RAPID PROTOTYPING OF POLYMERIC MEDICAL DEVICES

高分子医疗器械的快速原型制作

• 批准号: 3753508
• 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/3753508
• 关键词: biomaterial development /preparation; dental materials; polymers; surface property

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 through a printhead onto regions where the powder is to be joined. By moving the printhead over 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. Featuresize, 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. Key Words: polymer, PCL, PLA, PGA, biomaterials, rapid prototyping, CAD

工业快速成型技术在加速成型方面具有不可估量的价值 从设计到成品的转变过程。三 三维打印(3DP)是一种固体自由制造(SSF) 这项技术是由麻省理工学院的研究人员在1990年开发的。3DP跟随 一种从CAD文件中切片的算法，并制造出三维 通过将粘合剂的液滴“打印”到一叠 二维粉末层。取决于期末考试的目的 部分，选择性地喷洒适当的液体粘结剂(即 打印)通过打印头顺序地打印到每一层粉末上 粉末要加入的区域。通过将打印头移动到 每一层粉末以栅格扫描的方式，都可以得到精确的图案 以两个维度制作的。此过程在 逐层样式，直到整个三维对象 完成。在未粘结的粉末从打印件中分离后， 适当的处理程序(如果有的话)的执行取决于 关于所使用的材料，以及印刷件的最终用途。 3DP的灵活性和适应性，以及它的控制能力 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在尝试 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)是一种高密度的半结晶聚合物。 溶解性、低熔点和卓越的混合能力 其他聚合物。PCL是Capronor的主要基质材料， 年植入式避孕器。聚乙醇酸(PGA)是 最简单的线型脂肪族聚酯，具有高结晶度和熔融性 指向。它降解很快，临床上用作可吸收物质 缝合，德克森。额外的甲基使聚乳酸 疏水性强于PGA。这种减少的吸水率降低了 与PGA相比，聚乳酸主干的水解。聚乳酸-聚乙醇酸共聚物较少 结晶比纯的聚乳酸或纯的PGA都要好。这一数字减少了 结晶度与水解率的增加有关。这些 共聚物降解更快，其临床应用可以 在缝合线中发现(Vicryl)。我们的目标之一是定义限制和 探索在3DP中使用这些类型的聚合物的可能性。 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-溶剂结合和印刷性能。特征大小， 对尺寸精度和加工变形进行了研究 材料和打印参数。一系列构建策略，使用 具有多种粘结剂的不同聚合物和无机粉末 调查以建立对具体情况的基本理解 材料性能与加工参数之间的关系。 一旦基础科学被量化，我们的团队就开始初步的 对开发3DP能力这一革命性概念的调查 生产具有各向异性微结构的聚合物医疗器械和 异质成分。 关键词：聚合物、聚乳酸、生物材料、快速成型、计算机辅助设计