Critical evaluation of the glucose oxidase-like activity of gold nanoparticles stabilized by different polymers

Polymer stabilizers are widely used to synthesize gold nanoparticles (Au NPs) to prevent their aggregation and improve their stability. Although stabilizers are known to greatly influence both the structure and size of Au NPs, limited efforts explore their effects on the activity of Au NPs for biocatalysis. Herein, different polymers are used as stabilizers to synthesize Au NPs. For the glucose oxidase-like activity, we find that without the spatial barrier from stabilizers, naked Au NPs show significantly high catalytic activity as well as the worst stability. Among the polymers, polyacrylic acid-stabilized Au NPs exhibit the highest activity, whose V_max (0.74 μM·s⁻¹) is higher than that of the natural glucose oxidase (0.37 μM·s⁻¹) due to the smallest particle size (< 2 nm) and the weak spatial resistance of polyacrylic acid. These variable catalytic results derive from the comprehensive effects including size, steric hindrance, and electronic effect. However, further selectivity and activity tests have exposed shortcomings. They possess universal activities for aldose oxidation, whereas cannot retain activities in typical physiological environments. Our findings highlight the role of polymer stabilizers in imposing effects on the glucose oxidase-like activity of Au NPs and provide a basis for further Au NPs engineering and applications.