FAD-based glucose dehydrogenase immobilized on thionine/AuNPs frameworks grafted on amino-CNTs: Development of high power glucose biofuel cell and biosensor

Enzymatic glucose oxidation has attracted tremendous interest in terms of biofuel cells design and sensing application. Flavine adenine dinucleotide-dependent glucose dehydrogenase has shown excellent selectivity toward glucose sensing and power supply application. Here, a 3-dimensional framework combined of thionine and gold nanoparticles grafted on amino-carbon nanotubes/graphene support is designed as a novel platform for enhancing activity of enzyme toward glucose oxidation. Through sonicatlon of thionine with gold nanoparticles the well-arranged nanorods, alike the metal-organic frameworks, are formed. Then, integration of these frameworks with amino-carbon nanotube through electrochemical treatment is the key of effective enzyme entrapment and subsequent electron transfer. The resulted bioelectrode displays high sensitivity ca. 0.177 A M-1 cm(-2), with onset and peak potential of -0.24 V and -0.16 V vs. Ag/AgCl at pH 7.4, respectively. The performance of the bioanode combined with bilirubin oxidase immobilized on amino-carbon nanotubes/graphene, as biocathode, in an assembly glucose/O-2 biofuel cell is evaluated and offers an open circuit voltage of 0.705 V. Under a 5 mM glucose concentration, as a normal concentration in physiological fluid, current and power density are obtained as much as 0.925 mA CM-2 and 0.27 mW cm(-2), respectively. Moreover, the proposed bioanode is able to detect glucose at a concentration range of 0.5 to 6.9 mM with limit of detection of 50 mu M.