CuS Nanodot-Loaded Thermosensitive Hydrogel for Anticancer Photothermal Therapy.

The purpose of this research is to establish an injectable hydrogel encapsulating copper sulfide (CuS) nanodots for photothermal therapy against cancer. The CuS nanodots were prepared by one-pot synthesis, and the thermosensitive Pluronic F127 was used as the hydrogel matrix. The CuS nanodots and the hydrogel were characterized by morphous, particle size, serum stability, photothermal performance upon repeated 808 nm laser irradiation, and rheology features. The effects of the CuS nanodots and the hydrogel were evaluated qualitatively and quantitatively in 4T1 mouse breast cancer cells. The retention, photothermal efficacy, therapeutic effects, and systemic toxicity of the hydrogel were assessed in tumor bearing mouse model. The CuS nanodots with a diameter of about 8 nm exhibited satisfying serum stability, photoheat conversion ability, and repeated laser exposure stability. The hydrogel encapsulation did not negatively influence the above features of the photothermal agent. The nanodot-loaded hydrogel shows a phase transition at body temperature and, as a result, a long retention in vivo. The photothermal-agent-embedded hydrogel played a promising photothermal therapeutic effect in the tumor bearing mouse model with low systemic toxicity after peritumoral administration.

Activatable unsaturated liposomes increase lipid peroxide of cell membrane and inhibit tumor growth.

The cancer chemodynamic therapy based on the Fenton reaction has been attracting more and more attention. However, the performance of the Fenton reaction is restricted by the unsuitable physiological pH value and inadequate H2O2 content in the tumor microenvironment (TME). In this study, we proposed a novel method of inducing lipid peroxide (LPO) of the cancer cell membrane, whose performance is not limited by the pH value and H2O2 in the TME. The activatable LPO-inducing liposomes were constructed by encapsulating Fe3+-containing compound ferric ammonium citrate (FC) in the unsaturated soybean phospholipids (SPC). It was found that the FC could be reduced by the overexpressed glutathione (GSH) in the TME and produce iron redox couple. The Fe3+/Fe2+ mediated the peroxidation of the unsaturated SPC and induced the LPO in the cancer cells. Finally, LPO accumulation led to cancer cell death and tumor growth inhibition. Furthermore, the activatable liposomes did not damage healthy tissues because of the low GSH content in normal tissues and the GSH-triggered activation of the nanocarrier. Together, our findings revealed that FC-SPC-lipo displayed excellent anti-tumor performance and its therapeutic effects are less influenced by the TME, compared with the traditional ferroptosis.