Fabrication of photosensitizer-polyethylene glycol-conjugated gold nanostars for simultaneous photothermal and photodynamic cancer therapy under near-infrared laser irradiation

Abstract

The unique optical properties of gold nanoparticles have facilitated their application as novel nanomedicines in cancer therapy. In the current study, we examined the medical use of gold nanostars (GNSs), gold nanoparticles with protrusions on the surface. Under near-infrared (NIR) laser irradiation, GNSs exhibit an absorption peak at ∼700 nm, and this absorption peak can be targeted in photodynamic therapy using photosensitizers. GNSs were conjugated with polyethylene glycol (PEG) to form PEG-GNSs, which were further conjugated with a photosensitizer (talaporfin sodium, TPS) at the end of the PEG chain, forming TPS-PEG-GNSs. Energy absorption under NIR-laser irradiation increased the temperature of the TPS-PEG-GNSs and produced reactive oxygen species derived from TPS. The combination of TPS-PEG-GNSs and NIR-laser irradiation exhibited remarkable cytotoxic effects against A549 lung cancer cells in vitro upon optimization of the strength of the NIR laser. TPS-PEG-GNSs are thus effective multifunctional nanoparticles for simultaneous use in both photothermal and photodynamic therapy using single NIR-laser irradiation. The current results provide a useful model of nanomedicine for cancer therapy using NIR lasers.