Abstract
Direct electron transfer (DET) from biomolecules to electrode is a process without electron-mediator, thus superior selectivity and sensitivity is expected in order to monitor electron transfer between electrode and biomolecules without any mediator interference. However, DET occur hard because a redox center which is an electron active center of proteins such as enzymes is buried deep. So, unique electrode nanostructure to reach the redox center is a critical factor. Here we have systematically investigated terms for DET using various nanofiliformed electrod morphology and enzyme concentrations. It is pointed out that the reaction-site is below 100 nm, the ration amounts of adsorbed enzyme per surface area are below 1.0 are contributed to the DET. As a great application, we have developed a biosensor monitoring the hydrogen peroxide (H_2O_2) detecting capability from peroxidase directly. The fabricated HRP/nTOF/Ti-electrodes observed the catalytic current value was linear according to increase in the concentration of H_2O_2 up to 100 μM, which indicates a good potential for H_2O_2 biosensor.
