Biomimetic Structured Porogen Freeform Fabrication System for Tissue Engineering

本项目的研究目标是将生物材料研究、仿生建模、固体自由形态制造、系统与控制、组织工程等集成在一个智能系统中，形成结构化、高孔性的生物材料，并将其应用于骨组织工程支架。该制造系统基于以下原理：(1)基于计算机断层扫描或磁共振成像的图像和使用逆向工程的内部结构建模来创建骨的计算机辅助设计模型。(2)利用一种特殊设计的蔗糖材料，利用Solid Free Format制造技术，构建了一种具有骨细胞外基质空洞负结构的结构化造孔剂骨架。(3)将聚合物/陶瓷生物复合材料浇铸到蔗糖负极骨架中，气固化。(4)用水除去蔗糖致孔剂，低温烧结生物复合支架，提高其机械完整性和强度。生物相容性将在细胞培养试验中进行测试。该项目的成功将使组织工程师能够优化骨组织工程支架的机械、运输、材料和生物学特性，目前还没有达到一定程度的结构控制。骨组织工程可能提供一种不那么痛苦的替代传统骨移植的方法，每年植入80多万个植入物，感染风险更低。新的仿生结构致孔剂自由形式制造系统也将应用于其他组织的支架，包括血管组织。更广泛的好处包括培训两名博士生，“仿生组织模型及其自由形式制造”和“生物材料机械性能测量”的新课程模块，以及一个生物材料生物兼容性案例研究。通过这种跨学科合作，以及为德雷克塞尔大学工程学院和生物医学工程学院开发新的跨学科课程模块，可以加强教育和研究基础设施。该项目还将用于为当地高中和社区大学学生举办的外联讲习班，其中包括许多代表性不足的少数族裔学生。

The research objective of this project is to integrate biomaterials research, biomimetic modeling, solid freeform fabrication, systems and control, and tissue engineering in one intelligent system for structured, highly porous biomaterials, which will be applied to bone tissue engineering scaffolds. The manufacturing system is based on the following principles: (1) A computer-aided design model of bone is created based on images of computed tomography or magnetic resonance imaging and internal structure modeling using reverse engineering. (2) A specially designed sucrose material is used to build a structured porogen, a skeleton that has the negative structure of bone extra-cellular matrix voids, using Solid Freeform Fabrication technology. (3) A bio-composite of polymer and ceramic is cast into the sucrose negative skeleton and air-solidified. (4) The sucrose porogen is then removed using water; and the bio-composite scaffold is sintered at a low temperature to improve its mechanical integrity and strength. Biocompatibility will be tested in cell culture assays.Success in this project will enable tissue engineers to optimize mechanical, transport, material, and biological properties of bone tissue engineering scaffolds with a degree of structural control not currently available. Bone tissue engineering may offer a less painful alternative to traditional bone grafts in over 800,000 implants per year, with lower risk of infection. The new biomimetic structured porogen freeform fabrication system will also have application to scaffolds for other tissues, including vascularized tissue. Broader benefits include training of two Ph.D. students, new course modules on "Biomimetic Tissue Modelingand its Freeform Fabrication" and "Biomaterial Mechanical Property Measurement," and a biomaterials biocompatibility case study. The educational and research infrastructure can be enhanced by this interdisciplinary collaboration, and by development of new cross-disciplinary course modules for both College of Engineering and Biomedical Engineering School at Drexel University. The project will also be used in outreach workshops for local high school and community college students, including many underrepresented minority students.