【作者】 陈美花；

【导师】 史廷春；

【作者基本信息】 杭州电子科技大学 ， 检测技术与自动化装置， 2012， 硕士

【摘要】 随着现代社会经济的发展,脊髓损伤的发生率也呈逐年上升的趋势。而组织工程技术的兴起,为治疗脊髓损伤带来新的希望。制造出性能优良、符合与正常组织、器官类似的支架是组织工程发展的关键。支架的制备方法很多,各有优缺点,快速成形的出现为支架的制备提供了新途径。作为新的快速成形工艺,低温沉积制造工艺不仅具备快速成形工艺所共有的特点,而且集成了热致相分离过程的优点,成为制备组织工程支架的新宠。本文利用低温沉积制造工艺加工脊髓组织工程支架。首先根据脊髓组织工程队支架的性能要求,从多种生物材料中遴选出PLGA作为脊髓组织工程支架的成形材料。然后以脊髓生理结构为出发点,设计了一种将灰质和白质区域的孔隙率、孔隙尺寸及材料用一个隔离层加以区分的脊髓仿生支架,诱导移植到缺损部位后的细胞能定向分化,促进脊髓组织的再生。低温沉积过程实质上就是由计算机三维模型转化为数控信息,驱动成形机在低温环境下将材料堆积成形的过程。支架的大孔结构通过喷头的喷射和扫描运动来实现,在这个过程中喷头温度和成形室温度直接影响到大孔的形状误差和粘接强度,所以对这两个温度的调控以及使喷丝速度与扫描速度匹配成为低温沉积过程中两个最重要的环节。本文从软件设定、浆料性质、速度匹配和温度调控四个方面,研究了材料配制、分层和利用成形机制造等一系列工艺过程中参数对成形结构的影响,制造出具有大孔结构和微孔结构的三维脊髓仿生支架。通过对支架进行孔隙率的表征、降解率和亲水率的测定实验,表明用低温沉积制造的支架的平均孔隙率达87.43%,降解实验和支架的亲水性能都能很好的满足组织工程脊髓支架的要求。然后将培养的纯度达到95%以上的雪旺细胞种植在PLGA支架上,每天换培养液,到第三天后扫描电镜观察。观察显示,雪旺细胞在PLGA支架上粘附性良好,迅速生长、增殖,表明PLGA支架材料适合雪旺细胞的粘附和生长。最后建立脊髓损伤模型,将得到的雪旺细胞+PLGA支架移植到大鼠脊髓损伤部位,观察雪旺细胞的存活及动物的恢复情况。结果表明,在最初的一周内,各组大鼠在脊髓横断损伤后均有不同程度的截瘫表现,从第2周开始,各组动物的BBB评分开始恢复。更多还原

【Abstract】 With the modern social and economic development, the incidence of spinal cord injury also showed increasing trend. The emergence of tissue engineering technology has brought new hope to the treatment of spinal cord injury. It is a key point to the development of tissue engineering technology that the scaffold is manufactured with excellent properties. There are many manufacturing methods, each of which has separate advantages and disadvantages. The development of rapid prototyping (RP) technology provides a new way of scaffold manufacturing. As a novel RP technique, Low-temperature Deposition Manufacturing (LDM) not only has the common characteristics of RP, but also has the advantage of thermally induced phase separation process. So it has become the new daring of making tissue engineering scaffolds.In this thesis, the spinal cord tissue engineering scaffolds was modeled using LDM technique. Firstly, according to the performance requirements of spinal cord tissue engineering scaffold, PLGA was selected as the manufacturing material. Then based on the spinal cord physical structure, the spinal cord bionic scaffold was designed with an insulating layer to distinguish of porosity, pore size and material of gray matter and white matter, which could indu(?) oriented differentiation of cell after transplantation into the defect site and promote regeneration of the spinal cord tissues.LDM is essentially a process that the computer-aided 3D model is transformed into numerical control (NC) information to drive the LDM machine to extrude and deposit the material in low temperature environment. Macro-porous structure of the scaffold was made by extrusion and scanning of the nozzle. In this process, the temperature of the nozzle and that in the modeling room has direct impact on the macro-porous shape errors and adhesive strength. So it is the most important part in LDM to regulate the two temperatures and match the extruding speed and scanning speed. The impact to the modeling results was mainly studied through four aspects in this thesis:parameters setting in the software, property of the slurry, match of the velocity and regulation of temperature, and then 3D spinal cord bionic scaffolds with macro-porous and micro-porous structure were formed.The porosity, degradation rate and hydrophilic rate of the scaffold were measured. The results indicated that the average porosity of scaffold manufactured by LDM was 87.43% and degradation and hydrophilic can well meet the requirements of the spinal cord tissue engineering scaffolds. Then the cultured Schwann cells of purity of more than 95% were implanted in PLGA scaffold. The medium was changed every day and SCs were scanned after three days by electron microscopy. SEM examination confirmed that Schwann cell grow rapidly after inoculated in PLGA scaffolds, which shows that the PLGA scaffolds have excellent biocompatibility and bioactivity. Lastly, the spinal cord was set up and the complex of Schwann cells and PLGA scaffolds were transplanted into rats with spinal cord injury site. The result showed that each rat has different levels of paraplegia in the first week, but from the second week beginning, the BBB score of rats began to recover.更多还原