Abstract
Nicotinamide adenine dinucleotide (NAD(+)) is a key coenzyme for human redox reactions, vital for cellular health and metabolic balance. Lots of NAD(+)-dependent redox enzymes, like alcohol dehydrogenase (ADH) and lactate dehydrogenase, can catalyze both forward and reverse reactions. However, substrate accumulation and inadequate NAD(+) replenishment hinder forward reactions, disrupting the proper metabolism of these substrates. In this work, we reported atomic Ce-doped Pt (Ce(1)Pt) nanoparticles with abundant oxygen vacancy sites to boost NADH oxidase (NOX)-like activity for coenzyme regeneration. Mechanistic studies reveal that atomic Ce doping increases electron density of Pt and surface defects, enhancing O(2) adsorption and accelerating the rate-limiting step. Furthermore, Ce(1)Pt employs a 4e(-) pathway for O(2) reduction during NADH oxidation, minimizing toxic H(2)O(2) byproducts and improving detection accuracy by reducing oxidative interference. Finally, Ce(1)Pt enables NAD(+) regeneration and substrate metabolism, offering a promising strategy to counteract excessive alcohol intake or lactate accumulation. Through competitive adsorption between the reduced coenzyme NADH of ADH and chromogenic substrates, a microfluidic device integrated with immobilized Ce(1)Pt achieves blood alcohol detection with a low limit of detection of 0.012 mM.