Freestanding biopellet electrodes based on carbon nanotubes and protein compression for direct and mediated bioelectrocatalysis

The fabrication of bioelectrocatalytic protein electrodes by the simple compression carbon nanotube and powders was investigated using a series proteins including bilirubin oxidase (BOx), bovine serum albumin (BSA), catalase, cytochrome C (Cyt C), diaphorase, FAD-dependent glucose dehydrogenase (FAD-GDH), galactose (GAOx), (GOx), horseradish peroxidase (HRP), laccase urease. isoelectric points (pI) ranged from 3.5 to 12 molecular weights 12.4 480 kDa. laccase, BOx, FAD-GDH, catalase urease gave mechanically stable biopellets in 0.1 M phosphate buffer pH 7.4. For Cyt C, BSA, GAOx, GOx, HRP, contact with destabilised biopellet induced fast destruction composite. In parallel, redox pellets were obtained differently charged mediators: hexaammineruthenium (III) chloride, potassium hexacyanoferrate or 1,4-naphthoquinone. Several parameters explored shed new light on factors that determine stability. Stable capable direct mediated electron transfer subsequently elaborated, for O2 reduction oxidation, respectively, based simplified procedure does not require stabilising protection membranes holders contrary existing methods.