Amperometric biosensor based on glucose dehydrogenase and plasma-polymerized thin films.

A novel design is described for an amperometric biosensor based on NAD(P)-dependent glucose dehydrogenase (GDH) combined with a plasma-polymerized thin film (PPF). The GDH is sandwiched between several nanometer thick acetonitrile PPFs on a sputtered gold electrode (PPF/GDH/PPF/Au). The lower PPF layer plays the role as an interface between enzyme and electrode because it is extremely thin, adheres well to the substrate (electrode), has a flat surface and a highly-crosslinked network structure, and is hydrophilic in nature. The upper PPF layer (overcoating) was directly deposited on immobilized GDH. The optimized amperometric biosensor characteristics covered 2.5-26 mM glucose concentration at +0.6 V of applied potential; the least-squares slope was 320 nA mM(-1) cm(-2) and the correlation coefficient was 0.990. Unlike conventional wet-chemical processes that are incompatible with mass production techniques, this dry-chemistry procedure has great potential for enabling high-throughput production of bioelectronic devices.