明胶/磁复合羟基磷灰石骨组织工程支架的制备及性能研究

【作者】 李静；

【导师】 陈庆华； 夏开略；

【作者基本信息】 昆明理工大学 ， 材料工程（专业学位）， 2022， 硕士

【摘要】 近些年来,每年有数百万患者遭受骨折、骨质疏松症或癌症的折磨。尽管骨骼具有显著的自愈能力,但大规模骨缺损的愈合仍然需要外界的帮助,因此,能帮助骨愈合的骨组织工程支架就尤为重要。如今研究者虽然已经用有机泡沫浸渍法、发泡法、造孔剂法等多种方法制备出了骨组织工程支架,但支架的孔径分布和成分与人骨还具有一定的差距,并且都很难实现工业化生产。基于以上背景,本研究用金属模具挤压成型和冷冻干燥相结合的方法,通过调整挤出支架的直通孔径,制备出贴合细胞生长的蜂窝多孔支架结构;并调整羟基磷灰石含量,使支架更能符合人体骨无机成分的含量;同时加入磁性颗粒或磁复合羟基磷灰石,使其能利用微小磁场促进骨生成。具体研究内容如下:(1)通过三种不同的模具,用挤压成型和冷冻干燥相结合的方法,分析不同直通孔径对蜂窝支架的孔径分布、力学性能和降解性能等。实验表明三种不同支架的中值孔径相同,孔隙率相差不大;抗压强度都在2.5MPa以上,且直通孔越小,力学性能越好。(2)用最小直通孔的模具挤压支架,通过调整加入HAP的含量,研究了其力学性能、形状记忆效应和降解性能等。实验表明,支架的抗压强度随着HAP的加入先降低后升高;孔径分布范围都在150～580μm,但中值孔径和孔隙率随HAP含量的变化而变化;纯明胶支架的降解率较高,不适合用于骨修复,复合支架90天内的降解率都不超过50%;同时随着HAP含量的增加,支架的形状记忆效应慢慢减弱。(3)研究了加入功能性的磁性颗粒后复合支架的力学性能、形状记忆效应和细胞毒性等。结果表明,磁性颗粒的加入会使支架的力学性能降低,但磁性羟基磷灰石法制备的支架形状记忆效应较好;虽然加入了磁性粒子,但支架并无细胞毒性,且支架的生物相容性良好。更多还原

【Abstract】 In recent years,millions of patients have suffered from fractures,osteoporosis or cancer each year.Despite the remarkable self-healing ability of bones,the healing of large-scale bone defects still requires external help.Therefore,bone tissue engineering scaffolds that can help bone healing are particularly important.Although researchers have prepared bone tissue engineering scaffolds by organic foam impregnation method,foaming method,pore-forming agent method and other methods.However,the pore size distribution and composition of scaffolds still have a certain gap with human bone,and it is difficult to achieve industrial production.Based on the above background,in this study,a method combining metal mold extrusion molding and freeze-drying was used to prepare scaffolds.By adjusting the straight pore size of the extruded scaffold,a cellular porous scaffold structure that fits cell growth is fabricated.And adjust the content of hydroxyapatite to make the scaffold more in line with the content of the inorganic components of human bone.At the same time,magnetic particles or magnetic composite hydroxyapatite are added,so that it can use a tiny magnetic field to promote bone formation.The specific research contents are as follows:(1)The scaffolds were prepared by a combination of extrusion molding and freeze-drying through three different molds.And analyze the pore size distribution,mechanical properties and degradation performance of honeycomb scaffolds with different straight pore sizes.Experiments show that the median pore size of the three different scaffolds is the same,and the porosity is not much different;the compressive strength is above2.5MPa,and the smaller the through hole,the better the mechanical properties.(2)The stent was extruded with a die with the smallest through hole,and its mechanical properties,shape memory effect and degradation properties were studied by adjusting the content of HAP.Experiments show that the compressive strength of the scaffold first decreases and then increases with the addition of HAP.The pore size distribution ranges from 150 to 580μm,but the median pore size and porosity vary with the HAP content.The degradation rate of pure gelatin scaffolds is high,which is not suitable for bone repair.The degradation rate of composite scaffolds within 90 days does not exceed 50%.At the same time,with the increase of HAP content,the shape memory effect of the scaffold gradually weakened.(3)The mechanical properties,shape memory effect and cytotoxicity of the composite scaffolds after adding functional magnetic particles were studied.The results showed that the addition of magnetic particles would reduce the mechanical properties of the scaffolds.However,the scaffolds prepared by the magnetic hydroxyapatite method had better shape memory effect.Although magnetic particles were added,the scaffolds were not cytotoxic and had good biocompatibility.更多还原