| Conducting polymer also known as conducting macromolecule materials, the kind of good conductive polymer was prepared by composite or doping method. In conducting polymer, polypyrrole（PPy） has been widely applied in the construction of electrochemical sensor, due to the excellent electrical conductivity, membranous property, stability and excellent biocompatibility. Compared with the traditional analysis methods, the electrochemical sensor owns many advantages including simple operation, low cost, non-toxic environmental protection, low detection limit, high sensitivity and so on. Based on this, the study has designed two kinds of sensors on conductive polymer PPy. One kind is immunosensor, which is based on carboxyl functional surfaces of PPy. The other kind is biosensor, which is based on the electrochemical catalytic activity of alloy PPy. The detail research contents are as follows:1. In situ polymerization of carboxylate polypyrrole on the surface of Multi-walled carbon nanotubes for the construction and application of SAA immunosensorThis study chose ion liquid solution（IL）, chitosan（Chit） and multi-walled carbon nanotubes（MWCNTS） as the matrix materials of the electrode. It not only increases obviously the conductivity of electrochemical sensor, but also could prevent the aggregation of MWCNTS. Subsequently, we conducted the cyclic voltammetry（CVs） method to in situ polymerizate pyrrole on the surface of MWCNTS. Conducting the method of CVs polymerization could control the thickness of PPy and avoid membrane coarse. In order to immobilize antibody on the surface of membrane successfully, we conducted the balance voltage method to polymerizate carboxylate pyrrole. It could make PPy of surface functionalization with lots of carboxylic functional groups, due to the carboxyl and amino amido reaction, fixed successfully human serum amyloid A（SAA） antibody. A series of changes were characterized by sanning electron microscopy（SEM） after PPy modified on the surface of MWCNTS. Besides, we proved the carboxyl groups modified on the PPy successfully by Fourier transform infrared spectra（FTIR）. Under the optimal detection conditions, our prepared immunosensor exhibited a good linear response to SAA in the 0.001 ng mL-1 to 900 ng mL-1 and a lower detection limit of 0.3 ng mL-1（S/N = 3）. Besides, assay results of real human serum samples were compared with traditional enzyme linked immunosorbent assay（ELISA）. The result was found that there was no significant difference, indicated that the research could provide convenience for rapid and sensitive detection of inflammatory markers in clinical application.2. Fabrication of the electrochemical sensor based on bimetallic polypyrrole/GOx and application for the detection of sialic acid glycosylations in human serumAuPt-PPy nanocomposite, synthesized through sequential reduction by utilizing pyrrole monomer as a reducting agent. The nanocomposite owns higher conductivity and film forming property. And it shows also higher electrocatalytic activity toward H2O2 reduction due to the existence of AuPt bimetallic. Subsequently, to increase the electrochemical signal, GOx was employed instead of the usual sealers – bovine serum albuim（BSA）. More importantly, in the presence of glucose, these localized GOx further enhanced the electrochemical signal, which was achieved by the efficient catalysis of glucose. In terms of detection targets, we chose Sambucus nigra agglutinis（SNA） as an excellent candidat in the bioesneor fabrication, due to its highly specific binding affinity with α2,6-sialylated glycans. According to the specific recognition, α2,6-sialylated glycans in the serum samples could be determined. The whole test system was accomplished in phosphate buffer solution（PBS）. The electrochemical measurements were performed by adding PBS solution containing H2O2 and glucose. Under the optimal detection conditions, our prepared biosensor exhibited a good linear response to SAA in the 0.01 pg mL-1 to 800 ng mL-1 with a low detection limit of 0.003 pg mL-1（S/N=3）. The biosensor may have potential application for the rapid and sensitive detection of α2,6-sialylated glycans in the clinical work. |
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