
Much of the FDA guidance encour-ages proactively managing cybersecurityrisk. AAMI TIR57 is an example of a riskmanagement approach tuned to themedical device industry. An article inMedical Design Briefs also treated this indetail.6 The regulation and guidanceidentifies what should be protected,rather than how it should be protected.
This article summarizes steps medicaldevice OEMs can take to improve prod-uct security. A number of resources arediscussed throughout, with exampleshighlighted in the sidebar, “Resources.”
TrainingThe first place to start is with training.
You don’t expect someone at random offthe street to be able to competently repairyour car, so why would you expect some-one without adequate training to writesafe and secure software for your medicaldevice? Sadly, most of the top universitycomputer science programs skip cyber -security as a requirement. Industry, howev-er, provides many opportunities to obtaincybersecurity training as a professional.
publish) new attacks, security is not a“do it once” or “learn it once” and be
done. Software developers must befamiliar with existing vulnerabilitiesand watch for new vulnerabilities andexploits. Industry and government pro-vide great resources to get up to speed.For example, Microsoft STRIDE pro-vides an abstract threat model that is agreat way to think about bad thingsthat attackers can do with or to the system. Free resources from the OpenWeb Application Security Project(OWASP) and from Mitre provide suc-cessively detailed breakdowns of weak-nesses and vulnerabilities.
RequirementsSecurity does not happen by accident.
It must be designed in. The firststep is to capture comprehensivesecurity requirements that addressthe vulnerabilities and protectconfidentiality, integrity, and avail-ability of the device. These willnecessarily cut across privacy, safe-ty, and business concerns. Re -quirements should focus on thedesired properties, rather than onimplementation solutions. TheFDA premarket guidance recom-mends providing the NationalInstitute of Stand ards andTechnology (NIST) cy bersecurityframework, specifically to identify,
protect, detect, respond, and recoveradverse cybersecurity threats. Note the lat-ter three elements are responses to events.
Since attacks continue to evolve, no con-nected device should be consideredsecure for all time. Therefore, manufac-turers should provide a means to distrib-ute security updates to address newly dis-covered vulnerabilities. Require mentsshould be developed before selectingdesign components. This is especially truefor key components such as operating sys-tems (OSs).
Companies often quickly build func-tional prototypes to prove out key con-cepts. This is fine as long as the prototypeis replaced with a safe and secure productimplementation. Instead, financial andtime-to-market considerations can lead todecisions that the prototype is goodenough, and an attitude that the engineer-ing team should simply slap on some ofthat security goodness before shipping.
Designing Cybersecurity intoConnected Medical Devices
ISOSCELES-Based Medical Device
OEM Medical Applications
ISOSCELES Platform Services
ISOSCELES Separation Layer
OEM Device Hardware
Fig. 1 – ISOSCELES concept, showing secure separation layer andessential services on which medical device companies can buildtheir own medical applications.
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22 www.medicaldesignbriefs.com Medical Design Briefs, August 2017
Unfortunately, the features thatmake rapid prototyping approach-es so effective, such as being ableto easily and quickly pull in addi-tional functionality, remain, andthese last-minute additions areexactly what makes them easy forattackers to compromise.
ArchitecturesThe remainder of this article
discusses principles that shouldbe incorporated into a safe andsecure medical device architec-ture. These principles are moti-vated by military, avionics, andprocess control systems, whichhave had to deal with cybersecurity fordecades.
Minimal Interfaces. Relying solely ona strong perimeter defense is no longersufficient. Attackers apply automatedtools that tirelessly present combina-tions of inputs to the various deviceinterfaces until they uncover vulnerabil-ities in that perimeter that allow them togain a foothold in the device. They then“pivot” on this foothold and bury theirway deeper into the device or onto otherdevices on the same network. A key wayto slow down or prevent this sort ofattack is to reduce the physical and logi-cal interfaces to only those essential fordevice functionality. This reduces theattack surface, i.e., the number of placesthat an attacker can try to get in.
Separation. Next, each remaining inter-face should be isolated from the rest ofthe device’s functionality. For example, ifan infusion pump requires a network con-nection, e.g., to maintain current druglibraries, the network stack and code asso-ciated with retrieving the drug libraryshould be wholly separate from the soft-ware that monitors the rate at which thedrug is being pumped. In safety architec-tures, each unit of separation is called apartition. Separation kernels and somereal-time operating systems (RTOSs) pro-vide strong separation. In general, com-modity embedded OSs do not provideadequate separation without significantand specialized engineering efforts.
Least Privilege. Least privilege, a com-mon recommendation to secure systems,refers to eliminating access permissionsand other privileges to only those neededto operate the deployed device.Unfortunately, the aforementioned rapid-prototyping efforts often assume thateverything runs with root or administratorprivileges. This makes development easy,
since any software component can accesseverything on the device. It also makes iteasy for the attacker to have free access tothe device once they are in. Instead, oncea critical software service is developed, itsprivileges should be reduced so that if anattacker compromises that service, it cando nothing more than what it was origi-nally intended to do.
Strip Unintended Functionality. Relatedto least privilege, another technique is toremove unnecessary functionality. Forexample, a common software develop-ment approach is to include existing soft-ware libraries rather than develop newsoftware from scratch. A developer canoften acquire a library, write some wrappercode, and have new functionality proto-typed after just a few hours. That library,however, is often that: a collection of manydifferent functions. The developer mightneed only one function, but insteadincludes many functions when he or sheuses that library. Those other functionsmay contain flaws that an attacker canexploit. Both developers and attackers canacquire automated tools that search theselibraries for known vulnerabilities.Developers should either move to librariesthat do not have those vulnerabilities orstrip out the vulnerable functionality.
Non-bypassability. Attackers are likewater: they will seep through the smallestcrack. Non-bypassability prevents anattacker from easily working aroundsecurity controls. Human and machineusers of device interfaces should beauthenticated, and specific actions theuser is permitted to execute should beauthorized based on the user. Theseauthentication and authorization stepsshould not be bypassable, except for safe-ty critical “break glass” functionality,which should be observable if used.
Controls. Responding to new attacks
can require new or updatedapproaches. Yet again, industrycomes to the rescue, withresources such as the Center forInternet Security’s CriticalSecurity Controls. While thesecontrols were developed for typi-cal IT systems, each control canrelate to medical devices.Developers might consider eachcontrol, and if the control is notselected for the medical device,document precisely why it isunnecessary. For example, ver-sion 6.1 has a control specificallyaround e-mail and Web browserprotections. A connected infu-
sion pump might not have e-mail, so thatfunction can be documented as “NotApplicable.” If, however, the pump usese-mail as a mechanism for reporting orfile transfer, then those controls apply.Note, however, that while these controlsare necessary, they should not be treatedas a “sufficient checklist” for security.
AssistanceTo help the medical device industry
support these architectural principles,the U.S. Department of HomelandSecurity (DHS) funded several pro-grams to advance Cyber-Physical System(CPS) Security. One of these programs— Intrinsically Secure, Open, and SafeCyber-physically Enabled, Life-criticalEssential Services (ISOSCELES) — isdeveloping a reference architecture toenable medical device products to bebuilt from a secure foundation.ISOSCELES provides a separation layerand essential services for connectedmedical devices (see Figure 1).ISOSCELES will release as open sourcerequirements model-based systemsengineering tools for analysis and con-figuration and for example hardwareand software implementations. Usersadopting the ISOSCELES architecturewill be able to select their hardware andbuild their own medical application ontop of these services.
For example, with ISOSCELES, net-working functions are wholly separatefrom the safety monitors. In an infusionpump, these safety monitors would limitthe maximum rate at which a drug isdelivered. ISOSCELES relies on model-based systems engineering tools to spec-ify, analyze, and configure the separa-tion architecture. The specificationincludes the allowed communicationspatterns between the partitions, which
Designing Cybersecurity
Tire tracks in the grass around a security barrier, demonstratingbypassability of a poorly thought out security control. (Credit:unknown)
Our innovative sensor solutions make medical devices even safer and more efficient.
Medical Design Briefs, August 2017 www.medicaldesignbriefs.com
enables the tools to identify when safety-critical partitions are mistakenly con-nected to external networking inter-faces. This will prevent errors caused bymanual configuration, and it will alsocatch errors when developers create aconnection “just for debugging.”
BenefitsDeveloping a new medical device with
security built in may reduce the time tomarket for products by addressing thenew FDA guidelines for safe and securedevices. Once in the field, devices thatadopt these principles will be better pre-pared to address newly discovered secu-rity vulnerabilities, while leaving thesafety-critical components of the med-ical application untouched.
References1. “Security and Privacy for Implantable
Medical Devices,” IEEE, http://ieeexplore.ieee.org/abstract/document/4431854
2. “MEDJACK: Hackers Hijacking MedicalDevices to Create Backdoors in HospitalNetworks,” Computerworld, www.
3. “Short Seller Muddy Waters Renews Claimsof St. Jude Medical Cyber Vulnerabilities,”Marketwatch, http://www.marketwatch.com/story/short-seller-muddy-waters-renews-claims-of-st-jude-medical-cyber-vulnerabilities-2016-10-19
4. “FDA Should Expand Its Consideration ofInformation Security for Certain Types ofDevices,” http://www.gao.gov/assets/650/647767.pdf
5. “Content of Premarket Submissions forManagement of Cybersecurity in MedicalDevices,” FDA, https://www.fda.gov/downloads/medicaldevices/deviceregulationandguidance/guidancedocuments/ucm356190.pdf
6. “Managing Cybersecurity Risks in ConnectedMedical Devices,” Medical Design Briefs,http://www.medicaldesignbriefs.com/component/content/article/25210
7. “Did the Mirai Botnet Really Take LiberiaOffline?” Krebs on Security, November 4, 2016,https://krebsonsecurity.com/tag/mirai-botnet/
This article was written by Todd Carpenter,Chief Engineer and Co-owner of AdventiumLabs, Minneapolis, MN. For more informa-tion, visit http://info.hotims.com/65854-160.
AppCheck, Commercial Tool – SearchesBinaries for Known Vulnerabilities,http://www.codenomicon.com/files/pdf/AppCheck-Brochure.pdf
OWASP, “OWASP Top Ten Project,”https://www.owasp.org/index.php/Category:OWASP_Top_Ten_Project,https://capec.mitre.org/,https://cwe.mitre.org/, andhttps://cve.mitre.org/
FDA, “Postmarket Management ofCybersecurity in Medical Devices,”https://www.fda.gov/downloads/medicaldevices/deviceregulationandguidance/guidancedocuments/ucm482022.pdf
FDA, “Public Workshop – Cybersecurity ofMedical Devices: A Regulatory ScienceGap Analysis,” May 18–19, 2017,https://www.fda.gov/MedicalDevices/NewsEvents/WorkshopsConferences/ucm549732.htm
Microsoft, “The STRIDE Threat Model,”https://msdn.microsoft.com/en-us/library/ee823878(v=cs.20).aspx
24 www.medicaldesignbriefs.com Medical Design Briefs, August 2017
Until recently, developers and manu-facturers of medical devices have
not been required to consider securityin their products. New guidance fromthe U.S. Food and Drug Administration(FDA) and expanded European Unionrequirements for personal data protec-tion now make security design in med-ical devices a necessity. While IT networkattacks get most of the press, it is impor-tant to remember that physical attacks,such as accessing a maintenance serialport, can be just as dangerous.
