Leaf-inspired fluorescence-switchable nanosystem for visual loading of mixed drugs and targeted delivery

Abstract Inspired by the structure of leaves that possesses hollow veins and mesophyll with high surface area, a novel MnO2-based biomimetic fluorescence-switchable nanosystem was constructed to visually monitor drug loading and deliver mixed drugs. Leaf-like MnO2 with hollow tubes and wrinkled sheets was first synthesized, and further modified by dopamine for effective loading both hydrophilic and hydrophobic drugs. The degradation of MnO2 can be well controlled by adjusting the thickness of polydopamine film, and the strong π-π interactions between them also establish a strong fluorescence resonance energy transfer system, which allows us unprecedentedly to conveniently monitor drug loading process under naked eyes just by judging solution color changes. Additionally, in vitro experimental results demonstrate that the co-drug loaded system exhibits outstanding cancer therapy effect than single therapy, and we also report its first experimental example for effectively anti-cancer migration. The novel biomimetic synthesis method, effective co-loading different drugs with a visual pattern, and much better anticancer and anti-migration effect make our work potentially valuable in many fields.