Abstract
A direct electron transfer-type glucose sensor was constructed using a bacterial membrane-bound thermostable periplasmic glucose dehydrogenase complex (FADGDH), which was composed of a FAD-containing catalytic subunit, a cytochrome c subunit containing heme c as the electron transfer unit, and a chaperone-like subunit. To allow for subcutaneous insertion of the electrode, a stainless-based needle-type miniaturized electrode having the same diameter as a 30-G needle (0.3 mm) was designed. To achieve high current density, we investigated the use of carbon nanoparticles with various surface areas as sensor components. The current density correlated well with the surface area of the carbon nanoparticles, and Ketjen Black was found to be the best carbon nanoparticle in combination with FADGDH. The sensor responded quickly to glucose and demonstrated potential application for monitoring glucose levels in vivo.
