Ch3. Nanotubes, Nanowires, and Nanocantilevers in Biosensor Development

Part - II

2009년 5월 12일서현권

davidsuh79@snu.ac.kr

2

Contents

1 Flow-injection Analysis, Carbon Nanotube Array1 Flow-injection Analysis, Carbon Nanotube Array

2 Nanowires2 Nanowires

3 Nanocantilevers for Biosensors3 Nanocantilevers for Biosensors

1) Silicon 1) Silicon NanowireNanowire--based Biosensorbased Biosensor

2) Conducting Polymer 2) Conducting Polymer NanowireNanowire--based Biosensorbased Biosensor

3) Metal Oxide 3) Metal Oxide NanowireNanowire--based Biosensorbased Biosensor

Part I Part I –– Carbon Carbon NanotubesNanotubes in Biosensor Developmentin Biosensor Development

Part II Part II –– NanowiresNanowires in Biosensor Developmentin Biosensor Development

3

3.2.4. Flow-Injection Analysis

What is F.I.A.?What is F.I.A.?First described in Denmark by First described in Denmark by RuzickaRuzicka and Hansen(1975)and Hansen(1975)The The analysis of a chemical substanceanalysis of a chemical substance by inserting a by inserting a sample into a carrier stream of reagent using a sample sample into a carrier stream of reagent using a sample injection valve that propels the sample downstream where injection valve that propels the sample downstream where mixing occurs in a coiled tube, then mixing occurs in a coiled tube, then passes into a flowpasses into a flow--through detectorthrough detector and a recorder or other data handling and a recorder or other data handling device.device.

[Ch.3] Biosensors – Part I[Ch.3] Biosensors – Part I

4

3.2.4. Flow-Injection Analysis

FeaturesFeaturesReal time analysis, continuous analysisReal time analysis, continuous analysisSimple, but high performance (reproducibility)Simple, but high performance (reproducibility)Design flexibilityDesign flexibilityCommonly used in quality control systems because of Commonly used in quality control systems because of accurate and fast resultsaccurate and fast resultsDesign parameters : flow rate, Design parameters : flow rate, microfluidicmicrofluidic channel channel

dimensions, flow cell geometrydimensions, flow cell geometry

Detector MaterialDetector MaterialConventional Detectors: gold, platinum, various forms of Conventional Detectors: gold, platinum, various forms of carboncarbon흡광도흡광도, , 전위차전위차, , 전류값전류값 등을등을 측정하여측정하여 반응대상물의반응대상물의 농도를농도를 측정측정

[Ch.3] Biosensors – Part I[Ch.3] Biosensors – Part I

5

3.2.4. Flow-Injection Analysis

Why Carbon Why Carbon NanotubeNanotube? ? –– The Route Toward Applications?The Route Toward Applications?Carry high currents with no heatingCarry high currents with no heatingHave high electrochemically accessible surface areaHave high electrochemically accessible surface area(porous (porous nanotubenanotube arrays)arrays)Minute size of the Minute size of the nanotubenanotube sensing element and the sensing element and the correspondingly small amount of material required for a responsecorrespondingly small amount of material required for a responseLess surface fouling of the sensorsLess surface fouling of the sensors

CNTCNT--based Electrode offersbased Electrode offers……Enhanced sensitivityEnhanced sensitivityLongLong--term stabilityterm stability

((①① Baughman, Science 2002)Baughman, Science 2002)

(p.75, Textbook)(p.75, Textbook)

[Ch.3] Biosensors – Part I[Ch.3] Biosensors – Part I

6

3.2.4. Flow-Injection Analysis

Issues (Shankar Ghosh et al, 2003)Issues (Shankar Ghosh et al, 2003)Flow of a liquid on CNT bundles induces a voltage in the sample Flow of a liquid on CNT bundles induces a voltage in the sample along the direction of the flowalong the direction of the flowMagnitude of the voltage depends sensitively on the Magnitude of the voltage depends sensitively on the ionic ionic conductivity and on the polar nature of the liquidconductivity and on the polar nature of the liquidFlow velocity and the voltage was attributed to a direct forcingFlow velocity and the voltage was attributed to a direct forcingof the free charge carriersof the free charge carriers

