UAB - ECTC 2014 PROCEEDINGS - Section 1 Page · measured piece of freezer paper on top of aluminum...

SECTION 1

BIO-MEDICAL / BIOENGINEERING

UAB School of Engineering - ECTC 2014 Proceedings - Vol. 13 1

Proceedings of the Fourteenth Annual Early Career Technical Conference The University of Alabama, Birmingham ECTC 2014 November 1 – 2, 2014 - Birmingham, Alabama USA

PAPER-BASED MICROFLUIDIC LOW-COST DIAGNOSTIC DEVICES

Stephanie B Collins University of Georgia

Athens, GA USA

Ramana M Pidaparti University of Georgia

Athens, GA USA

ABSTRACT Two easily accessible low cost products, Janus paper

(commonly known as freezer paper) and aluminum foil can be purchased at any grocery store and combined for potential use in medicine or drug delivery. Janus paper and aluminum foil were irreversibly bonded under heat and pressure to create microfluidic channels for diagnostic device applications. Several microfluidic channels were fabricated and tested to assess their functionality. The results from experiments suggest that it is feasible to design and fabricate microfluidic channels with integrated pH paper. More in-depth studies are required to develop diagnostic device applications.

INTRODUCTION Low cost diagnostic devices have taken off as helpful tools

to improve global health, especially in the developing world. The Bill and Melinda Gates Foundation’s “Grand Challenges Explorations” grant program has set a surge of innovative ideas in motion. The $100 million program is taking a large step towards solving some of the world’s biggest health issues. [1]

A significant issue in global health care is the cost of medical materials, particularly in third world countries. Recent research has focused on finding lower cost solutions to creating biomedical devices. Lower cost devices will be more accessible for labs across the globe.

Latest developments in the lab-on-a-chip and microfluidic device communities include Dr. Samuel K. Sia of Columbia University’s development of an innovative and low-cost diagnostic device for HIV testing. The device allows a patient to be tested for HIV from anywhere in the world with just a finger prick and in a mere fifteen minutes. In addition, the device is small and easily portable. The Bill and Melinda Gates Foundation, among others have supported the research because it is a useful and inexpensive innovation. [2]

Recently, in the quest to find low-cost materials for diagnostic devices, researchers have turned to paper-based

products. Paper is an excellent material for microfluidic devices due to its low-cost, easy availability, naturally lightweight characteristic, compatibility with biological samples, and its ability to be chemically modified. Paper is also flexible and commonly white which allows researchers to see the fluids going through the paper. Additionally, paper is easy to store and dispose of since it can be burned. [3]

These paper-based products can be useful for microfluidic devices as disposable platforms for chemical and biological examinations. Paper-based products can be used in combination with many different materials. Research done by An-liang Zhang and Yan Zha created a paper-based device similar to Dr. Sia’s but with the use of sheet copper. [4] Recently, Dr. Rahim Rahimi of Purdue University discovered the effectiveness of Janus-paper in liquid delivery devices. The Janus-paper has been used in combination with a PDMS substrate where the two materials become irreversibly bonded. The bonding of these materials is useful for devices involving liquid delivery. The plastic side of the freezer paper is hydrophobic, allowing the material to suppress moisture and it allows the material to bind with other materials under heat. The aforementioned products can also be used for cell culturing and tissue engineering procedures. [5]

Our objective is to create similar devices at an even lower cost. While the use of Janus-paper significantly lowers the cost of these devices, PDMS is still an expensive material. In this article, the substitution of PDMS with every day kitchen aluminum foil is explored as a possibility for an even lower cost approach to these devices. The dull side of the aluminum foil is able to bind with the plastic coated side of the Janus-paper under pressure and heat. This bond creates a material that may be useful for drug or medicine delivery because it protects against moisture and can keep materials safe in cold temperatures. The freezer paper works to protect materials inside from freezer burn or moisture while the aluminum foil is impermeable to oxygen or water. The aluminum foil can serve to suppress heat as well as cold temperatures from the material


inside. Both of these materials can be easily found at the grocery store at a very low-cost and thus offer many possibilities for the development of diagnostic microfluidic devices.

Figure 1: Step by step demonstration of the tube making

process. (a) Measure and cut freezer paper and aluminum foil into the same size. (b) Place freezer paper (plastic side down) directly on top p of aluminum foil (dull side up). (c)Place cloth on top and iron for two minutes to cause materials to bind. (d) Fold material in half. (e) Seal

the two halves using ethyl cyanoacrylate. (f) Demonstration of sealed product thus far. (g) Wrap

material into a tube like structure using wooden rod. (h) Seal the tube using ethyl cyanoacrylate. (i) Final product

is a tube with aluminum foil coating the outside and inside and freezer paper in the middle.

DESIGN AND MANUFACTURING OF TUBES The technique used to create the janus-paper and aluminum

foil material is illustrated in the figure above. The freezer paper and aluminum foil were measured and cut into identical sizes then placed on an ironing board, janus-paper side up. The plastic coated hydrophobic side of the janus-paper faced down directly on top of the section of aluminum foil, dull side up. A thin cloth was placed on top of the materials in order to prevent any burning of paper. Using an iron on the cloth for approximately two minutes, the materials became bonded to each other, creating one material through pressure and heat. The

use of steam from the iron contributed to quicker bonding of the two materials.

