Thin-film glucose biosensor based on plasma-polymerized film: simple design for mass production

We propose a simple thin-film glucose biosensor based on a plasma-polymerized film. The film is deposited directly onto the substrate under dry conditions. The resulting films are extreme thin, adhere well onto the substrate (electrode), and have a highly cross-linked network structure and functional groups, such as amino groups, which enable a large amount of enzyme to be immobilized. Since this design allows fabrication through a dry process, with the exception of the enzyme immobilization, which is the last stage of the process, the chip fabrication can be designed as a full-wafer process to achieve mass production compatibility. The resulting sensors produced using this film are more reproducible, exhibit lower noise, and reduce the effect of interference to a greater degree than sensors made using conventional immobilization methods, e.g., via 3-(aminopropyl)triethoxysilane. The obtained film is a good interfacial design between enzyme and electrode; enzyme two-dimensionally locates very close to the electrode in a manner that is quite reproducible. Therefore, a wide dynamic range (up to 60 mM) and rapid response time (11.5+/-0.8 s) were obtained. Because of its highly cross-linking network structure, the amperometric response due to interferences such as ascorbic acid and acetaminophen was reduced by size discrimination of plasma-polymerized films.