Evaluation Of Copper Sulphide Nanoparticles For Combined Magnetic Resonance Imaging And Photothermal Therapy

Recent years, near-infrared （NIR） laser-induced photothermal ablation （PTA）therapy which can localized elimination of tumor cells without affecting healthytissues, provides a new idea for cancer therapy. To ensure the safety and effcacy ofthe photothermal ablation, the location and size of cancers must be identified beforetherapy and the treatment procedure needs to be monitored during therapy. Magneticresonance imaging could be an ideal technique for imaging-guided photothermalablation of cancer cells. Currently, several nanocomposites have been designed torealize MRI and photothermal therapy integration by combining MRI contrastagents with nanostructures that have strong absorption in the near infrared （NIR）region. However, expensive processes of gold surface coating, complicated chemicalmodifcations and poor thermal stability, limits the further application of thesenanostructures. The semiconductor copper sulfide is a latest promising photothermalcoupling agent and has gained great interest in the nanomedicine areas due to its lowcost, easy preparation, low cytotoxicity and stable optical property.Herein, novel CuS nanoparticles （NPs） that combined MRI and PTA therapywere developed. The Gd-diethylene triamine pentacetate acid （DTPA） whichconfered on the CuS NPs the paramagnetic characteristics required for T1-weightedMRI had been exploited to functionalize the CuS NPs. Further more, the MRIcontrast agents can prolong the circulation time in vivo by integrating withnanoparticles. These novel CuS NPs had a uniform diameter of12nm with a narrowsize distribution. They have good biocompatibility and outstanding stability, and cangreatly enhance the effect of MRI. They have a high T1relaxivity coeffcient （r1）value of8.65mM^-1·s^-1which is nearly twice as high as that of the conventionalGd-DTPA. The novel CuS nanoparticles have excellent photo-thermal stability andare able to localized elimination cancer cells efficiently based on photothermalefect.In conclusion, MRI and PTA therapy were combined organically byincorporation of MRI contrast agent and photosensitive materials which haveadvantages of both of them, and meanwhile overcome their disadvantages. Owing totheir convenient preparation, stabilized optical property, outstanding imaging andphotothermal effect, these novel CuS NPs could be used as a promising platformwith combined MRI diagnosis and efficient photothermal therapy for cancer cells.