Small molecular target-based multifunctional upconversion nanocomposites for targeted and in-depth photodynamic and...

A novel multifunctional nano-system, ZnPc-UCNPs-PEG-G, was designed for targeted and in-depth photodynamic therapy. The nano-system was built via covalent conjugation, in which phthalocyanine zinc (ZnPc), Gefitinib (G), NaYF₄: Yb, Er (UCNPs) and PEG derivatives were employed as the photosensitizer, target moiety, upconversion nanomaterial and linker unit, respectively. The photophysical/chemical properties, in-depth photodynamic activity, cancer cell specificity and anticancer activity of ZnPc-UCNPs-PEG-G were investigated. The as-prepared ZnPc-UCNPs-PEG-G exhibits excellent photosensitizing ability, generating reactive oxygen species (ROS) via effective energy transfer from UCNP to phthalocyanine zinc. In addition, the composite exhibits specific affinity to HepG2 cancer cells and high anticancer activity. To the best of our knowledge, this is the only example of a UCNP platform that is capable of molecular targeted and in-depth photodynamic and chemo-anticancer therapy via the introduction of a small molecular targeting drug moiety.