Multifunctional nanoplatform for enhanced photodynamic cancer therapy and magnetic resonance imaging

Co-delivery of photosensitizers and synergistic agents by one single nanoplatform is interesting for enhancing photodynamic therapy (PDT) of cancer. Here, a multifunctional nanoplatform for enhanced photodynamic therapy and magnetic resonance imaging of cancer was constructed. The poly (lactide-co-glycolide) (PLGA) nanoparticles (NPs) loaded with hematoporphyrin monomethyl ether (HMME) were coated with multifunctional manganese dioxide (MnO₂) shells, which were designed as PLGA/HMME@MnO₂ NPs. Once the NPs were effectively taken up by tumor cells, the intracellular H₂O₂ was catalysed by the MnO₂ shells to generate O₂. Meanwhile, the higher glutathione (GSH) promoted the degradation of MnO₂ into Mn²⁺ ions with the ability of magnetic resonance (MR) imaging. After the degradation of outer layer, the release of photosensitizer was promoted. Under irradiation, the released HMME produced cytotoxic reactive oxygen species (ROS) to damage the tumor cells when the O₂ was generated in the hypoxic tumor site. Furthermore, the decreased GSH level further inhibited the consumption of the produced ROS, which greatly enhanced the PDT efficacy. Therefore, this study suggested that this multifunctional system has the potential for enhanced photodynamic therapy and magnetic resonance imaging.