((②② GhoshGhosh, Science 2003), Science 2003)

[Ch.3] Biosensors – Part I[Ch.3] Biosensors – Part I

7

3.2.5. Carbon Nanotube Array-based Biosensors

Key issues in Biosensor DesignKey issues in Biosensor Design-- Establishment of a Establishment of a fast electronfast electron--

transfertransfer between the enzyme between the enzyme active site and the electrochemical active site and the electrochemical transducertransducer

-- Surface areaSurface area

CarbonNanotube

Array

[Ch.3] Biosensors – Part I[Ch.3] Biosensors – Part I

8

3.2.5. Carbon Nanotube Array-based Biosensors

Sofia Sofia SotiropoulouSotiropoulou (2003)(2003)-- Aligned multiAligned multi--wall carbon wall carbon

nanotubesnanotubes (MWNT) grown on (MWNT) grown on platinum substrate are used platinum substrate are used for the development of an for the development of an amperometricamperometric biosensorbiosensor

-- NanotubeNanotube array allows for the array allows for the efficient immobilization of the efficient immobilization of the model enzymemodel enzyme

-- Platinum substrate provides Platinum substrate provides direct transduction platformdirect transduction platformfor signal monitoringfor signal monitoring

-- Carbon Carbon nanotubesnanotubes can play a can play a dual roledual role, both as , both as immobilization matricesimmobilization matrices and as and as mediatorsmediators

< Schematic diagram of the carbon < Schematic diagram of the carbon nanotubenanotubearray biosensor. The enzyme immobilization array biosensor. The enzyme immobilization allows for the direct electron transfer from allows for the direct electron transfer from the enzyme to platinum transducer.>the enzyme to platinum transducer.>

((③③ SotiropoulouSotiropoulou, 2003), 2003)

[Ch.3] Biosensors – Part I[Ch.3] Biosensors – Part I

9

Joseph Wang, Gang Chen

3.2.5. Carbon Nanotube Array-based Biosensors

Fabrication SchemeFabrication Scheme-- Nickel particles were Nickel particles were

randomly depositedrandomly deposited on on CrCr--coated silicon coated silicon substrate by applying a substrate by applying a pulse currentpulse current

-- CNTsCNTs were grownwere grown on the on the Ni particles (CVD)Ni particles (CVD)

-- This layer of This layer of epoxy resin epoxy resin was coatedwas coated

-- CNTsCNTs beyond the polymer beyond the polymer resin was resin was mechanically mechanically removedremoved

((④④ Biosensors based on Carbon Biosensors based on Carbon NanotubesNanotubes))

[Ch.3] Biosensors – Part I[Ch.3] Biosensors – Part I

10

FeaturesFeatures-- Vertically aligned Vertically aligned CNTsCNTs have good material propertieshave good material properties

Good electrical conductivityGood electrical conductivity, capability to promote , capability to promote electron transfer reactionelectron transfer reaction

-- But, But, spacing needs to be sufficiently largerspacing needs to be sufficiently larger than the than the diameter of the diameter of the nanotubesnanotubes to prevent diffusion layer to prevent diffusion layer overlapoverlap from the neighboring electrodesfrom the neighboring electrodes

Gooding et al (2003)Gooding et al (2003)-- Found that Found that the rate of electron transfer remains the samethe rate of electron transfer remains the same

regardless of the lengths of the tubesregardless of the lengths of the tubesEnables molecules to be located several hundred Enables molecules to be located several hundred nanometers from a macroscopic substrate electrode with nanometers from a macroscopic substrate electrode with no loss in performanceno loss in performance

3.2.5. Carbon Nanotube Array-based Biosensors

[Ch.3] Biosensors – Part I[Ch.3] Biosensors – Part I

11

12

3.3. Nanowires in Biosensor Development

What is What is NanowiresNanowires??A A nanowirenanowire is a is a nanostructurenanostructure, with the diameter of the , with the diameter of the order of a nanometer (10order of a nanometer (10−−99 meters)meters)Structures that have a Structures that have a thickness or diameter constrained thickness or diameter constrained to tens of nanometers or lessto tens of nanometers or less and an unconstrained length and an unconstrained length Also known as Also known as ““quantum wiresquantum wires”” (at these scales, quantum mechanical effects are important)(at these scales, quantum mechanical effects are important)

[Ch.3] Biosensors – Part II[Ch.3] Biosensors – Part II

13

Why Why NanowiresNanowires??

