CuS@PDA-FA nanocomposites: a dual stimuli-responsive DOX delivery vehicle with ultrahigh loading level for synergistic photothermal-chemotherapies on breast cancer.

In this study, CuS@PDA nanoparticles were synthesized and used to create a novel tumor-targeting nanocomposite platform composed of copper sulfide@polydopamine-folic acid/doxorubicin (CuS@PDA-FA/DOX) for performing both photothermal and chemotherapeutic cancer treatment. The nanocomposite platform has ultrahigh loading levels (4.2 ± 0.2 mg mg-1) and a greater photothermal conversion efficiency (η = 42.7%) than CuS/PDA alone. The uptake of CuS@PDA-FA/DOX nanocomposites is much higher in MCF-7 cells than in A549 cells because MCF-7 cells have much higher folic acid receptors than A549. Under near infrared (NIR) irradiation, the CuS@PDA-FA/DOX system using a synergistic combination of photothermal therapy and chemotherapy yields a better therapeutic effect than either photothermal therapy or chemotherapy alone. The treatment is very effective with the cell viability is only 5.6 ± 1.4%.