Glucose biosensor based on nano-SiO2 and "unprotected" Pt nanoclusters.

The "unprotected" Pt nanoclusters (average size 2 nm) mixed with the nanoscale SiO(2) particles (average size 13 nm) were used as a glucose oxidase immobilization carrier to fabricate the amperometric glucose biosensor. The bioactivity of glucose oxidase (GOx) immobilized on the composite was maintained and the as-prepared biosensor demonstrated high sensitivity (3.85 microA mM(-1)) and good stability in glucose solution. The Pt-SiO(2) biosensor showed a detection limit of 1.5 microM with a linear range from 0.27 to 4.08 mM. In addition, the biosensor can be operated under wide pH range (pH 4.9-7.5) without great changes in its sensitivity. Cyclic voltammetry measurements showed a mixed controlled electrode reaction.