Medical Security in the NewsSecurity experts have reported weak-
nesses in hospital and clinic networks forseveral years. Even though these net-works contain extremely sensitivepatient data and connect life criticalequipment, they continue to be proveneasy to infiltrate. While networkingequipment, like routers, may be state ofthe art in terms of security, the medicalequipment on the network often has lit-tle to no security protection. Breachinga device with malware can open a backdoor to allow remote hackers access tosensitive data across the network, andmoreover, cause the device to operate ina dangerous manner.
Since 2015, there has been muchregulatory activity on security thataffects medical device design. In theEU, the recent adoption of the newGeneral Device Protection Regulation,which applies to all devices, has strictrequirements for the protection ofpersonal data. Additional regulationsare soon to be released specifically formedical and intravenous deliverydevices.
For device designers, the more spe-cific recommendations from FDA pro-vide more useful guidance as to how tomeet security requirements. FDA hasissued formal guidance on both pre-market submissions and postmarketmanagement of security in medicaldevices. A key item in the premarketguidance states that security hazards
should be part of the risk analysis, whilethe postmarket guidance clearly refersto the need for secure software updateprocedures. The new postmarket guid-ance states that FDA typically will notneed to clear or approve medicaldevice software changes that are madesolely for updating cybersecurity fea-tures in the field. This latitude is toenable fast response to emergingthreats. Going even further, FDA issueda Safety Communication that was trig-gered, for the first time, by cybersecuri-ty vulnerabilities of one type of infusionpump. This communication recom-mended discontinuing the use of sever-al previously approved devices solelybased on their vulnerability to attack.
What to Do to Ensure CybersecurityWhile medical equipment developers
are experienced at developing systems
to meet functional safety requirements,cybersecurity adds another dimension tothe design process. It is advisable to con-sult with experts to evaluate the differ-ent trade-offs to achieve an appropriatesecurity level for the product. For exam-ple, INTEGRITY Security Services (ISS),a Green Hills Software company, helpsclients address FDA and EU require-ments with an end-to-end embeddedsecurity design. ISS supports medicaldevice developers in the application ofthe following five rules of embeddedsecurity.
Rule 1: Communicate without trust-ing the network. An increasing percent-age of medical devices are always con-nected, and many devices are requiredto be connected for maintenance orupgrades (see Figure 1). While protect-ing patient data is critical, a device’s fun-damental operating parameters, such as
26 www.medicaldesignbriefs.com Medical Design Briefs, August 2017
maximum dose limits on infusionpumps, are also critical. Even withoutsensitive data, if connected on a hospitalnetwork, a device can be a target forhackers to penetrate the network.
To prevent a security breach, it isnecessary to authenticate all end-points, including the device itself, anyhuman users interacting with thedevice, and any other connected sys-tems. Secure designs should neverassume users and control software arevalid just because the received mes-sages have the correct format. In theinfusion pumps that were the target ofFDA’s safety communication, a hackerwas able to gain access to the net-work, reverse engineer the proto-col, and send properly formedcommands that would haveallowed a lethal dose of medica-tion to be administered to thepatient. Authentication protectsmedical devices from executingcommands originating from un -known sources.
Rule 2: Ensure that software isnot tampered with. There aremany ways for malware to beinjected into a device, including:• Using a hardware debug inter-
face such as JTAG.• Accessing test and debug inter-
faces, such as Telnet and FTP.• Exploiting control protocols that
were developed without consider-ing security.
• Simulating a software update thatassumes trustworthiness with outverification.System software should not be
trusted until proven trustworthy.The point where authenticationstarts is called the root-of-trust, andfor high-assurance systems, this point mustbe in either hardware or in immutablememory. A secure boot process starts atthe root-of-trust and verifies the authentic-ity of each software layer before allowing itto execute (see Figure 2).
Secure boot verifies the source andintegrity of software using digital signa-tures. Software is signed during releaseand verified each time it is loaded. Thisguarantees that a device is free of mal-ware and operates to the quality it wasdeveloped. As a result, by preventing mal-ware, secure boot prevents any targetingof the larger network — meeting newFDA guidelines that recommend that if adevice has invalid software, it can detectand report it.
Rule 3: Protect critical data. Patientdata, key operating parameters, andeven software need to be protected notjust in transit over the network, but alsowithin the device. This is accomplishedby a security design that incorporatesseparation and encryption to ensurethat only authenticated software andusers have access to stored data.
Protecting data in transit requiresthat data can only be viewed by theproper endpoint. Note that standardwireless encryption does not providesecure communication; it protects thedata link only, but not the data. Anyother system that can access the wireless
network is also able to view the packetsin decrypted form. Data protection isaccomplished through network securityprotocols, such as TLS, which enablessecure client/server communicationthrough mutually authenticated anduniquely encrypted sessions.
Rule 4: Secure keys reliably. Keysused for encryption and authenticationmust be protected, because if thesekeys are compromised, an attacker mayuncover sensitive data or emulate avalid endpoint. For this reason, keysare isolated from untrusted software.Keys stored in nonvolatile memoryshould always be encrypted, and onlydecrypted following secure boot verifi-cation. Since protection of patient data
is paramount, especially for the EU,use of high-assurance kernels and secu-rity modules also provide layered sepa-ration for fail-safe design.
Keys need to be protected in manu-facturing and throughout the productlife cycle by an end-to-end securityinfrastructure. If a key is readable atany time, all of the devices using it arevulnerable. An enterprise securityinfrastructure protects keys and digitaltrust assets across distributed supplychains, but can also provide additionaleconomic benefits beyond softwareupdate such as real-time device moni-toring, counterfeit device protection,
and license files to control avail-ability of optional features (seeFigure 3).
Rule 5: Operate reliably. As allmedical designers know, among thebiggest threats to a system areunknown design errors and defectsthat can occur during the develop-ment of complex devices. Toaddress these potential threats, it isa good idea to implement princi-ples of high- assurance softwareengineering (PHASE). These prin-ciples include the following:• Minimal implementation —
Code should be written to per-form only those functionsrequired to avoid “spaghetticode” that is not testable ormaintainable.
• Component architecture —Large software systems shouldbe built up from componentsthat are small enough to be eas-ily understood and maintained;safety and security critical servic-es should be separated fromnoncritical ones.
• Least privilege — Each componentshould be given access to only theresources (e.g., memory, communica-tions channels, I/O devices) that itabsolutely needs.
• Secure development process — High-assurance systems, like medical devices,require a high-assurance developmentprocess; additional controls beyondthose already in use, such as designtools security and secure coding stan-dards, may be needed for ensuring asecure design.
• Independent expert validation —Evaluation by an established thirdparty provides confirmation of secu-rity claims. It is also often requiredfor certification. As with functional
Medical Design Briefs, August 2017 27Free Info at http://info.hotims.com/65854-775
safety, components that have alreadybeen certified for cybersecurity arepreferred as reliable building blocksin a new design.
These principles are used in the devel-opment of Green Hills Software’sINTEGRITY real-time operating system.When applied to application develop-
ment, they minimize the likelihood andimpact of a software error or a newcybersecurity attack.
Creating an End-to-End SecuritySolution
Building a secure medical system thatmeets the new regulatory environmentrequires an end-to-end security designthat addresses the security of data andreliability within the networked devicethroughout the product life cycle. Thisrequires a device security architecture,which safeguards operation by ensuringthat keys, certificates, and sensitive dataare protected throughout operation andmanufacturing supply chain by an enter-prise security infrastructure. The opti-mum selection of both device and enter-prise security solutions depends ondevice operating and manufacturingenvironments, as well as business trade-offs, so it is advisable to consult expertsin the field.
This article was written by Mary SueHaydt, Field Applications Engineer for GreenHills Software, Santa Barbara, CA. For moreinformation, visit http://info.hotims.com/65854-163.
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28 www.medicaldesignbriefs.com Medical Design Briefs, August 2017
As in any industry, new technologiesand material choices present new
opportunities and challenges for OEMslooking to build brand equity, bringproducts to market faster, and meet con-sumer demand. Medical device manu-facturers are faced with multifacetedchallenges to meet the highest degreesof performance, efficacy, regulatorycompliance, and safety in the service ofprotecting the health and well-being ofpatients. From the integration ofadvanced technologies all the waythrough to the type of material used,every design decision has lasting real-world consequences.
Embracing and rising to these real-world challenges is the mainstay of med-ical device development experts. Theincreasing scrutiny of hospital-acquiredinfections (HAIs) — and the methods tocombat them — places new importanceon the smart selection and rigorous test-ing of medical device housings. This arti-cle explores the most recent cleaningprotocols and their impact on medicaldevice housings in terms of patient safe-ty, device performance, and hospitaloperations. In addition, it explores newmaterial options and testing that canguide manufacturers in choosing andtesting materials that will meet theseincreased demands.
HAIs: Changing the GameHAIs are a concern for all aspects of
healthcare. In 2009, the Centers forMedicare and Medicaid Services (CMS)began refusing payment for some read-missions due to HAIs. Beginning in2012, CMS lowered reimbursementsacross the board for hospitals withexcess readmissions, including HAIs.
Today, hospitals face an additional 1 per-cent reduction in reimbursement if theyare in the top 25 percent of hospitalsthat don’t meet this year’s milestones.
To make sure they don’t lose theseMedicare reimbursements, hospitals arepreventing HAIs on two fronts: environ-mental cleaning and aseptic protocols.Both involve the frequent use of aggres-sive disinfectants that can damage devicehousings and other components.
New Cleaning Protocols: Great forHAI Prevention, Bad for DeviceHousings
Because of new cleaning protocolsthat require more frequent use ofaggressive disinfectants, the number ofHAIs has been significantly reduced.These new, stringent protocols includethe repeated application of isopropylalcohol (IPA), IPA + chlorhexidine,bleach, and other harsh chemical disin-fectants. Additional recommended stepsfor some applications include steriliza-tion with ethylene oxide (EtO) orgamma radiation.
Excellent progress has been reportedin HAI prevention, according to themost recent CDC report. However, oneunintended consequence has been thatthe repeated exposure to aggressive dis-infectants has led to substantial deterio-ration of device housings and hardware.At the same time, greater portability andconnectivity present new risks for acci-dental impact.
Cracking, crazing, discoloration, andpremature failure are all leading clini-cians to question the quality and safetyof medical devices. In fact, many devicesdesigned only a few years ago are alreadyexperiencing performance and func-
tional issues that are negatively impact-ing the life cycle of housings made withcommonly used materials. Keep inmind, most equipment is intended tolast 8–10 years.
