Synergistic integration of polysulfobetaine brush-grafted porphyrinic covalent organic frameworks with native enzymes for electrolyte-sensitive aerobic photobiocatalysis

Abstract

Biocatalysis has emerged as a potent technique in synthetic chemistry, leveraging enzymes to generate exceptionally specific products under mild conditions. Combining photoregenerated cofactors with enzymes sequentially offers an effective approach for targeted compound synthesis. Nevertheless, integrating enzymes and photocatalysts faces challenges from rapid biomaterial degradation due to photoinduced reactive oxygen species (ROS), which can denature and deactivate enzymes. Herein, we introduce porphyrinic covalent organic frameworks (TpDh-P COFs) with surface-attached polysulfobetaine brushes as visible-light-mediated nanophotoreactors. This innovation enables stable and circular photobiocatalysis in aerobic environments. The hydrophobic interior porphyrin-based COF cores efficiently convert reduced nicotinamide adenine dinucleotide (NADH) to its oxidized form NAD⁺, while the hydrophilic exterior polymer brushes shield enzymes (glucose dehydrogenase, leucine dehydrogenase and formate dehydrogenase) from ROS generated during the photoreaction. The electrolyte-sensitivity of polysulfobetaine brushes directly regulates the NADH oxidation rate. After twelve regeneration cycles, the enzymes remain active and TpDh-P maintain their morphology and photocatalytic efficiency, underscoring their potential for the development of sustainable and value-added photobiocatalytic systems.