Synthesis And Surface Coating Of Nano-luminescent Material YPO₄:Sm³⁺ And Its Interaction With Protein

In biological systems,nucleic acids,proteins,and sugars are the three most basic elements of biology.The interaction between proteins and small molecules is the basic problem of initiating chemical reactions in biological systems.Therefore,research and development of new fluorescent probes with good selectivity,high sensitivity and good biocompatibility are of great practical significance and academic value.In this paper,the best experimental scheme is first studied by orthogonal experiment method,and then on this basis,the effect of pH on the performanc e of YPO₄:Sm³⁺nanoluminescent material is mainly studied.The YPO₄:Sm³⁺p hosphor is coated with chitosan?CS?and PEG to prepare YPO₄:Sm³⁺@CS and YPO₄:Sm³⁺@PEG fluorescent probes,through XRD?X-ray diffraction?,SEM?sca nning electron microscope?,TEM?transmission electron microscope?,fluorescenc e spectrophotometer,IR?infrared spectroscopy?,UV?ultraviolet spectroscopy?and other instruments were used to characterize the structure,morphology and lumi nescence properties of the product.The results show that the rare earth nano p hosphors before and after coating have a single tetragonal?YPO₄?structure,an d the prepared phosphors are spherical,and the thickness of the coating layer i s about 5¹0nm.And the surface-modified samples have better water solubility and biocompatibility.The core-shell structure of YPO₄:Sm³⁺@PEG nano fluores cent probe has increased fluorescence performance.The calibration of BSA by YPO₄:Sm³⁺@CS and YPO₄:Sm³⁺@PEG at roomtemperature was studied,and the corresponding linear formulas were obtained.Fluorescence method was used to study the adsorption of YPO₄:Sm³⁺@CS and YPO₄:Sm³⁺@PEG to BSA at different times,and the corresponding adsorption curve and maximum adsorption amount were obtained.The results show that the adsorption process of YPO₄:Sm³⁺before and after coating is different.The adsorption effect before coating is desorbed and the secondary adsorption phenomenon makes the adsorption process more complicated,and the adsorption after coating is monolayer adsorption.The interaction between the fluorescent probe YPO₄:Sm³⁺@PEG and bovine serum albumin was studied by fluorescence method.At four different temperatures,YPO₄:Sm³⁺@PEG quenched the fluorescence of bovine serum albumin.And get the corresponding binding constant and the number of binding sites.Through the study of thermodynamic parameters and force,it is judged that the reaction between the two is a spontaneous exothermic reaction,and the interaction between the rare earth nano fluorescent probe and BSA not only has theeffect of electrostatic force,but also has hydrogen bonding and van der Waals force.effect.Finally,the effect of YPO₄:Sm³⁺@PEG on the conformation of BSA was explored using simultaneous fluorescence spectroscopy and three-dimensional fluorescence spectroscopy.The experimental results show that when YPO₄:Sm³⁺@PEG is combined with BSA,it only binds to the vicinity of tryptophan residue,making its structure loose,the polarity around the tryptophan becomes larger,and the hydrophobicity increases.