Amperometric L-lactate sensor based on sol-gel processing of an enzyme-linked silicon alkoxide.

A novel organically modified silica material has been prepared by covalent linking of the carboxylic acid group of lactate dehydrogenase to the amino group of an organoalkoxysilane precursor via a carbodiimide coupling reaction during the sol-gel process. The material was used to fabricate a leak-free biosensor. The experimental variables and characteristics of the biosensors were studied by electrochemical methods. Results showed that the coenzyme concentration, mediator concentration, and electrode rotation speed will influence the sensitivity of the biosensor. The biosensors exhibited high sensitivity (1.47 microA/mM), low detection limit (1.5 microM), reasonable apparent activity (1.31 min(-1)), good fabrication reproducibility, and good long-term operational stability (approximately 1 week).