Shape effects of gold nanoparticles in photothermal cancer therapy

Gold Nanoparticles based Plasmonic Photothermal Therapy (PPTT) has recently been extensively studied in cancer treatment, based on the local hyperthermia induced by their plasmonic photothermal effect on cancer cells or tissues. Although AuNPs with various morphologies have shown photothermal conversion capabilities, their performance in photothermal therapy is still in debate. To reveal the AuNPs with the most promising PPTT performance, three commonly established gold nanostructures: gold nanospheres (AuNSs), gold nanorods (AuNRs), gold nanostars (AuNSTs), were synthesized in this study with identical mPEG-SH surface modification. The corresponding PTT performance and antitumor effect were evaluated and compared. It was found that all AuNPs can convert 808 nm Near-Infrared (NIR) laser light energy into heat through the Localized Surface Plasmon Resonance effect, and AuNSTs showed the highest photothermal conversion efficiency. In vitro cell experiments demonstrated that all PEGylated AuNPs had low cytotoxicity and AuNSTs were the most capable ones in inducing local hyperthermia under an identical condition of 10 min 300 mW/cm2 NIR light irradiation. Therefore, with the same surface modification, AuNSTs should be the most promising agent for PTT therapy among their counterparts.