RESUMO
Nanotechnology is receiving increasing attention due to its fantastic advantages and potential applications in nanofood and nanomedicine. However, the safety of touching manufactured nanoparticles is still uncertain for human beings. Here, we track inorganic nanoparticles in the digestive system of the mouse through upconversion fluorescence and X-ray imaging, and try to demonstrate whether or not the inorganic nanoparticles will penetrate the digestive system to enter the blood system. Lanthanide-doped upconversion nanoparticles, which can convert infrared light to visible light and are simultaneously sensitive to X-rays, were selected as model inorganic nanoparticles. The investigation clarifies that even the ultrathin nanoparticles (â¼5 nm) could not penetrate the digestive tract to enter the bloodstream or surrounding tissues, but were gradually excreted out. Our results help assess the safety of inorganic nanoparticles potentially used in nanofood and nanomedicine.
RESUMO
Here, we report the enhanced upconversion luminescence of NaLuF4:18%Yb(3+),2%Er(3+) through core/shell structures. Among NaYF4, NaGdF4, and NaLuF4 shells, the first one presents the highest efficiency. These upconversion fluorescent nanoprobes with an oleic acid/PEG hybrid ligand can efficiently capture Rhodamine B (RB) and sodium fluorescein (SF) in opaque fishes to present their residues in vivo through luminescence resonant energy transfer (LRET) processes. It can be confirmed based on LRET technology that no RB is absorbed by opaque fishes after incubating in the aqueous solution of 1 µg ml(-1) RB for one day, while SF residue can be obviously detected after incubating in the aqueous solution of 1 µg ml(-1) SF for one day. The merit of this LRET technology with the upconversion nanoparticle (UCNP) donor is ascribed to the deep penetration depth of the infrared pumping laser and high signal to noise ratio.