Construction of Amperometric Glucose Biosensor based on In-situ Fabricated Hierarchical Mesomacroporous SiO2 Modified Au Film Electrodes

Gold nanoparticles（GNPs） modified hierarchical meso-macroporous（HMMP） SiO2 layer on the surface of Au film electrode was developed as a novel enzyme immobilization matrix for biosensors construction.HMMP SiO2-Au bilayer film electrodes were in-situ fabricated with magnetron sputtering process and templating method.The as-prepared HMMP SiO2 films were characterized by SEM,TEM,and cyclic voltammetry（CV）.The modified layer of HMMP SiO2 has interconnected pore channels,and the sizes of macropores and mesopores are about 330 nm and 9 nm,respectively.The HMMP SiO2 modified gold film electrodes not only have no diffusion barrier for electrochemical probes,but also exhibit good electrochemical properties.In addition,the activity and stability of the immobilized enzyme can be commendably retained in HMMP SiO2.The biosensor exhibits an excellent bioelectrocatalytic response to glucose with a linear range of 1.0×10-4M-1.0×10-2M,high sensitivity of 18.0 μA·m M-1·cm-2,as well as good reproducibility and stability.

Synthesis of core-shell structured Au@Bi2S3 nanorod and its application as DNA immobilization matrix for electrochemical biosensor construction

The core-shell structured Au@Bi2S3 nanorods have been prepared through direct in-situ growth of Bi2S3 at the surface of pre-synthesized gold nanorods.The product was characterized by X-ray diffraction,transmission electron microscopy and energy-dispersive X-ray spectroscopy.Then the obtained Au@Bi2S3 nanorods were coated onto glassy carbon electrode to act as a scaffold for fabrication of electrochemical DNA biosensor on the basis of the coordination of-NH2 modified on 5’-end of probe DNA and Au@Bi2S3.Electrochemical characterization assays demonstrate that the Au@Bi2S3 nanorods behave as an excellent electronic transport channel to promote the electron transfer kinetics and increase the effective surface area by their nanosize effect.The hybridization experiments reveal that the Au@Bi2S3 matrix-based DNA biosensor is capable of recognizing complementary DNA over a wide concentration ranging from 10 fmol/L to 1 nmol/L.The limit of detection was estimated to be 2 fmol/L(S/N=3).The biosensor also presents remarkable selectivity to distinguish fully complementa ry sequences from basemismatched and non-complementary ones,showing great promising in practical application.