Albumin-Templated Bi 2 Se 3 -MnO 2 Nanocomposites with Promoted Catalase-Like Activity for Enhanced Radiotherapy of Cancer.

Novel and effective radiosensitizers that can enhance radiosensitivity of tumor tissues and increase the local radiation dose are highly desirable. In this work, templated by bovine serum albumin (BSA), Bi ₂ Se ₃ -MnO ₂ nanocomposites (Bi ₂ Se ₃ -MnO ₂ @BSA) were fabricated via biomineralization, while Bi ₂ Se ₃ nanodots act as radiosensitizers to increase the local radiation dosage because of their strong X-ray attenuation ability, and MnO ₂ with catalase-like activity can increase the oxygen concentration in tumors by triggering the decomposition of tumor endogenous H ₂ O ₂ so as to improve the hypoxia-associated radioresistance of tumors. Owing to the interaction of the two components in the interface, Bi ₂ Se ₃ -MnO ₂ @BSA showed promoted catalytic activity compared to MnO ₂ @BSA, favoring tumor radiotherapy (RT) sensitization. BSA templating enabled the nanocomposites with high colloidal stability and biocompatibility as well as satisfactory tumor targeting both in vitro and in vivo; thus, an enhanced RT efficacy was obtained. Moreover, the proposed Bi ₂ Se ₃ -MnO ₂ @BSA exhibited excellent performances in computerized tomography and magnetic resonance imaging. Thus, this work provides a tumor microenvironment-responsive multifunctional theranostic nanoagent with an improved performance for imaging-guided tumor RT sensitization.