Low-Coordination Configuration Single-Atom Manganese Nanozymes for NIR-Imaging-Oriented Efficient Catalytic...

Single-atom nanozymes (SAzymes) with low coordination structure has more active sites at an atomic level, which is one of the effective strategies to improve the efficiency of tumor catalytic therapy. Herein, it is reported that simple preparation of single-atom manganese-doped carbon dots (SA Mn-CDs) with low coordination (Mn-N₂) configuration formed by chelating manganese atoms with ethylenediamine tetraacetic acid (EDTA). SA Mn-CDs show good dispersibility of different solvents, excellent biological safety and stability, and show deep level (34 µm) of two-photon fluorescence imaging ability and exclusive function (Pearson's correlation coefficient: 0.752) of targeting lysosomes at the cellular level. This further promotes the high-efficiency peroxidase (POD)-like activity (SA = 0.64 U mg^-1) produced by the Fenton-like reaction mediated by SA Mn-CDs and shows excellent ability to kill tumor cells and shrink tumor tissues in vitro and in vivo respectively. This work proves the great potential of SA Mn-CDs nanozyme in near-infrared fluorescence-guided tumor catalytic therapy.