Construction Of Vascular Tissue Engineering Scaffold Based On Nanofiber Yarn Forming Technology

Nowadays,the incidence of cardiovascular diseases is getting higher and higher,which leads to the shortage of the replacement materials of blood vessel.Therefore,designing an ideal vascular scaffold material with a highly biomimetic structure,composition and function and inducing good mechanical properties and biocompatibility in vascular tissue is significant in vascular tissue engineering.The main work of this paper is as follows:Firstly,the silk fibroin peptide(TSF)was extracted.TSF was extracted from tussah silk which of silk fibroin with Arg-Gly-Asp(RGD)tripeptide sequence,possesses good biocompatibility.Tussah silk was degummed with sodium carbonate solution,and then dissolved with calcium chloride,followed by thermal degradation with hydrochloric acid,next was neutralized with sodium carbonate.Finally,TSF with molecular weight of 300-5000 D was intercepted through nanofiltration.The result indicated that the highest yield of TSF was 51%.Meantime,there were more amino acids on the surface of silk fibroin macromolecule chain after degradation,which demonstrated the hydrophilicity of TSF was increasing,facilitating the improvement of biocompatibility.Secondly,in order to obtain the small-diameter vacsular material,poly(L-lactic-co-poly(?-lactolactone)copolymer(PLCL)nanofiber core yarns were firstly prepared by electrospinning with nylon filament as the core yarn,and then the core filament was withdrawn from yarn.Subsequently,TSF was grafted in it through Plasma,obtianing tube-shaped nanofiber scaffold material,which of the outer diameter was 1.1 mm.Results displayed that the mechanical properties of the PLCL/TSF nanofiber vascular scaffolds were improved,and the Yong's modulous increase to 8.6 ± 0.19 MPa.Meanwhile the optimal protein adsorption performance of the vascular scaffold materials was also achieved.In vitro cell culture suggested that PLCL/TSF nanofiber vascular scaffolds could preferably promote the proliferation and adhesion of endothelial cells(VECs)and possess better biocompatibility.Thirdly,to further mimic the similar composition,structure and function of human blood vessels,a small-diameter nanofiber scaffold(PLCL/PCL/TSF)with PLCL/TSF as inner layer and PCL/TSF as outer layer was prepared.The results indicated that the PLCL/PCL/TSF nanofiber vascular scaffolds had a compact double layer structure with an inner diameter of 700 ?m and an outer diameter of 1.1 mm.In addition,the burst pressure of PLCL/PCL/TSF nanofiber vascular scaffolds increased to 14950 ± 254 mm Hg.The results of cell culture showed that both the inner layer of PLCL/TSF and the outer layer of PCL/TSF nanofibers could better promote the adhesion and proliferation of VECs and smooth muscle cells(VSMCs)after TSF grafting,as compared with PLCL/PCL nanofiber scaffolds,which resulted the higher cell activity.In conclusion,the small-diameter nanofiber tubular vascular scaffold materials with highly biomimetic multi-layer will be one kind of excellent vessels substitute materials,which may be used in clinical treatment for blood vessels.