Preparation And Biological Activity Of Drug Sustained-release Silk Fibroin/Sodium Alginate Composite Scaffold

In this paper,the silk fibroin/sodium alginate composite scaffolds were prepared by freeze-drying method using natural silk fibroin and sodium alginate as raw materials.The three-dimensional porous composite scaffold material was characterized by FESEM,porosity,FTIR,XRD,water absorption,degradation and other tests.The release properties and release rules of composite scaffolds were studied by the silk fibroin/sodium alginate composite scaffold loaded with vancomycin hydrochloride(VAN)was prepared which used the composite scaffold material as carrier.In vitro bioactivity of silk fibroin/sodium alginate composite scaffold and VAN@silk/sodium alginate was studied by cell experiments.The specific research work is as follows:(1)Preparation of silk fibroin/sodium alginate composite scaffoldFirst,the silk fibroin/sodium alginate solution sonication to form a gel,and the silk fibroin/sodium alginate composite scaffold was prepared by freeze-drying technique.Through the porosity test of different proportions of silk fibroin/sodium alginate,it was found that the porosity of all scaffold materials could reach over 98%,and the higher the proportion of sodium alginate,the higher the porosity Experiments show that the water absorption of the prepared composite scaffold material is better than that of the pure silk fibroin scaffold,which is benefit to the adhesion and proliferation of cells on the scaffold.At the same time,the increased proportion of sodium alginate in the silk fibroin/alginate composite scaffold will increase its compressibility.In all scaffolds,the silk fibroin/sodium alginate composite scaffold with the mass ratio of 90/10 has the best mechanical properties.(2)Drug sustained-release properties of silk fibroin/sodium alginate composite scaffold and its in vitro biomimetic mineralizationThe drug release behavior of different mass ratios of silk fibroin/sodium alginate under different pH conditions was studied by using silk fibroin/alginate composite scaffold as carrier and VAN as drug model.The study results showed that with the increase of the mass ratio of sodium alginate in the composite scaffold,VAN drug molecules would have higher initial release rate and average release rate.The release kinetics of the composite scaffold was affected by pH.The cumulative release rate of the same composite scaffold in a solution with a pH of 4.5 is significantly higher than that in a solution with a pH of 7.4,indicating a decrease in pH promote the release of VAN drugs.The silk fibroin/sodium alginate composite scaffold was used to induce the formation of hydroxyapatite crystals by in vitro biomimetic mineralization.It was found by FTIR and EDS that the amount of hydroxyapatite crystals increased as the mass ratio of sodium alginate increased.(3)In vitro cytological study of composite scaffoldsThe silk fibroin/sodium alginate scaffold and VAN@silk fibroin/sodium alginate scaffold were cultured in combination with BMSCs cell which in rat bone marrow respectively in order to evaluate the cell proliferation ability and cytocompatibility of the silk fibroin/sodium alginate composite scaffold and the VAN@silk fibroin/sodium alginate composite scaffold.Laser confocal MTT assays showed that the silk fibroin/alginate composite scaffold significantly promoted the adhesion and proliferation of BMSCs.When the mass ratio of silk fibroin/sodium alginate is 80/20,it is most benefit for the proliferation of cells.Compared with the VAN@silk fibroin/sodium alginate composite scaffold,the same mass ratio of the silk fibroin/sodium alginate composite scaffold has better cell proliferation effect.The morphology of the cells in the composite scaffold was observed by FESEM.It was found that the adhesion and spreading of BMSCs were well on the composite scaffold.