Dual Single-Atom Engineered NADH Oxidase-Mimic Boosts In Situ NAD⁺ Biotransformation for Targeted Myocardial...

Myocardial ischemia/reperfusion (I/R) injury is a globally recognized pathological condition that results in life-threatening organ dysfunction. Supplementation with nicotinamide adenine dinucleotide (NAD⁺) can improve myocardial energy metabolism, alleviate inflammation, and mitigate I/R injury. However, its clinical applicability is constrained by the poor efficacy and delivery limitations of current NAD⁺ supplementation strategies. Here, we design a dual single-atom nanozyme with nicotinamide adenine dinucleotide (NADH) oxidase-mimicking activity for in situ NAD⁺ biotransformation and I/R injury treatment. Upon M2 macrophage membrane coating, the nanozyme selectively targets ischemic myocardium, facilitating in situ NAD⁺ biotransformation by eliminating excess NADH, while concurrently scavenging reactive oxygen species, restoring mitochondrial bioenergetics, attenuating inflammation, and inhibiting apoptosis. Mechanistic investigations demonstrate that the nanozyme activates the NAD⁺-SIRT1 axis, enhancing ATP biosynthesis and oxidative phosphorylation, while suppressing TNF signaling and NF-κB pathways. Collectively, the engineered NOX-like nanozyme offers a novel therapeutic strategy for myocardial I/R injury by modulating both mitochondrial bioenergetics and oxidative stress defense pathways through restoring NAD⁺/NADH homeostasis.