Smart releasing CuS/ZnS nanocomposite dual drug carrier and photothermal agent for use as a theranostic tool for cancer therapy

Multifunctional nanoparticles consisting of different therapeutic modalities and potential for imaging could hold promise to revolutionize cancer treatment and management. In this study, we have reported the synthesis of multifunctional CuS–ZnS nanocomposites modified in situ for targeted cancer therapy. CuS element of the nanocomposite enabled near-infrared light responsive photothermal therapy, whereas ZnS showed potential for photoluminescence. Successful nanocomposite formation was confirmed by UV–Visible spectroscopy, inductively coupled plasma atomic emission spectroscopy and energy-dispersive X-ray spectroscopy. These nanocomposites were coated with chitosan by exploiting electrostatic interactions as was confirmed by zeta potential analysis and FTIR spectroscopy. Chitosan also allowed encapsulation of hydrophilic and hydrophobic drugs with encapsulation efficiencies of 98% and 42% respectively. Release profiles of the drugs indicated pH dependent behavior and zero order kinetics. In vitro studies demonstrated selective uptake in HeLa cells, biocompatibility and haemocompatibility. NIR absorption of the nanocomposites led to high photothermal conversion efficiency (∼40%) which translated into thermal ablation of 80% MCF-7 cells in vitro. In vivo assessments in a 4T1 model showed significant reduction in tumors when treated with the nanocomposite. These results demonstrated the potential application of the nanocomposite for chemo-photothermal therapy in a targeted and stimulus responsive manner.