Polydopamine-mediated bio-inspired synthesis of copper sulfide nanoparticles for T1-weighted magnetic resonance imaging guided photothermal cancer therapy

Abstract Copper sulfide nanoparticles(CuS NPs) have attracted considerable interest in the field of photothermal therapy(PTT) due to its low cost, easy preparation and favorable photothermal effect. However, lack of reliable visualization and relatively poor biocompatibility restrict its further bio-application. To overcome these limitations, polydopamine(PDA, a melanin-like biopolymer) stabilized CuS NPs and further chelated with iron ions (denoted as CuPDF) were designed as a versatile nanoplatform for T 1 -weighted MR imaging-guided PTT. In this system, PDA served as both bio-template to synthesis CuS NPs and an active platform to give MRI diagnostic capability. The as-prepared CuPDF NPs demonstrated strong absorption at NIR region, nearly three times higher than that of pure PDA NPs at 808 nm. Moreover, toxicity studies and histology evalution verified that CuPDF NPs possess excellent biocompatibility. In addition, CuPDF NPs showed significant MRI signal enhancement with high longitudinal relaxivity (r 1  = 4.59 mM −1  s −1 ). In vivo MRI and biodistribution test confirmed the efficient accumulation of CuPDF NPs in the tumor region. After intravenous injection of CuPDF, irreversible tumor ablation was successfully achieved without inducing any obvious side effects by using 808-nm laser irradiation. All in all, these results indicated that the developed CuPDF NPs hold great potential as an effective theranostic agent for MR imaging guided PTT in vivo .