基于聚乳酸和氧化石墨烯的功能化改性及生物医学应用研究

发布时间：2018-07-03 01:57

本文选题：聚乳酸 + 氧化石墨烯　；参考：《上海大学》2016年博士论文

【摘要】：现代生物材料要求材料可以促进细胞在其表面黏附、增殖等,从而可以使生物材料植入人体后快速与周围组织整合,加速损伤组织或器官修复,避免其它并发症的出现。这就要求对传统的生物材料进行功能化改性,引入生物活性分子。本文以可生物降解的高分子材料聚乳酸(Poly(lactic acid),PLA)和新型碳材料氧化石墨烯(Graphene Oxide,GO)的功能化改性为研究对象,并系统地研究了改性后的材料与成骨细胞的相互作用,探索了其在生物医学领域的应用。聚乳酸(Poly(lactic acid),PLA)又称聚丙交酯,因其性能良好,PLA已被美国食品和药品管理局(FDA)批准广泛用作药物控释载体、医用手术缝合线及骨折内固定材料等生物医用高分子材料。然而,聚乳酸,还存在一些不可忽视的缺点,如亲水性低,细胞亲和性差,以及降解中会导致局部酸性积累而使植入体部位出现非感染性炎症等。以上性能缺陷限制了聚乳酸在生物医学领域中的应用。为克服上述缺陷,人们对PLA做了大量的改性研究工作,以提高其亲水性,改善其降解性能。本文创新性地设计合成了多聚赖氨酸改性聚乳酸的树枝状聚合物PLLA-d,该树枝状聚合物以疏水的PLLA为核心,赖氨酸分支在两端提供了足量的表面正电荷。合成产物的化学结构通过核磁共振氢谱(1H NMR)和凝胶渗透色谱(GPC)得到了证实。随着赖氨酸的引入,PLLA的熔点降低,弹性模量降低,但亲水性提高。得到的产物PLLA-d采用Breath-Figure方法制备了蜂窝状多孔膜H-PLLA-d,用于研究小鼠成骨细胞MC3T3-E1与合成材料之间的相互作用。结果表明,相对于PLLA膜,MC3T3-E1细胞功能包括细胞黏附、增殖和分化在H-PLLA-d膜上有显著地提高。氧化石墨烯(GO),石墨烯的重要衍生物,是从氧化石墨剥离而得到的。和石墨烯相比,GO在水中分散性好,表面含氧基团丰富使其更容易被功能化改性,而且制备成本低,因此,氧化石墨烯已经被广泛应用于生物传感器、生物成像、药物递送,以及组织工程支架材料等生物医学领域。GO在生物医学领域的应用已经显示出很大的潜力,但其生物相容性仍然没有定论,为了开拓其在生物医学领域的应用,提高其生物相容性非常必要。为此,我们采用精氨酸-甘氨酸-天冬氨酸(Arg-Gly-Asp,RGD)三肽序列改性GO得到GO-RGD,通过对GO上的羧基进行活化后,一步合成了GO-RGD。得到的产物通过元素分析和傅氏转换红外线光谱分析(FTIR)证实了新的化学结构的出现,采用扫描电子显微镜(SEM)和透射电子显微镜(TEM)对GO-RGD的表面形貌进行了研究,通过TEM观察改性前后GO形貌的变化进一步确定了RGD的绑定。细胞实验结果表明,相对于GO膜,MC3T3-E1细胞功能包括细胞黏附、增殖和分化在GO-RGD膜上有显著地提高,而且这种促进作用和RGD含量相关。该GO-RGD的促进成骨作用,使得其有望应用于骨修复等生物医学领域。同时,我们通过一步反应,制备了明胶(gelatin)功能化改性的GO。通过FTIR、X射线光电子能谱分析(XPS)、SEM等表征手段确认了功能化的完成。并在生物医用镍钛合金表面制备了GO涂层GO@NiTi,以及gelatin功能化改性GO的涂层GOGel@NiTi。通过系统地研究涂层样品对MC3T3-E1成骨细胞的影响,结果表明,相对于NiTi合金,涂层后样品明显提高了细胞黏附、增值和分化,特别是GOGel@NiTi在三者中具有最好的成骨细胞相容性。此外,我们采用菌落计数法、死活细胞染色法,以及SEM研究了涂层样品对大肠杆菌E.coli的影响。通过对涂层样品的抗菌性能研究,发现涂层对大肠杆菌E.coli具有一定的抗菌能力,细菌的细胞膜结构被涂层样品破坏。总体来说,GO基涂层显示出良好的成骨细胞相容性,同时具有抑制细菌的作用。这一发现,使得GO有潜力应用于植入材料表面改性和涂层方面。总之,通过对PLA和GO的功能化改性,明显提高了它们的生物相容性,为开拓它们在生物医学领域的应用提供了基础。本研究也为设计、合成新型的具有生物功能的PLA和GO基生物材料提供了理论和数据支持。
[Abstract]:Modern biomaterials require materials to promote the adhesion and proliferation of cells on its surface, which can make biomaterials integrated quickly with surrounding tissues, accelerate damaged tissue or organ repair, and avoid other complications. This requires the functional modification of traditional biological materials and the introduction of bioactive molecules. The functional modification of biodegradable polymer material polylactic acid (Poly (lactic acid), PLA) and new carbon material Graphene Oxide (GO) was studied. The interaction between the modified material and osteoblast was studied systematically, and its application in the field of biomedicine (Poly (lactic acid), P was explored. LA) also known as polylactide. Because of its good performance, PLA has been approved by the US Food and Drug Administration (FDA) to be widely used as a drug controlled-release carrier, surgical suture and fracture internal fixation materials. However, polylactic acid has some inattention shortcomings, such as low hydrophilicity, poor cell affinity, and degradation. In order to overcome these defects, people have done a lot of research on the modification of PLA to improve its hydrophilicity and improve its degradation performance. The dendritic polymer PLLA-d of polylactic acid modified polylactic acid, the dendrimer with hydrophobic PLLA as the core, the lysine branch provides full surface positive charge at both ends. The chemical structure of the synthetic product is confirmed by nuclear magnetic resonance (1H NMR) and gel permeation chromatography (GPC). With the introduction of lysine, the melting point of PLLA Decreasing the modulus of elasticity, but increasing the hydrophilicity, the product PLLA-d obtained the honeycomb