自成孔纳米纤维支架的制备与电化学表面修饰研究

发布时间：2018-05-25 10:52

本文选题：PLLA + PCL　；参考：《东华大学》2012年硕士论文

【摘要】：本文针对现有细胞支架制备方法中的不足以及PLLA力学性能的缺陷即质硬而且韧性较差,缺乏柔性和弹性,研究了聚-L-乳酸(PLLA)复合支架的制备、改性及生物相容性。首次采用自成孔的方法即热致相分离和相反转技术相结合制备了具有三维孔隙结构的PLLA/PCL复合多孔纳米纤维支架；并采用电化学矿化技术,对支架进行表面改性以提高其生物相容性,构建了具有生物活性的三维多孔纳米纤维支架。主要研究内容包括两部分： 1.采用自成孔技术制备PLLA/PCL复合支架,研究了不同PLLA/PCL比例对复合支架孔隙率和形态的影响。发现添加与PLLA不相容的PCL可作为致孔剂和增强剂,不同PCL含量对于支架的多孔形貌和特性有显著影响。扫描电子显微镜(SEM)观察发现,PLLA/PCL复合支架呈多孔纳米纤维结构,纤维直径小于200nm,孔径分布在10μm-100μm之间；多孔形貌及孔径随着PCL含量的不同而不同。红外光谱(FTIR)分析结果发现,在不同比例的复合支架中均有PCL的特征峰,表明复合支架制备过程,PCL不仅作为致孔剂,还能作为支架的组成部分,从而改善PLLA支架的力学性能。力学性能测试发现,PCL的添加在一定程度上提高了支架的力学性能,并且随着PCL含量的增加而增加。另外,复合支架的孔隙率、溶胀性、体外降解性及热学性能等,都会随着PLLA/PCL比例的变化而改变。SEM观察表明猪髋动脉内皮细胞(PIECs)在纯PLLA支架及PLLA/PCL复合支架上具有良好的黏附形貌,呈多角形扁平状；采用MTT法测PIECs的黏附和增殖情况,结果表明PIECs在复合支架上具有很好的黏附和增殖能力,并且当PLLA/PCL的比例为60：40时,细胞的黏附和增殖情况明显好于其他比例的复合支架。综上,PLLA/PCL复合三维多孔支架具有良好的理化特性及生物相容性,有望作为组织工程支架应用于组织修复等领域。 2.通过电化学矿化技术对PLLA/PCL复合支架进行表面改性和修饰,并探究了将牛血清白蛋白(BSA)和羟基磷灰石(HA)协同矿化到三维多孔支架上的可能性。SEM观察发现,当矿化电压为3V,电解液温度为37℃时,沉积的晶体结构细腻,均匀分布在支架的孔壁上,且晶体呈细针状,这种形态与天然骨组织成分羟基磷灰石(HA)形态类似。当加入牛血清白蛋白后,沉积的晶体由针状结构转变为叶片状结构。FTIR结果显示复合涂层中存在磷酸钙盐成分并出现了蛋白质的氨基特征峰。X-射线衍射(XRD)图谱分析证明,在矿化电压为3V,电解液温度为37℃下沉积的晶体成分主要为HA；体外细胞实验结果表明,大鼠前成骨细胞(MC3T3-E1)在电化学协同矿化BSA和HA的复合支架上具有良好的黏附和增殖能力及较高表达的碱性磷酸酶(ALP)活性和骨钙素(OCN)含量,ALP的表达含量在培养到第7天时达到最高,是空白玻片的三倍,高达3.25pg/cell。OCN的含量随着培养时期延长而提高,当培养到14天时其含量明显提高,是空白玻片的两倍。因此,电化学矿化技术可成功应用于在三维多孔纳米纤维支架上进行生物活性分子和无机物的协同矿化,从而得到具有一定生物活性的复合多孔纳米纤维支架并有望应用于骨组织损伤修复等领域。
[Abstract]:In this paper, the preparation, modification and biocompatibility of the poly -L- lactic acid (PLLA) composite scaffold are studied in view of the shortcomings of the existing scaffold preparation methods and the defects of the mechanical properties of PLLA, namely, hard and poor toughness, and the lack of flexibility and elasticity. PLLA/PCL composite porous nanofiber scaffolds with three-dimensional pore structure and electrochemical mineralization are used to improve the biocompatibility of the scaffolds to improve their biocompatibility. The three-dimensional porous nanofiber scaffolds with biological activity are constructed. The main contents of this study include two parts:
1. the effect of different PLLA/PCL ratios on the porosity and morphology of the composite scaffolds was studied by self pore forming technology. It was found that the addition of PCL incompatible with PLLA could be used as a pore forming agent and reinforcing agent. The content of different PCL content had a significant effect on the porous morphology and properties of the scaffold. The scanning electron microscope (SEM) observed, PLLA/P was found, PLLA/P was observed, PLLA/P The CL composite scaffold is a porous nanofiber structure with a diameter of less than 200nm and a diameter of 10 u M-100 mu m. The porous morphology and pore size are different with the PCL content. The results of infrared spectroscopy (FTIR) analysis show that the characteristic peak of PCL in the composite scaffold of different proportions shows that PCL is not only a cause of the preparation of the composite scaffold. The pore agent can also be used as a component of the scaffold to improve the