Daptomycin-Biomineralized Silver Nanoparticles for Enhanced Photothermal Therapy with Anti-Tumor Effect

Silver nanoparticles as photothermal agents have the problems of low stability and low photothermal conversion efficiency. Amphiphilic daptomycin can improve the stability of silver nanoparticles, thereby improving their photothermal conversion efficiency. Herein, daptomycin-biomineralized silver nanoparticles (Dap-AgNPs) were prepared by reducing silver nitrate with sodium borohydride in the presence of daptomycin as a stabilizer and biomineralizer. The Dap-AgNPs had good solution stability and peroxidase-like activity. Furthermore, the photothermal conversion efficiency of the Dap-AgNPs was as high as 36.8%. The Dap-AgNPs displayed good photothermal stability under irradiation. More importantly, the Dap-AgNPs showed good cell compatibility with HeLa cells and HT-29 cells without irradiation by 808-nanometer near-infrared light at a concentration of 0.5 mM, and the cell viability was greater than 85.0%. However, the Dap-AgNPs displayed significant anti-tumor ability with irradiation by 808-nanometer near-infrared light, which was due to the increasing temperature of the culture medium caused by the Dap-AgNPs. In conclusion, Dap-AgNPs have potential applications as photothermal agents in the treatment of tumors.