Study Of Chemical Sensors And Biosensors Based Modified One-Dimensional Nanomaterials

The fabrication and properties of chemical sensors and biosensors based modified one-dimensional nanomaterials have been studied in this doctorial dissertation. The main results can be concluded as follows:First, the functionalized SiNWs, chemically modified with Au nanoparticles, and with amino-terminated organic molecules anchored on the surface of the nanoparticles, were fabricated into the electrochemical biosensors for glutathione (GSH). The biosensor showed good linear response to GSH of low concentration (0.33-2.97μM), high sensitivity (48.5 mA.mmol-1), and a low limit of detection (0.33μM, measured) by virtue of strong sorption ability and high electrical conductivity of the modified SiNWs based electrode.Second, the dispersion of silicon nanowires in Nafion toward the fabrication of amperometric biosensors for glucose was studied. We demonstrated a convenient method of the dispersion of SiNWs in solvent in virtue of the interaction between Nafion and the surface of SiNWs. The dispersion of the HF-etched SiNWs and Au nanoparticles modified SiNWs exhibited homogeneous and long time steady properties. Moreover, the Au nanoparticles modified SiNWs could be used to modify the enzyme-electrode as the biosensors for glucose sensing, which proved to have an effect of enhancement for the detection of glucose. The present method of the dispersion of the SiNWs and the modification of electrode could be extended to the construction of the one-dimensional nanostructures based nanodevices.Third, the direct electrochemical biosensor for cytochrome c based on the silicon nanowire arrays was fabricated. The silicon nanowire arrays were prepared from the etched silicon wafer, which were then treated with nitrohydrochloric acid and HF to remove the cladding silicon oxide sheath. The modified silicon nanowire arrays were further used as the electrode for fabricating the direct electrochemical biosensors for the detection of cytochrome c, which exhibited linear response to cytochrome c at low concentration and high sensitivity of 2.75μA.mM-1 due to the vast surface-to-bulk ratio of the silicon nanowire arrays and the interaction between the carboxyl group of cytochrome and Si-H group provided by the surface of the modified silicon nanowire arrays.Fourth, an amperometric biosensor based on enzyme-modified ZnO nanotube arrays for the sensitive detection of glucose was demonstrated. The ZnO nanotube arrays based electrode exhibited high sensitivity of 30.85μA cm-2 mM-1 , wide linear detection range from 10μM to 4.2 mM and the low limit of detection (LOD) of 10μM (measured) for the glucose detection, which benefited from the coupling of the vast surface-to-bulk ratio and the uniquely tubular morphology with the good contact between the substrate electrode (ITO-coated glass) and ZnO nanotube arrays. The fabrication methodology of the present biosensor could be extended to other biosensors based oxidase, such as those for detection of acetylcholine, cholesterol, phenol, etc.