Synthesis of one-for-all type Cu5FeS4 nanocrystals with improved near infrared photothermal and Fenton effects for simultaneous imaging and therapy of tumor.

CuS materials exhibit excellent near infrared (NIR) photoabsorption and photothermal effect, but they are lack of magnetic resonance imaging (MRI) ability. Fe-based nanomaterials possess MRI capacity, but they usually exhibit poor NIR photoabsorption. In order to solve the above problems, we synthesize three kinds of CuxFeySz samples, including FeS2, CuFeS2 and Cu5FeS4 nanomaterials. With the Cu/Fe ratios increase from 0/1.0 to 1.0/1.0 and 5.0/1.0, the localized surface plasmon resonances (LSPRs) characteristic peaks shift to longer wavelength, and the photothermal transduction efficiencies go up from 24.4% to 36.6% and 45.9%. Thus, Cu5FeS4 is found to be the most excellent sample. Especially, Cu5FeS4 exhibits photothermal-enhanced Fenton effect, which can produce hydroxyl radical (·OH) under a wide pH range (e.g., pH = 5.4-7.4) to realize the chemodynamic effect. In addition, Cu5FeS4 can be employed as an efficient MRI contrast agent. When Cu5FeS4 dispersion is intravenously injected into the mouse, the tumor can be detected by MRI as well as thermal imaging, and eliminated through photothermal-enhanced chemodynamic effect. Therefore, Cu5FeS4 can be used as an efficient "one-for-all" type agent for MRI-guided photothermal-enhanced chemodynamic therapy of tumor.