3D打印双响应紫外光固化水凝胶及其形状记忆功能的研究

发布时间：2018-11-07 16:13

【摘要】：3D打印是一种利用计算机软件控制机器将材料逐层堆叠构建起目标模型的技术。当其应用到生物医学领域时,也被称为“生物打印”,即通过计算机辅助技术将生物材料、活细胞、生长因子等逐层堆叠为组织或器官并使其具有活性。利用3D生物打印技术可以快速、高效、精确制造不同尺寸的模型以及复杂的内部结构,并通过与药物、活性因子、细胞等混合打印,使模型功能化,实现器官定制、药物控释的目的。然而,目前3D打印生物材料仍存在诸多问题,如可选材料种类少、打印条件苛刻(高温、激光等)、成型效果不好、材料制备复杂等。本论文通过化学改性Pluronic F127(PEO100-PPO65-PEO100),使其具备温度响应和紫外光响应的双响应特性,从而快速高效3D打印出具有复杂内部结构及药物控释功能的水凝胶模型。在此基础上,将Pluronic F127与海藻酸钠复合,该材料可通过3D打印制备具有形状记忆功能的模型。一、具有双响应特性的改性F127合成及用于3D打印的研究本体系利用丙烯酰氯对温度敏感的Pluronic F127(PEO100-PPO65-PEO100)进行化学改性,在长链段端基中引入碳碳双键,使改性F127具备光响应特性。通过旋转流变仪确定了改性F127的打印浓度及打印温度,利用3D生物打印机(3D-Bioplotter)进一步确定打印喷头直径(0.25 mm)、打印平台温度(40~45?C)、打印速度(30 mm/s)、挤出压力(0.6 bar)等打印参数,配合使用365 nm的紫外光源可使材料在5秒内高效成型。SEM表征实验结果显示3D打印是物理状态的逐层叠加过程,溶胀实验、弹性模量实验结果表明模型的力学性能随着打印墨水浓度提高而增强,药物释放实验反映出3D打印模型的药物释放行为与传统制备方法类似但缓释效果更好,而细胞毒性实验证实高浓度的改性F127(0.20 g/mL)具有较好的生物相容性,能满足3D打印后直接使用无需后处理的需求。2、改性F127与海藻酸钠混合制备形状记忆水凝胶及用于3D打印的研究海藻酸钠作为目前3D打印领域应用最广泛的材料之一,具有可生物降解、无毒以及能在钙离子作用下凝胶化成型的特点。由于改性F127可以形成具有一定力学性能的网络结构,因此通过与海藻酸钠混合打印,利用钙离子和碳酸根离子的相互交换实现形状记忆功能。利用3D-Bioplotter对从打印过程流畅程度、打印精度、成型效果、形状记忆效果(固定率、回复率)等方面探究最佳打印墨水配方,实验结果表明由0.16g/mL的改性F127溶液与0.04 g/mL的海藻酸钠溶液所组成的打印墨水能实现理想打印效果,其中,喷嘴直径为0.25 mm,加热温度为35~40?C,平台温度为40~45?C,挤出压力为0.8 bar,打印速度为30 mm/s。打印模型能在0.01 g/mL的CaCl2溶液和0.02 g/mL的Na2CO3溶液作用下实现临时形状和原始形状的变换。
[Abstract]:3D printing is a kind of technology which uses computer software to control the machine to stack the material layer by layer to construct the target model. When it is applied to biomedical fields, it is also called "bio-printing", that is, biological materials, living cells, growth factors and so on are stacked into tissues or organs layer by layer and made active by computer-aided technology. Using 3D bio-printing technology, we can quickly, efficiently and accurately manufacture different sizes of models and complex internal structures, and through mixed printing with drugs, active factors, cells and so on, we can functionalize the model and realize organ customization. The purpose of controlled drug release. However, at present, there are still many problems in 3D printing biomaterials, such as few kinds of optional materials, harsh printing conditions (high temperature, laser, etc.), poor molding effect, complex preparation of materials, and so on. In this paper, Pluronic F127 (PEO100-PPO65-PEO100) was chemically modified to possess the double response of temperature response and ultraviolet response, so that the hydrogel model with complex internal structure and controlled drug release could be printed quickly and efficiently. On this basis, Pluronic F127 was combined with sodium alginate. The model with shape memory function could be prepared by 3D printing. First, the synthesis of modified F127 with double response and its application in 3D printing. The chemical modification of Pluronic F127 (PEO100-PPO65-PEO100), which is temperature-sensitive, was carried out by using acryloyl chloride. Carbon and carbon double bonds were introduced into the long chain end group. The modified F 127 has the characteristics of light response. The printing concentration and printing temperature of modified F127 were determined by rotary rheometer, and the diameter of printing nozzle (0.25 mm), printing platform temperature) was further determined by using 3D biological printer (3D-Bioplotter). Printing parameters such as printing speed (30 mm/s), extrusion pressure (0.6 bar) and UV source of 365 nm can make the material be formed efficiently in 5 seconds. The results of SEM characterization experiment show that 3D printing is a stacking process of physical state layer by layer. The results of swelling test and elastic modulus test showed that the mechanical properties of the model increased with the increase of printing ink concentration. The drug release experiment showed that the drug release behavior of the 3D printing model was similar to that of the traditional preparation method but the slow release effect was better. The cytotoxicity test showed that high concentration of modified F127 (0.20 g/mL) had good biocompatibility and could meet the requirement of 3D printing without post-treatment. Preparation of shape memory hydrogel with modified F127 and sodium alginate as one of the most widely used materials in 3D printing, sodium alginate is biodegradable. Non-toxic and can be gelatinized under the action of calcium ion. Because the modified F127 can form a network structure with certain mechanical properties, the shape memory function can be realized by the exchange of calcium ion and carbonate ion by mixed printing with sodium alginate. Using 3D-Bioplotter to explore the best formula of printing ink from the aspects of printing process fluency, printing accuracy, shaping effect, shape memory effect (fixed rate, recovery rate), etc. The experimental results show that the printing ink composed of modified F127 solution of 0.16g/mL and sodium alginate solution of 0.04 g/mL can achieve the ideal printing effect, in which the nozzle diameter is 0.25 mm, and the heating temperature is 35? The temperature of the platform is 40,45C, and the extrusion pressure is 0.8 bar,. The printing speed is 30 mm/s.. The printing model can realize the transformation of the temporary shape and the original shape under the action of the CaCl2 solution of 0.01 g/mL and the Na2CO3 solution of 0.02 g/mL.
【学位授予单位】：暨南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R318.08;TP391.73

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