Amperometric biosensor based on multilayer containing carbon nanotube, plasma-polymerized film, electron transfer mediator phenothiazine, and glucose dehydrogenase.

We report on a novel fabrication approach of amperometric biosensor based on multilayer films containing carbon nanotubes (CNT), a nano-thin plasma-polymerized film (PPF), electron transfer mediator phenothiazine (PT), and enzyme glucose dehydrogenase (GDH). The configuration of the electrochemical electrode is sequentially composed of sputtered gold, acetonitrile PPF, PT, GDH, and acetonitrile PPF (denoted as PPF/GDH/PT/CNT/PPF/Au). First PPF deposited on Au acts as a permselective membrane and as a scaffold for CNT layer formation. Second PPF directly deposited on GDH acts as a matrix for enzyme immobilization. To facilitate the electrochemical communication between the CNT layer and GDH, CNT was treated with nitrogen plasma. The electron transfer mediator PT plays a role as the mediator in which the electron caused by enzymatic reaction transports to the electrode. The synergy between the mediator and CNT provides benefits in terms of lowering the operational potential and enhancing the sensitivity (current). The optimized glucose biosensor revealed a sensitivity of 5.1 ± 0.9 μA mM(-1) cm(-2) at + 0.2V vs. Ag/AgCl, linear dynamic range of 4.9-19 mM, and a response time of 5 ± 1 s. 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. Furthermore, those devices can be applied and expands for the cell biological functional field as a useful, helpful, or indispensable tool.