Preparation Of Conducting Polymer Composites And Their Applucation In Biochenmical Analysis

The electrochemical method and chemical oxidation method were used toprepare the modified electrode of conductive polymer composite.Based on these conductive polymer composites,we constructed several different electrochemical biosensors.Byscanningelectronmicroscope,photoelectronspectroscopy,electrochemical impedance and differential pulse voltammetry methods for these nanowires composite microstructure,element composition,electrochemical performance and the sensing ability have been characterized.We hope these new biosensor platforms will provide more ideas for the development of new conductive polymer composites.The main work of this subject is summarized as follows:(1)electrochemical deposition was carried out by electrochemical cyclic voltammetry,and the modified electrode of peptide-PEDOT was prepared.BRCA1 is a gene that related to hereditary breast cancer.Monitoring of this gene could be regarded as monitoring of early breast cancer.In this paper,a novel electrode substratecompositehasbeenconstructedbyelectropolymerizationof poly(3,4-ethylene dioxythiophene)(PEDOT)and peptide.PEDOT is a superb material with excellent electrical conductivity,highly environmental stability,and highly mechanical properties.Combined with the biocompatibility of peptide,an electrochemical biosensor for sensitive detection of BRCA1 was constructed and has good specificity.The range of detection is 1 fM-100 pM and the limit of detection is0.35 fM.(2)we utilized graphene oxide and ferric chloride and synthesised GO-PB compounds,then GO-PB/PEDOT compounds were prepared by electrochemical deposition with cyclic voltammetry.The introduction of carboxyl groups on the surface of graphene oxide were used to modify amino DNA probe.Prussian blue is used to produce electrochemical signals.This material had a good electrical conductivity,possessed active group and its own electrichemical signal.Then the DNA probe with amino is modified to the electrode,and it is applied to the DNA biosensor through the specific recognition between the target DNA and the probe DNA.The constructed sensor has a good specificity for the target DNA,and the detection range is 1 fM-1 nM,and the detection limit is 0.343 fM.(3)in this work,we synthesised PPy-PEG conducting polymer hydrogels by chemical oxidation with the use of good biocompatibility polypyrrole(PPy)and carboxyl modified polyethylene glycol(PEG).PEG is used as a supporting polymer to form hydrogel by chemical bonding.The PPy-PEG hydrogels that we obtained owned good conductive and good biological affinity followed by PPy and PEG.Then,we coated PPy-PEG hydrogels on GCE surfaces to couple amino modified DNA probe,obtained a modified electrodes to recognize specific DNA sequences.Under the best experimental conditions,the detection response range of the prepared sensor to the target DNA was 10~-1212 M-10~-77 M,and the detection limit was 3.25�10~-1313 M.