Amperometric Glucose Biosensor Based on Layer-by-layer Covalent Attachment of ASNPs and GOx

A feasible approach to construct multilayer films of aminated silica nanoparticles/glucose oxidase (ASNPs/GOx) on the Au electrode surface using a glutaraldehyde as a covalent attachment cross-linker is described. The gold electrodes modified with the ASNPs/GOx multilayer films were studied by cyclic voltammetry (CV) and showed excellent electrocatalytical response to the oxidation of glucose when ferrocenemethanol was used as an artificial redox mediator. The linear response range of the biosensor constructed with four bilayers of ASNPs/GOx to the concentration of glucose can extend at least to 8 mM and reached 95% of the steady-state current in less than 4 s with the sensitivity of 5.11 mA/mM cm(2) and the detection limit of 9 mM.