porous membrane H-PLLA-d using the Breath-Figure method to study the interaction between the MC3T3-E1 and the synthetic materials in the mouse osteoblasts. The results show that the MC3T3-E1 cell function includes cell adhesion, proliferation and differentiation in H-PLLA-d relative to the PLLA membrane. Graphene oxide (GO), an important derivative of graphene, is obtained from graphite oxide. Compared with graphene, GO has good dispersibility in water and rich surface oxygen group, which makes it easier to be functionalized and has low preparation cost. Therefore, graphene oxide has been widely used in biosensors. The application of.GO in biomedical fields, such as physical imaging, drug delivery, and tissue engineering scaffold, has shown great potential in biomedical field, but its biocompatibility is still unsettled. In order to develop its application in the field of biomedicine, it is necessary to improve its biocompatibility. Therefore, we use arginine glycine. Arg-Gly-Asp (RGD) three peptide sequence modified GO obtained GO-RGD. After activation of the carboxyl group on GO, the products obtained by GO-RGD. were synthesized by elemental analysis and Fourier transform infrared spectroscopy (FTIR), which confirmed the appearance of new chemical structure, used scanning electron microscope (SEM) and transmission electron microscope (TEM). The surface morphology of GO-RGD was studied. The binding of RGD was further determined by the changes of GO morphology before and after the modification of TEM. The results of cell experiments showed that the function of MC3T3-E1 cells, including cell adhesion, proliferation and differentiation on the GO-RGD membrane, was significantly higher than that of the GO membrane, and this promotion was related to the RGD content. The GO-RGD To promote osteogenesis, it is expected to be applied to biomedical fields such as bone repair. At the same time, we have prepared the functional modified GO. of gelatin (gelatin) through FTIR, X ray photoelectron spectroscopy (XPS), SEM and other characterization methods to confirm the completion of the functionalization, and the preparation of GO coating GO@N on the surface of the biomedical NiTi alloy. ITi, and the gelatin functional modified GO coating GOGel@NiTi. systematically studied the effects of coated samples on MC3T3-E1 osteoblasts. The results showed that compared to NiTi alloy, the coated samples significantly improved cell adhesion, increment and differentiation, especially the best osteoblast compatibility of GOGel@NiTi in the three. In addition, we used the coating. Colony counting, dead cell staining, and SEM studied the effect of coating samples on Escherichia coli E.coli. Through the study of the antibacterial properties of the coated samples, it was found that the coating had certain antibacterial ability to the Escherichia coli E.coli, and the membrane structure of the bacteria was damaged by the coated samples. Generally, the GO based coating showed good osteogenesis. Cell compatibility and inhibition of bacteria. This discovery has the potential to apply GO to the surface modification and coating of implant materials. In a word, the biocompatibility of PLA and GO has been significantly improved by functional modification, which provides a basis for developing their applications in the biomedical domain. The new biological and functional PLA and GO based biomaterials provide theoretical and data support.
【学位授予单位】：上海大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：R318.08

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