Simple construction of an enzymatic glucose biosensor based on a nanocomposite film prepared in one step from iron oxide, gold nanoparticles, and chitosan

The one-step synthesis is reported of a nanofilm composed of iron oxide and gold nanoparticles in a chitosan matrix that can act as a novel matrix for the immobilization of glucose oxidase (GOx) to fabricate a glucose biosensor. The use for the composite film strongly increased the effective electrode surface for loading of GOx. The size and shape of the iron oxide nanoparticles were examined by transmission electron micrograph. Direct electron transfer and electrocatalysis by GOx was investigated via cyclic voltammetry and chronoamperometry. Under optimized conditions, the biosensor has a response time of 6 s and a linear response in the range between 3 mu M and 0.57 mM of glucose, with a detection limit of 1.2 mu M at a signal-to-noise ratio of 3. This novel and disposable mediatorless glucose biosensor may form the basis for a future mass-produced glucose biosensor.