Synthesis, Characterization, And Biosensing Application Of Nanomaterials

Nanomaterials have offered a good platform for the development of electrochemical biosensors. Now, the performance of biosensors has greatly improved through using nanomaterials because nanomaterials possess unique physical and chemical properties. for example, these biosensors based on nanomaterials have high sensitivity, fast response, wide linear range, well selectivity and high stability. The major results of the thesis are as follows:1. Nanoplated bismuth titanate sub-microspheres (NBTSMs) were for the first time synthesized by a facile hydrothermal synthesis strategy. The NBTSMs were employed as a supporting matrix to explore a novel immobilization and biosensing platform of redox proteins through a combined hydrogen bond and electrostatic assembly process. The NBTSMs-based composite film has good biocompabiliity, direct electron transfer capacity, and good electrocatalytic properties such as wide linear range (2-430μM), low detection limit (0.46μM), low Michaelis-Menten constant (204μM), and good stability and reproducibility.2. ZnO/SnO₂ Composite nanomaterials were prepared with SnO₂ nanorods as the template via a secondary growth methode. A completely new biosensor composed of ZnO/SnO₂ composite nanomaterials, chitosan, and hemoglobin was fabricated. The ZnO/SnO₂-based composite film has good biocompabiliity, direct electron transfer capacity, and good electrocatalytic properties such as wide linear range (2-370μM), low detection limit (0.57μM), and good stability and reproducibility.3. A new biosensor composed of cube-shaped AucoreCo₃O_4shell nanoparticles, polyacrylic acid (PAA), and horseradish peroxidase (HRP) was fabricated. The biocompatibility and electrochemical properties of the resulting AucoreCo₃O_4shell-PAA-HRP composite film were studied by UV-visible spectroscopy, electrochemical impedance spectroscopy, and cyclic voltammetry. The immobilized HRP shows a pair of quasi-reversible redox peaks at -0.31 V in 20 mM PBS (pH 7.0), and the biosensor shows a fast amperometric response to hydrogen peroxide with a linear range of 2-370μM. The kinetic parameters such as ks (electron transfer rate constant) and KM (Michaelis–Menten constant) are evaluated to be about 7.4 s^-1 and 0.91 mM, respectively.