|
Abstract
|
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 sonication 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/O2 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 μM.
|