Surface modification of spherical fluorescent nano-material YPO4:Sm3+ and its adsorption for BSA

Fluorescent nano-probes have great potential applications for diagnostics and therapy. In this work, the microwave-assisted Stöber method was used for the surface modification of the spherical nano-phosphor YPO 4 :2%Sm 3+ to solve the problems of hydrophilicity and biocompatibility of spherical fluorescent nano-material YPO 4 :Sm 3+ . Their structural, morphology and optical properties were determined using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectra, TG–DTA curve and fluorescence spectrophotometry. And the adsorption of YPO 4 :2%Sm 3+ @SiO 2 to bovine serum albumin was studied by the static isothermal adsorption method. Results indicated that YPO 4 :2%Sm 3+ @SiO 2 was uniformly monodisperse core–shell nano-sphere with an average diameter of 60–90 nm. The crystal structure and morphology of the phosphor YPO 4 :Sm 3+ was not changed after the surface modification, the thickness of the coating layer was approximately 10–20 nm and the fluorescence intensity and lifetime of the modified product were reduced. The adsorption of YPO 4 :2%Sm 3+ @SiO 2 to protein was the mono-molecular layer adsorption, the adsorption formula was Y  = 0.0051 X −0.0000037 and the maximum adsorption amount q  = 198.89 mg/g. This study successfully solved the problems of hydrophilicity and biocompatibility of spherical nano-phosphor YPO 4 :2%Sm 3+ .