Extremely sensitiveExtremely sensitive for detection of for detection of biointeractionsbiointeractions on on their surfacetheir surfaceElectronically Electronically switchableswitchable properties of properties of semiconductingsemiconductingnanowiresnanowires provide a sensing modalityprovide a sensing modalityFeasible for the Feasible for the miniatruizedminiatruized devicesdevices to detect multiple to detect multiple samples real time in vivo samples real time in vivo ((생체조건내에서생체조건내에서))

Candidate materials for the Candidate materials for the nanowiresnanowires are unlimitedare unlimitedGives researchers great Gives researchers great flexibilityflexibility in selecting the in selecting the

right materials for the functionality of the desired device.right materials for the functionality of the desired device.

3.3. Nanowires in Biosensor Development

[Ch.3] Biosensors – Part II[Ch.3] Biosensors – Part II

(p.84, Textbook)(p.84, Textbook)

14

Nanowires in Biosensor Development

Silicon Nanowire-based1.

2. Conducting Polymer Nanowire-based

3. Metal Oxide Nanowire-based

[Ch.3] Biosensors – Part II[Ch.3] Biosensors – Part II

15

FeaturesFeatures-- 부피부피 대비대비 표면적표면적 비율이비율이 높음높음, , 전기적전기적 특성특성 조절조절 가능가능

높은높은 효율과효율과 탐지능력탐지능력을을 지님지님

-- 실리콘실리콘 위주의위주의 반도체반도체 산업의산업의 발전과발전과 더불어더불어 함께함께 발전발전

-- 다른다른 물질들에물질들에 비해비해 공정이공정이 용이하며용이하며 산업화하기에산업화하기에 용이용이함함

-- CNTCNT와와 같은같은 다른다른 11차원차원 나노시스템에나노시스템에 비해비해 그그 특성들이특성들이구조적인구조적인 변화에변화에 의해의해 크게크게 영향을영향을 받지받지 않음않음

-- DNA, proteins, virus DNA, proteins, virus 등의등의 탐지를탐지를 위해위해 널리널리 사용사용

3.3.1. Silicon Nanowire-based

[Ch.3] Biosensors – Part II[Ch.3] Biosensors – Part II

16

3.3.1. Silicon Nanowire-based

[Ch.3] Biosensors – Part II[Ch.3] Biosensors – Part II

Electrical detection of Electrical detection of single virusessingle viruses

-- Electrical detectionElectrical detection of single of single viruses using viruses using SiSi NanowireNanowire

-- Virus bindsVirus binds on a on a nanowirenanowireConductance changeConductance change occursoccurs

-- Virus unbindsVirus unbindsConductance value returnsConductance value returns to to

the baseline valuethe baseline value-- Simultaneous detection of Simultaneous detection of

multiple virusesmultiple viruses using different using different nanowiresnanowires

((⑤⑤ PatolskyPatolsky, 2004), 2004)

17

Electrical detection of single virusesElectrical detection of single viruses

3.3.1. Silicon Nanowire-based

[Ch.3] Biosensors – Part II[Ch.3] Biosensors – Part II

((⑤⑤ PatolskyPatolsky, 2004), 2004)

18

Conducting Polymer (Conducting Polymer (전도성전도성 고분자고분자))

