RAPID PROTOTYPING OF POLYMERIC MEDICAL DEVICES BY THREE DIMENSIONAL PRINTING

通过三维打印快速制作聚合物医疗器械原型

• 批准号: 3732448
• 负责人: BENJAMIN M WU
• 金额: --
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3732448
• 关键词: biomaterial development /preparation; biomedical automation; copolymer; dental materials; polymers; surface property

Dimensional Printing Industrial rapid prototyping techniques are invaluable in accelerating the transformation process from design to finished product. Three Dimensional Printing (3DP) is an Solid Freedom Fabrication (SSF) technology which are developed by MIT researchers in 1990. 3DP follows a slicing algorithm from a CAD file, and manufactures three dimensional objects by "'printing" droplets of binder onto a stack of two-dimensional powder layers. Depending on the purpose of the final part, the appropriate liquid binder is selectively sprayed (i.e. printed) sequentially onto each layer of powder in a raster-scan fashion, precise patterns can be produced in two dimensions. This process is repeated in a layer-by-layer fashion until the entire three dimensional object is completed. After the unbound powder is separated from the printed part, the appropriate processing procedures, if any, are performed depending on the materials used, and the ultimate purpose of the printed part. The flexibility and adaptability of 3DP, plus its ability to control microstructure and composition, sets 3DP apart from all other rapid prototyping techniques. Prior to this project, only ceramic and metal powders have been studied in 3DP. Our research term a MIT is attempting to merge two developing technologies (3DP and biomaterials processing). Degradable polymeric materials of interest include poly-caprolactone, polyglycolic acid, polylactic acid, and their copolymers. Poly--caprolactone (PCL) is a semicrystalline polymer with high solubility, low melting point, and exceptional ability to blend with other polymers. PCL is the principal matrix material in Capronor, a one year implantable contraceptive device. Polyglycolic acid (PGA) is the simplest linear, aliphatic polyester with high crystallinity and melting point. It degrades rapidly and is used clinically as a resorbable suture, Dexon. An additional methyl group makes polylactic acid more hydrophobic than PGA. This reduced water uptake decreases the rate of PLA backbone hydrolysis, as compared to PGA. PLA-PGA coplymers are less crystalline than either pure PLA or pure PGA. This decreased crystallinity is associated with increased rate of hydrolysis. These copolymers degrade more rapidly, and their clinical application can be found in sutures (Vicryl). One of our goals is to define the limits and explore the possibilities of using these types of polymers in 3DP. Experiments are performed to study the fundamental processes in powder processing, classification, spreading, solvent solubility, jet stability, powder-solvent binding and printing behavior. Feature size, dimensional accuracy, and processing distortion are studied with various materials and printing parameters. A range of build strategies using different polymeric and inorganic powders with a number of binders are investigated to establish a fundamental understanding of the specific relationship between material properties and processing parameters. Once the basic science is quantified, our team began preliminary investigations on a revolutionary concept of exploiting 3DP's ability to produce polymeric medical devices with anisotropic microstructures and heterogeneous compositions.

立体印刷 工业快速成型技术在加速生产过程中具有不可估量的价值 从设计到成品的转化过程。三维 印刷(3DP)是一种固体自由制造(SSF)技术，它是 由麻省理工学院的研究人员于1990年开发。3DP遵循以下切片算法 一个CAD文件，并通过“‘打印”来制造三维对象 粘结剂的液滴落在一堆二维粉末层上。取决于 在最后一部分中，适当的液体粘结剂为 按顺序选择性地喷洒(即打印)到每一层粉末上 采用光栅式扫描方式，可以在两个维度上产生精确的图案。 这个过程以逐层的方式重复，直到完整的三个 标注对象已完成。在将未粘结的粉末从 打印的部件、适当的处理程序(如果有)是 根据所使用的材料和 打印件。3DP的灵活性和适应性，以及它的能力 控制显微组织和成分，使3DP有别于所有其他快速 原型技术。在这个项目之前，只有陶瓷和金属 在3DP中对粉末进行了研究。我们的研究术语麻省理工学院正试图 融合两项正在开发的技术(3DP和生物材料加工)。 感兴趣的可降解聚合物材料包括聚己内酯， 聚乙醇酸，聚乳酸，及其共聚物。 聚己内酯(PCL)是一种高溶解度的半结晶聚合物， 低熔点，并具有与其他聚合物混合的卓越能力。 PCL是Capronor的主要基质材料，一年可植入 避孕器。聚乙醇酸(PGA)是最简单的线性， 高结晶度、高熔点的脂肪族聚酯。它会降解 快速，临床上用作可吸收缝线，Dexon。一项额外的 甲基使聚乳酸比PGA更疏水。这减少了 吸水率降低了聚乳酸主链的水解率 PGA。聚乳酸-聚乙醇酸共聚物的结晶度低于纯聚乳酸或纯聚乙交酯 PGA。这种结晶度的降低与增加的速率有关 水解液。这些共聚物降解更快，它们的临床 可在缝合线(Vicryl)中找到应用。我们的目标之一是定义 使用这些类型的聚合物的局限性和可能性 3DP。对粉末的基本过程进行了实验研究 加工、分类、铺展、溶剂溶解度、喷射稳定性、 粉末-溶剂粘合和印刷性能。特征大小、尺寸 精度和加工变形研究了不同的材料和 打印参数。使用不同聚合物的一系列构建策略 以及含有许多粘结剂的无机粉末被研究以建立 对材料之间的具体关系有一个基本的理解 属性和处理参数。一旦基础科学被量化， 我们的团队开始对一个革命性的概念进行初步调查 利用3DP的能力生产聚合物医疗设备 各向异性的微观结构和不均匀的成分。