| Damage to the integrity of human tissue caused by trauma or serious disease is inevitable.Although the body has a certain degree of self-healing,it is far from enough for some serious injury or necrosis.Thus,tissue engineering dedicated to functional tissue regeneration has been established and developed.Cell targeting with three-dimensional polymer scaffolds has become a common strategy in tissue engineering.The sustainable development of this field depends to a certain extent on the development of new materials and the improvement of support processing technology.In recent years,the research on biocompatibility and biodegradability of tissue engineering materials has made it have a prominent application in biomedicine.Collagen,as one of the most competitive biomaterials in tissue engineering and medical applications,has been widely studied and reported.However,the properties of collagen vary from source to source.The poor mechanical properties of pure collagen materials also lead to limited application.In this study,pure fish skin collagen and its composites were prepared and studied.First,type Ⅰ collagen was extracted and purified from the skin of Japanese sea bass and Nile tilapia.The samples were characterized by UV,FTIR and SDS-PAGE.The physical and chemical properties were compared with commercial pig collagen.In terms of thermal stability,TC and PC were stronger than SBC.After incubated at 37 ℃,only a small amount of collagen was degraded in TC and PC,and the degradation in SBC was serious.In terms of mechanical stability,the compressive stress of TCH is 0.099 MPa,SBCH 0.047 MPa,PCH 0.003 MPa.The results of amino acid test showed that the content of hydroxyproline in TC was similar to that in PC,which was higher than that in SBC,and that was consistent with the result of thermal stability.And the cystine content in tilapia was significantly higher than that in pig and bass,which was consistent with the result of mechanical properties.These results show that the contents of hydroxyproline and cysteine play an important role in the thermal and mechanical properties of the three kinds of collagen hydrogel.In the second part,spider silk protein Ma Sp1-12 was used as the basic unit,the spider silk protein sequence connected to p ET28 a vector was gradually added to Ma Sp1-48 by tandem.Restriction endonuclease analysis showed that the sequence of Ma Sp1-24,36,48 protein was obtained successfully.The Ma Sp1 protein plasmid was transformed into host cell to express protein and be purified.The results of SDS-PAGE showed that the high-purity Ma Sp1 protein was obtained.The Ma Sp1 protein / TC composite hydrogel was prepared by mixing Ma Sp1 protein and TC with different mass ratio.The results of mechanical properties test show that the maximum compressive stress of the composite hydrogel is higher than that of TCH,and the mechanical properties of the composite hydrogel are better with the increase of the ratio of Ma Sp1 protein into the composite hydrogel.In the third part,PEGDA was synthesized by dissolving PEG and acrylic chloride in DCM catalyzed by TEA.NMR spectroscopy showed that the double bonds were integrated into PEG,indicating the successful synthesis of PEGDA.PEGDA was mixed with TC,PEGDA was crosslinked under 365 nm UV irradiation to form a network structure,then PEGDA/TC composite hydrogel with interpenetrating network structure was formed by physical cross-linking with TC.The results of mechanical properties test showed that the maximum compressive stress of p H 5.0 PEGDA/TC composite hydrogel was 0.94 MPa,which was significantly higher than that of TCH and Ma Sp1/TC composite hydrogel.In this study,the reasons for the differences in the properties of collagen from different sources were analyzed,which provided certain guiding significance for the search for collagen with good performance.The modification of collagen laid a good foundation for the application of tissue engineering with high mechanical properties. |
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