Toxicity Assessments of Near-infrared Upconversion Luminescent LaF(3):Yb,Er in Early Development of Zebrafish Embryos

This study reports the effects of upconversion nanoparticles (UCNPs) LaF(3):Yb,Er on zebrafish, with the aim of investigating UCNPs toxicity. LaF(3):Yb,Er were prepared by an oleic acid/ionic liquid two-phase system, and characterized by transmission electron microscope and X-ray powder diffraction. 140 zebrafish embryos were divided into six test groups and one control group, and respectively were injected into 5, 25, 50, 100, 200, 400 μg/mL LaF(3):Yb,Er@SiO(2) solution, and respectively were raised for 5 days. Each experiment was repeated ten times. Results showed that water-soluble LaF(3):Yb,Er were successfully prepared, and did not exhibit obvious toxicity to zebrafish embryos under 100 μg/mL, but exhibited chronic toxicities 200 μg/mL in vivo, resulting in malformations and delayed hatching rate and embryonic and larval development. The excretion channels of LaF(3):Yb,Er in adult zebrafish were mainly found in the intestine after being injected evenly for 24 h. In conclusion, the exploration of LaF(3):Yb,Er for in vivo applications in animals and humans must consider UCNPs biocompatibility.