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 VA mM(-1) cm(-2), as well as good long-term stability and reproducibility. These performances could be ascribed to the GNPs-MPS's features, such as excellent conductivity, large surface area and good biocompatibility. (c) 2006 Elsevier B.V. All rights reserved.