Gold nanoparticles-mesoporous silica composite used as an enzyme immobilization matrix for amperometric glucose biosensor construction

Gold nanoparticles-mesoporous silica composite (GNPs-MPS) is developed as a novel enzyme immobilization matrix for biosensor construction. The mesoporous silica SBA-15 is chosen and the GNPs-SBA-15 is formed from AuCl4− adsorbed H2N-SBA-15 by NaBH4 reduction. The synthesis process of the composite is monitored by UV–vis spectroscopy and the product is characterized by transmission electron microscopy (TEM) measurement. An amperometric glucose biosensor is built by immobilizing IO4−-oxidized-glucose oxidase (IO4−-oxidized-GOD) on GNPs-MPS modified Au electrode using 2-aminoethanethiol as a cross-linker. Cyclic voltammetry (CV) and amperometry are employed to investigate the catalytic behavior of the biosensor to the oxidation of glucose. As a result, the biosensor exhibits an excellent bioelectrocatalytic response to glucose with a fast response time less than 7 s, a broad linear range of 0.02–14 mM, high sensitivity of 6.1 μA mM−1 cm−2, as well as good long-term stability and reproducibility. These performances could be ascribed to the GNPs-MPSʹs features, such as excellent conductivity, large surface area and good biocompatibility.