CuxO nanorods with excellent regenerable NADH peroxidase mimics and its application for selective and sensitive fluorimetric ethanol sensing

Highlights: • Cu_xO NRs displaying excellent regenerable NADH peroxidase mimics. • The catalytic oxidation NADH to NAD cofactor strictly follows the enzymatic kinetics with high catalytic rate and strong affinity. • Coupled Cu_xO NRs with alcohol dehydrogenase, a sensitive and selective fluorimetric sensor for ethanol was established. Cu_xO nanorods with excellent NADH peroxidase mimics were synthesized by a simple hydrothermal method. The catalytic oxidation of NADH to NAD cofactor strictly follows the enzymatic kinetics with high catalytic rate and strong affinity. The catalytic mechanism of Cu_xO NRs was that in the presence of hydrogen peroxide, the catalytic oxidizing NADH to NAD ⁺ involving with O₂^.-.anion production, making it realistic to mutually convert between coenzymes. Considering that the mutual transformation of NADH/NAD cofactors plays an important role in biological function, combination of Cu_xO NRs with alcohol dehydrogenase, a highly selective method for fluorimetric detection of ethanol was established. The as-proposed sensing platform is capable of dectecting alcohol with the limit of detection of 26.7 μM (S/N = 3) and applied in practical sample with satisfied accuracy and recovery. The as-developed regenerable NADH peroxidase mimics would also cast lights in biocatalysis, synthetic biology and bioenergy.