One-pot synthesis of a quaternary ammonium-functionalized methylene blue-backboned polymer for robust NADH oxidation

Abstract

Compared to natural oxidases, artificial NADH oxidase (NOX) has distinct advantages in terms of cost, stability and manufacturing. Methylene blue is a redox-active phenothiazine derivative with a weak NOX-like activity in mediating electron transfer. Herein, we used a one-pot iron-catalyzed oxidative polymerization method to prepare a methylene blue-backboned polymer (MBPN-10) with pendant quaternary ammonium groups and compared its catalytic activity for NADH oxidation with that of methylene blue. MBPN-10 showed increased NADH binding affinity, improved catalytic performance, and increased shelf-life and was compatible with organic solvents. The reaction catalyzed by MBPN-10 is efficient and affords H₂O₂ without the need for metals or light. These features make MBPN-10 a highly promising synthetic NOX mimic.