Dandelion-Inspired Hierarchical Upconversion Nanoplatform for Synergistic Chemo-Photodynamic Therapy In Vitro

Herein, inspired by the structure of a dandelion, we develop a fresh preparation of an upconversion nanoplatform (UCNPs@C₆₀-DOX-FA). The target part folic acid (FA) modified with β-CD-NH₂ can enhance dispersibility and afford the nanoplatform to arrive at the tumor and enter cancer cells easily. After the mouse breast cancer (4T1) cell incubation with the nanoplatform, the abundant glutathione (GSH) in cells cuts the -S-S- bonds like scissors, just as dandelion encountering wind, and the drug doxorubicin (DOX) flows into the nucleus for chemotherapy. Meanwhile, the photodynamic therapy (PDT) effect is enhanced with the decrease content of GSH, which promotes the reactive oxygen species to accumulation. The synergistic chemotherapy and PDT are outstanding in killing 4T1 cells. The rest part UCNPs@C₆₀ possesses excellent biocompatibility and low cytotoxicity. As for cancer diagnosis, UCNPs can be used as a visual imaging agent. Benefited by the delicate structure, all of the functional parts of the nanoplatform go and coordinate well. On account of an FA ligand and the -S-S- bond, the nanoplatform works very well in 4T1 cells while it is able to avoid damage to normal cells since the FA receptors and GSH have overexpression in the 4T1 cells. Thus, this work shows an accessible strategy to design a dandelion-like hierarchical nanoplatform for potential bioimaging-guided synergistic chemo-photodynamic therapy.