Bioinspired Ultrastable Cu(I)-Bovine Serum Albumin Single-Atom Nanozymes Enable MRI-Trackable Synergistic Catalytic Therapy and Cuproptosis for Tumors.

Abstract

Monovalent copper (Cu(I)) drives cuproptosis and catalytic therapy, yet its rapid oxidation reduces the activity. We developed bioinspired Cu(I)-bovine serum albumin single-atom nanozymes (Cu(I)-BSA SAzymes) via mild biomineralization, achieving stability (>90 days) and dual enzyme-like activities (peroxidase (POD)/catalase (CAT)) to convert tumor H₂O₂ into cytotoxic reactive oxygen species (ROS) while alleviating hypoxia. These SAzymes deplete glutathione to amplify oxidative stress and release Cu(I), which aggregates dihydrolipoamide S-acetyltransferase (DLAT) to induce cuproptosis─distinct from apoptosis/ferroptosis. Mechanistically, transcriptomics analyses suggest that Cu(I)-BSA SAzymes exerted their effects by regulating the oxidative stress and energy metabolism in 4T1 cells. The tumor microenvironment further mediates SAzymes aggregation and <i>in situ</i> transformation into paramagnetic Cu(II), enabling self-amplified T₁-weighted MRI contrast for real-time activation monitoring. In breast (4T1) and colon (CT26) tumors, Cu(I)-BSA SAzymes suppress growth by 68.8% and 80.3% ([Cu] = 4 mg kg^-1). This study reports a stable Cu(I) platform for catalytic-plus-cuproptosis theranostics.