Polymers that Polymers that conduct electricity or that act as electrical conduct electricity or that act as electrical semiconductorssemiconductors (p(plastic) lastic) Able to Able to bendbend (like plastic), very light (weight)(like plastic), very light (weight)High surface areas, chemical specificities, High surface areas, chemical specificities, tunable tunable conductivities, material flexibilities, ease processingconductivities, material flexibilities, ease processingCompatible with biological moleculesCompatible with biological molecules in neutral aqueous in neutral aqueous solutionssolutionsElectronic conductivity of conducting polymers changes over Electronic conductivity of conducting polymers changes over several orders of magnitude in response to changes in pH several orders of magnitude in response to changes in pH and their environmentand their environmentServe as Serve as good matrices for the immobilization of enzymesgood matrices for the immobilization of enzymes

3.3.2. Conducting Polymer Nanowire-based

[Ch.3] Biosensors – Part II[Ch.3] Biosensors – Part II

19

ApplicationsApplications

Health care: In medical diagnosis (glucose, fructose, lactate, Health care: In medical diagnosis (glucose, fructose, lactate, ethanol, cholesterol, urea etc.)ethanol, cholesterol, urea etc.)ImmunosensorsImmunosensors: Can be used in medical diagnostics and : Can be used in medical diagnostics and environmental sensorsenvironmental sensorsDNA sensors: In the detection of various genetic disorders.DNA sensors: In the detection of various genetic disorders.Environmental monitoring: For control of pollution and Environmental monitoring: For control of pollution and detection of hazardous chemicals in biosensors (detection of hazardous chemicals in biosensors (polyphenolspolyphenols, , sulfites, peroxides, formaldehyde etc.)sulfites, peroxides, formaldehyde etc.)Food analysis: For detection of glucose, fructose, ethanol, Food analysis: For detection of glucose, fructose, ethanol, sucrose, lactate, sucrose, lactate, malatemalate, , galactosegalactose, citrate, lactose, urea, , citrate, lactose, urea, starch etc. in food industries.starch etc. in food industries.

3.3.2. Conducting Polymer Nanowire-based

[Ch.3] Biosensors – Part II[Ch.3] Biosensors – Part II

((⑥⑥ Gerard, 2001)Gerard, 2001)

20

3.3.2. Conducting Polymer Nanowire-based

[Ch.3] Biosensors – Part II[Ch.3] Biosensors – Part II

((⑥⑥ Gerard, 2001)Gerard, 2001)

21

FeaturesFeaturesWidely used for Widely used for gas sensinggas sensingCapable of operating at elevated temperatures and in Capable of operating at elevated temperatures and in harsh environmentsharsh environmentsMechanically robust and relatively inexpensive and offer Mechanically robust and relatively inexpensive and offer exquisite sensing capabilitiesexquisite sensing capabilitiesSurface treated Surface treated nanowiresnanowires as ammonia sensors at room as ammonia sensors at room temperature (Li et al, 2003)temperature (Li et al, 2003)Small, fast and sensitive devices for detecting Small, fast and sensitive devices for detecting ppmppm--level level ammonia at room temperature under UV light (Law et al, ammonia at room temperature under UV light (Law et al, 2002)2002)

3.3.3. Metal Oxide Nanowire-based

[Ch.3] Biosensors – Part II[Ch.3] Biosensors – Part II

((⑦⑦ Law, 2002)Law, 2002)

22

23

-캔틸레버, 외팔- Beam or structuresupported on only one end

3.4. Nanocantilevers

[Ch.3] Biosensors – Part II[Ch.3] Biosensors – Part II

24

3.4. Nanocantilevers

NanomechanicsNanomechanicsThe bending of each cantilever was The bending of each cantilever was measured in situmeasured in situ((정위치정위치)), using an optical , using an optical beam deflection techniquebeam deflection technique-- Accuracy 0.1nmAccuracy 0.1nm

Not require labeling, for example, with Not require labeling, for example, with fluorescence or radioactive tagsfluorescence or radioactive tags

[Ch.3] Biosensors – Part II[Ch.3] Biosensors – Part II

((⑧⑧ Fritz, 2003)Fritz, 2003)

26

Carbon Carbon NanotubeNanotube Array Fabrication SchemeArray Fabrication Scheme-- CVD (Chemical Vapor Deposition)CVD (Chemical Vapor Deposition)