Self-assembled Cu2−xS nanochains network with tunable diameters for efficient photothermal conversion

Cu 2−x S nanochains network (NCNW) with tunable diameter in the range of 5–9 nm is prepared by a self-assembly strategy. Control experiments reveal that poly (sodium 4-styrenesulfonate) plays a key role in guiding the assembly of the nanochains. The Cu 2−x S NCNW demonstrates a broad localized surface plasmon resonance (LSPR) band in the near-infrared-Ⅱ region, which matches the optical window of biological tissues. The LSPR band of the Cu 2−x S NCNW red-shifts and intensifies with the increase of diameter. The Cu 2−x S NCNW with an average diameter of 8.7 nm exhibits a high photothermal conversion efficiency of 80.7% under 808 nm laser (0.75 W cm −2 ). Furthermore, the thermal effect stability of the Cu 2−x S NCNW is also good. In vitro experiments demonstrate that all the nanochains possess low cell cytotoxicity. The 8.7 nm Cu 2−x S NCNW own the maximum cellular uptake, and can cause> 90% apoptosis rate of Hela cells under low power density laser (808 nm, 0.75 W cm −2 ), demonstrating its promising application in photothermal therapy.