The reason for premature device fail-ures could be that the materials usedmay be structurally unable to handle theincreased frequency of cleaningrequired in today’s healthcare facilities.
The Real Cost of Device FailureThe design engineer may be the last
one to hear about the effects of disinfec-tants on an innovative and promisingproduct design — or may only get partof the story. And quality engineers caneasily misdiagnose failures and blamethem only on a drop or accidentalimpact — especially if they don’t have agood understanding of how plasticsreact to chemical attack.
By considering the impact that aggres-sive disinfectants have on plastics, itbecomes more apparent that many fail-ures could be prevented by simplychanging to a different material.However, doing so is often viewed asrisky and costly. But this is not always thecase, as a manufacturer’s material costdifferential for change may be insignifi-cant compared with repair and servicecosts of a failed device. Even more criti-cal is what unreliable devices can costthe hospital or clinic — in physicalrepairs, patient access, and satisfactionlevels. And of course, there is the risk topatient health and safety.
It’s a simple fact that certain materialsare better (and better suited) to certainmedical device applications based on avariety of factors, such as molding,processability, end-use robustness, dura-
New HAI-Prevention CleaningProtocols Reinforce Need forMaterial Consideration forMedical Device Housings
30 www.medicaldesignbriefs.com Medical Design Briefs, August 2017
bility, cost, avoidance of repetitive fail-ures, and varying degrees of chemicalresistance. A material’s chemical resist-ance is now more important than evergiven the current — and effective —HAI-prevention cleaning requirements.
Advanced Testing: Taking the ExtraStep
Chemical resistance is a function ofthe material itself, the types of disinfec-tants and chemicals the material is sub-jected to, and its repeated handling. Tobetter predict functionality in real-worldhospital environments, stress should befactored into chemical resistance test-ing. This is because stress accelerates theeffect of chemical attack and chemicalexposure accelerates the reduction ofimpact strength.
Grounded in sound science, a newfour-step testing protocol has beendeveloped. This protocol, based onmodified ASTM D543 and ASTM D4812(step 4 only) standards, is designed tomimic failures from typical usage condi-tions to better understand why common-ly used plastics fail and help medicaldevice designers confidently choose thebest material for their devices.
This new four-step test has been devel-oped to ensure that it is replicable, reli-able, and accurate. The first three stepswill be familiar to any device manufac-turer, but the fourth step is a key differ-entiator that is critical in determiningthe robustness required for today’s HAIprotocols: 1. Select the appropriate jig. Choose a
strain level that most appropriatelyreflects environmental stress cracking.
2. Load flex bars onto the jig.Remember to load control samples.
3. Apply chemicals to flex bars using pre-soaked pieces of cotton. Enclose theentire sample jig in a plastic bag toprevent evaporation and leave it atroom temperature for 24 hours.
4. Perform reverse side impact test. Thisis the differentiating step. The fourth step — the reverse side
impact test — offers a more accurateassessment of how a given material willhold up in a real-world setting. Resultsshow that a material may or may notexhibit visually apparent changes afterthe first three steps. However, varyingdegrees of cracking and crazing becomenoticeable and significant after thereverse side impact test is performed.
To best interpret the results, it is rec-ommended that testers document the
Medical Device Housings
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impact strength of exposed and controlsamples to calculate the percentage ofreverse side impact strength retention.Higher retention translates to betterreliability after exposure.
All medical device manufacturersshould consider applying this test asthey develop or retrofit their currentproduct lines.
Limits to DesignMany medical device designers have
proved quite adept at trying to “designout” the stress in a particular devicecomponent. What this does notaccount for is the impact of the actualmolding process and the stress thatresults from the assembly of a device.This includes the vibration impactfrom sonic welding and the repeatedrough handling and disinfection in thehospital setting. This stress is preciselywhat step four attempts to replicate.
In repeated testing, a specialtycopolyester material was compared tolegacy polymers using this four-stepprotocol. Results indicated superiorimpact resistance and durability com-pared to polycarbonate, polycarbon-
ate/PBT, polycarbonate/ABS, andPVC. The material was able to with-stand rigorous use across a wide spec-trum of disinfectants, including thosemade with bleach compounds, whileoffering increased durability andreduced product failures for a widevariety of applications.
ImplicationsThe results of rigorous cleaning pro-
tocols have dramatically reduced HAIrates for patients in hospitals, ambula-tory care centers, and other facilitieswhere repeat-use medical devices arefrequently employed. The impacts onhospitals and medical device manufac-turers are now starting to be morewidely understood and require affirma-tive steps.
These cleaning regimens are havinga negative impact on device housingsmade with commonly used materials.Cracking, crazing, and discolorationare being observed, requiring costlyrepair, replacement, and shortenedlife cycles.
Beyond a strict cost-benefit analysis,this product degradation negatively
affects the brand equity and brandpromise of both the OEM and the hos-pital itself. Devices that appear old ordamaged risk perceptions of equip-ment being out of date or, in the worst-case scenario, unsafe or ineffective.
Medical device manufacturers cantake advantage of new materials — andnew testing — that will ensure not onlythe reliability and safety of their prod-ucts but the continued beneficial rela-tionship with hospitals and medicalcare centers.
While issues with medical housingsmay well be an unintended and nega-tive consequence of these new HAI-prevention cleaning protocols, theypresent new opportunities for thenext generation of devices that willcontinue to enhance patient care, pro-vide peace of mind and brand confi-dence for hospitals, and allow manu-facturers to bring to market betterperforming products.
This article was written by Dr. Yubiao Liu,Medical Application Development Scientistfor Eastman, Kingsport, TN. For more infor-mation, visit http://info.hotims.com/65854-164.
32 www.medicaldesignbriefs.com Medical Design Briefs, August 2017
Printed circuit boards (PCBs) are crit-ical components in many medical
devices. Prior to shipment to the OEM,PCBs must undergo a thorough clean-ing process to remove excess solder,rosins, and other contaminants at theend of the manufacturing cycle. If notcleaned properly, PCBs — especiallythose with complex configurations —may ship with unwanted contaminants.
A guidance document advises medicaldevice OEMs that PCBs should meet a cer-tain standard, noting “…a potential suppli-er of electronic circuit boards is requiredto provide circuit boards at a certain clean-liness level (minimizing reactive residues)to avoid reliability and performance issuesassociated with residue remaining fromthe soldering process.”1 In the last severalyears, FDA has become even more con-cerned about supplier management ascritical components such as PCBs havecontinued to fail, leading to recalls andother issues. Risk management, includingunderstanding how the supplier is clean-ing the PCB, can help device manufactur-ers protect themselves against failures dueto inadequately cleaned PCBs.
Ultrasonic cleaners have proved highlyeffective in cleaning PCBs, and theprocess is far superior to manual process-es that involve soaking and scrubbingusing high purity alcohol, flux removalsprays, and biodegradable solvents. Bycontrast, these time-consuming manualprocesses risk damaging delicate compo-nents and frequently fail to completelyremove contaminants. This articleexplains why requiring ultrasonic clean-ing can be an important factor whenevaluating PCB suppliers. It describeselements that contribute to properlyemployed procedures and presents ques-tions to ask regarding equipment, clean-ing solution chemistries, and the careand maintenance of equipment.
How It WorksUltrasonic sound is generally defined as
sound wave frequencies above the rangeof human hearing, generally 20,000cycles per second (20 kHz) and higher.
Ultrasonic cleaning is performed whenthe implosion of billions of minute vacu-um bubbles against surfaces of objectsimmersed in an ultrasonic cleaning solu-tion quickly and safely strips away con-taminants on those surfaces. Cavitation,the formation and collapse of these bub-bles, is produced by the ultrasonic soundwaves passing through the liquid. Thesound waves are in turn produced by thehigh-frequency vibration of generator-powered transducers bonded to theultrasonic cleaning tank.
Ultrasonic cleaner transducers deter-mine the ultrasonic frequency generatedfor the cleaning process. Ultrasoniccleaners can be specified to operate atfrequencies such as 25, 37, 45, and 80kHz or higher. Some models operate atdual frequencies. The point to keep inmind is the higher the frequency, the(relative) smallness of the cavitation bub-bles. Lower frequencies produce morevigorous cleaning and are usually usedfor heavily soiled parts. As the frequencyincreases, bubbles get (relatively) smallerfor gentler cleaning and with better abil-ity to penetrate tiny cracks, crevices, andsurfaces typical of delicate PCBs used inmanufacturing medical devices.
Bugaboos DispelledEarly concerns about using ultrasonic
cleaners for PCBs related to water dam-age and to unmodulated (fixed frequen-cy) operation creating harmonic vibra-tions that could shatter PCB components.These concerns no longer apply whenthe proper cleaning solution is employedin cleaners equipped with what is called asweep mode, which provides a slight contin-uous variation in the unit’s frequency.Another benefit of the sweep mode is amore uniform distribution of cleaningaction throughout the bath.
Several water-based biodegradableformulations are available for use incleaning PCBs. However, boards thathave electromechanical properties likerelays, as well as solid-state relays andoptocouplers, may not be suitable forthese solutions. It is best to look at the
manufacturer’s data sheets to verify thatthe process is acceptable. The case studybelow indicates that trial and error exer-cises may prove useful in selecting a cor-rect formulation. Experimenting onobsolete or broken boards can helpdevelop and refine the procedures. Adiscussion with cleaning solution suppli-ers is also helpful.
The Nuts and BoltsIt is important to request an ultrasonic
cleaner that offers the sweep mode toprovide safe, uniform distribution ofcleaning energy throughout the bath.Ultrasonic frequencies of 37 kHz andabove should be considered. Dual-frequency cleaners operating at frequen-cies such as 37 and 80 kHz allow manu-facturers options in developing the mosteffective processes for their PCB clean-ing procedures.
Another specification point to consid-er is ultrasonic power. Without gettinginto the nitty-gritty, more power usuallyindicates faster and more effective clean-ing, but more power is not always better.For example, too much power can dam-age electronic parts and other delicateitems. For cleaning extremely sensitiveitems, equipment with adjustable powerallows the PCB manufacturer to experi-ment to select the best power for a givenPCB, or to accommodate a variety ofPCB configurations.
It is critical that the supplier has acleaner that accommodates the OEM’sPCBs. While this seems to be a “no brain-er,” it is essential when it comes to speci-fying cleaning tank dimensions and,equally important, cleaning basketdimensions (which are slightly less thantank dimensions). The baskets hold thePCBs in a vertical position without crowd-ing or board-to-board contact and mustbe of sufficient size to allow total immer-sion in the cleaning solution. This spec iscalled working depth and is the distancebetween the bottom of the basket and thesurface of the cleaning solution. If thisinformation is not available on the specsheets, ask the manufacturer to supply it.
to aid positioning boards in the bath.Cleaning time and temperature con-trols are essential for establishing andmaintaining preferred PCB cleaningprocedures. Both of these are influ-enced by the condition of the PCBsand the recommendations providedby cleaning solution manufacturers.Cleaners equipped with heaters willcut the time needed to reach the rec-ommended cleaning temperature,but it is important to note that theprocess of ultrasonic cavitation createsheat and warms the solution. Excessiveheat can damage PCBs or subject themto thermal shock during rinsing. A use-ful accessory is a cooling coil. Check tosee whether the supplier has a unit witha timer and automatic cutoff at the endof the timed cleaning cycle.
