Amperometric glucose biosensor based on direct assembly of Prussian blue film with ionic liquid-chitosan matrix assisted enzyme immobilization

A facile fabrication procedure was developed for the construction of glucose biosensor. Prussian blue (PB) was modified on the electrode through simple direct assembly process. The ionic liquid (IL) assisted chitosan (Chi) matrix was used for the glucose oxidase (GOx) immobilization on the PB electrode. Cyclic voltammetry (CV), chronoamperometry and electrochemical impedance spectroscopy (EIS) were used to evaluate the performance of the prepared GOx/Chi/IL/PB/Pt biosensor. The presence of IL (1-butyl-3-methylimidazolium tetrafluoroborate, [bmim]BF4) can effectively enhance the electron transfer rate and reduce the interfacial resistance. This biosensor exhibited a fast response time within 3 s, a linear range up from 0.01 to 4.2 mM, low detection limit of 5 μM and a sensitivity of 37.8 μA mM−1 cm−2. Because of the biocompatibility of the IL-Chi composite matrix, the biosensor exhibited satisfactory storage stability over 40 days with retention of 90.4% activity. Additionally, the biosensor exhibited good selectivity which was attributed to the low operating potential employed (−0.05 V vs. Ag/AgCl).