Copper Phosphide Nanoparticles Used for Combined Photothermal and Photodynamic Tumor Therapy

Copper-based nanomaterials are widely used in near-infrared (NIR) light-mediated deep tumor treatment because of their abundant photothermal and photodynamic properties. However, copper phosphide (Cu₃P) nanoparticles (NPs) are rarely investigated. Herein, Cu₃P NPs were prepared to strengthen their local surface plasmon resonance absorption in the NIR region, exhibiting promising photothermal and photodynamic properties. After surface modification by polyethylene glycol, the formed pCu₃P NPs showed negligible influence on the viability of 4T1 cells, presenting remarkable biocompatibility. However, with 808 nm irradiation, pCu₃P NPs could induce HSP70 and HO-1 protein expression and enhance intracellular reactive oxygen species levels, leading to dramatic cell death. In 4T1 tumor-bearing mice, an intravenous injection of biocompatible pCu₃P NP could lead to remarkable aggregation in the tumor region and significantly inhibit tumor growth under 808 nm laser irradiation, presenting great potential for tumor therapy.