One-step self-assembly of ZnPc/NaGdF4:Yb,Er nanoclusters for simultaneous fluorescence imaging and photodynamic effects on cancer cells

Upconversion luminescence (UCL) nanoparticles hold great promise as potential photosensitizer carries for photodynamic therapy (PDT). In this study, one-step self-assembly fabrication of ZnPc/NaGdF4:Yb,Er nanoclusters was developed using an amphiphilic PMAO-PEG to encapsulate simultaneously photosensitizer zinc phthalocyanine (ZnPc) and NaGdF4:Yb,Er nanocrystals via polymer solidification, which has provided a facile and versatile strategy for the design of a drug carrier platform. The ZnPc/NaGdF4:Yb,Er nanoclusters possessed good dispersibility and excellent UCL. Upon 980 nm light irradiation, the singlet oxygen generated by ZnPc was examined owing to the occurrence of FRET from the NaGdF4:Yb,Er nanocrystals to the ZnPc molecules. Confocal imaging and cell viability (about 50%) performed on HeLa cells exhibited the cell internalization and the remarkable PDT effects of the ZnPc/NaGdF4:Yb,Er nanoclusters. These results demonstrate that the nanoclusters as a drug carrier nanoplatform would be a promising theranostic strategy for the diagnosis and therapy of cancers.