柞蚕丝素的溶解再生及其丝蛋白复合材料的结构与性能研究

发布时间：2018-05-28 05:49

本文选题：柞蚕丝素 + 家蚕丝素　；参考：《武汉纺织大学》2017年硕士论文

【摘要】：柞蚕丝素蛋白(ASF)具有优异的生物相容性和缓慢的降解能力,而且携带哺乳动物细胞的整合素受体RGD三肽序列,在生物材料领域的应用方面拥有广泛的潜力。然而,一方面,柞蚕丝素溶解比较困难,再生的ASF材料力学性能较差,其溶解、再生以及材料的力学有待进一步的提高。另一方面,通过将ASF与不同材料的共混,能够调控其结构与性能,拓展其作为生物材料的应用。本文首先研究了在硝酸钙体系下,不同溶解条件对ASF的分子量和丝素膜力学性能的影响,从而获得高分子量的ASF,以增强ASF材料的力学性能。研究发现,柞蚕丝素纤维的溶解与其溶解的温度和时间密切相关。温度过低,溶解的能力有限,低于90℃时柞蚕丝素纤维难以溶解;温度越高,溶解时间越长,对柞蚕丝素的破坏越大,所得再生丝素蛋白分子量也越小。进一步,以不同溶解方法获得的ASF制备丝素膜,研究了溶解条件对丝素膜力学性能的影响。结果发现,温度为90℃下溶解4 h时,丝素膜的力学性能最佳,干态和湿态下的平均断裂强度分别为28.1±2.4 MPa,2.2±0.3 MPa。在本文中,柞蚕丝素纤维的最佳溶解条件为90℃下溶解4 h。其次,研究了柞蚕丝素蛋白/家蚕丝素蛋白(BSF)共混丝素蛋白溶液的凝胶化行为。研究结果发现ASF凝胶快,5%浓度的ASF在37℃下,33 min左右就能完全凝胶化。但是,ASF水凝胶力学性能差,在浓度低于5%时均无法形成凝胶,而且凝胶在冻干后易碎,难以保持完整形态。家蚕丝素蛋白凝胶十分缓慢,5%浓度的BSF在37℃下,要7天左右才能完全凝胶化。凝胶动力学测试表明,ASF/BSF共混溶液的凝胶化速率可以通过调节共混比例来进行调控。随着ASF的含量逐渐增加,凝胶速率逐渐加快,而随着BSF含量的增加,其凝胶的力学性能增加。再次,研究了ASF/BSF共混膜的结构和性能。研究结果表明,不同比例ASF/BSF共混膜结构主要以无规卷曲为主,并存在少量β-折叠结构,经乙醇处理后,β-折叠为主要分子构象。在力学性能上,ASF/BSF共混膜的断裂强度和断裂伸长性能随着BSF含量的增加而增加。进一步,研究了ASF膜、BSF膜以及共混膜的酶降解行为。研究发现,ASF膜在PBS溶液中溶失更大,酶降解速率更快。在降解21天后,ASF膜的降解剩余率仅为46.4%,而BSF膜降解剩余率为77.0%,50ASF/50BSF的降解剩余率为62.3%。通过调节ASF和BSF的共混比,能够调节共混丝素膜的降解速率。本文的研究结果表明,通过改变ASF和BSF的共混比,可以在一定范围内调控丝素蛋白膜的力学性能和降解速率。最后,初步研究了氧化石墨烯(GO)对ASF/BSF共混膜的结构与性能的影响。结果发现,GO的加入对共混膜的分子构象没有明显的影响。但是,GO含量而过高和过低都会造成共混膜强度下降,会明显降低其强力和断裂伸长,这可能与GO对共混膜内丝素蛋白分子间作用力和结晶结构的影响以及氧化石墨烯与柞蚕丝素可能存在相分离有关,其作用机理有待今后的进一步研究。通过本文的研究发现,溶解条件对ASF的分子量具有重要影响,通过优化溶解条件可以提高ASF的分子量,提高材料的力学性能。同时,通过调节ASF和BSF的共混比例,可以有效调节丝素蛋白的凝胶化速率以及丝素膜的降解速率和力学性能,从而为调控丝素蛋白生物材料的性能提供了新的思路和途径。而GO的加入对ASF/BSF共混膜的分子构象没有明显的影响,但GO的含量对共混膜力学性能具有明显影响。
[Abstract]:Tussah silk fibroin (ASF) has excellent biocompatibility and slow degradation ability, and the integrin receptor RGD three peptide sequence of mammalian cells has a wide potential in the application of biological materials. However, on the one hand, tussah silk fibroin is difficult to dissolve, the mechanical properties of regenerated ASF materials are poor, and then they dissolve. On the other hand, by blending ASF with different materials, the structure and properties of different materials can be adjusted to expand its application as a biomaterial. In this paper, the influence of different dissolving conditions on the molecular weight and the mechanical properties of ASF membrane in the system of calcium nitrate is first studied. It is found that the dissolving of tussah silk fibroin fiber is closely related to the temperature and time of dissolving. It is found that the solubility of tussah fibroin fiber is closely related to the temperature and time of dissolving. The temperature is too low and the ability of dissolving is limited, and the tussah fibroin fiber is difficult to dissolve at 90 C. The higher the temperature, the longer the dissolution time is, the greater the destruction of tussah silk fibroin, the regenerative fibroin protein is obtained. The molecular weight is also smaller. Further, the effect of dissolution conditions on the mechanical properties of silk fibroin film is studied by ASF obtained by different dissolution methods. The results show that the mechanical properties of silk fibroin film are the best when the temperature is 4 h at 90 C, and the average fracture strength under dry and wet state is 28.1 + 2.4 MPa respectively, and 2.2 + 0.3 MPa. in this paper, tussah The optimum dissolving condition of silk fibroin fiber was 4 h. at 90 C and then 4 h.. The gelation behavior of tussah