a disposable on-chip phosphate sensor with planar cobalt ...zouz/biosensor slides.pdf · atp and...

@@ UniversityUniversity ofof CincinnatiCincinnati

Zhiwei ZouZhiwei Zou, Jungyoup Han, Am Jang*, Paul L. Bishop*, , Jungyoup Han, Am Jang*, Paul L. Bishop*, and Chong H. Ahnand Chong H. Ahn

MicroSystems and BioMEMS LabMicroSystems and BioMEMS LabDepartment of Electrical and Computer Engineering and Computer SDepartment of Electrical and Computer Engineering and Computer Sciencecience

*Department of Civil and Environment Engineering*Department of Civil and Environment EngineeringUniversity of Cincinnati, Cincinnati, OH 45221University of Cincinnati, Cincinnati, OH 45221--0030, USA0030, USA

A Disposable OnA Disposable On--Chip Phosphate Chip Phosphate Sensor with Planar Cobalt Sensor with Planar Cobalt

Microelectrode on Polymer SubstrateMicroelectrode on Polymer Substrate

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Toronto, Biosensors 2006Toronto, Biosensors 2006

UniversityUniversity ofof CincinnatiCincinnati

MicroSystems and BioMEMS Lab MicroSystems and BioMEMS Lab –– www.BioMEMS.uc.eduwww.BioMEMS.uc.edu

OutlineOutline

IntroductionDevice Concept and Design FabricationExperiment ResultsConclusions

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IntroductionIntroductionEnvironment

Phosphate is the major source of eutrophication of rivers and lakes.

AgriculturePhosphate is an essential nutrient for all plants; phosphate fertilizer has beenextensively used.

Clinical diagnosticsPhosphate concentration in human body is directly related to the diagnosis of several diseases.

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IntroductionIntroduction

Spectrophotometry Atomic Emission Spectrometry

Standard phosphate measurement methodsHigh accuracy Expensive instrument and long analysis time

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Research MotivationResearch Motivation

Environmental applicationsLarge scale field deploymentMass data collection

Clinical applicationsSingle-use and disposableRapid detection

MiniaturizedInexpensiveSimplified

RapidAccurate

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Previous ApproachPrevious Approach

Enzyme materialsAlkaline phosphatase, pyruvate oxidase, maltose phosphorylase, et al.

AdvantagesHigh selectivity and sensitivity

LimitationsEnzyme materials are relative expensive and unstable.The sensor structure is relative complicated.

Enzyme Based BiosensorsEnzyme Based Biosensors

H. Nakamura, M. Hasegawa, Y. Nomura, Y. Arikawa, R. Matsukawa, K. Ikebukuro, and I. Karube, “Development of A Highly Sensitive Chemiluminescence Flow-Injection Analysis Sensor for Phosphate-Ion Detection using Maltose Phosphorylase”, Journal of Biotechnology, Vol. 75, pp. 127-133, 1999.

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CobaltCobalt--WWire Electrodeire ElectrodePrevious ApproachPrevious Approach

Xiao et al., (1995) first introduced cobalt metal as a phosphate-sensitive electrode material.

They showed that the metallic Co-wire has a selective potential response toward dihydrogen phosphate (H2PO4

-1) in the aqueous medium. Selectivity

Sensitivity

Simplicity

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Previous ApproachPrevious ApproachCobaltCobalt--WWire Electrodeire Electrode

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Tyrosine Tyrosyl

e-

RE CEWE

R OH0.7 V

R O + H+ + e-

Insulin sensor

200 μmRE

WE

CE

MicrofabricatedMicrofabricated OnOn--CChip Biosensorship Biosensors on Polymer Substrateon Polymer SubstratePrevious WorkPrevious Work

C. Gao, H.L.R. Rilo, P. Myneni, and C.H. Ahn, “A New On-Chip Insulin Biosensor for Monitoring Dynamic Response of Human Islet Cells”, Proceedings of the 8th International Conference on Miniaturized Systems in Chemistry and Life Sciences (microTAS 2004), Malmo, Sweden, Sep. 26-30, 2004

X. Zhu, C. Gao, J.-W. Choi, P.L. Bishop, and C.H. Ahn, “On-Chip Generated Mercury Microelectrode for Heavy Metal Ion Detection”, Lab on a Chip, Vol. 5, pp. 212-217, 2005.

