Intratumorally Injected Photothermal Agent-Loaded Photodynamic Nanocarriers for Ablation of Orthotopic Melanoma and Breast Cancer

Traditional chemotherapy of cancers may lead to serious adverse reactions due to little drug distribution in tumors. Here, a combination of photothermal therapy (PTT) and photodynamic therapy (PDT) was used for local treatment of orthotopic melanoma and breast cancer via intratumoral (i.t.) injection of photothermal agent-loaded photodynamic nanocarriers. A hydrophobic derivative of indocyanine green, DCC, was synthesized and entrapped into a pH-sensitive photosensitizer-core copolymer, PDCZP, to form DCC@PDCZP. The nanocarriers showed remarkable fluorescence, high singlet oxygen quantum yields, and strong photothermal effect. Flow cytometry suggested that the nanocarriers were efficiently internalized by cancer cells. Near infrared thermal imaging and fluorescence self-imaging showed that the i.t. injected DCC@PDCZP mainly remained in the tumors but the intravenous (i.v.) nanocarriers were distributed a little. One i.t. injection of DCC@PDCZP was enough to ablate the orthotopic B16-F10 and 4T1 mouse tumo...