Study Of Biosensors Based On Inorganic Nano-composite Materials And Organic Thin-film Materials

Biosensor is an essential part of biotechnology and attracts so much attention from the researchers for a long time. Electrochemical biosensor and organic field effect transistor based biosensor are two kinds of the most typical biosensing devices, both of them have the advantages like fast detecting speed, high sensitivity, easy for operating and wide application range. Besides, the development of the functional nano-composite materials and organic materials bring new opportunities and challenges for this area. Thus, in this work we studied the application of inorganic nona-composite materials in electrochemical biosensors and designed an organic field effect transistor based biosensor. The main results are as follow:1. Systemically amount-controlled Ag nanoparticles coated NiO nanowires(diameter~130 nm) were fabricated by using a facile electrospinning techniquetogether with seed-mediated growth procedure. The biosensing properties towardglucose of the Ag coated Ni O NWs based on glass carbon electrode werecarefully studied. The liner range is 0-1.28 m M and the results indicated that thebiosensing properties of Ni O nanowires were significantly improved by thecoating of Ag NPs.2. Graphene oxide based Cu O nanoparticles composites with different Cu O NPs loading amount were synthesized using a hydrothermal method. The influence of hydrothermal temperature, GO sheet, and loading amount of Cu O naonparticle size and structure of Cu O was systemically investigated. The nonenzymatic biosensing properties of Cu O/GO composites and Cu O NPs toward glucose were studied based on glass carbon electrode. The detection limit is 0.69μM. Besides, it also showed outstanding long term stability, good reproducibility, excellent selectivity and accurate measurement in real serum sample. It is believed that Cu O/GO composites show good promise for further application on nonenzymatic glucose biosensors.3. A series of Au nanoparticles and graphene oxide sheets composites were successfully synthesized by reduction of gold(III) using sodium citrate. Then the Au NP/GO composites were used to construct nonenzymatic electrodes for the detection of ascorbic acid(AA) in human sera and pharmaceuticals, the errer ranges were all no more than 10%. The detection limit is 100 n M/m L.4. We describe a sensitive organic thin film transistor(TFT) sensor platform for real time detection of low concentration protein analytes in solution. Using glial fibrillary acidic protein(GFAP) as a model protein analyte, this sensor platform demonstrated significant sensitivity and the detection limit is 4ng/m L. Considering about the penetration of aqueous analyte solutions into organic semiconductors, we introduced the concept of a remote floating gate influencing the current of OFET, with the analyte solution capacitively coupled to the floating gate but not chemically associated with the organic semiconductor.