Ultrastable AgBiS2 hollow nanospheres with cancer cell-specific cytotoxicity for multimodal tumor therapy

Specific cytotoxicity for catalytic nanomedicine triggered by the tumor microenvironment (TME) has attracted increasing interest. In this work, we prepared AgBiS2 hollow nanospheres with narrow bandgaps via rapid precipitation in a weakly polar solvent, which lowered the intrinsic energy gap for the active production of highly reactive hydroxyl radicals (•OH), especially in the TME. The as-prepared AgBiS2 hollow nanospheres exhibited enhanced optical absorption and high photothermal conversion efficiency (44.2%). In addition, the hollow structured AgBiS2 nanospheres were found to have a peroxidase-mimicking feature to induce cancer cell-specific cytotoxicity while exhibiting negligible cytotoxicity toward normal cells, which might be attributed to the efficient production of highly reactive •OH originating from the overexpression H2O2 in the TME caused by surface catalysis. In particular, the cancer cell-specific cytotoxicity of the nanospheres was greatly enhanced both in vitro and in vivo upon irradiation with a near-infrared (NIR) laser (808 nm). The above-mentioned features of the hollow structured AgBiS2 will make it a promising candidate for tumor therapy.