Hybrid of gold nanostar and indocyanine green for targeted imaging-guided diagnosis and phototherapy using low-density laser irradiation

Phototherapy is widely studied with the development of photothermal nanomaterials. However, the laser power density for reaching effective phototherapy is still high and dangerous for normal tissues. In this research, based on multi-functional polydopamine, we proposed a general strategy to design diverse core–shell nanoparticles with different surface charges, and synthesized a targeted nanoplatform, AuNS@PDA–PEI–FA (APP), by coupling gold nanostar (AuNS) with polyethylenimine–folate (PEI–FA). Owing to the electrostatic interaction, the as-prepared APP can anchor a negatively-charged photosensitizer, indocyanine green (ICG), for photothermal and photodynamic synergistic cancer therapy. The APP–ICG is able to realize the targeted phototherapy for tumor cells even at the low power laser density of 0.33 W cm−2 both in vitro and in vivo. Furthermore, APP–ICG is not only a treatment nanoplatform but also a diagnosis agent. The integrative diagnosis results can be acquired by dual imaging technologies: the near-infrared fluorescence images and the photothermal images acquired by an in vivo imaging system and a thermal imaging camera, respectively. This new nanoplatform is a good diagnosis and treatment system and has the potential for further theranostics application.