PCB Cleaning CycleCleaning tanks have a fill line to indi-
cate the maximum level of cleaning solu-tion. The supplier should fill the tank halfway with water, add the correct amount ofcleaning solution concentrate for a full
tank, and then continue adding water tothe fill line. The unit is turned on to mixand degas the solution. Degassing freshcleaning solutions removes trapped airthat interferes with cavitation. Degassingtime depends on solution volumes butgenerally takes 10–15 minutes. Someunits are equipped with a degas modethat can speed the operation.
It is important to note that PCBs willcause solution displacement. An experi-enced PCB supplier will know how toaccommodate displacement. The pointto keep in mind is that an overfilled orunderfilled tank should be avoided.
Once the solution is prepared, it isready to clean the PCBs. The operat-ing parameters are set and the unitis turned on. The PCBs are placed inthe basket or rack and lowered intothe solution. The timer is set. At theend of the cycle, the PCB is removedand inspected. If it is a go, theboards are rinsed with deionizedwater to wash away cleaning solutionresidues and allowed to dry.
Cleaning Solution Maintenanceand Disposal
The large majority of today’s cleaningsolution formulations are biodegradableand can be disposed of in sanitary drains,depending on local regulations. Cleaningeffectiveness should be maintained byskimming off contaminants, including sol-der flux rosins that float to the surface,and putting them aside for later disposal.
Larger ultrasonic cleaners may beequipped with skimmers and weirs todirect floating contaminants to collec-tion containers. They may also beequipped with filtering systems that trapsuspended and settled contaminants,returning treated solution to the tank.
Medical Design Briefs, August 2017 33Free Info at http://info.hotims.com/65854-778
Control panel of an Elmasonic P series ultrasonic cleaner.Controlling the cleaning time and temperature are essen-tial to maintaining preferred PCB procedures.
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Eventually the solution must bereplaced. The tank is drained and shouldbe thoroughly cleaned according to themanufacturer’s recommendations. ThePCB supplier should be especially aware ofsolid contaminants that have fallen to thebottom of the tank. If allowed to remain,these will, over time, serve as drills that maycause holes to develop, necessitating a tankor complete unit replacement. The PCBmanufacturer should never use an abrasivecleanser on an ultrasonic cleaner tank.
Case Study: IDCOhio-based Independent Digital Con -
sulting (IDC) builds, tests, and delivers cir-cuit board assemblies. This case studyrelates how the company developed itsoptimum PCB cleaning process throughexperimentation. Owner Tom Schurrnotes that the importance of clean circuitboards in medical applications cannot bestressed enough and explains why.
“In many medical designs, there arehigh impedance circuits that are very sen-
sitive to stray current being introduced byother nearby circuitry,” he says. “Even ifcreepage and clearance distances areobserved, any residue left on the circuitboard after cleaning will provide a pathfor leakage currents to cause intermittentor faulty operation. Residue will provideconduction paths for high-frequency dig-ital signals to leak into sensitive analogcircuitry, which can cause faulty readingsor worse.
“No residue can be left on theassembly, either on the board surfaceor on the leads of the components,” heexplains. “The most difficult place toclean is between the board surface andthe portion of the components thatrests on the board. When followingproper procedures, ultrasonic clean-ing reaches those locations when othertechniques will not. When the board isnot properly cleaned, the solderingprocess can leave behind a surface filmthat may be initially benign to conduc-tion and leakage, but over time willabsorb moisture and provide thoseundesirable leakage paths. In addi-tion, an improperly cleaned board maynot allow environmental coatings toadhere to the board.”
For IDC, Schurr uses the heater-equipped dual-frequency ElmasonicP180H model with internal tank dimen-sions of 12.9 in. long, 11.8 in. wide, and 7.9in. deep, with a liquid capacity to 5 gallons.He chose this unit because the three linesin the P series offer adjustable ultrasonicpower that can be set from 30 to 100 per-cent of the P180H unit’s 330-W effective
34 Medical Design Briefs, August 2017
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Removing cleaned PCBs. At IDC, a 5.5 percentdilution is prepared by combining 13 quarts ofwater and 0.75 quart of Elma Tec Clean A1 inthe cleaning tank.
power. He also wanted the option of using a less-aggressive ultra-sonic frequency of 80 kHz in addition to 37 kHz. “The P line alsoprovides the critical sweep function to prevent harmonic vibra-tions that could damage delicate PCB electronics, and a degasmode to drive off cavitation-inhibiting entrapped air,” he says.
Specifying ultrasonic cleaning solution chemistry is asimportant as the equipment. Today’s biodegradable clean-ing solution concentrates are formulated for a variety ofcleaning challenges. In this case, the mildly alkaline concen-trate Elma Tec Clean A1 proved the best choice for cleaningelectronics such as PCBs. This concentrate should be dilut-ed to 3–10 percent with water.
“For our operations, a 5.5 percent dilution was prepared bycombining 13 quarts of water and 0.75 quart of A1 in the clean-ing tank,” Schurr says. The unit is started, and the degas modeis activated to thoroughly mix and degas the solution. This stepapplies to each time fresh cleaning solution is prepared.
IDC’s PCB Cleaning StepsBoards are carefully positioned in the cleaning basket so that
they do not contact each other. The ultrasonic cleaner is read-ied by turning on the power, setting the frequency to 80 kHz,activating the sweep mode, setting the thermostat to 40 °C(104 °F), and setting the power to 30 percent. Set and actualvalues are displayed on the control panel. When all is ready,the basket is immersed in the solution and the timer set for 7minutes.
“Selecting the correct power level was achieved by experi-mentation during operational tests,” Schurr explains. “Wewanted gentle but thorough cleaning, and this is optimizedby keeping the level below 10 W per quart. Since ultrasoniccavitation produces heat, 40 °C was specified so the boardsdo not get too warm and are not subject to thermal shockduring the rinsing operation.”
Schurr adds that the 7-minute cleaning cycle may varydepending on the number of boards cleaned and their condi-tion. “At the end of the cycle, the basket is removed and theboards are rinsed using deionized water and then air driedunder a fan,” he says, cautioning that while the process in gen-eral is excellent for PCB cleaning, there are exceptions as men-tioned earlier.
A Caution on SolventsThis discussion centers on water-based biodegradable clean-
ing solution formulations. Solvent-based cleaning solutions forwater insoluble fluxes may require special precautions. Forexample, nonflammable solvent-based solutions can be usedvery effectively on water-insoluble fluxes. However, if these areused in filter-equipped tanks, it is essential that the filtering sys-tem is compatible with the formulation. If flammable solventsare used, an explosion-proof ultrasonic cleaner must be usedand must comply in what is termed a hazardous area. This is asubject unto itself and calls for consultations with suppliers ofexplosion-proof ultrasonic cleaners.
Reference1. GHTF/SG3/N17:2008, “Quality Manage ment System – Medical
Devices – Guidance on the Control of Products and ServicesObtained from Suppliers,” Global Harmonization Task Force, 2008.
This article was written by Dr. Rachel Kohn, Director and Co-founder of Tovatech, Maplewood, NJ. For more information, visithttp://info.hotims.com/65854-166.
36 www.medicaldesignbriefs.com Medical Design Briefs, August 2017
■ New System Eliminates Needfor Pacemaker Batteries Researchers have developed a piezo-
electric system that converts the heart’svibrational energy into electricity topower pacemakers, eliminating theneed for batteries. Unlike conventionalpacemakers, leadless pacemakers areabout the size of an AAA battery. Theyare delivered via a catheter through the
leg to the heart, where they regulate the heart beat and blood flow.An initial device is roughly 1 cm3 and is shaped like the letter
S. Results show that it produces sufficient power (at least 10 μW)for heart rates from 20 to 100 beats per minute. It does not usemagnetics, making it compatible with MRI machines. A newdevice is a piezoelectric strip that is only about a half centimeterlong. It is designed to buckle as it absorbs vibrational energyfrom the heart. Simulations suggest it can generate enoughenergy to power a heart rate up to 150 beats per minute.
The researcher’s next step is to conduct physical experi-ments on the new device and to develop a way to attach a back-up power source to the device.
For more information, visit www.medicaldesignbriefs.com/component/content/article/1104-mdb/features/27119.
■ Smart Materials Used in Ultrasound Behave Like WaterA team of researchers is
gaining new insight into thesmart materials used in ultra-sound technology, findingstriking similarities with thebehavior of water. They inves-tigated a behavior of smartmaterial called piezoelectricity,which is the interchange ofmechanical energy with electrical energy. In piezoelectricity,applying an electric field to a material reorients dipoles within it;this is the key to the functionality of the material.
As the positive ions move off center, the cages of ions sur-rounding them either shrink or elongate in a concerted fashion,causing the material to change shape. In ultrasound devices, pro-viding voltage makes the material change shape, or vibrate, andthose vibrations enter the human body and echo around.
Recently, a set of materials was discovered that scientistsbelieve gives higher piezoelectric performance than previousones. As the material cools down, the dipoles clump intogroups called polar nanoregions. As these regions grow larger,it becomes increasingly difficult for them to respond. Theresearchers showed that, while at higher temperatures, thedipoles are in fact floating free as the temperature cools. Thedipoles find each other and form the polar nanoregions.Domain walls between dipolar regions lead to enhanced piezo-electric properties in the material.
For more information, visit www.medicaldesignbriefs.com/component/content/article/1104-mdb/features/27120.
■ Microhole Chip Allows Analysis of Single Cells A microhole chip allows single cells to be picked out of the
blood sample, placed on separate holes in the substrate foranalysis, and removed individually afterwards. A slight under-pressure is applied to the cells that holds each one in its allot-ted place by suction.
In a collaborative research project concerning the identifica-tion of circulating tumor cells, a two-step cell analysis method was
applied. In the first step, suspicious-looking cells were selected using amicroscope. In the second step, theselected cells underwent detailedanalysis using the more time-intensivemethod of Raman spectroscopy.
Another advantage of the newmicrohole chip is that it can be popu-lated with 200,000 cells, each one in aseparate hole, in a matter of minutes.A micropipette is used to remove indi-
vidual tumor cells from the chip for further analysis. The level ofunderpressure chosen to hold them in place is too low to causeany damage. The new chip has other possible applications,including as a selection system for protein-producing cells.Microchips with well-defined micropores can be used as a sub-strate for in-vitro modeling of physiological barriers such as theblood-brain barrier or the intestinal barrier.
For more information, visit www.medicaldesignbriefs.com/component/content/article/1104-mdb/features/27121.
■ Ultrasound ‘Drill’ Targets Deep Vein Blood ClotsResearchers have developed a new surgical tool that uses low-
frequency intravascular ultrasound to break down blood clots thatcause deep vein thrombosis. The tool isthe first ultrasound “drill” that can beaimed straight ahead, allowing doctorsto better target clots, which holdspromise for significantly reducingtreatment time.
