Study On The Synthesis And Biocompatibility Of GdVO₄:Eu Luminescent Nanoparticles

Rare earth has unique 4f electronic structure,so they can produce abundant electronic energy levels,they can absorb or emit different wavelength electromagnetic radiation range between ultraviolet,visible to near infrared region,they can present abundant optical properties.Rare earth luminescent nanoparticles have optical properties,such as long luminescence lifetime,large Stokes shift,pure luminescent color,narrow half emission peaks,and so on.Rare earth luminescent nanoparticles have been successfully used in cell labeling,luminescence resonance energy transfer and biological molecules determination.We studied the preparation method and performance of Eu3+ doped rare earth vanadate luminescent nanoparticles.Firstly,we synthesized LnVO₄:Eu（Ln=Gd,Lu,Y,La）nanoparticles and chose the host materials based on the luminescence intensity.Secondly,we try several commonly synthetic methods of GdVO4:Eu nanoparticles and choosed the best synthesis method.With phosphoryl polyacrylic acid（POCA）,polythioetherimide（PEI）and sodium citrate as ligand synthesized GdVO4:Eu nanoparticles,we chose the suitable organic ligand based on the luminescence intensity.On the basis of the above experiments,the nanoparticles were synthesized with sodium citrate as ligand by hydrothermal method,and the synthetic conditions were optimized based on the luminescence and water-solubility of GdVO4:Eu nanoparticles.The luminescence intensity of the as-prepared nanoparticles were high and stable and the lifetime was 0.87 ms.GdV04:Eu nanoparticles were characterized by many methods.The results showed that the as-prepared GdVO4:Eu nanoparticles were tetragonal with the average size of about 10 nm.GdVO₄:Eu nanoparticles were coated with SiO2 and GdVO4.The result of IR showed that GdVO4:Eu nanoparticles have been successfully coated with SiO2;luminescence intensity of the nanoparticles coated with GdVO4 showed the more Eu3+ ion occupied cells for the crystal center symmetric.By detecting the resonance rayleigh scattering intensity of GdVO4:Eu nanoparticles bound and unbound with trypsin,we studied the state of bound between GdVO4:Eu nanoparticles and biomolecules.The results showed that the GdVO4:Eu nanoparticles could couple with trypsin by electrostatic interaction and the best experimental conditions were investigate.The circular dichroism experiments showed the structure of trypsin did not been changed bound and unbound with nanoparticles and the nanoparticles have good biocompatibility.