Potentially implantable biocathode with the function of charge accumulation based on nanocomposite of polyaniline/carbon nanotubes

Abstract

A potentially implantable biocathode with the function of charge accumulation based on a nanobiocomposite including multiwall carbon nanotubes, polyaniline, and bilirubin oxidase is developed. The regularities of the functioning of the obtained electrode are studied in air–saturated phosphate buffer solution, pH 7.4 (PB), and also in phosphate buffer solution containing redox–active blood components (BMB). The open circuit potential of the biocathode is 0.33 and 0.08 V vs. the saturated calomel electrode in PB and BMB, respectively; it is completely restored after at least three self-charge/discharge cycles with connection to resistors with different resistance. Bioelectrocatalytic current density of oxygen reduction is 0.50 and 0.42 mA cm^–2 with the residual activity of 78 and 60% of the initial value after 12 h of continuous operation in PB at 25°C and in BMB at 37°C, respectively.