Strategies for efficient photothermal therapy at mild temperatures: Progresses and challenges

Photothermal therapy (PTT), typically ablates tumors via hyperthermia generated from photothermal agents (PTAs) under laser irradiation, has attracted great attentions in the past decades. Unfortunately, longstanding, frequent and high-power density laser irradiations are needed to maintain the hyperthermal status (>50 °C) for efficient therapy, which will damage the skin and nearby healthy tissues. Suppressing cancer cells with a mild temperature elevation is more attractive and feasible for PTT. Recently, low-temperature photothermal therapy (LTPTT), which could inhibit tumor under mild hyperthermia, has been widely investigated by researchers. Herein, we systematically summarized the strategies to achieve LTPTT. Diverse PTAs including organic and inorganic materials reported for LTPTT were introduced. The established strategies for LTPTT were intensively described. Finally, the challenges as well as future perspectives in this field were discussed. This review systematically summarized the established strategies toward efficient photothermal therapy under mild hyperthermia. Diverse photothermal agents were discussed, and the tactics including organelle-targeting, autophagy regulation, gas sensitization, heat shock protein inhibition, and the combination with chemotherapy, photodynamic therapy, chemodynamic therapy, radiotherapy, starvation therapy, immunotherapy as well as multimodal therapy were highlighted. The current limitations and the potential future directions for low temperature photothermal therapy were also pointed out. [Display omitted]