Biocompatibility of silica coated NaYF4 upconversion fluorescent nanocrystals

Here we report the synthesis of uniform silica coated hexagonal-phase NaYF4 nanocrystals with Strong NIR-to-visible upconversion fluorescence and its cytotoxicity and biodistribution in a rat model. The silica coated NaYF4 nanocrystals were incubated with rat skeletal myoblasts and bone marrow-derived mesenchymal stem cells and cytotoxicity was assessed by using MTS and LDH assay. Healthy rats were injected intravenously with the nanocrystals so as to further investigate their biocompatibility and tissue distribution. The results from this study revealed that the silica coated NaYF4 upconversion nanocrystals displayed good in vitro and in vivo biocompatibility, demonstrating their potential applications in both cellular and animal imaging systems. (C) 2008 Elsevier Ltd. All rights reserved.