Redox-Magnetohydrodynamic Microfluidics Without Channels and Compatible; withElectrochemicalDetectionUnderImmunoassayConditions

by Weston, Melissa Christine; Nash, Christena K.; Fritsch, Ingrid

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A unique capability of redox-magnetohydrodynamics (redox-MHD) for; handlingliquidsonasmallscalewasdemonstrated.A1.2muLsolution; plugwaspumpedfromaninjectionsitetoadetectorwithouttheneed; forachanneltodirecttheflow.Theredoxpumpingspeciesdidnot; interferewithenzymaticactivityinasolutioncompatiblewith; enzyme-linkedimmunoassays.Alkalinephosphatase(AP),acommonenzyme; label,convertedp-aminophenylphosphate(PAPP)top-aminophenol; (PAP(R))inthepresenceof2.5mMRu(NH3)(6)Cl-2and2.5mMRu(NH3)(6); Cl-3,in0.1MTrisbuffer(pH=9).AsolutionplugcontainingPAPP; (noAP)waspumpedthroughthesurroundingsolutioncontainingAP(no; PAPP),andtheenzymaticallygeneratedPAPRwaseasilydetectedand; distinguishableelectrochemicallyfromthepumpingspecieswithsquare; wavevoltammetrydownto0.1mMconcentrations.Thetestdevice; consistedofasiliconchipcontainingindividuallyaddressable; microbandelectrodes,placedona0.5TNdFeBpermanentmagnetwiththe; fieldorientedperpendiculartothechip.A8.0mmwidex15.5mmlong; x1.5mmhighvolumeofsolutionwascontainedbya; poly(dimethylsiloxane)gasketandcappedwithaglassslide.A; steady-statefluidvelocityofsimilarto30mum/swasgeneratedina; reinforcingflowconfigurationbetweenoppositelypolarizedsetsof; pumpingelectrodeswithsimilarto2.1muA.

Journal
Analytical Chemistry
Volume
82
Issue
17
Year
2010
Start Page
7068
ISBN/ISSN
0003-2700
PMID
20681513
DOI
10.1021/ac101377a