Practical applications of glucose oxidase in enzymatic biofuel cells (BFC) are limited by the enzyme’s short lifetime and the low electron transfer rate between its active center and the BFC’s electrode. Recent development in nanomaterials with sizes similar to those of the enzyme have opened new options to improve the enzyme’s performance. The objective of this work is to present a novel method for manufacturing enzyme-based glucose oxidase (GOx) nanocomposites with high stability and enhanced electrochemical properties. The GOx nancomposites were manufactured by entrapping cross-linked GOx aggregates within a graphitized mesoporous carbon network. The entrapping process was conducted by using the strong tendency of graphitized mesoporous carbon for self-aggregating in aqueous buffer solution to form these carbon networks. The produced nanocomposites were characterized by means of confocal microscopy, transmission electron microscopy (TEM), enzymatic assay of glucose oxidase, and electrochemical techniques (e.g., cyclic voltammetry). Confocal and TEM images confirmed that the enzyme has been immobilized in a compact mesoporous carbon network. The GOx-nanocomposite presented good stability, keeping up to 99% of its initial enzymatic activity after a thermal shock test at 60ᵒC for 4 hours while the free enzyme was completely deactivated. In addition, a fast electron transfer rate with a rate constant of 5.18 ± 1.09 s<sup>-1</sup> was observed. The mediatorless BFC manufactured with the GOx-nanocomposite delivered a maximum power density of 22 µW/cm<sup>2 </sup>when a 10 mM glucose solution was used as a fuel. Our results suggest that the enzyme immobilization method presented here can efficiently increase the enzyme stability and electrochemical performance.

High performance nanocomposites produced with cross-linked glucose oxidase aggregates and graphitized mesoporous carbon

249th National Meeting (2015)

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