新型骨植入镁合金组织和降解产物及其生物相容性评价

发布时间：2018-02-06 01:35

本文关键词： 骨植入镁合金显微组织降解产物演变生物相容性生物材料　出处：《郑州大学》2017年硕士论文　论文类型：学位论文

【摘要】：镁合金具有极大的潜在医用推广价值,但是在进一步的生产运用中,仍然需要探究镁合金的降解过程对细胞进一步增殖分化的作用。因此,必须将已开发的镁合金材料反复进行生物相容性评价,研究降解产物的变化规律及其对细胞的影响,并通过评价结果进行工艺改进或是进一步的表面改性,以满足其在人体中正常替代器官或组织的目的。本文主要通过表征合金浸提液与合金自身分别对细胞增殖分化的影响来说明Mg-Zn-Y-Nd-Zr合金的生物相容性。在此之前,先利用金相显微镜(OM)、扫描电子显微镜及能谱仪(SEMEDS)、X射线衍射仪(XRD)等表征分析合金材料基本的微观结构特征及物相组成,初步确立加工工艺对合金的优化方式。主要以铸态Mg-Zn-Y-Nd-Zr合金和挤压态Mg-Zn-Y-Nd-Zr合金对照,研究了Mg-Zn-Y-Nd-Zr合金在模拟体液(SBF)和培养基(DMEM)中的降解产物和表面变化规律。通过对比细胞在合金浸提液中和合金表面的增殖性能和分化性能变化,初步考察了合金的生物相容性。该研究为继续深入优化Mg-Zn-Y-Nd-Zr合金的工艺处理和医用性能提供科学依据。将铸态合金和挤压态合金的微观组织进行了对比,将挤压加工过程对合金合金组织和降解性能的改变进行了研究。挤压加工后,晶粒尺寸缩小了10倍左右,第二相由晶界处被打碎均匀分布至合金中。同时合金中产生了简单丝织构,但合金的相组成没有发生改变。挤压态合金的降解电流密度降低了40%,同时其在模拟体液中的降解速度也发生了明显的降低。本文探讨了Mg-Zn-Y-Nd-Zr合金在模拟体液中的降解表面演变。在浸泡的过程中,铸态合金的降解产物呈现“形核→碎屑脱落→长大→铺满→长大→大块脱落→继续铺满”的过程,而挤压态合金的降解产物呈现“形核→长大→致密→铺满→层状叠加→小块脱落→继续生长→铺满”的过程,因此细胞更易在变化较缓的挤压态集体表面生长。浸提液中,通过MTT细胞毒性测试铸态合金和挤压态合金均不产生细胞毒性。在低浓度中,挤压态合金浸提液中细胞增殖率更高;高浓度中,铸态合金浸提液的细胞增殖率较好,但考虑到实验误差两者没有明显差异。不同种类细胞中成骨细胞在合金材料浸提液中的生长最好。细胞在挤压态合金浸提液中的分化表现较好,且能产生明显的钙磷沉积现象。预处理对比扫描结果表明,Mg-Zn-Y-Nd-Zr合金在选择预处理时间为2h时的表面形貌较为平整,且其表面降解产物中富集了亲和细胞生长的钙磷元素。细胞在共培养周期内,合金表面及孔内整体黏附率呈先升高后降低的趋势,细胞在裸合金表面能够进行一定的增殖表达。
[Abstract]:Magnesium alloys have great potential medical promotion value, but in the further production and application, it is still necessary to explore the degradation process of magnesium alloys on the role of cell proliferation and differentiation. It is necessary to evaluate the biocompatibility of the developed magnesium alloy materials repeatedly, to study the changes of degradation products and their effects on cells, and to improve the process or further surface modification through the evaluation results. In order to satisfy the purpose of replacing normal organs or tissues in human body, the effects of alloy extractant and alloy on cell proliferation and differentiation were characterized in this paper to explain the effect of Mg-Zn-Y-Nd-Zr alloy on cell proliferation and differentiation. Biocompatibility. Before that. The basic microstructure and phase composition of alloy materials were analyzed by means of metallographic microscope, scanning electron microscope and energy dispersive spectrometer (EDS) X-ray diffractometer (XRD). The optimization method of the processing technology for the alloy was preliminarily established, which was mainly compared with the as-cast Mg-Zn-Y-Nd-Zr alloy and the extruded Mg-Zn-Y-Nd-Zr alloy. The effects of Mg-Zn-Y-Nd-Zr alloy on simulated body fluid (SBF) and culture medium (DMEM) were studied. By comparing the proliferation and differentiation properties of cells in the alloy extract and on the surface of the alloy. The biocompatibility of the Mg-Zn-Y-Nd-Zr alloy was preliminarily investigated. This study provides a scientific basis for further optimization of the processing and medical properties of the Mg-Zn-Y-Nd-Zr alloy. The microstructure of the as-cast alloy and the extruded alloy is studied. The tissue was compared. The microstructure and degradation properties of the alloy were studied during extrusion. After extrusion, the grain size was reduced by about 10 times. The second phase is evenly distributed from the grain boundary to the alloy. At the same time, a simple silk texture is produced in the alloy, but the phase composition of the alloy remains unchanged. The degradation current density of the extruded alloy is reduced by 40%. At the same time, the degradation rate of Mg-Zn-Y-Nd-Zr alloy in simulated body fluid also decreased obviously. In this paper, the degradation surface evolution of Mg-Zn-Y-Nd-Zr alloy in simulated body fluid was discussed. The degradation products of as-cast alloys present "nucleation" 鈫扗ebris shedding. 鈫扜row up. 鈫扖overed with. 鈫扜row up. 鈫払ulk shedding. 鈫扵he process of "spreading" continues, while the degradation products of the extruded alloy are "nucleated". 鈫扜row up. 鈫扗ense. 鈫扖overed with. 鈫扡ayered superposition. 鈫扴mall shedding. 鈫扖ontinue to grow. 鈫扗ue to the process of "spreading", the cells grow more easily in the slowly changing squeeze state. In the extract, both the as-cast alloy and the extruded alloy do not produce cytotoxicity by MTT cytotoxicity test. In low concentration, the cell toxicity of as-cast alloy and extruded alloy is not observed. The cell proliferation rate was higher in the extractives of extruded alloy. In high concentration, the cell proliferation rate of as cast alloy extract was better. However, there was no significant difference between the experimental errors. Osteoblasts of different types of cells grew best in the alloy material extract. The differentiation of cells in the extruded alloy extract was better. The results showed that the surface morphology of Mg-Zn-Y-Nd-Zr alloy was smooth when the pretreatment time was 2 h. Moreover, the surface degradation products were enriched with calcium and phosphorus elements of affinity cell growth. During the co-culture cycle, the overall adhesion rate of the alloy surface and pore showed a tendency of first increasing and then decreasing. The cells could proliferate and express on the bare alloy surface.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG146.22;R318.08

【相似文献】