“Our new ultrasound tool is forward-facing, like a drill, but still breaks downclots into very fine particles,” saysXiaoning Jiang, a professor of mechanical and aerospace engi-neering at NC State. “Our approach improves accuracy withoutrelying on high doses of blood thinners, which we hope willreduce risks across the board.”
The tool incorporates an injection tube that allows users toinject microbubbles at the site of the clot, making the ultra-sound waves more effective at breaking down the clot. Theresearchers tested a prototype of the device in a synthetic bloodvessel using cow’s blood. The device dissolved 90 percent of aclot in 3.5 to 4 hours without using any blood thinners. Theresearchers have filed a patent on the technology and are interest-ed in working with industry partners to help develop the device.
For more information, visit www.medicaldesignbriefs.com/component/content/article/1104-mdb/features/27122.
The piezoelectric systemconverts the heart’s vibra-tional energy into electrici-ty. (Credit: University ofBuffalo)
The material model reveals the behav-ior of relaxor ferroelectric materials.(Credit: University of Pennsylvania)
The new microhole chip canbe populated with 200,000single cells, each held inplace in separate holes.(Credit: Fraunhofer IBMT)
The first ultrasound “drill”that can be aimed straightahead. (Credit: NC State)
■ Wet-Tolerant Adhesive Patch Inspired by OctopiResearchers have developed an artificial, biologically
inspired, reversible wet/dry adhesion system that is basedon the dome-like protuberances found in the suction cupsof octopi. To mimic the architecture of these protuber-ances, the researchers use a simple, solution-based, air-traptechnique that involves fabricating a patterned structure asa polymeric master and using it to produce a reversed archi-tecture, without any sophisticated chemical syntheses or sur-
face modifications.The micrometer-scale domes in
the artificial adhesive enhance thesuction stress. This octopus-inspired system exhibits strong,reversible, highly repeatable adhe-sion to silicon wafers, glass, andrough skin surfaces under variousconditions (dry, moist, under water,and under oil). To demonstrate apotential application, they alsoused an adhesive to transport alarge silicon wafer in air and under
water without any resulting surface contamination.The adhesives might be useful when applied over skin or a
wound and so they partially assist with wound healing. Theresearchers are investigating stem-cell and drug-loadingapproaches to improve the adhesives’ practical utility.
For more information, visit www.medicaldesignbriefs.com/component/content/article/1104-mdb/features/27123.
■ Rapid Screening Test Helps Find SuperbugA new test helps quickly identify people who may be infected
with the superbug MRSA when admitted to hospital. Currently,when patients are admittedto hospital, they are tested forMRSA — a form of Staphy -lococcus aureus bacteria that isresistant to a number ofantibiotics. Such so-calledsuperbugs present a signifi-cant problem for hospitals.Inpatients are generally givena swab test for MRSA, whichcan take several days to produce a result.
The new LGX test, which can produce a result within 30minutes, uses a quick and affordable nasal probe to screenpatients to determine which patients have some form ofStaphylococcus aureus colonization or infection, including bothmethicillin sensitive (MSSA) and methicillin resistant (MRSA)strains.
While the new test doesn’t differentiate between MRSAand other strains, it would act as a gatekeeper, allowing med-ical staff to quickly identify which patients require furtherlab testing.
“It can give a result within 30 minutes, saving valuable timeand resources and allowing staff to filter those patients whomay have MRSA from those who definitely don’t,” says Dr.Adam Le Gresley, associate professor at Kingston University inLondon.
The researchers are in discussions with hospitals to run trialswith anonymous patient swabs, which will allow them to com-pare results with those obtained within hospital labs.
For more information, visit www.medicaldesignbriefs.com/component/content/article/1104-mdb/features/ 27124.
Medical Design Briefs, August 2017 37Free Info at http://info.hotims.com/65854-781
Colonies of Staphylococcus aureusbacteria. (Credit: Burger/Phanie/Rex/Shutterstock)
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38 www.medicaldesignbriefs.com Medical Design Briefs, August 2017
New Technique Makes Brain Scans BetterBoosting quality of patientMRIs could enable large-scale studies of strokeoutcomes.MIT, Cambridge, MA
People who suffer a stroke oftenundergo a brain scan at the hospital,allowing doctors to determine the loca-tion and extent of the damage.Researchers who study the effects ofstrokes would love to be able to analyzethese images, but the resolution is oftentoo low for many analyses.
To help scientists take advantage ofthis untapped wealth of data from hospi-tal scans, a team of MIT researchers,working with doctors at MassachusettsGeneral Hospital and many other insti-tutions, has devised a way to boost thequality of these scans so they can be usedfor large-scale studies of how strokesaffect different people and how theyrespond to treatment.
“These images are quite uniquebecause they are acquired in routineclinical practice when a patient comes inwith a stroke,” says Polina Golland, anMIT professor of electrical engineeringand computer science. “You couldn’tstage a study like that.”
Using these scans, researchers couldstudy how genetic factors influencestroke survival or how people respond to
different treatments. They could alsouse this approach to study other disor-ders such as Alzheimer’s disease.
Golland is the senior author of thepaper, which was presented at theInformation Processing in MedicalImaging conference. The paper’s leadauthor is Adrian Dalca, a postdoc inMIT’s Computer Science and ArtificialIntelligence Laboratory. Other authorsare Katie Bouman, an MIT graduate stu-dent; William Freeman, the Thomas andGerd Perkins Professor of ElectricalEngineering at MIT; Natalia Rost, direc-tor of the acute stroke service at MGH;and Mert Sabuncu, an assistant profes-sor of electrical and computer engineer-ing at Cornell University.
■ Filling in DataScanning the brain with magnetic res-
onance imaging (MRI) produces many2D slices that can be combined to forma 3D representation of the brain.
For clinical scans of patients who havehad a stroke, images are taken rapidlydue to limited scanning time. As a result,the scans are very sparse, meaning thatthe image slices are taken about 5–7 mmapart. (The in-slice resolution is 1 mm.)
For scientific studies, researchers usuallyobtain much higher-resolution images,with slices only 1 mm apart, which requireskeeping subjects in the scanner for a muchlonger period. Scientists have developed
specialized computer algorithms to ana-lyze these images, but these algorithmsdon’t work well on the much more plenti-ful but lower-quality patient scans taken inhospitals.
The MIT researchers, along with theircollaborators at MGH and other hospi-tals, were interested in taking advantageof the vast numbers of patient scans,which would allow them to learn muchmore than can be gleaned from smallerstudies that produce higher-quality scans.
“These research studies are very smallbecause you need volunteers, but hospi-tals have hundreds of thousands ofimages. Our motivation was to take advan-tage of this huge set of data,” Dalca says.
The new approach involves essentiallyfilling in the data that is missing fromeach patient scan. This can be done bytaking information from the entire set ofscans and using it to recreate anatomicalfeatures that are missing from other scans.
“The key idea is to generate an imagethat is anatomically plausible, and to analgorithm looks like one of thoseresearch scans, and is completely consis-tent with clinical images that wereacquired,” Golland says. “Once you havethat, you can apply every state-of-the-artalgorithm that was developed for thebeautiful research images and run thesame analysis, and get the results as ifthese were the research images.”
Once these research-quality images aregenerated, researchers can then run a setof algorithms designed to help with ana-lyzing anatomical features. These includethe alignment of slices and a processcalled skull-stripping that eliminates every-thing but the brain from the images.
Throughout this process, the algo-rithm keeps track of which pixels camefrom the original scans and which werefilled in afterward, so that analyses donelater, such as measuring the extent ofbrain damage, can be performed onlyon information from the original scans.
“In a sense, this is a scaffold that allowsus to bring the image into the collectionas if it were a high-resolution image, andthen make measurements only on thepixels where we have the information,”Golland says.
■ Higher QualityNow that the MIT team has developed
this technique for enhancing low-qualityimages, they plan to apply it to a large
Researchers at MIT and other institutions have devised a way to boost the quality of low-resolutionpatient MRI scans so they can be used for large-scale studies. Images produced by their algorithm,shown in the center column, are much closer to high-resolution scans shown in the right column. Inthe left column are images produced by a different technique for improving low-resolution scans.(Credit: MIT)
Medical Design Briefs, August 2017 www.medicaldesignbriefs.com 39
set of stroke images obtained by theMGH-led consortium, which includesabout 4,000 scans from 12 hospitals.
“Understanding spatial patterns of thedamage that is done to the white matterpromises to help us understand in moredetail how the disease interacts with cog-nitive abilities of the person, with their
ability to recover from stroke, and so on,”Golland says.
The researchers also hope to applythis technique to scans of patients withother brain disorders.
“It opens up lots of interesting direc-tions,” Golland says. “Images acquired inroutine medical practice can give
anatomical insight, because we lift themup to that quality that the algorithmscan analyze.”
The research was funded by the NationalInstitute of Neurological Disorders and Strokeand the National Institute of BiomedicalImaging and Bioengineering. For more infor-mation, visit www.news.mit.edu.
Sugar-Coated Nanomaterial Excels at Promoting BoneGrowthMethod offers pathwayfor improving patientoutcomes after spinalfusion surgery.
Northwestern University,Evanston, IL
There hasn’t been a gold standard forhow orthopedic spine surgeons promotenew bone growth in patients, but nowNorthwestern University scientists havedesigned a bioactive nanomaterial thatis so good at stimulating bone regenera-tion it could become the method sur-geons prefer.
While studied in an animal model ofspinal fusion, the method for promotingnew bone growth could translate readilyto humans, the researchers say, where anaging but active population in the UnitedStates is increasingly receiving this surgeryto treat pain due to disc degeneration,trauma, and other back problems. Manyother procedures could benefit from thenanomaterial, ranging from repair ofbone trauma to treatment of bone cancerto bone growth for dental implants.
“Regenerative medicine can improvequality of life by offering less-invasiveand more successful approaches to pro-moting bone growth,” says SamuelStupp, who developed the new nanoma-terial. “Our method is very flexible andcould be adapted for the regenerationof other tissues, including muscle, ten-dons and cartilage.”
Stupp is director of Northwestern’sSimpson Querrey Institute for Bio -Nanotechnology and the Board ofTrustees Professor of Materials Scienceand Engineering, Chemistry, Medicineand Biomedical Engineering.
For the interdisciplinary study, Stuppcollaborated with Dr. Wellington Hsu,associate professor of orthopedic surgery,
and Erin Hsu, research assistant profes-sor of orthopedic surgery, both atNorthwestern University Feinberg Schoolof Medicine. The husband-and-wife teamis working to improve clinically employedmethods of bone regeneration.
