Electrochemistry And Electrochemiluminescence Array Detection Chip

Nowadays,in order to integrate the functions of various devices in the analysis lab together as much as possible,improve the sensitivity of detection,achieve rapid and high-throughput detection,meet the demands of real-time analysis,and also lower the sample consumption and analytical cost,the miniaturization,integration and portability of the analysis equipment is becoming an important trend in the development of current analytical science.Therefore,microchip including microarray(biological)chip and microfluidic chip,which combines microelectronics,analytical chemistry,biological chemistry,material chemistry,medicine,and many other disciplines together,complies with the time development tidal current,and has become an important tool in the analysis field.Electrochemical analysis,as an important means of testing,has become an important detection tool of microchip due to its simple,easy to miniaturization and integration.People have paid more and more attention to this important field.This thesis mainly involved the construction of new-style array chips,the studies of the electrochemical mechanism for bipolar system on the chip,and their application for electrochemical or electrochemiluminescence sensing.1.A microarray chip based electrochemical platform:towards high-throughput detectionHere a novel microarray chip based electrochemical platform towards high-throughput detection is presented.This microarray chip is made of three layers of materials,a polydimethylsiloxane(PDMS)as the top layer with 8x5 well-organized oval holes(O-hole,each less than 100 uL),a PDMS sandwich film owning 8×5 pairs of small circular holes(SC-hole,two SC-holes for each pair in one O-hole)and an indium-tin-oxide(ITO)-coated aluminosilicate glass substrate.8x5 ordered arranged cells with a pair of ITO disc electrodes in each cell served as working electrodes were formed on the chip.8 home-made Pt-Ag/AgCl coaxial electrodes were fabricated and inserted in the 8 cells on the array chip separately,where Pt on the coaxial electrodes is used for counter electrode while Ag/AgCl for reference electrode.Then 8 groups of three-electrode detection system would be made up.Each ITO electrode with two separated ITO discs could assemble different materials.Carboxyl graphene nanosheets-methylene blue(CGS-MB)and carboxyl graphene nanosheets-Prussian blue(CGS-PB)nanocomposites with excellent electrochemical activity selected as redox indicators were coated on the two discs,respectively.Two kinds of antibodies(anti-carcinoembryonic(anti-CEA)and anti-a-fetoprotein(anti-AFP)),as model biological samples,were linked to the above nanocomposites,separately.Then the two kinds of antigens(carcinoembryonic antigen(CEA)and a-fetoprotein(AFP))were detected based on the increasing spatial blocking and impedance from the formed immunocomplex.8 group of analytes with various concentrations were detected simultaneously and only 5 times were needed to detect the whole 40 samples on the chip.The chip platform not only took full advantage of the tractable sandwich PDMS film upon the ITO glass on the chip to form working electrodes we wanted,but also masterly used the mobile and reusable Pt-Ag/AgCl electrodes to form a universal high-through detection system.2.An ITO bipolar array for electrochemiluminescence imaging of H2O2 A closed ITO bipolar system with 8 multipled bipolar electrodes(BPEs)was constructed.The potentials on the BPE poles would be changed as the variation of the applied voltage.Silver nanoparticle reduced graphene oxide(AgNP-rGO)composites were simultaneously coated on the cathodes of the BPE array via a one-step electrodeposition approach.Compared to naked ITO,the above composites exhibited notable electrocatalytic activity to H2O2.The concentration of H2O2 on the cathodic poles of the BPE array could be indicated by the ECL image of Ru(bpy)32+/2-(dibutylamino)ethanol(DBAE)at anodes based on charge balance.This bipolar system,provided a manner to electrodeposite nanocomposites on bipolar electrodes,avoided the disturb between the analytes and ECL reported reagents and realized high-throughput visual detection.3.Studies of Electrochemical Behaviors at Closed Bipolar cellIn this work,a novel closed bipolar cell including a bipolar electrode(BPE)and its three-electrode control system was successfully constructed and its electrochemical behaviors were studied.The schematic circuit diagram was shown in scheme 3.It acts as a series of cell 1 and cell 2.The redox potential of species on pole 2 is directly related to the reactions in cell 1.The impacts of reaction reagents,electrodes' materials and control models on the electrochemical behaviors of the bipolar cell were investigated in details.When reversible redox couple existed in cell 1 and same material was used as electrode 1 and pole 1,the electrochemical information of the pole 2 could be got directly due to the negligible potential difference in cell 1.The reason of the potential drift in the bipolar cell was stated from the perspective of the superposition of potentials.The optimized driving voltage in the application of electrochemiluminescence(ECL)sensing were described in the light of electrochemistry.This research could really deepen the understanding of the bipolar electrochemistry,and expand its application.4.High-throughput electrodeposition and visual screening of nanocatalyst candidates with a closed bipolar electrode array chipA closed bipolar array chip was fabricated by chip fabrication technique.Catalyst candidates bimetallic PtAu-reduced graphene oxide(PtAu-rGO)nanocatalysts in varying metal proportions were properly electrodeposited on the cathodic poles of the BPE array,simultaneously,whose operating conditions were just like that in traditional three-electrode system.Afterward,high-throughput screening of the nanocatalyst candidates was carried out by the above electrodeposited bipolar array system based on charge balance and ECL imaging on the anodic poles.