Lactate Sensor

Oxygen Sensor

Glucose Sensor

Glucose permeable membrane

Immobilized glucose oxidase

Reference electrode Counter electrode

Glucose, lactate, and pO2 sensors

CE RE

Mercury droplet WE

M M

Mn+

Hg

Mn+

Heavy metal ion sensor

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PDMS microfluidic

system

On-Chip Glucose Biosensor

Cultured Islet Cells

Chemical/Culture media loading

channelOn-Chip Insulin

Biosensor

Polymer LabPolymer Lab--onon--aa--Chip Chip —— Cell MonitoringCell MonitoringPrevious WorkPrevious Work

0

200

400

600

800

1000

1200

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

Insulin Concentrations /uM

Peak

Cur

rent

/nA

0

0.2

0.4

0.6

0.8

1

1 2 3 4 5 6Days

Glu

cose

Con

sum

ptio

n

Healthy CellUnhealthy Cell

C. Gao, H.L.R. Rilo, P. Myneni, and C.H. Ahn, ”A New On-Chip Insulin Biosensor for Monitoring Dynamic Response of Human Islet Cells,” Proceedings of the 8th International Conference on Miniaturized Systems in Chemistry and Life Sciences (microTAS 2004), Malmo, Sweden, Sep. 26-30, 2004

Captured islet

Islet

Filtering pillars

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C.H. Ahn, J.-W. Choi, G. Beaucage, J. Nevin, J.-B. Lee, A. Puntambekar, and J.Y. Lee, "Disposable Smart Lab on a Chip for Point-of-Care Clinical Diagnostics" Proceedings of the IEEE, Special Issue on Biomedical Applications for MEMS and Microfluidics, Vol. 92, pp. 154 - 173, 2004.

Solid-propellant (AIBN)

Waste chamber

Lateral metallic

microneedle

Calibration pouch

Biosensor array

sPROMs (passive valve)

AIBN heater

150 um

Microneedle

200 um

Mold injection

Rapid injection molding

Pouch

Integration of pouch

Pressure source

AIBN

Screen printing

Biochemical sensor

Techniques for MASS-PRODUCTION

Spray and screen printing

Integration of Metal needle

Polymer LabPolymer Lab--onon--aa--Chip Chip —— Clinical DiagnosticsClinical DiagnosticsPrevious WorkPrevious Work

POLYMER SUBSTRATE

Optical transparency

Biocompatibility

Mass production

Very low cost

Cyclic Olefin Copolymer (COC)

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Research ObjectivesResearch ObjectivesMiniaturized on-chip phosphate sensor using planar cobalt microelectrodes on polymer substrate

Measurement of both inorganic and organic phosphate in aqueous solutions

Integrated with polymer microfluidic system to achieve disposable lab-on-a-chips

BenefitsLow cost, mass production, less analyte consumption, rapid detection, easy-to-use, long storage time, et al.High sensitivity and selectivity

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Device Concept and DesignDevice Concept and Design

Electric contact

Sensing chip

Microfluidic chip

Integrated biochip

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Sensing chip

Pump-33 dual syringe pump


Microfluidic chip

Inlet

Outlet

Automatic fluidic system using micro-pump and micro-vales

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3CoO+2H2PO4-+2H+ ↔ Co3(PO4)2+3H2O

CoAu

2Co+O2 ↔ 2CoO

AuAg/AgCl

ER EW

PO2

O2

O2

P

P

P

O2


Microfluidic chip

Sensing chip

Model 215 bench-top pH/mV meter

BalanceTalk SLTM software

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Fabrication ProcessFabrication ProcessSensing ChipSensing Chip

