一种有良好力学性能和生物相容性的抗菌丝蛋白材料研究

发布时间：2018-04-25 15:52

本文选题：丝蛋白 + 庆大霉素　；参考：《南方医科大学》2017年硕士论文

【摘要】：研究背景现在内固定系统已广泛运用于临床骨折的治疗,但是内植物感染和材料的不可吸收是骨科内固定手术后需进行二次手术的重要原因。丝蛋白材料已被证明是一种具良好力学性能和生物相容性的可降解生物材料,然而感染仍然是丝蛋白材料需要面临的一个问题。因此探究抗菌丝蛋白材料的制备也成为了必然趋势。研究目的本研究期望通过在丝蛋白中加入庆大霉素来制备具有良好抗菌性能的可吸收丝蛋白骨科内固定材料,同时能保持良好生物相容性及生物力学性能。我们详细探讨了新型抗菌材料的抗菌性能,并从生物相容性、生物力学强度、降解速率及吸水性等角度初步评价了抗菌丝蛋白材料相关性质的改变,为后期临床应用提供依据。研究方法从蚕茧中提取丝蛋白并在六氟异丙醇溶解过程中加入庆大霉素来制备不同浓度的抗菌丝蛋白材料。利用抑菌圈、平板计数法及扫描电镜评估材料在体外对金黄色葡萄球菌和大肠杆菌的抗菌性能。同时也对比了抗菌丝蛋白材料与普通丝蛋白材料相关性质的改变,包括体内外的生物相容性和体外的生物力学性能、膨胀性以及降解性能等。研究结果普通丝蛋白材料明显促进金黄色葡萄球菌的生长(抑菌率-306.0±3.6%),加入了庆大霉素(16mg/g)的抗菌丝蛋白材料1小时后对金黄色葡萄球菌和大肠杆菌的抑菌率均达到100%,当降低庆大霉素浓度至8mg/g及6mg/g后该时间均延长到12小时。扫描电镜提示抗菌丝蛋白材料表面两种细菌数量均较少,并且金黄色葡萄球菌黏附形态受到不同程度影响。此外抗菌丝蛋白材料在酶溶液中降解4周后对两种细菌的抑菌率仍能维持在90%以上。而生物力学方面,抗菌丝蛋白材料最大弯曲强度为202.8±7.8Mpa、最大剪切强度为35.4±6.1Mpa、弹性模量8.5±0.7Gpa,和普通丝蛋白材料并没有显著的差异(p0.05)。同时在体外抗菌丝蛋白材料未对MC3T3-E1细胞的增殖和凋亡产生不良影响,体内实验也证明其并不会引起明显的炎症反应和毒性反应,对成骨也未产生影响。研究发现相比普通丝蛋白,抗菌丝蛋白材料的降解速率明显加快,并且符合三次函数,而其吸水性却明显下降。结论庆大霉素的最适浓度为16mg/g,此时抗菌丝蛋白材料不仅具有高效、快速、持久的抗菌性,而且能保持其良好的生物力学性能及生物相容性,更重要的是亦可逐渐被降解。该新型抗菌可吸收丝蛋白内固定材料应用于临床有望在一定程度上降低骨科内固定手术后的二次手术率。
[Abstract]:Background the internal fixation system has been widely used in the treatment of clinical fractures, but the internal plant infection and the non-absorbability of materials are the important reasons for the secondary operation after orthopedic internal fixation. Silk protein material has been proved to be a biodegradable material with good mechanical properties and biocompatibility. However, infection is still a problem for silk protein material. Therefore, it has become an inevitable trend to explore the preparation of antibacterial silk protein materials. Objective to prepare absorbable fibroin orthopedic internal fixation materials with good antibacterial properties by adding gentamicin into silk protein and maintain good biocompatibility and biomechanical properties. The antimicrobial properties of new antibacterial materials were discussed in detail, and the changes of the properties of antibacterial silk protein materials were preliminarily evaluated from the aspects of biocompatibility, biomechanical strength, degradation rate and water absorption, which provided the basis for later clinical application. Methods the silk protein was extracted from silkworm cocoon and gentamicin was added in the dissolution process of hexafluoroisopropanol to prepare different concentrations of antimicrobial silk protein materials. The antibacterial properties of the materials against Staphylococcus aureus and Escherichia coli in vitro were evaluated by bacteriostasis, plate counting and scanning electron microscopy. At the same time, the changes of the properties of antibacterial silk protein material and common silk protein material were compared, including biocompatibility in vivo and in vitro, biomechanical properties in vitro, expansibility and degradability. Results the common silk protein material significantly promoted the growth of Staphylococcus aureus (bacteriostasis rate -306.0 卤3.6%). After adding gentamicin (16mg / g), the antimicrobial silk protein material reached both Staphylococcus aureus and Escherichia coli inhibition rate 1 hour after adding Gentamicin to Staphylococcus aureus and Escherichia coli. When gentamicin concentration was reduced to 8mg/g and 6mg/g, the time was prolonged to 12 hours. Scanning electron microscope (SEM) showed that the number of two bacteria on the surface of antibacterial silk protein materials was relatively small, and the adhesion morphology of Staphylococcus aureus was affected to some extent. In addition, the bacteriostatic rate of antimicrobial silk protein material to two kinds of bacteria remained above 90% after degradation in enzyme solution for 4 weeks. In biomechanics, the maximum bending strength, shear strength and elastic modulus of antibacterial silk protein material were 202.8 卤7.8 Mpaand 35.4 卤6.1 Mpaand 8.5 卤0.7 Gpa.There was no significant difference between antibacterial silk protein material and common silk protein material. At the same time, the antibacterial silk protein material had no adverse effect on the proliferation and apoptosis of MC3T3-E1 cells in vitro, and the in vivo experiments showed that it did not cause obvious inflammatory and toxic reactions, nor did it affect osteogenesis. It was found that the degradation rate of antibacterial silk protein was faster than that of common silk protein, and the degradation rate of antimicrobial silk protein was in accordance with cubic function, but its water absorption was obviously decreased. Conclusion the optimum concentration of gentamicin is 16 mg / g. The antibacterial silk protein material not only has high efficiency, fast and lasting antibacterial properties, but also can maintain its good biomechanical properties and biocompatibility, and more importantly, it can be degraded gradually. The new antimicrobial absorbable filamentine internal fixation material is expected to reduce the rate of secondary surgery after orthopedic internal fixation to some extent.
【学位授予单位】：南方医科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R318.08;R68

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