Sugar molecules on the surface of thenanomaterial provide its regenerativepower. The researchers studied in vivo theeffect of the sugar-coated nanomaterialon the activity of a clinically used growthfactor, called bone morphogenetic pro-tein 2 (BMP-2). They found the amountof protein needed for a successful spinalfusion was reduced to an unprecedentedlevel: 100 times less of BMP-2 was needed.This is very good news, because the BMP-2 growth factor is known to cause danger-ous side effects when used in the amountsrequired to regenerate high-quality bone,and it is expensive as well.
Stupp’s biodegradable nanomaterialfunctions as an artificial extracellularmatrix, that mimics what cells in the bodyusually interact with in their surround-ings. BMP-2 activates certain types of stemcells and signals them to become bonecells. The Northwestern extracellular
matrix, which consists of tiny nanoscalefilaments, binds the protein by moleculardesign in the way that natural sugars bindit in our bodies and then slowly releases itwhen needed, instead of in one earlyburst, which can contribute to sideeffects.
To create the nanostructures, theresearch team led by Stupp synthesized aspecific type of sugar that closely resem-bles those used by nature to activate BMP-2 when cell signaling is necessary forbone growth. Rapidly moving flexiblesugar molecules displayed on the surfaceof the nanostructures “grab” the proteinin a specific spot that is precisely the sameone used in biological systems when it istime to deploy the signal. This potenti-ates the bone-growing signals to a surpris-ing level that surpasses even the naturallyoccurring sugar polymers in our bodies.
In nature, the sugar polymers areknown as sulfated polysaccharides, whichhave super-complex structures impossibleto synthesize at the present time withchemical techniques. Hun dreds of pro-teins in biological systems are known tohave specific domains to bind these sugarpolymers in order to activate signals. Suchproteins include those involved in thegrowth of blood vessels, cell recruitmentand cell pro liferation, all very importantbiologically in tissue regeneration.Therefore, the approach of the Stuppteam could be extended to other regener-ative targets.
Spinal fusion is a common surgicalprocedure that joins adjacent vertebratogether using a bone graft and growthfactors to promote new bone growth,which stabilizes the spine. The boneused in the graft can come from thepatient’s pelvis — an invasive procedure— or from a bone bank.
“There is a real need for a clinicallyefficacious, safe, and cost-effective way toform bone,” says Wellington Hsu, a
The colored region in a micro-CT image showsregenerated high-quality bone in the spinewith minimal use of growth factor. (Credit:Northwestern)
40 www.medicaldesignbriefs.com Medical Design Briefs, August 2017
spine surgeon. “The success of thisnanomaterial makes me excited thatevery spine surgeon may one day sub-scribe to this method for bone graft.Right now, if you poll an audience ofspine surgeons, you will get 15–20 differ-ent answers on what they use for bonegraft. We need to standardize choice andimprove patient outcomes.”
In the in vivo portion of the study, thenanomaterial was delivered to the spineusing a collagen sponge. This is the waysurgeons currently deliver BMP-2 clini-cally to promote bone growth.
The Northwestern research teamplans to seek approval from the Foodand Drug Administration to launch aclinical trial studying the nanomaterialfor bone regeneration in humans.
“We surgeons are looking for optimalcarriers for growth factors and cells,”
Wellington Hsu says. “With its numerousbinding sites, the long filaments of thisnew nanomaterial is more successfulthan existing carriers in releasing thegrowth factor when the body is ready.Timing is critical for success in boneregeneration.”
In the new nanomaterial, the sugarsare displayed in a scaffold built fromself-assembling molecules known as pep-tide amphiphiles, first developed byStupp 15 years ago. These synthetic mol-ecules have been essential in his work onregenerative medicine.
“We focused on bone regeneration todemonstrate the power of the sugarnanostructure to provide a big signalingboost,” Stupp says. “With small designchanges, the method could be used withother growth factors for the regenera-tion of all kinds of tissues. One day we
may be able to fully do away with the useof growth factors made by recombinantbiotechnology and instead empower thenatural ones in our bodies.”
The findings were published in thejournal Nature Nanotechnology. The paperis titled “Sulfated Gly copeptideNanostructures for Multi potent ProteinActivation.” Stupp and Wellington andErin Hsu are senior authors of thepaper, and postdoctoral fellows SungsooLee and Timmy Fyrner are first authors
The National Institute of Dental andCran iofacial Research of the National In sti -tutes of Health (grant 5R01DE015920-10)and the Louis A. Simpson and Kimberly K. Querrey Center for Re generative Nano medicine at North western Universityprovided funding for this research. For more information, visit https://news.northwestern.edu.
Drug-Loaded Collagen Scaffolds Prevent ImplantInfection Scaffolds loaded with aparticular antibioticprevent two infection-causing bacteria.NUI of Galway, Galway, Ireland
A study led by scientists from the Re -gen erative, Modular, and Develop mentalEngineering Laboratory (RE MODEL)and the Science Foundation IrelandCentre for Research in Medical Devices,CÚRAM, has developed a new type ofimplantable device to provide localizeddrug treatment and prevent infection. Ithas already proven effective against twotypes of major device infection bacteria.
Publishing their results in the journalBiomedical Materials, the NUI Galwayresearch team show that stabilized colla-gen scaffolds loaded with a particularantibiotic were able to prevent two infec-tion- causing bacteria, Escherichia coli andStaphylococcus epidermidis from forming.
Lead author of the paper, Dr DimitriosZeugolis from NUI Galway’s REMODELand CÚRAM says, “Implant infectionsremain a major healthcare problem. Theycan require long hospitalization periodsto disturb and treat bacterial biofilm for-mation. There can also be a need for addi-tional surgeries to remove or replace theinfected implant, which if not done in
time, may lead to sepsis. Although local-ized drug treatment via an implanted scaf-fold has shown promise, the ideal scaffoldcross-linking (to initially withstand theaggressive infection environment) anddrug (to fight against infection) have not,until now, been found.”
The NUI Galway research team, includ-ing Dr. Gerard Wall of Micro biology andCÚRAM, first ventured to identify theoptimal hexamethylene diisocyanate(HMDI) concentration that would offersuitable biomechanical, biochemical, and
biological properties. HMDI was chosenas it is a Food and Drug Administrationapproved cross-linking agent for collagen-based medical devices.
They then loaded the optimally cross-linked collagen scaffolds with variableconcentrations of the antibiotics Cefaclorand Ranalexin to identify the minimumeffective concentration required to inhib-it the growth of Escherichia coli andStaphylococcus epidermidis, two of the mostfrequently encountered bacteria in med-ical device infection.
Antimicrobial activity of Ran- and Cef-loaded scaffolds. Ran, even at the highest concentration of 500 μgml−1, was completely ineffective even against the lowest (106 CFU/ml) E. coli and S. epidermidis con-centration. Cef, at 100 μg ml−1, was effective against both low (106 CFU/ml) and high (108 CFU/ml)E. coli and S. epidermidis concentrations. (Credit: Biomedical Materials/IOP Publishing).
Medical Design Briefs, August 2017 www.medicaldesignbriefs.com 41
Active Implants: How Gold Binds to Silicone RubberFlexible electronics partscould greatly improveimplants.University of Basel,Basel, Switzerland
Flexible electronic parts could signifi-cantly improve medical implants.However, electroconductive gold atomsusually hardly bind to silicones.Researchers from the University of Baselhave now been able to modify short-chain silicones in a way, that they buildstrong bonds to gold atoms. The resultshave been published in the journalAdvanced Electronic Materials.
Ultrathin and compliant electrodesare essential for flexible electronicparts. When it comes to medicalimplants, the challenge lies in the selec-tion of the materials, which must bebiocompatible. Silicones were particu-larly promising for application in thehuman body because they resemble thesurrounding human tissue in elasticityand resilience. Gold also providesexcellent electrical conductivity, butonly weakly binds to silicone, whichresults in unstable structures.
■ Molecular Conductive GlueAn interdisciplinary research team of
the Biomaterials Science Center and theDepartment of Chemistry at the Uni -versity of Basel has developed a proce-dure that allows binding single goldatoms to the ends of polymer chains. Thisprocedure makes it possible to form sta-ble and homogeneous two-dimensionalgold films on silicone membranes. Thus,for the first time, ultrathin conductive lay-ers on silicone rubber can be built.
The novel approach: First, the thermalevaporation of organic molecules andgold atoms under high-vacuum condi-tions enables preparing ultrathin layers.Second, their formation from individualislands to a confluent film can be moni-tored with atomic precision by means of
ellipsometry. Using masks, the sandwichstructures that are fabricated can convertelectrical energy into mechanical worksimilar to hu man muscles.
■ Energized Silicone RubberThese dielectric artificial muscles could
simultaneously serve as pressure sensorsand, in the future, may even be used toharvest electrical energy from body move-ment. For this purpose, the silicone mem-branes are sandwiched between elec-trodes. The relatively soft silicone thendeforms according to the applied voltage.
So far, the silicone membranes wereseveral micrometers thick and required
high voltages to reach the desired strain.These new nanometer-thin siliconemembranes with ultrathin gold elec-trodes allow operation through conven-tional batteries. To bring such a productto the market, the production costswould have to be reduced drastically.However, Dr. Tino Töpper, first authorof the study, is optimistic: “The perfectexperimental control during the fabrica-tion process of the nanometer-thin sand-wich structures is a sound basis for long-term stability — a key prerequisite formedical applications.”
For more information, visit www.unibas.ch.
Extracted dielectric functions of Au nanoparticles grown on PDMS. The imaginary part ’’ (a), the realpart ’ of the dielectric function (b), the refractive index n (c), and the extinction coefficient k of ther-mally evaporated Au (d) on UV cured DMS-V05 are extracted from spectroscopic - and -spectraand at characteristic deposition times of 120, 240, 480, 840, 1,300, 1,800, and 2,400 s withcorresponding film thicknesses of 2.7, 5.3, 7.1, 9.5, 12.2, 14.6, and 16.8 nm, respectively, color-coded from blue to red. (Credit: Advanced Electronic Materials/Wiley-VCH Verlag GMBH & Co. KGaA)
“The development of our drug-loadedcollagen device marks an important stepforward,” says Dr. Zeugolis. “First, thesustained and localized delivery systemthat we developed avoids issues associat-ed with systemic drug administration,such as antibiotic resistance. Further, we
contributed towards finding a solutionagainst a severe economic burden tohealthcare systems internationally.”
Professor Abhay Pandit, ScientificDirector of CÚRAM adds, “CÚRAM’sgoal is to develop affordable transforma-tive solutions to improve quality of life
for people suffering from chronic ill-nesses. Dr. Zeugolis’ work continues topush towards this goal and will have realimpact for patients and for the futuremedical device development.”
The valve is designed torepair itself and grow withthe patient.Eindhoven University ofTechnology, Eindhoven, The Netherlands
About 300,000 patients each yearreceive a heart valve replacement that iseither a mechanical device or producedfrom animal tissue. Although thesevalves generally improve survival andquality of life, they do not consist of liv-ing tissue and therefore cannot growwith the patient or repair themselves incase of damage. Especially for youngerpatients, this results in a high probabilityof repeated valve replacements, withassociated risks to health and even life.