mechanical properties of the PLLA stents. The mechanical properties test shows that the addition of PCL increases the mechanical properties of the stent to a certain extent, and increases with the increase of the PCL content. In addition, the porosity, swelling, in vitro degradation and thermal properties of the composite support will follow the PLLA/P. The change of CL ratio and changes in.SEM observation showed that the porcine hip artery endothelial cells (PIECs) had good adhesion morphology on the pure PLLA stent and PLLA/PCL composite scaffold. The adhesion and proliferation of PIECs were measured by MTT method. The results showed that PIECs had good adhesion and proliferation ability on the composite scaffold and when PLLA/P was in PLLA/P. When the ratio of CL is 60:40, the cell adhesion and proliferation is better than that of the other composite scaffolds. To sum up, the PLLA/PCL composite three-dimensional porous scaffold has good physical and chemical properties and biocompatibility. It is expected to be used as a tissue engineering scaffold in tissue repair and other fields.
2. the surface modification and modification of PLLA/PCL composite scaffold were carried out by electrochemical mineralization technology, and the possibility of.SEM observation on the possibility of CO mineralization of bovine serum albumin (BSA) and hydroxyapatite (HA) on the three-dimensional porous scaffold was found. When the mineralization voltage was 3V and the electrolyte temperature was 37 C, the crystal structure was fine and distributed uniformly in the branch. On the hole wall of the frame, the crystal is thin needle like, this form is similar to the natural bone tissue component hydroxyapatite (HA). After adding bovine serum albumin, the deposited crystal is transformed from acicular structure to leaf like structure,.FTIR results show that there is a calcium phosphate salt formation in the composite coating and the amino characteristic peak of protein.X- ray derivative appears in the composite coating. XRD atlas analysis showed that the crystal components deposited at the mineralization voltage of 3V and the electrolyte temperature at 37 C were mainly HA. In vitro cell experiment results showed that the rat anterior osteoblast (MC3T3-E1) had good adhesion and proliferation ability and high expression of alkaline phosphatase (ALP) on the composite scaffold of electrochemical CO mineralized BSA and HA. The content of sex and Osteocalcin (OCN), the expression of ALP reached the highest at seventh days, three times the blank slide, and the content of up to 3.25pg/cell.OCN increased with the incubation period. When the culture reached 14 days, its content was obviously improved, which was two times of the blank slide. The biomineralization of bioactive molecules and inorganic materials on the nanofiber scaffolds can be used to obtain a composite porous nanofiber scaffold with certain bioactivity and is expected to be applied to the repair of bone tissue damage.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R318.08

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