Monitoring of the Natural Excretion of YVO 4 :Yb, Er Upconversion Nanoparticles from a Land Snail

A method for the preparation of samples from a biological material for the detection of upconversion nanoparticles (UNPs) contained in it is proposed on the basis of confocal microscopy techniques. The method was tested by monitoring the natural excretion of an injected colloidal solution of YVO 4 :Yb, Er nanoparticles with sizes from 10 to 700 nm (0.2 mL, containing 15 mg UNPs and with a dosage of 600 mg/kg) into the body of Helix lucorum . The experiments showed that the animal excreted the nanoparticles from the body in a natural way within 3 days, while the excretion rate decreased over time. The sensitivity threshold in the experiments was one nanoparticle per 1 µL.