A specific HeLa cell-labelled and lysosome-targeted upconversion fluorescent probe: PEG-modified SrYbF:Tm .

In this study, water-soluble PEG-modified SrYbF:Tm was prepared conveniently by a one-pot solvothermal method, where the molar ratio of Sr to Yb was controlled between 3 : 2 and 1 : 1. The optimum red-light emission at 677-699 nm was modulated via 0.7% Tm doped under irradiation at 980 nm. Interestingly, biological experimental results showed that the PEG-modified SrYbF:Tm with low toxicity, excellent cell membrane permeability and high photostability can not only distinguish HeLa cells from mouse embryonic fibroblasts but also target the subcellular organelle lysosome in HeLa cells; therefore it can be anticipated that the as-prepared material would be a potential tool for cancer diagnosis.