资源描述：
《quantitative sensing of nanoscale colloids using a microchip Coulter counter》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。
1、REVIEWOFSCIENTIFICINSTRUMENTSVOLUME72,NUMBER12DECEMBER2001QuantitativesensingofnanoscalecolloidsusingamicrochipCoultercountera)O.A.SalehandL.L.SohnDepartmentofPhysics,PrincetonUniversity,Princeton,NewJersey08544~Received27June2001;acceptedforpublication20September2001!Wehavefabr
2、icatedamicrochipCoultercounteronaquartzsubstrate,andhaveusedittodetectindividualnanoscalecolloidalparticleswithasensitivityproportionaltoeachparticle'ssize.Wedemonstratetheabilityofthisdevicetosensecolloidsassmallas87nmdiameter,andtodistinguishbetweencolloidswhosediametersdiffer
3、bylessthan10%.Furtherreductionsintheporesize,easilydonewithcurrentnanofabricationtechniques,makeourdeviceapplicabletomeasuringbiologicalmacromolecules,suchasDNAandproteins.©2001AmericanInstituteofPhysics.@DOI:10.1063/1.1419224#I.INTRODUCTIONII.EXPERIMENTOurdevice,showninFig.1~a!
4、,isfabricatedinmultipleQuantitativemeasurementsofthesizeandconcentrationstages.Eachstageconsistsoflithographicpatterngeneration,ofnanoscaleparticlesarecriticalforstudiesofcolloidalandfollowedbypatterntransferontoaquartzsubstrateusingmacromolecularsolutions.Traditionally,thisisac
5、complishedeitherreactiveionetching~RIE!ormetaldepositionandthroughultracentrifugation,chromatography,gelliftoff.The®rststageisthefabricationofthepore.Alineis12electrophoresis,ordynamiclightscattering.Herewedis-patternedonthesubstrateusingeitherphotolithography~PL!cussanalternati
6、vemethodbasedontheCoultertechniqueofforlinewidths>1mm,orelectron-beamlithography~EBL!3particlesensing.Coultercounterstypicallyconsistoftwoforlinewidthsbetween100and500nm,andthenetchedintoreservoirsofparticle-ladensolutionseparatedbyamem-thequartzusingaCHF3RIE.Thesubstratesubsequ
7、entlybraneandconnectedbyasingleporethroughthatmem-undergoesasecondstageofPLandRIEtode®networes-brane.Bymonitoringchangesintheelectricalcurrentervoirsthatare3.5mmdeep,separatedby10mm,andcon-throughtheporeasindividualparticlespassfromonereser-nectedtoeachotherbythepreviouslyde®ned
8、channel@seeFig.1~a!#.Thelengthoftheporeisde®ned
