Near-Infrared Light Responsive Imaging-Guided Photothermal and Photodynamic Synergistic Therapy Nanoplatform Based on Carbon Nanohorns for Efficient Cancer Treatment

Indocyanine green (ICG) is an effective light absorber for laser-mediated photodynamic therapy. However, applications of ICG are limited due to its rapid degradation and poor photostability in water. Herein, we report the development of a multifunctional nanoplatform by coating ICG on the surface of single-walled carbon nanohorns (SWNHs) through pi-pi stacking, obtaining SWNH-ICGs with high solubility and stability under physiological conditions. The SWNH-ICGs could be used as a single nanoplatform to simultaneously produce satisfactory hyperthermia and reactive oxygen species under near-infrared (NIR) laser irradiation. In addition, the SWNH-ICGs not only improved the photostability of ICG in different media, but also protected it from light degradation. The SWNH-ICGs exhibited highly efficient thermal/photoacoustic (PA) imaging-guided photothermal therapy (PTT) and photodynamic therapy (PDT) effects, even under low-power laser irradiation (0.3 W cm(-2)) in vitro. Combined PTT and PDT effectively killed triple-negative breast cancer 4T1 cells, demonstrating a markedly improved and synergistic therapeutic effect compared to PTT or PDT alone. Furthermore, significant tumor growth inhibition as well as tumor cell death were observed following PTT/PDT at 808 nm laser irradiation, confirming the synergistic effects of SWNH-ICGs over free ICG in vivo. This facile and simple methodology for thermal/PA imaging-guided PTT/PDT suggests that SWNH-ICGs may serve as an effective nanoplatform for cancer therapy.