One-Pot Synthesis of Quaternary Ammonium-Functionalized Methylene Blue-Backboned Polymer for Robust NADH Oxidation

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