Co

Au

COC

Ni S1818

SU-8

Ag/AgCl electroplating

Au etching

Co etching and patterning

Au/Co evaporation and patterning

SU-8 patterning

Ni electroplating

Injection molding

SU-8 removal

Standard microfabrication technology

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Fabrication ProcessFabrication ProcessMicrofluidic ChipMicrofluidic Chip

Co

Au

COC

Ni S1818

SU-8


Au etching



SU-8 patterning

Ni electroplating

Injection molding

SU-8 removal

Injection Mold process

High throughput plastic micromachining

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Fabrication ProcessFabrication ProcessChipChip BondingBonding

Co

Au

COC

Ni S1818

SU-8

UV adhesive bonding


Au etching



SU-8 patterning

Ni electroplating

Injection molding

SU-8 removal

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Fabricated DeviceFabricated Device

Outlet

Electric contact

Microchamber

InletRE

WE

500 µm

WE CoRE Ag/AgCl

Chip size: 1.5 cm×2 cmChamber volume: 2 µlElectrode: 200 µm×1.5 mm

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Output potential vs. various KH2PO4 concentrations

0 100 200 300 400 500-800

-750

-700

-650

-600

-550

-500

10-2 M

10-3 M10-4 M

Pote

ntia

l (m

V)

Time (sec)

10-5 M

-5 -4 -3 -2-800

-780

-760

-740

-720

-700

-680

-660

Pote

ntia

l (m

V)log [Concentration (M)]

Experiment Experiment RResultsesults

KH2PO4 has been diluted to different concentrations using buffer solution. The buffer solution was made by potassium hydrogen phthalate (KHP) and KCl in de-ionized water at pH 5.0.

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Experiment Experiment RResultsesultsTime-dependent potential response in 10-5 M KH2PO4

0 5 10 15 20 25 30 35-800

-600

-400

-200

0

Pote

ntia

l (m

V)

Time (min)The proposed on-chip sensor presents a steady-state response for more than 30 minutes in 10-5 M

KH2PO4 solution , which is sufficient for disposable sensor applications.

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Experiment Experiment RResultsesultsOutput potential vs. various organic phosphate concentrations

Adenosine 5'-triphosphate (ATP)

Adenosine 5'-diphosphate (ADP)

-5 -4 -3 -2-660

-630

-600

-570

-540

-510

-480

-450

Pote

ntia

l (m

V)

log[Concentration (M)]-5 -4 -3 -2

-660

-630

-600

-570

-540

-510

-480

-450

Pote

ntia

l (m

V)log[Concentration (M)]

ATP and ADP have been diluted to different concentrations using buffer solution. The buffer solution was made by potassium hydrogen phthalate (KHP) and KCl in de-ionized water at pH 5.0.

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Experiment Experiment RResultsesultsReproducibility of the fabricated sensor

1 2 3 40

-200

-400

-600

-800

-1000 KH2PO4

ATP

Pote

ntia

l (m

V)Sensor number

0 2 4 6 8 100

-100

-200

-300

-400

-500

-600

-700

Pote

ntia

l (m

V)

Number of injection

Potential responses to ten times repeated injections of 10-3 M ADP to the same phosphate sensor

Chip-to-chip deviation of four different phosphate sensors in measuring 10-3 M KH2PO4 and 10-3 M ATP

RSD = 0.6% RSD = 2.5% and 2.1%

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ConclusionsConclusionsA new on-chip phosphate sensor using planar cobalt microelectrodes has been designed and fabricated.The feasibility of using the proposed sensor to monitor bothinorganic and organic phosphate has been presented.Can be quickly fabricated with low cost and high yieldcompared to the bulk cobalt-wire based phosphate sensor, while still keeping the good performance.Fully integrated with polymer microfluidic system and can be easy developed as multi-analyte polymer lab-on-a-chips.Especially suitable for the large-scale field deployment for mass environmental data collections and disposable point-of-care testing (POCT) in clinical diagnostics.

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AcknowledgementsAcknowledgements

Financial supportNIH-P021-L684

Technical assistanceMr. Ron FlennikenInstitute for Nanoscale Science and Technology (INST) at the University of Cincinnati

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