Bioactive NIR-II gold clusters for three-dimensional imaging and acute inflammation inhibition.

Strong fluorescence and high catalytic activities cannot be achieved simultaneously due to conflicts in free electron utilization, resulting in a lack of bioactivity of most near-infrared-II (NIR-II) fluorophores. To circumvent this challenge, we developed atomically precise Au clusters with strong NIR-II fluorescence ranging from 950 to 1300 nm exhibiting potent enzyme-mimetic activities through atomic engineering to create active Cu single-atom sites. The developed AuCu clusters show 18-fold higher antioxidant, 90-fold higher catalase-like, and 3-fold higher superoxide dismutase-like activities than Au clusters, with negligible fluorescence loss. Doping with single Cu atoms decreases the bandgap from 1.33 to 1.28 eV by predominant contributions from Cu states, and Cu with lost electron states effectuates high catalytic activities. The renal clearable clusters can monitor cisplatin-induced renal injury in the 20- to 120-minute window and visualize it in three dimensions using NIR-II light-sheet microscopy. Furthermore, the clusters inhibit oxidative stress and inflammation in the cisplatin-treated mouse model, particularly in the kidneys and brain.