The researchers in the ImaValve(Intelligent materials for in-situ heartValve tissue engineering) project want torealize the dream of a creating a livingheart valve that is grown inside thepatient’s body at the site of destinationand that consists of the patient’s own tis-sue. As such, the valve should be able torepair itself and grow with the patient.The ImaValve is a device that consists of aslowly degrading elastomeric polymer,processed into a valve shape via a processcalled electrospinning. The valve can beplaced in the body in a minimally invasivefashion using a stent and a delivery device.
According to the researchers, thevalve uses the body’s wound repairprocesses. The valve is created with asupramolecular polymer that has theright properties to communicate withthe processes in the human body. Thispolymer is produced into a fibrous struc-ture using electrospinning. The materialis formed into the shape of a heart valvethat is sutured to a stent, which is used todeliver the valve at the right site.
The system is based on a stented heartvalve, which can be introduced via thegroin or via a very small incision in thebody. This enables the heart valves to bereplaced in a very fast and safe mannerin many patients. The researchers saythat under live imaging such as fluo-roscopy, or echo, they can deliver theheart valves to patients in a very con-trolled manner.
“The most fascinating thing is that wecreate a polymeric-based valve that is sosmart to attract the right cells in the
right moment within the body to trans-form into a living heart valve, says Prof.Dr. Max Emmett, cardiac surgeon at theUniversity of Zurich.
ImaValve is a collaborative projectfunded by the European Commissionunder the Seventh European Frame workProgram. Within this consortium, lead-ing academic and industrial partners inthe field of biomaterials science and tis-sue engineering from The Netherlands(Leading House), Switz erland, and Ger -many are brought together. The projectis coordinated by Carlijn Bouten, head ofthe Department for Soft Tissue Bio -mechanics & Tissue Engi neering atEindhoven Uni versity of Technology.
With a highly multidisciplinary ap -proach, merging biomaterials research,in vitro and in silico modeling, andtechnological de vel opments to preclini-cal studies, the ImaValve consortiumaims at framing innovative solutions forthe challenging research field of in situcardiovascular tissue engineering.
The goal of the project is the develop-ment of an off-the-shelf available syn-thetic heart valve that gradually trans-forms into a living heart valve at the siteof implantation and that lasts a lifetime.The researchers say that the ImaValvecombines the unique expertise andexperience necessary to achieve theambitions of the project in a time frameof about four years.
For more information, visit www.tue.nl.
42 www.medicaldesignbriefs.com Medical Design Briefs, August 2017
The supramolecular polymer material is formedinto the shape of a heart valve that is suturedto a stent.
Hydrogel Material Improves Success of TransplantingIslet CellsNew approach couldbenefit patients with type 1 diabetes.Georgia Institute ofTechnology, Atlanta, GA
Combining a new hydrogel materialwith a protein that boosts blood vesselgrowth could improve the success rate fortransplanting insulin-producing islet cellsinto persons with type 1 diabetes. In ananimal model, the technique enhancedthe survival rate of transplanted insulin-
producing cells, restoring insulin produc-tion in response to blood glucose levelsand curing these diabetic animals.
The technology could also helppatients who must have their pancreasremoved because of severe pancreatitis,an inflammatory disease. Using thematerial and protein combination, theresearchers evaluated multiple locationsfor implanting the islet cell clusters, thefirst time such a direct comparison oftransplant sites has been made.
“We have engineered a material thatcan be used to transplant islets and pro-mote vascularization and survival of the
islets to enhance their function,” saysAndrés García, a Regents’ Professor inthe Woodruff School of MechanicalEngineering at the Georgia Institute ofTechnology. “We are very excited aboutthis because it could have immediatepatient benefits if this proves successfulin humans.”
■ Type 1 Diabetes Affects MillionsAbout 1.25 million Americans have
type 1 diabetes, also known as juvenilediabetes, a disease characterized by thebody’s inability to produce insulin. Tocontrol the disease, patients must fre-
Medical Design Briefs, August 2017 www.medicaldesignbriefs.com 43
quently test their glucose levels andinject insulin to maintain the properbalance. But some patients suffer life-threatening hypoglycemic episodes,and the disease has other serioushealth consequences.
Using cells from cadavers, doctorshave been experimentally trans-planting pancreatic islets intohumans for decades, but as many as60 percent of the transplanted isletsdie immediately because they are cutoff from their blood supply and arekilled by an immune response dueto direct injection into the blood-stream, and those that survive thetransplant usually die within severalmonths. In testing done so far, the isletshave been placed into the vasculatureof the liver, which has significant bloodsupply — but might not be the ideallocation because of the hostile immuneenvironment.
■ Engineering a New SolutionWith this information, García and
collaborators, including Georgia Techpostdoctoral researcher and firstauthor Jessica Weaver, set out to engi-neer a new approach to transplantingthe cells. They developed a newdegradable polymer hydrogel materialused to deliver the cells as they areinjected into the body. And they incor-porated into the gel a protein known asvascular endothelial growth factor(VEGF), which encourages the growthof blood vessels into the transplantedcells.
“The transplanted islets need a lot ofoxygenation and a connection to thebody’s circulatory system to sense theglucose levels and transport the insulin,”notes García, who is also the Rae andFrank H. Neely Endowed Chair inMechanical Engineering. “In addition toprotecting the islets, our engineeredmaterial promotes the formation of newblood vessels to nourish the cells.”
VEGF has been tried before, but inquantities too large, it stimulates thegrowth of leaky blood vessels that don’tprovide long-term oxygenation. Too lit-tle VEGF doesn’t grow vessels rapidlyenough to maintain the transplantedislets, which are clusters containing hun-dreds of cells. Without sufficient vascula-ture in the clusters, the cells in the cen-ter don’t survive.
Weaver used diabetic mice to comparelocations in the body where the trans-planted cells could be placed. She stud-
ied locations in the liver, under the skin,in the mesentery regions near the intes-tines, and in an epididymal fat pad inthe abdomen.
■ Treating More Patients“We were able to study the transplant
sites in parallel and really look at thepros and cons of each to compare thesurvival rates of the cells in each area,”says Weaver. “Islet cells are very preciousbecause we get so few from each donor.We need them all to survive to help apatient with type 1 diabetes get offinsulin.”
In the liver location, as many as threedonors are now required to get enoughtransplantable islets to provide glucosecontrol in a single patient. If researcherscould reduce the loss of cells, they couldone day treat two or even three times asmany patients from the limited numberof cadaver donors available, Garcíasays.
■ Evaluating the TechniqueWeaver studied the animal models for
as long as 100 days and found that theislet clusters transplanted with thehydrogel and VEGF developed manyblood vessels and engrafted into theirnew locations. As expected, the hydro-gel material disappeared and wasreplaced by new tissue, which grewaround the islets.
To track the long-term viability of theislet cells, she used cells with a gene thatproduces a green luminescence whenexcited by certain wavelengths of light. Bymeasuring the signal returned from thetransplant locations, she was able todetermine how many of the cells sur-vived. Introducing a dye into the blood-stream then allowed her to image thegrowing vasculature around the islets.
The abdominal fat pad turned outto provide the most optimal trans-plant location. In humans, theequivalent structure is called theomentum, a blood vessel-rich regionthat other researchers are also evalu-ating as an islet transplant location.
If the new technique is used inhumans, the cells could be placed inabdominal fat pad laparoscopicallyin a minimally invasive procedure.The hydrogel material would beinjected in liquid form and wouldpolymerize in the transplant site,creating a flexible gel that wouldconform to bodily structures toimprove both blood vessel connec-
tions and tissue integration.
■ What’s NextAs a next step, García and Weaver
would like to study the technique in larg-er animals. After that, human clinical tri-als would be required to show whetherthe combination of hydrogel materialand protein will benefit patients withtype 1 diabetes. Ultimately, the re -searchers hope that stem cells mightprovide a source of islets that could betransplanted without the need of cadav-eric donor islets and immune systemsuppression.
Weaver, a researcher at the DiabetesResearch Institute before joiningGeorgia Tech, says she was surprised athow well the new technology worked.The imaging provided a clear view of thegrowing vascular system surroundingthe islet clumps.
“When we first started doing the imag-ing, I’m pretty sure I screamed the firsttime I saw it,” says Weaver. “It was sobeautiful to see the vasculature. I wasn’texpecting to see such perfect blood ves-sel growth into the islets.”
The findings were reported June 2,2017 in the journal Science Advances.
This research was supported by the JuvenileDiabetes Research Foundation (grant 2-SRA-2014-287-Q-R), the NIH Innovation andLeadership AQ37 in En gin eering Technologiesand Therapies Postdoctoral Training (grantT90-DK097787-03), and the Ruth L.Kirschstein National Research Service Award(F30AR069472) from the National In stituteof Arthritis and Musculoskeletal and SkinDiseases. Any opinions, findings, and conclu-sions or recommendations expressed in thismaterial are those of the authors and do notnecessarily reflect the views of the sponsoringorganizations. For more information, visitwww.news.gatech.edu.
Jessica Weaver, a postdoctoral researcher in GeorgiaTech’s Woodruff School of Mechanical Engineering, holdsa multiwell plate containing hydrogels with pancreaticislet cells. (Credit: Christopher Moore, Georgia Tech)
44 www.medicaldesignbriefs.com Medical Design Briefs, August 2017
What’s the most efficient way to design the appropriateembedded logic into a laboratory device? More and
more often, the answer is to use computer-on-modules, evenfor ARM-based designs. Heitec used an NXP i.MX6-basedQseven module from Congatec in the design of a spectro -photometric analyzer from Implen.
Spectrophotometric instruments for small-volume samplingare used in molecular biological, biochemical, and biomedicallaboratories for a wide range of applications. The spectro -photometers are designed to perform different types of analy-sis based on very small samples. Examples include the measure-ment of protein and nucleic acid concentrations as well as themeasurement of absorption and transmission characteristics. Acompany specializing in such analyzers is Implen, whosenanophotometers are mainly used for concentration measure-ments and quality control of nucleic acids and proteins inresearch and manufacturing.
■ Individual Functional ElementsThe Implen NanoPhotometer® allows users to work with dif-
ferent sample sizes, depending on the application. The sampleto be analyzed can either be placed directly onto the micro -volume pedestal using a pipette or, alternatively, it can be meas-ured in a temperature-controlled cuvette port. An integratedvortexer is used to mix the samples to obtain exact measure-ments. The results of the respective spectrophotometric proce-dure are automatically analyzed and graphically displayed on atouch screen.
Tablet PCs and smart phones can be connected via a Wi-Fihotspot, while USB, WLAN, or Ethernet are available forWindows PCs. A large external screen can be connected viaHDMI, and it is also possible to exchange data via a USB stick.The Linux-based system features an NXP i.MX6 ARM proces-sor with 1 GHz performance for fast sample measurement,data processing, and visualization.
