电化学生物传感器芯片上检测氧化应激的免疫细胞

BIOMICROFLUIDICS5,032008(2011)

Electrochemicalbiosensorsforon-chipdetectionof

oxidativestressfromimmunecells

JunYan,1ValberA.Pedrosa,2JamesEnomoto,1AleksandrL.Simonian,2

andAlexanderRevzin1,a)

DepartmentofBiomedicalEngineering,UniversityofCalifornia,Davis,451EastHealth

SciencesSt.#2619,Davis,California95616,USA2DepartmentofMaterialsEngineering,AuburnUniversity,Auburn,Alabama36849,USA

(Received25January2011;accepted19July2011;publishedonline20September2011)1

Seamlessintegrationofbiologicalcomponentswithelectrochemicalsensorsiscritical

inthedevelopmentofmicrodevicesforcellanalysis.Thepresentpaperdescribesthe

integrationminiatureAuelectrodesnexttoimmunecells(macrophages)inorderto

detectcell-secretedhydrogenperoxide(H2O2).Photopatterningofpoly(ethylene

glycol)(PEG)hydrogelswasusedtobothimmobilizehorseradishperoxidase

moleculesontoelectrodesandtode neregionsforcellattachmentinthevicinityof

sensingelectrodes.Electrodesmicropatternedinsuchamannerwereenclosedinside

poly(dimethylsiloxane) uidconduitsandincubatedwithmacrophages.Thecells

attachedontotheexposedglassregionsinthevicinityoftheelectrodesandnowhere

elseonthenon-foulingPEGhydrogelsurface.Amicro uidicdevicewasconverted

intoanelectrochemicalcellbyplacing ow-throughAg=AgClreferenceandPtwire

counterelectrodesattheoutletandinlet,respectively.Thismicrodevicewith

integratedH2O2-sensingelectrodeshadsensitivityof27lA=cm2mMwithalimit

ofdetectionof2lM.Importantly,thismicrodeviceallowedcontrollableseedingof

macrophagesnexttoelectrodes,activationofthesecellsandon-chipmonitoringof

H2O2releaseinrealtime.Inthefuture,thisbiosensorplatformmaybeutilizedfor

monitoringofmacrophageresponsestopathogensorforthestudyofin ammatory

C2011AmericanInstituteofPhysics.signalinginmicropatternedcellcultures.V

[doi:10.1063/1.3624739]

INTRODUCTION

In ammatoryprocessesplayanimportantroleinanumberofpathologiesincludingdiabe-tes,cancer,2andtissue brosis.3Moleculesreleasedbyimmunecellsduringin ammationarecriticalincombatingpathogens.Macrophagesareimmunecellsthatresideinthetissueandare rsttorespondtoinvadingpathogens.Thesecellshaveproduceanarrayofin ammatorymarkersincludingcytokinesandreactiveoxygenspecies(ROS).4ROSisacollectivetermthatreferstochemicalspeciesformedbyincompletereductionofoxygen,includingsuperoxideanion(O2ÁÀ),hydrogenperoxide(H2O2),andhydroxylradical(ÁOH).5ROScompoundssuchassuper-oxideanion(O2ÁÀ)areunstableand,upondegradation,formamorestableH2O2compound.ROSmoleculesarereleasedbymacrophagesandotherimmunecellstoeliminatepathogensandcleansesiteoftheinjury.Therefore,appearanceofROSisanimportantindicatorofin ammationandmayserveasadiagnosticmarkeroftheimmunesysteminteractionwithpathogens.

BioanalyticalapproachesfordetectionofH2O2describedintheliteratureincludechemilu-minescence,6 uorescence,7andelectrochemistry.8,9Thelatterapproachisparticularlyattractiveduetosimplicityandreliabilityofmeasurements,andthepossibilityforminiaturization.Elec-trochemicalbiosensorscommonlyrelyontheenzyme,horseradishperoxidase(HRP)—anoxi-doreductaseenzymethatcatalyzesreductionofH2O2.Thisreductioncanbedetectedattheelectrodeeitherdirectly,10,11orthroughredoxmediatorssuchasferrocene-andosmium-based1a)Authortowhomcorrespondenceshouldbeaddressed.Electronicmail:arevzin@ucdavis.edu.

5,032008-1C2011AmericanInstituteofPhysicsV1932-1058/2011/5(3)/032008/11/$30.00

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