Study On The Preparation And Application Of Natural Protein And Polysaccharide Biomaterials

Natural biomaterials generally have good biocompatibility,which can promote tissue healing by transmitting biochemical signals in the organism.Currently,natural biomaterials have been identified as a method to promote healing,especially for tissue repair and regeneration.Type Ⅰ collagen has good biocompatibility and low immunogenicity.The development and utilization of collagen-based biomedical materials has attracted widespread attention.Porcine skin contains a large amount of type Ⅰ collagen.The traditional acid extraction method can cause certain damage to the collagen structure,which is likely to lose the biological activity of the extracted product.However,the enzymatic method has long extraction cycle and low extraction rate.Therefore,the method for extracting collagen needs to be improved in order to obtain high-yield,high-purity collagen and ensure the biological activity of collagen.Collagen and chitosan have good biocompatibility.Collagen is the main component of extracellular matrix(ECM).Chitosan has similar properties according to glycosaminoglycan(GAG)substances in ECM,making these two materials become ideal material to promote tissue repair.This article mainly includes four aspects of research on the above two materials:(1)After comparing direct enzymatic hydrolysis and acid-enzymatic hydrolysis to extract type Ⅰ collagen from porcine skin,it was found that the acid-enzyme combination method extracts collagen from porcine skin with a higher yield of 74.97±2.78 %,which was 1.15 times better than the one from direct enzyme extraction method.The acid-enzymatic hydrolysis reaction took 24 h to complete,which was half of the extraction time used by the direct enzymatic hydrolysis method.It greatly improves the extraction efficiency.Through SDS-PAGE gel electrophoresis,infrared spectroscopy,and amino acid composition detection,the collagen extracted by acid-enzymatic hydrolysis was proved to be type Ⅰ collagen,and the triple helix structure was basically intact.(2)Study on the modified collagen sponge(GA-Coll)prepared by glutaric anhydride and ultraviolet cross-linking.In the mechanical experiment,when 10 %(w/v)modified collagen was irradiated for 60 min,the maximum tensile strength was 1.89±0.18 MPa and the elongation at break was 14.31±1.62%.SEM and water absorption performance measurement showed that CSEM had porous structure and good water absorption ability.In vitro cell experiments showed that the modified collagen sponge promoted the proliferation and adhesion of fibroblasts.It proved CSEM has good biocompatibility,and is also beneficial to promote wound healing.In vivo experiments proved that the use of modified collagen sponge can promote tissue regeneration and has a good effect on wound healing.The healing rate is100% in 14 days.It is an effective skin wound dressing.(3)This study investigated a chitosan electrospun membrane(CSEM)prepared by a needleless technology called Nanospider.Scanning electron microscopy revealed that CSEM is a laminated nanofiber with good mechanical properties.The fiber is uniform with the diameter distributing in the range of 100～120 nm.The tensile strength can reach 27.45±6.30 MPa with a maximum elongation at break of 18.50±1.44 %,which makes it stick easily to damaged parts but not to be easily damaged by tissue friction.The growth of S.aureus on CSEM was 59.18% lower than the control at 10 h,which indicates its better antibacterial property.In addition,CSEM has good coagulant and biocompatibility characteristics.It can perform hemostatic function within 10 min and the L929 mouse fibroblast viability on it was92.18% ±1.08% on the seventh day.In vivo experiments indicated that the effect of CSEM on wound healing is 97.17±1.50% healing rate in 14 days.In addition,CSEM can significantly prevent peritoneal adhesions within four weeks after surgery with wound surface coverage.These results indicate that CSEM is a promising anti-adhesion barrier material.