■ Computer-on-Modules — the Fast Track to DevelopmentHeitec implemented the appropriate embedded logic for
Implen. For this purpose, Heitec used a Qseven computer-on-module as the application-ready embedded computing coreand then developed the carrier board with the specific func-tionality required for the spectroscopic analyzer around thismodule. Such a combination lets developers enjoy both thedesign freedom of a custom-specific solution and the conven-ience of a fully developed and certified board while alsoenabling them to leverage the comprehensive ecosystem ofSGET’s Qseven standard for the finished custom module.
The advantage: Custom modules and their ecosystem offerdevelopers significantly more application readiness than any ofthe standard evaluation platforms for ARM designs, where sup-port is frequently limited to allowing developers to copy exist-ing circuit board layouts. They need to design everything elsethemselves. The carrier board option provides developers withflexibility, because it is less challenging to design than a fullcustom board. Essentially, it’s just a matter of routing the sys-
tem interconnects and implementing the required additionalcontrollers. What is more, with just one board design, develop-ers can design scalable systems that are easily upgraded withnewer processors. Thanks to standardization, there is no ven-dor tie-in.
■ The Customization in DetailFor the carrier board, compactness, cost, and energy effi-
ciency each played an equally important role in the selectionof the electronics and components such as the battery and heatmanagement devices. In addition to all standard functions,such as touch controller interface, LVDS interface to the TFTpanel, USB hub, and the integration of an external audiocodec for provisioning an audio interface, the following spe-cial features were implemented:• Battery charge control for mobile use without power connec-
tion. A powerful 4S3P battery pack was installed, which allowsthe device to be operated without a mains connection for awhole working day and allows it to handle power consump-tion spikes when “pulling” measurements.
• Standby control and soft on/off using a low-power FPGAbecause, unlike x86 processors, the i.MX6 has no deep-sleepfunction. The FPGA replicates the advanced configurationand power interface (ACPI), which is standard with x86, andswitches off all current to the processor, thereby increasing
Embedded System Design and Development for ARM-BasedLaboratory Analyzers
The Implen NanoPhotometer® integrates a Qseven computer-on-moduleas the application-ready embedded computing core. (Credit: Implen)
The NanoPhotometer® family from Implen is versatile and can be used in bio-logical, chemical, medical, and pharmaceutical laboratories. (Credit: Implen)
Medical Design Briefs, August 2017 www.medicaldesignbriefs.com 45
the availability of a nonconnected system from days to weeks.Thanks to quick boot, the processor can ramp up to full oper-ation, including applications, within milliseconds.
• Integrated motor control for the vortexer, including a “snub-ber” circuit to avoid unwanted system vibrations, which is keyfor the measurement of the absorption and transmissionbehavior of samples.
• Controlled film heating as well as a special measuring bridgeto the cuvette port to ensure highly accurate temperaturemeasurement of samples, which is key for accurate analysis.
■ Overcoming the Space Shortage Since there was scarcely enough space (200 × 200 × 120 mm,
W × D × H) in the system to fit in all the offered functions, theHeitec developers had to work very closely with Implen’smechanical design team and had to use thermal simulation tooptimize cooling. The board was ulti-mately laid out in an L-shape and theQseven module mounted on its head.The heat spreader, which matches themodule, now contacts the metal bottomplate of the housing via a gap filler, whilethe remaining housing is mainly made ofplastic. An additional heat sink withinthe battery charge control ensures effi-cient handling of this hotspot.
Heitec oversaw the complete supplychain management of the project and allproduction, as well as type testing and cer-tification. So, the customer got compactand maintenance-free electronic assem-blies (equipped boards) with comprehen-sive functionality from a single source.And even though Heitec was not requiredto ensure that standards were met formedical device development and production with batch trace-ability for this project, it was reassuring for the customer Implento know that the company is trained to work in compliance withthe high-quality standards for medical devices. Implen could restassured that it would not be a challenge for Heitec to implementthe Ethernet interface of the system in accordance with DIN EN60601-1, which is required for a medical IoT application.
■ Combining Software with Dedicated HardwareThe required customization of the embedded Linux was real-
ized by Implen in-house since the company has on staff experi-enced software developers for Linux, Android, iOS, andWindows. Both the Heitec developers, who had to provide thespecific interface and component logic, and the Implen engi-neers, who were responsible for the interaction between theapplication and the hardware, were aided by personal integrationsupport provided by Qseven module supplier Congatec. Itensures that customers have a dedicated contact person and donot have to wait in anonymous helpline queues to ultimately endup with a different call partner each time. This premium serviceis made available by Congatec so that customers can always reachtechnical support during their working hours.
“It is quite a different experience to work with modules wherethe supplier provides a complete platform with all the necessarydrivers specified in the standards. This makes working with full-custom designs much easier, speeding up the time to market andultimately reducing NRE [nonrecurring engineering] costs. It is
great that Qseven now also caters for ARM processor technology,where as a rule only test and evaluation systems used to be avail-able. While you can copy [a test and evaluation system] layouts,this is not a fully certified component,” explains WolfgangChristl, project manager, electronic system design, at Heitec.
“The entire package of software components for the conga-QMX6 is very mature, comprehensive, and convenient. Werarely need the personal integration support offered byCongatec. But — and perhaps precisely because of this — it wasexcellent to experience how well the assigned service staff sup-ported us. I felt perfectly cared for. He was familiar with ourproject and not only a specialist for Linux and ARM — he alsoknew about the FPGA, which replicates the ACPI functions andis an important element for the shelf time, i.e., the standbyreadiness of our systems without mains connection. I had toexplain my concerns only once and always got a prompt and
competent answer, which is a real plus inthe rather unfriendly 800 service land-scape,” explains Johannes Bauer, head ofsoftware development at Implen.
Qseven computer-on-modules withcomprehensive board support package(BSP) and personal integration sup-port are equipped with an NXP (for-merly Freescale) processor of thei.MX6 ARM Cortex A9 processor fami-ly, which can be scaled from one to fourARM cores and provides a 3D-capableHD graphics interface. The Qsevenmodule is available in four processorvariants, from the Freescale i.MX6 SoloARM Cortex A9 with 1.0 GHz and 512
kB cache to the Quad ARM Cortex A9 with 1.2 GHz and 1 MBcache. The scalability and long-term availability of at least 10years make the processors of the i.MX6 family the perfectchoice for ARM-based system designs. In the future, the mod-ule family will also be available with the successor of thei.MX6 so that developers can leverage an even wider perform-ance range and extend the long-term availability.
Despite low power draw, the graphics core that has been inte-grated into the i.MX6 is powerful and offers a video processorunit (VPU), 2D and 3D graphics (GPU2D/3D), four shaderswith up to 200 MT/s (million triangles/second), and a dualstream of 1080p/720p. A dual HDMI v1.4 graphics interface isavailable, with the second HDMI port being shared with anLVDS interface. LVDS is also implemented as 18/24 bit dualchannel with a resolution of up to 1920 × 1200 pixels (WUXGA).A microSD socket can be used for low-cost mass storage, with theoption of adding up to 16 GB in the form of a soldered solid-state drive (eMMC) for robust applications. A choice of inter-faces is available, including 1x PCI Express 2.0, 2x SATA 2.0, 6xUSB 2.0, Gigabit Ethernet, 1x SDIO, CAN Bus, LPC, and I2SSound. The conga-QMX6 module is equipped with the U-Bootbootloader and further features Multi Watchdog Timer, CAN,and I²C Bus, making the application faster and more reliableeven when the system is in standby mode.
This article was written by Zeljko Loncaric, Marketing Engineer at Congatec, San Diego, CA. For more information, visithttp://info.hotims.com/65854-162.
As a finished product backed by the comprehen-sive ecosystem of the Qseven standard, theconga-QMX6 computer-on-module from Congatecoffers significantly greater application readinessthan standard evaluation platforms for ARM,whose only advantage, as a rule, is that the circuitboard layouts can be copied. (Credit: Congatec)
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50 www.medicaldesignbriefs.com Medical Design Briefs, August 2017
GLOBALL INNOVATIONSI
Scientists from the Netherlands andRussia have developed a new tech-nology for enhancing the local sen-
sitivity of magnetic resonance imaging(MRI) scanners. The metasurface-basedMRI has been tested on human test sub-jects for the first time. The metasurfaceconsists of thin resonant strips arrangedperiodically. Placed under a patient’shead, it provides much higher imagequality from the local brain region.
The results, published in ScientificReports, show that the use of metasurfacesmay reduce image acquisition time, makethe procedure more comfortable forpatients, and acquire higher resolutionimages, all of which together enable dis-eases to be diagnosed at an earlier stage.
MRI is a widely used medical technologyfor examination of internal organs thatcan provide, for example, information onstructural and functional damage in neu-rological, cardiovascular, and muscu-loskeletal conditions, as well as playing amajor role in oncology. However, due to itsintrinsically lower signal-to-noise ratio, anMRI scan takes much longer to acquirethan a computed tomography or ultra-sound scan. This means that a patientmust lie motionless within a confinedapparatus for up to an hour, resulting insignificant patient discomfort, and rela-tively long wait times in hospitals.
Specialists from Leiden UniversityMedical Center in the Netherlands andITMO University in Russia have
acquired human MR images withenhanced local sensitivity provided by athin metasurface — a periodic structureof conducting copper strips. Theresearchers attached these elements to athin flexible substrate and integratedthem into the close-fitting receiving coilarrays inside the MRI scanner.
“We placed such a metasurface underthe patient’s head, which increased localsensitivity by 50 percent. This allowed usto obtain detailed scans of the occipitalcortex in half the usual time. Suchdevices could potentially reduce theduration of MRI studies and improve itscomfort for subjects,” says Rita Schmidt,the lead author of the paper andresearcher in the department of radiolo-gy at Leiden University Medical Center.
The metasurface enhances the signal-to-noise ratio in the region of interest.
“This ratio limits the MRI sensitivity andduration of the procedure,” notes AlexeySlobozhanyuk, a research fellow at ITMOUniversity’s International Laboratory ofApplied Radioengineering. “Often thescans must be repeated many times andthe signals added together to separateactual data from random noise.”
According to the scientists, the meta-surface can also increase the definitionof the resulting scans.
“The size of voxels, or 3D pixels, isalso limited by the signal-to-noise ratio.Instead of accelerating the procedure,we can adopt an alternative approachand acquire more detailed images inthe same amount of time as before,”says Andrew Webb, leader of the projectand professor of radiology at LeidenUniversity Medical Center.
Until now, no one has succeeded atintegration of metamaterials intoclose-fitting receiver arrays becausethe metasurfaces’ dimensions were toowide. The novel 8-mm-wide design of the metasurface helped solve this issue.
“Our technology can be applied forproduction of metamaterial-basedultrathin devices for many differenttypes of MRI scans, but in each case,one should first carry out a series ofcomputer simulations as we have donein this project. One needs to make surethat the MRI device’s properties do notaffect the metasurface’s performance,”concludes Schmidt.
A new metasurface-based technology enhancesthe local sensitivity of MRI. (Credit: ITMOUniversity)
Comparison of MRI scans with and without the use of a metasurface. (Credit: ITMO University)
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