Artificial Bifunctional Photozyme of Glucose Oxidase–Peroxidase for Solar-Powered Glucose–Peroxide Detection in a Biofluid with Resorcinol–Formaldehyde Polymers

Abstract

Photozymes or artificial photosynthesis based on alternative natural enzymes is vital for the sustainable development of next-generation healthcare, energy, and materials science. Herein, we report resorcinol-formaldehyde (RF) resins as a solar-driven metal-free bifunctional glucose oxidase-peroxidase stand-alone photozyme for the colorimetric dual detection of hydrogen peroxide and glucose. The π-bond conjugated benzenoid-ortho/para quinoid RF polymers are efficient for glucose oxidation and hydrogen peroxide reduction with concurrent 3,3',5,5'-tetramethylbenzidine oxidation under natural sunlight. The photoinduced colorimetric process could detect H₂O₂ up to 3.5 μM at 652 nm with the linear range of 0.1-2 mM. A limit of detection of 9.2 μM was exhibited by the system while measuring glucose with a linearity from 0.2 to 8.5 mM. The formation of hydroxyl radicals (^<b>•</b>OH) from glucose oxidation reactions was evidenced by spin trapping electron paramagnetic resonance studies conducted herein. The results indicated that RF resins possessed strong intrinsic glucose oxidase and peroxidase (POx)-like activity under natural sunlight with promising storage and operation. This simple photozyme will definitely have potential uses in biomimetic solar-driven catalysis, bioenergy, and biomedicine.