A novel stable amperometric glucose biosensor based on the adsorption of glucose oxidase on poly(methyl methacrylate)–bovine serum albumin core–shell nanoparticles

A novel amperometric glucose sensor was constructed by immobilizing glucose oxidase (GOx) on poly(methyl methacrylate)–bovine serum albumin (PMMA–BSA) core–shell nanoparticles. The large surface area of these nanoparticles resulted in a high enzyme loading. The BSA protein shell provided biocompatible microenvironment to retain the native structure and bioactivity of the immobilized enzymes. Such biosensors were characterized by both cyclic voltammetry and chronoamperometry. The effects of the working potential, the amount of the immobilized enzymes and the operating pH on the response of the glucose sensor were investigated. Under an optimal preparation condition, the resultant biosensor had a short response time of less than 8 s, a sensitivity of 44.1 μA mM−1 cm−2, and a wide linear range from 0.2 to 9.1 mM with a correlation coefficient of 0.997. More important, such biosensors were thermally stable at room temperature (∼25 °C); which means there was nearly no change in their performance even after they were operated in pH 7.4 phosphate buffer solution for 23 days. The biosensor can be used directly to determine glucose in serum sample. The results show that PMMA–BSA nanoparticles provide a promising material for fabricating enzyme based amperometric biosensors.