Studies On Amperometric Biosensor Based On Ag, Zn And Cu Nano/Micro Hollow Spheres

With development of nanotechnology and biosensor, using nanomaterials in the study of biosensor is the inevitable trend. Biosensors based on nanomaterials play an important role in the information, materials, energy, environment, agriculture, biology and other fields due to their unique properties.As the diversity of nanomaterials, different structures determine their different practical applications. The hollow nanospheres can be widely used because they have light density and large specific surface area. And hollow nanospheres of metal compound have been well-studied in electrochemistry because they have good catalytic activity and electrical conductivity. Light density increse their stability when fixed on the electrode surface; the large specific surface area can make them adsorb more biological protein molecules; good catalytic performance can synergeticly catalyse with the protein molecule to improve sensitivity and the detection range of the biosensor; and excellent electrical conductivity is good for electron transfer. Therefore, the hollow nanospheres electrochemical biosensors based on metal/metal compounds have great research value. The details are summarized as follows:1. Pseudo-bi-enzyme glucose sensor:ZnS hollow spheres and glucose oxidase concerted catalysis glucoseThis work creatively uses ZnS hollow spheres (ZnS HSs) as peroxidase-like to cooperate with glucose oxidase (GOx) for glucose determinations. This approach is that the ZnS HSs electrocatalytic oxidate enzymatically generated H2O2to O2, and then the O2circularly participate in previous glucose oxidation by glucose oxidase. Au nanoparticles (AuNPs) and Carbon nanotube (CNT) are used as electron transfer and enzyme immobilization matrices, respectively. The biosensor of glucose oxidase/carbon nanotube/Au nanoparticle/ZnS hollow spheres/gold electrode (GOx/CNT/AuNPs/ZnS HSs/GE) exhibits a rapid response, a low detection limit (10μM), a wide linear range (20μM to7mM), as well as good anti-interference, long-term longevity and reproducibility.2. Non-enzymatic electrochemical hydrogen peroxide sensor based on copper oxide hollow microspheresA new type of non-enzymatic amperometric hydrogen peroxide sensor was fabricated by fastening copper oxide hollow microspheres (CuO HMS) on gold electrode. The copper oxide hollow microspheres (CuO HMS) were characterized by transmission electron microscopy (TEM).The response of the modified electrode towards hydrogen peroxide under neutral conditions was investigated by cyclic voltammetry (CV) and chronoamperometry. The results revealed that it has high electrocatalytic activity, with a linear range from1μM to4000μM and a detection limit of0.3μM(S/N=3). The modified electrode was equipped with long-term stability, excellent repeatability and high sensitivity.3. Direct electrochemistry of hydrogen peroxide biosensor based on electro-codeposition of hemoglobin entrapped in silver nano particles and sodium alginate composite filmWe assembled the silver nanoparticles, sodium alginate and hemoglobin in a certain proportion to the electrode surface in order to constructe the hydrogen peroxide sensor with superior performance. Electrochemical performance of the sensor was studied by the cyclic voltammetry (CV) and chronoamperometry. The sensor exhibited good amperometric response to the reduction of hydrogen peroxide with linear range fiom3×10-5mol L-1to1.2×10-3mol L-1, and detection limit of8×10-6mol L-1.