Preparation And Performance Rhubarb And Epimedium Polysaccharide/Gelatin Hydrogels By Cross-linking Method

Tissue engineering is an effective way to solve the problem of insufficient tissue and organ substitutes.Finding suitable biomaterials which can simulate extracellular matrix is the focus of tissue engineering.Extracellular matrix(ECM)is a dynamic water-rich network structure outside cells.It is composed of collagen,proteoglycan and glycoprotein.Its structure is similar to that of porous three-dimensional network hydrogel,so hydrogel is often used as the cell matrix in tissue and organ construction.However,the preparation cost of natural cell matrix molecules is relatively high except collagen.Our previous studies have shown that polysaccharides from traditional Chinese medicine have various activities.If they can be prepared into hydrogels with gelatin,they may mimic the cell matrix and even give more activity to the cell matrix.In this study,two kinds of polysaccharides,rhubarb polysaccharides and epimedium polysaccharides,which have many biological activities,were selected to prepare hydrogels together with gelatin to explore the possibility of the application of the hydrogels in tissue engineering.In this study,rhubarb polysaccharides and epimedium polysaccharides were extracted.Then the two kinds of polysaccharides were oxidized with different amounts of sodium periodate,and the aldehyde content in the polysaccharide was analysed.Gelatin was modified with ethylenediamine,and the amino group content in gelatin before and after modification was determined by TNBS method.Rhubarb polysaccharide/gelatin hydrogel(DGH-1,DGH-2,DGH-3,DGH-1',DGH-2',DGH-3')and epimedium polysaccharide/gelatin hydrogel(YGH-1,YGH-2,YGH-3,YGH-1',YGH-2',YGH-3')were prepared according to the volume ratio of polysaccharide to gelatin: 1:1,2:1,1:2.The prepared hydrogel were evaluated by electron microscopy,infrared spectroscopy,in vitro swelling,degradation,release experiments,rheological analysis,and cell compatibility experiments.The results of infrared spectroscopy indicated that the characteristic absorption peak of Schiff base bond appeared in the prepared rhubarb polysaccharide/gelatin hydrogel.The results of electron microscopy showed that rhubarb polysaccharide/gelatin hydrogel and epimedium polysaccharide/gelatin hydrogel have obvious porous structure.The swelling test in vitro showed that the swelling rate of rhubarb polysaccharide/gelatin hydrogel and epimedium polysaccharide/gelatin hydrogel was higher than that of neutral and alkaline solution in acidic solution.The in vitro degradation results showed that the degradation rate of rhubarb polysaccharide/gelatin hydrogel and epimedium polysaccharide/gelatin hydrogel was higher than other ratios when the volume ratio of polysaccharide to aminated gelatin was 1:1 during the degradation period of the test.The in vitro release results showed that the release rate of rhubarb polysaccharide/gelatin hydrogel and epimedium polysaccharide/gelatin hydrogel was higher than other ratios when the volume ratio of polysaccharide to aminated gelatin was 1:1 after 144 hours of release.The rheological results showed that both kinds of polysaccharide hydrogel have a certain mechanical strength.The results of cytocompatibility showed that the two kinds of polysaccharide hydrogel were not substantially toxic to BMSC cells and had a certain proliferative effect.In summary,rhubarb polysaccharide gelatin/hydrogel and epimedium polysaccharide/hydrogel prepared by covalent cross-linking method have potential application in tissue engineering.