The Study Of Bipolar Platform With Electrochemiluminescence And Its Applications In Biosensors

The term bipolar electrode(BPE)is an electronic conductor that be applied a voltage between two driving electrodes,which enables the two coupled redox reactions be generated at two opposite poles.The electronic conductor is contact with an ionically conductive phase to trigger an electric field,at sufficient intensity,the faradaic reactions will be performed.Recently,the ECL biosensor based on BPE with wireless contact,simplifies the experiment operation and offers the merits on high sensitivity,low cost and reagent consumption.Given its excellent characteristics,the BPE-ECL sensing platform has been broadly applied in molecular screening,substance enrichment,visual array detection of cells,DNA,etc.This is especially helpful in microfluidic systems,where the potential can be easier to control and the device can be portable.In this paper,by changing the structure of BPE-ECL detecting platform and investigating signal amplification strategy,we constructed several new sensors,the major contents are as follows:(1)Bipolar electrochemiluminescense detecting platform based on Indium-Tin-Oxide conductive glass for detecting H2O2Firstly,we made the transparent ITO bipolar electrode.Owing to the ITO glass is easy to damage under the high driving voltage,we electro-deposition the Au NPs on the surface of ITO,which could enchance conductivity,avoid the damage and instability of the output signals.Pt NPs were deposited on the anode of ITO,for catalyzing the H2O2.The Pt NPs also can increase the signal of ECL.To achieve an electrical stable BPE-ECL sensing platform,the ITO and poly(dimethylsiloxane)PDMS have been merely by air plasma.Furthermore,CdTe@ZnS QDs was as ECL luminophore for detecting H2O2 in the range of 1.0×10-5-4.0× 10-9 M.The limit of detection was 5.0×10-10 M.(2)Bipolar electrochemiluminescense sensing platform based on pencil core and paper reservoirsA closed bipolar electrochemiluminescene(ECL)sensing platform based on commercial pencil cores and paper reservoirs has been developed.A pencil core functions as bipolar electrode.Its two poles are placed in two separate paper reservoirs called sensing cell and reporting cell,respectively.The Ru[(bpy)3]2+/(NH4)2C2O4 was used as ECL system.On the principle of electric neutrality,the bipolar ECL has been successfully used for the measurement of Fe(CN)63-ions as models.Furthermore,platinum nanoparticles have been electroplated onto the bipolar electrode cathode to electro-catalyze the reduction of H2O2,which realize ECL signal amplification to detect H2O2 at lower potential.This work shows a new way toward the development of simple,low cost,portable and disposable bipolar ECL analytical device.(3)A Novel Switch Strategy to Fabricate the electrochemiluminescence chip for detecting Cancer BiomarkersA novel switch electrochemiluminescence chip was fabricated for the detection of carcinoembryonic antigen(CEA)based on a closed circular bipolar electrodes(BPE)array.The traditional sandwich-type immunosensors were designed as the sensing cells of the BPE array and Ru(bpy)32+/(NH4)2C2O4 was used as ECL system in the reporting cells.The CEA primary antibody(Ab1)was immobilized onto theamination of indium tin oxide(ITO)via cross-linking withglutaraldehyde(GA).The Pd-Pt bimetallic nanocrystals linked with secondary-antibody(Ab2)labels were synthesized to realize signal amplification which could catalyze hydrogen peroxide(H2O2).Introducing a switch into the BPEs array-ECL system made the multiplex detection of cancer biomarkers come true and provided a controllable,simple method for testing.Therefore,this design strategy demonstrated that this ECL platform enables sensitive detection with excellent operability,good reproducibility,good selectivity and acceptable stability.