Self-assembly synthesis of flower-like gold nanoparticles for photothermal treatment of cancer

Polymyxin E (PE) could be used as a soft template, because of its characteristics of self-assembly and ability of metal ions reduction. Here, PE induced gold nanoflowers (PE@AuNFs) were successfully synthesized by seed growth method. PE@AuNFs had anisotropy, large absorption cross section, and large surface plasmon resonance (LSPR) peak, resulting in high photothermal conversion efficiency of 34.9%. Moreover, the cell viability of PE@AuNFs for HeLa cells was 19% under near-infrared light irradiation, while cell viability of 15 nm citrate capped gold nanoparticles (SC@AuNPs) was 83%. PE@AuNFs showed good antibacterial effect with laser irradiation. Furthermore, the excellent inhibition efficacy of PE@AuNFs also was demonstrated in U14 tumor-bearing mice in vivo. Taken together, the flower-shaped PE@AuNFs prepared by this new method had good biocompatibility and outstanding near-infrared photothermal treatment effect, indicating their great potential in photothermal therapy.