Construction Of Functional Polysaccharide Nanoprobes Based On NaYF4:Yb,Er Upconversion Materials

Polysaccharide is one of the most important basic substances in organism.It not only can provide energy,but also is an important component of cells.Polysaccharide has many functions,such as improving organism immunity,enhancing hematopoietic function,resisting tumor,resisting virus,resisting senility and lowering blood sugar.Because of the complexity of polysaccharide biosynthesis and polysaccharide have the characteristics of multi hydroxyls and multi branches,the research methods of polysaccharide are currently not enough.So it is very important to aim at developing new research methods of the polysaccharide,new method of the experimental considerations for new method on structures and molecular mechanisms.In this paper,we use the nano-materials with excellent optical properties to label the polysaccharides,and then to establish the method of tracing the polysaccharides.In this paper,we use two kinds of nanomaterials,one is based on NaYF₄ : Yb,Er upconversion materials to build polysaccharide nanoprobe.Due to upconversion materials have some characteristics,such as strong penetration ability,less damage to biological tissues and no fluorescence interference in background,the sensitivity of the probes can be improved.Methods: Firstly,the bovine serum albumin?BSA?was conjugated with dextran by NaCNBH3.Then the free amino groups of BSA were covalently coupled with NaYF₄:Yb,Er.The experiment in the cell tracer showed that dextran probe can recognize and bind to the dextran receptor on the surface of THP-1 cell.The results indicate dextran probe possesses specific recognition ability,and clear fluorescence images.This method is simple and rapid,and provides a new method for the study of polysaccharides.The second method is based on the conjugation of CdTe fluorescent quantum dots and proteoglycan SBT which is extracted from ganoderma tsugae that is the special local product of Changbai Mountain,to study the receptors of SBT on the cell membrane and metabolic distribution of polysaccharides in animals.SBT and biotin,quantum dots and streptavidin?SA?were covalently coupled separately.Affinity interaction of biotin and SA were used to construct the SBT polysaccharide probe.It was found that SBT could bind to receptors in THP-1 cell surface,and the SBT receptor wasn't uniform distribution.In the study of metabolism in nude mice,we found that SBT polysaccharide was distributed in multiple organs in nude mice.This paper has constructed a novel NaYF₄:Yb,Er upconversion fluorescent probe and realized to trace the polysaccharide receptors in the cell membrane.The method that has been established in our laboratory was used to construct CdTe polysaccharide fluorescent probes.Used the SBT fluorescent probe realized the research on identification of polysaccharide receptors in the cell membrane and on metabolisms of polysaccharide in nude mice.These results will provide new methods for the studies of polysaccharides.