After bondage, the material was folded in half and ethyl cyanoacrylate (commonly known as “super glue”) was used to glue the material together. The new material was then formed into a tube where the ethyl cyanoacrylate was used on the seam to keep the material in a tube shape. Depending on the desired size for the tube, the material was wrapped around different size rods to form uniform tube structures. The final result was a tube made of Janus-paper in between two layers of aluminum foil. Aluminum foil lined the outside and the inside, insulating the tube. The Janus-paper in the middle of the tube makes the tube moisture and vapor resistant and protects the contents of the tube from cold temperatures.

Figure 2: Step by Step demonstration of the channel

making process. (a) Place measured aluminum foil on ironing board then place wooden rods on top of aluminum

foil at the desired locations of the channels. (b) Align measured piece of freezer paper on top of aluminum foil and rods. (c) Use an iron to apply heat and pressure to

bind the freezer paper and aluminum foil around the rods. (d) Remove rods and the final product is the aluminum foil and freezer paper bonded together except where the rods were inserted to create channels throughout the material. DESIGN AND MANUFACTURING OF CHANNELS

The combined Janus-paper and aluminum foil material was then used to create channels for fluid to travel through in the device. The channels are created by putting the aluminum foil dull side up on an ironing board. Wooden rods are placed on the aluminum foil at the channels’ desired locations. The freezer paper is then placed on top and ironed on to the aluminum foil. The wooden rods cause the freezer paper not to bond and thus create tube like channels throughout the aluminum foil and

A B C

D E F

G H I

A B

C D


Janus-paper. These channels can be used to transport fluids in several directions or to mix several fluids together. The design used for the following experiments involved three different channels: two for liquids to be inserted in and one for the combined liquids to exit the device. The design of this device is shown above in Figure 2.

CHARACTERIZATION The quality of the tubes is adequate in terms of sturdiness

and durability. The tubes can be made into any size or shape, providing a large range of possibilities for different uses in the field of microfluidic devices. The channels are durable for one time only use as the transfer of liquid through the devices can cause the device to curl up due to its paper material qualities. Through experimentation with colored water, as shown in Figure 3, it was noted that the channels do not let the liquid seep out beyond a quarter inch of the channels. Some liquid can get stuck in the channels if not cleansed thoroughly, specifically in the siding of the channels where the aluminum is bonded to the Janus-paper. This was demonstrated by squirting water with blue food coloring dye through the channels, and then squirting tap water through the channels. The device was allowed to sit until dry and then further examined. On the crevices of the channels, the paper developed a slight blue hue from the water that was inserted into the device. Due to this issue, the device is recommended for one time use or use with the same liquids. If other liquids were inserted into the channels, they may get contaminated with the residue of the last liquid. This can be fixed by thoroughly cleansing the channels immediately after use or by adding tubes throughout the channels of the device to limit the leakage of the liquid into the crevices of the device, allowing for more use of the device as shown in Figure 4.

Figure 3: Performing test with water mixed with blue food coloring

Figure 4: Device with tubes inserted in channels (rods have a 5/64th inch, or .2cm diameter)

Experiments testing the PH of different liquids were

performed to assess the quality of the channels and to examine their performance in a typical application setting. Our device has applications for PH testing of blood and urine but for this experiment, various other liquids with significant PH counts were used to examine the durability of the device and the device’s performance in an artificial way. For our experiment, PH testing strips were inserted onto the aluminum bottom of each channel. Using syringes, two types of liquids of different PH measurements were simultaneously squirted into the two channels where they were combined to come out of the third channel and the PH of the combined liquids was tested. The PH strips in the first two channels measured the original PH of each liquid while the PH strip in the third channel measured the combined liquid’s PH level. Figure 5 shows the results of the


test.

Figure 5: The combined PH level results obtained from

mixing various fluids of different PH levels together through the device.

One concern about the materials used for this diagnostic

device is the possibility of contamination of the liquids due to aluminum foil. With aluminum foil, there is a risk of the aluminum leaching off the foil and contaminating the liquids in the tubes or channels. This risk is however greater only when the foil is heated to high temperatures, especially with highly acidic substances. [6] It is unclear if at room temperature aluminum foil can undergo leaching and contaminate liquids.

Several different forms of paper were tested as possible substitutes for the Janus-paper and aluminum foil. Wax paper was experimented with as a substitute for both materials. The wax paper did not adhere as well to the aluminum foil as Janus-paper. The two materials came apart during the channel manufacturing. When the wax paper was substituted for the aluminum foil, the paper started to deteriorate after water was shot through the channels. However, research done by Emanuel Carrilho has opened the possibilities for paper-based microfluidic devices that incorporate wax. The use of a wax printer allows patterns of wax to create hydrophilic channels. [7] Another material experimented with as a substitute for aluminum foil was parchment paper but it too did not adhere well to the Janus-paper. The combination of aluminum foil and freezer paper created the most durable and effective material for the creation of tubes and channels.

