Comparative study of protective membranes for glucose biosensors based on electrodeposited hydrotalcites

The majority of the amperometric glucose biosensors employs stabilization membranes to prevent enzyme release and to improve selectivity. Here, we describe a comparative study between some of the most common membranes and two more innovative systems based on titania and Pd hexacyanoferrate hydrogels. The study has been carried out on electrodes modified by a Ni/Al hydrotalcite electrochemically deposited on Pt surfaces together with the enzyme glucose oxidase. The effect of the different membranes on the selectivity, stability and sensitivity of the biosensors has been described and the best ones have been successfully applied to the analysis of real matrices. To further improve biosensor selectivity a pre-oxidizing enzyme membrane containing also horseradish peroxidase was employed.