Two-Photon-Active Organotin(IV) Complexes for Antibacterial Function and Superresolution Bacteria Imaging

Antibacterial agents with two-photon absorption are expected to play a significant role in biomedical science. Herein, two novel organotin complexes, HLSn1 and HLSn2, based on coumarin were designed, synthesized, and systematically investigated. It was found that these complexes possessed suitable two-photon-active cross sections in the near-infrared region. Moreover, complex HLSn1 could efficiently inhibit the growth of Gram-negative Escherichia coli and Gram-positive Bacillus subtilis, especially the latter with a minimum inhibitory concentration (MIC; 90%) of 2 ± 0.14 μg mL^-1, which is lower than that of Kanamycin (Kana, 8 ± 0.42 μg mL^-1). Importantly, two-photon imaging and superresolution development of bacterial stain revealed that complex HLSn1 can react with bacterial membranes, producing reactive oxygen species (ROS) and leading to cell death. These outcomes provide promising applications in the superresolution bacteria imaging, diagnostics, and treatment of bacterial infectious.