Further research is to be done in the fall of 2014 on the design of this device. Materials will be designed and drawn with AutoCAD software and come to life with the use of a 3D printer.

CONCLUSION We were able to use two easily accessible and low-cost

materials to create tubes and channels for microfluidic devices. By using heat and pressure to bond freezer paper to aluminum foil, we were able to create a new durable material for the creation of hydrophobic tubes. The use of freezer paper, rods, and aluminum foil bonded together through heat and pressure created hydrophobic channels with applications for diagnostic

devices. Specifically, the material may be applied to urinalysis or blood analysis. We found that aluminum foil can be used as a low-cost substitute for PDMS in paper-based microfluidic devices. The results of limited experimentation suggest that it is feasible to design and fabricate microfluidic channels with integrated pH paper for low cost diagnostic device applications.

REFERENCES [1] "Why the Grand Challenges?." Why the Grand Challenges?.Grand Challenges in Global Health, n.d. Web. 14 July 2014. [2] "Fast, low-cost device uses the cloud to speed up diagnostic testing for HIV, more." Fast, low-cost device uses the cloud to speed up diagnostic testing for HIV, more. N.p., 24 Jan. 2013. Web. 14 July 2014. . [3] Martinez, Andres W., Scott T. Phillips, and George M. Whitesides. "Diagnostics for the Developing World: Microfluidic Paper-Based Analyitical Devices." . Analytical Chemistry, 1 Jan. 2010. Web. 14 July 2014. . [4] Microfluidic Device Using Printed Circuit Technology." (2012). AIP Scitation. Web. 1 Jan. 2014. . [5] Rahimi, Rahim, Manuel Ochoa, Tejasvi Parupudi, Amy Donaldson, Mehmet R. Dokmeci, Ali Khademhosseini, Amir Ghaemmaghami, Babak Ziaie. “A Janus-Paper PDMS Platform for Lab-On-A-Chip Applications.” Solid State Sensors, Actuators and Microsystems Workshop, 8 Jan. 2014. Print. 14 July 2014. [6] Bassioni, Ghada, Fathia S. Mohammed, Essam Al Zubaidy, and Issam Kobrsi. "Risk Assessment of Using Aluminum Foil in Food Preperation." International Journal of Electrochemical Science, 1 May 2012. Web. 14 July 2014. . [7] E. Carrilho, A. W. Martinez and G. M. Whitesides, Anal. Chem. 81, 7091 (2009). http://dx.doi.org/10.1021/ac901071p

Liquid #1 PH

•Lime Juice (1)•Lime Juice (1)•Lime Juice (1)•White Wine

Vinegar (2)•White Wine

Vinegar (2)•White Wine

Vinegar (2)

Liquid #2 PH

•Baking Soda (11)•Hydrogen

Peroxide (6)•White Wine

Viengar (2)•Hydrogen

Peroxide (6)•isopropyl alcohol

(6)

Combined PH

•11•1•1•2•6


http://dx.doi.org/10.1021/ac901071p


DESIGN CONCEPTS MIMICKING A BIOLOGICAL SYSTEM: NUCLEAR PORE COMPLEX

Mitchell A. Lynn, Undergraduate Student University of Georgia

Athens, GA, USA

Ramana M. Pidaparti, Professor University of Georgia

Athens, GA, USA

ABSTRACT The Nuclear Pore Complex (NPC) is a highly conserved structure in the nuclei of many different types of organisms. The

NPC controls the flux of all fluids, particles, proteins, etc. between the nucleus and the cytoplasm selectively and efficiently. In the world of microfluidics, precision and efficiency is key. The NPC has many different traits that could be used in a myriad of engineering fields. This paper seeks to apply current understanding of the mechanisms and functions of the NPC to the engineering field, especially propose some design concepts for further exploration.

No Final Manuscript



A PROTOTYPE MICROPUMP MODEL FOR POTENTIAL HYDROCEPHALUS TREATMENT OPTIONS

Matthew Amrit, Kanji Yamamoto Department of Physics University of Georgia

Athens, GA, USA

Ramana Pidaparti, Leidong Mao College of Engineering University of Georgia

Athens, GA, USA

Lisa Feldman, Bruce Mathern Department of Neurosurgery

School of Medicine Virginia Commonwealth University

Richmond, VA, USA

ABSTRACT The intracranial space consists of brain matter, cerebral blood and cerebrospinal fluid (CSF) surrounded by the skull. Hydrocephalus is a condition characterized an abnormal accumulation of CSF in the cavities of the brain. This causes increased intracranial pressure (ICP) which may lead to medical complications. Current hydrocephalus treatment is a surgical treatment utilizing a pressure relief valve (mechanical shunt) that opens, at increased pressure, and drains the additional CSF into other body cavities. Conventional CSF shunt systems are satisfactory; however, the valve opening pressure is not adjustable and is not able to manage the problem of over or under draining. Our goal is to develop a product for hydrocephalus treatment that addresses the shortcomings of current hydrocephalus treatment, primarily over and under draining by mechanical shunts. In this paper, we describe an early model for a miniaturized two-way pump system which can be remotely controlled. A prototype was made and briefly tested for feasibility.

No Final Manuscript



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