RAPID PROTOTYPING OF POLYMERIC MEDICAL DEVICES

高分子医疗器械的快速原型制作

• 批准号: 6238348
• 负责人: BENJAMIN M WU
• 金额: $ 4.9万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-07-01 至 1998-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6238348
• 关键词: biomaterial development /preparation; biomedical automation; copolymer I; dental materials; surface property

Three dimensional printing (3DP) offers precise control over macroscopic geometry and spatial distribution of multiple materials according to computerized 3D models. 3DP can also affect local composition and microstructure, and offer many new possibilities for the fabrication of biomedical devices. The ability to control microstructure is critical for drug delivery devices and tissue engineering matrices. The precise control of microstructure, however, requires a better understanding of the relationship between the material properties and processing variables. The proposed work focuses on identifying the critical parameters for controlling microstructure in 3DP polymeric parts. The ability to produce dense microstructure is critical in the fabrication of polymeric drug delivery devices. Preliminary results suggest that the ability to obtain dense microstructure is dependent on the powder material used, which is highly dependent on the purpose of drug delivery device. Oral dosage forms can be fabricated with pharmaceutical grade excipient powder and latex. The powder-binder interaction for this material combination is similar to that observed in conventional 3DP of ceramic (and stainless steel) parts, where loose ceramic particles are coated and gelled together by a polymer colloidal binder. The density of the typical pre-fired 3DP ceramic part is only on the order of 45-55o. Many of the post-processing techniques for industrial parts are inappropriate for the biomedical materials. Dense polymeric structures must, therefore, be obtained during printing. No previous work has been done on creating highly dense green parts directly by printing binder into porous powder bed. Implantable devices are designed to deliver drugs for months to years, and are typically constructed with bioerodable polymer powder and organic solvents. The powder-binder interaction for this material combination is unlike any other observed phenomena in 3DP. The neighboring polymeric particles are dissolved and joined together by the binder droplets. Oral and implantable devices with simple shapes will be fabricated with different combinations of 3DP processing variables, powder, and binder compositions. The devices will be sectioned and analyzed for density, and the results will be compared for various processing conditions. Physical models will be proposed to describe the critical phenomena which are responsible for the formation of dense structures for various materials systems. Real devices for oral delivery and implantation will be designed and constructed with 3DP, and device performance will be assessed by drug release profiles. Computer models will be proposed to model the release characteristics of the real devices. The second objective is to fabricate polymeric tissue engineering devices with controlled porosity. Tissue engineering devices are porous structures which act as scaffolds for guided tissue regeneration. The ability to preferentially promote cell adhesion and migration is accomplished by directing nutrient delivery in a complex, porous cell seeding structure. Experiments will be conducted to investigate various 3DP strategies to control channel dimensions (width and length), surface microporosity, and distribution of cell-matrix adhesion modifiers. The goal of the investigation is to determine the effects of these parameters on cell adhesion. The fundamental understanding of the relationship between material properties, 3DP variables, microstructure, and device performance will have real implications for device design and fabrication strategy of all future 3DP polymeric medical devices.

三维打印（3DP）提供精确的控制 宏观几何形状和多种材料的空间分布 根据计算机化的3D模型。 3DP也会影响局部 成分和微观结构，并提供了许多新的可能性， 生物医学设备的制造。 控制微观结构的能力 对于药物输送装置和组织工程基质至关重要。 然而，对微观结构的精确控制需要更好的 了解材料性能与 处理变量。 拟议的工作重点是确定 控制3DP聚合物部件中微观结构的关键参数。 在制造中，产生致密微观结构的能力是关键的 聚合物药物输送装置。 初步结果表明， 获得致密微观结构的能力取决于粉末材料 使用，这在很大程度上取决于药物输送装置的用途。 可使用药用级赋形剂制成口服剂型 粉末和乳胶。 这种材料的粉末-粘合剂相互作用 组合类似于在陶瓷的常规3DP中观察到的组合。 (and不锈钢）部件，其中涂覆有松散的陶瓷颗粒， 通过聚合物胶体粘合剂胶凝在一起。 典型的密度 预烧的3DP陶瓷部件仅在45- 55 °的量级。 许多 工业零件的后处理技术不适合 生物医学材料 因此，致密的聚合物结构必须 在印刷过程中获得。 以前没有做过创建 通过将粘合剂印刷到多孔粉末中直接获得高密度绿色部件 睡觉了 植入式装置被设计成可持续数月输送药物， 年，并且通常用生物可侵蚀的聚合物粉末构造， 有机溶剂 这种材料的粉末-粘合剂相互作用 组合不同于3DP中的任何其他观察到的现象。 的 相邻的聚合物颗粒溶解并通过聚合物颗粒结合在一起。 粘合剂液滴。 简单形状的口腔和植入式设备将被 用3DP处理变量的不同组合制造， 粉末和粘合剂组合物。 这些设备将被切片， 分析密度，并将结果与各种 加工条件 将提出物理模型来描述 关键现象是负责形成致密的 各种材料系统的结构。 真实的口服给药装置 植入物将采用3DP设计和构建， 性能将通过药物释放曲线来评估。 计算机模型 将提出模拟释放特性的真实的设备。 第二个目标是制造聚合物组织工程装置 具有受控的孔隙度。 组织工程器械是多孔的 作为引导组织再生的支架的结构。 的 优先促进细胞粘附和迁移的能力， 通过在复杂的多孔细胞中引导营养输送来实现 播种结构 将进行实验以研究各种 控制通道尺寸（宽度和长度）的3DP策略， 微孔性和细胞-基质粘附改性剂的分布。 的 研究的目的是确定这些参数的影响 对细胞粘附的影响。 对这种关系的基本理解 材料性能、3DP变量、微观结构和器械之间的关系 性能将对器件的设计和制造具有真实的意义 所有未来3DP聚合物医疗器械的战略。