silk fibroin / silk fibroin (BSF) blend silk fibroin solution was studied. The results showed that the ASF gel was fast and the 5% concentration of ASF could be completely gelatinized at about 33 min at 37 C. However, the mechanical properties of the hydrogel were poor and the concentration was lower than that of the gel. The gel was not formed at 5%, and the gel was fragile after freeze-drying, and it was difficult to maintain a complete form. The gels of silk fibroin protein were very slow, and the 5% concentration of BSF could be completely gelatinization at about 7 days at 37 C. The gel kinetics test showed that the gelation rate of the ASF/BSF blend solution could be regulated by adjusting the blending ratio. With A The content of SF increased gradually and the gel speed increased gradually, and the mechanical properties of the gel increased with the increase of BSF content. Again, the structure and properties of the ASF/BSF blend membranes were studied. The results showed that the structure of ASF/BSF blend membranes was mainly composed of random curling, and there was a small amount of beta folding structure, after ethanol treatment, beta folding. The fracture strength and elongation properties of ASF/BSF blend films increase with the increase of BSF content in mechanical properties. Further, the enzyme degradation behavior of ASF film, BSF film and blend membrane is studied. It is found that the ASF membrane dissolves more greatly in PBS solution and the rate of enzyme degradation is faster. After 21 days degradation, the degradation of ASF film is left. The residual rate is only 46.4%, while the residual rate of BSF film degradation is 77%. The degradation residual rate of 50ASF/50BSF is 62.3%. by adjusting the blending ratio of ASF and BSF. The results of this study show that the mechanical properties and degradation of the silk fibroin membrane can be regulated in a certain range by changing the blending ratio of ASF and BSF. At last, the effect of graphene oxide (GO) on the structure and properties of ASF/BSF blends was preliminarily studied. The results showed that the addition of GO had no obvious effect on the molecular conformation of the blend membrane. However, the content of GO, which was too high and too low, would cause the decrease of the strength of the blend membrane, which would obviously reduce the strength and elongation of the blends, which may be blended with GO. The influence of the intermolecular force and crystalline structure of the membrane and the possible phase separation of graphene oxide and tussah silk fibroin may be related to the further study on the molecular weight of ASF, and the molecular weight of ASF can be improved by optimizing the dissolving conditions. At the same time, by adjusting the blending ratio of ASF and BSF, the gelation rate of silk fibroin and the degradation rate and mechanical properties of silk fibroin membrane can be effectively regulated, which provides a new way of thinking and way to regulate the properties of silk fibroin biomaterials, and the molecular conformation of the ASF/BSF blend membrane has not been added by the addition of GO. Obviously, the content of GO has obvious effect on the mechanical properties of blend film.
【学位授予单位】：武汉纺织大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB33;R318.08

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