Upconversion NaYF:Yb/Er@silica-TPGS Bio-Nano Complexes: Synthesis, Characterization, and Tests for Labeling Cancer Cells.

Fluorescence imaging is an important technique used for early diagnosis and effective treatment of some incurable diseases including cancer. Herein, we report novel NaYF:Yb/Er@silica-TPGS bio-nano complexes for labeling cancer cells. The NaYF:Yb/Er nanoparticles have been successfully synthesized a hydrothermal route, further coated with a silica shell, and functionalized with d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS). The experimental results indicate that NaYF:Yb/Er@silica-TPGS emits stronger upconversion luminescence than NaYF:Yb/Er under an excitation of 980 nm. More significantly, the NaYF:Yb/Er@silica-TPGS bio-nano complexes could strongly label MCF-7 breast cancer cells for experiments detected by a fluorescence microscope. On the other hand, the complex could not typically probe healthy cells, which are HEK-293A human embryonic kidney cells, under the same experimental conditions. Because of their strong upconversion luminescence, good dispersibility, and biocompatibility, NaYF:Yb/Er@silica-TPGS bio-nano complexes can be a promising candidate/probe for biomedical labeling and diagnostics.