Polydopamine-coated gold nanostars for near-infrared cancer photothermal therapy by multiple pathways

Photothermal therapy (PTT) has attracted increasing attention as an effective anticancer strategy, which has minimal side effects and could suppress the tumor growth effectively. Herein, poly (ethylene glycol)-stabilized polydopamine-modified gold nanostars (AuNSs@PDA-PEG) nanoparticles (NPs) were fabricated for PTT of cancer. The AuNSs@PDA-PEG NPs exhibited strong near-infrared (NIR) absorbance and excellent photostability for highly efficient PTT. Cytotoxicity assay indicated that the NPs possess high biocompatibility. Moreover, the AuNSs@PDA-PEG NPs exhibited excellent photothermal killing performance in vitro, in which the cell viability decreased to 10.02% under the 808 nm laser irradiation. The apoptosis assay indicated that HeLa cells incubated with AuNSs@PDA-PEG NPs can be seriously destroyed by the NIR laser irradiation. The mechanisms of NIR PTT-induced cancer cell death involved mitochondrial dysfunction, increase in lysosomal membrane permeability, and autophagy. Western blot analysis confirmed AuNSs@PDA-PEG NPs-induced decrease in Bcl-2 expression and elevation of Bax expression. Thus, the biocompatible AuNSs@PDA-PEG NPs exhibit great potential in PTT of cancer.