Photothermal Composite Nanomaterials for Multimodal Tumor Therapy under MRI Guidance

Abstract Multifunctional nanomaterials for cancer therapy has attracted researchers’ attention for decades. In this study, a unique oxidative method using KMnO 4 or K 2 MnO 4 as oxidizing agents to oxidize dopamine (DA) to polydopamine (PDA) was reported. The oxidizing agent was reduced to MnO x to form MnO x /PDA composite NPs. Afterwards, the MnO x /PDA composite NPs were surface‐modified with bovine serum albumin (BSA) to form a multifunctional theranostic agent, named MnO x /PDA@BSA NPs, with improved colloidal stability and biocompatibility. Such a material would become a photothermal nanoagent, since the PDA renders the composite NPs an admirable photothermal transforming ability with the photothermal conversion efficiency of 27.06%. Meanwhile, as a commonly used T1 contrast agent, manganese (Mn 2+ ) endowed the MnO x /PDA@BSA NPs with MRI ability, rendering the as‐synthesized MnO x /PDA composite NPs a capability of imaging guided multi‐modal tumor therapy. Moreover, the formed MnO x /PDA@BSA NPs were used for drug loading, which was found to own the tunable drug loading and controlled drug releasing capacity. The as‐prepared composite NPs were successfully used for the combined tumor chemotherapy and photothermal therapy in vitro and in vivo. This research provides insights into the development of conjugated polymer‐based nanomaterial for various biomedical applications, especially in imaging guided cancer therapy.