Amperometric Biosensor: Increased Sensitivity Using Enzyme Nanoparticles

Here we present a comparative study of amperometric biosensor developed by using nanoparticles of Glucose oxidase enzyme-itself (GOx up) with that of enzyme immobilized on to gold nanoparticles (Au np-GOx). The biosensor developed by immobilizing the GOx np (45-70 nm in size) directly onto the Pt. electrode could detect glucose concentrations as low as 1 mM while the one with Au np-GOx (Au up 10-16 nm in size) showed a detection limit up to 5 mM only. Current response showed linearity up to 35 mM in both the cases. To the best of our knowledge the glucose biosensors prepared using various metal nanoparticles, Au, Ni, Ag (as reported in literature) showed a linear range from 2.7-30 mM glucose concentration. We are in the process of optimizing the immobilization methods and functionalization of the enzyme nanoparticles so as to have a wider temperature and pH stability of the biosensor. We feel the direct immobilization of enzyme nanoparticles, with proper choice of functionalization seems to be a promising strategy for biosensor development with higher sensitivities.