Exosomes/MoS₂ complex for targeting and effective photothermal therapy

Photothermal therapy (PTT) has been an attractive tumor treatment strategy in recent years. Two-dimensional molybdenum disulfide (MoS₂)-based nanomaterials with high photothermal conversion efficiency is a promising candidate for PTT. However, the tumor-targeting capability needs to be further improved for effective tumor treatment. In this work, we combine the MoS₂ nanodots with exosomes, native vesicles secreted from living cells, to construct a novel exosomes/MoS₂ complex (MoS₂@ME) for effective tumor-targeted PTT. Through ultrasonic self-assembly membranes, MoS₂ nanodots are incorporated into MCF-7 exosomes. Similar to the free MoS₂, the MoS₂@ME shows significant photothermal conversion effect, causing nearly 100% necrosis proportion of MCF-7 and 4T1 cells under 1064 nm laser irradiation within 5 min (0.4 W/cm²) in vitro. In particular, MoS₂@ME presents noteworthy affinity for tumor cells, and in vivo studies further prove that it could accumulate at the tumor site efficiently. After intravenous injection with MoS₂@ME plus near-Infrared (NIR) irradiation, the temperature of tumor site in 4T1 tumor-bearing mice could reach 46 °C within a short time (~ 2 min). Notably, with the prolongation of NIR irradiation time, the temperature of tumors gradually increases and reaches the maximum temperature (52.3 °C) at 8 min, which is far higher than that in the free MoS₂ group. More importantly, PTT using MoS₂@ME exhibits much more effective antitumor therapy, as the tumor volume and tumor weight of mice in the MoS₂@ME group are significantly lower than those in the PBS and MoS₂ groups (P < 0.05), and even the tumor disappears completely. In vitro and in vivo studies demonstrate that the MoS₂@ME shows excellent targeting capacity and photothermal effect, achieving effective photothermal cancer therapy. This work is expected to overcome the shortcomings of some photothermal nanomaterials, aiming to improve safety and effectiveness.