New amperometric glucose biosensor based on cross-linking of glucose oxidase on silica gel/multiwalled carbon nanotubes/polyacrylonitrile nanocomposite film

A new amperometric glucose biosensor was formed by cross-linking glucose oxidase (GOD) on nanocomposite material prepared by entrapping silica gel (SG) and multiwalled carbon nanotubes (MWNTs) in polyacrylonitrile (PAN) film. The optimal conditions for nanocomposite matrix preparation were studied. The influence of the amount of silica gel, MWNTs and enzyme concentration on the biosensor performance was examined. Silica gel/MWNT/PAN/GOD has linear range for the detection of glucose from 5 μM to 2 mM (a correlation coefficient of 0.999) with 16 s response time. The sensitivity of the biosensor was found to be 16.5 μA/mM. Moreover, its experimental detection limit is 1 μM (S/N = 3) and the apparent Michaelis–Menten constant was calculated to be 13.9 mM. The ascorbic acid interference and long-term stability of the biosensor are also assessed. All the results show that Silica gel/MWNT/PAN can provide a promising material for the biosensor designs for glucose detection.