MnO₂‑Based Nanoplatform Serves as Drug Vehicle and MRI Contrast Agent for Cancer Theranostics

Multidrug resistance (MDR) greatly impedes the therapeutic efficacy of chemotherapeutic agents. Overexpression of ATP-binding cassette (ABC) transporters, such as P-gp, on the surface of tumor cells is a major mechanism in MDR. In this study, we fabricated manganese dioxide (MnO₂)/doxorubicin (DOX)-loaded albumin nanoparticles (BMDN) for magnetic resonance imaging and reversing MDR in resistant tumor. BMDN facilitated the delivery of DOX into MDR tumor cells through their MDR reversal effects including enhanced cellular uptake, reduced drug efflux, and decreased hypoxic tumor microenvironment. BMDN also acted as an effective MRI contrast agent, thereby causing good in vitro and in vivo <i>T</i>₁-weighted imaging