BRIGE: The Fabrication of a Novel, Full Thickness, Artificial Bone Graft for Bone Tissue Engineering

0926970 freemann在美国，创伤或疾病导致的骨质流失非常普遍。每年进行的骨科手术超过300万例；其中约有50万例是骨移植手术，使骨成为仅次于血液的第二大移植材料。骨丢失通常用自体或同种异体移植来治疗。虽然它们都有自己的优点，但每一种材料都有一系列的缺点，限制了它们的使用范围。考虑到这一点，这个项目的目标是利用组织工程来创造新的支架，作为骨置换和再生的实用和功能性替代品。新的支架将具有纳米纤维结构，结构类似于天然骨，包含皮质和小梁区域以及微血管。为了完成这项任务，我们将完成以下目标：1)进行有限元分析，以发现支架承受适当载荷所需的纳米纤维方向。2)结合纳米纤维矿化、造孔和烧结技术，构建完全矿化、多孔的纳米纤维骨支架。3)利用微纤维和纳米纤维矿化的静电纺丝技术制造具有血管通道的皮质骨样结构。4)将骨小梁支架和皮质支架结合烧结技术，制成全厚度多孔承载支架。最终的结构将由矿化聚（l -乳酸）纳米纤维设计而成，并将设计成能够承受在承重骨骼中所经历的力量，同时具有足够的孔隙度以允许全厚度的细胞和组织浸润。智力优势：尽管许多研究已经创造了支架来替代骨，但大多数研究都只寻求替代小梁骨。目前没有可用的支架或技术试图模拟小梁骨和皮质骨的结构和特性，包括正确放置的血管系统。这种支架的创造也将解决纳米纤维支架中细胞运动的问题。通常，纳米纤维支架的孔隙太小，不能允许显著的细胞浸润。本课题所描述的微孔纳米纤维支架的制备方法将解决这一问题，并可用于其他组织工程的应用。更广泛的影响：拟议的研究将推动组织工程领域的发展，通过创造纳米纤维支架，不阻碍细胞运动和生产全厚度骨移植物。这项研究将为许多学生提供一个机会，以获得实验设计，数据分析，工程方面的经验，以及在团队环境中工作的能力。弗里曼博士致力于建立外展项目，从代表性不足的群体中招募学生进入工程和科学领域。目前，他指导的研究生来自各个代表性不足的群体。自从两年前来到弗吉尼亚理工大学，他还提到了三个未被充分代表的群体。弗里曼博士参与了弗吉尼亚理工大学的多元文化学术机会项目（MAOP）和工程多样性增强中心（CEED）。将从这些项目中选择学生进行基于该项目的研究。他将在演讲中使用这个项目的各个方面来鼓励学生对数学、科学和工程的兴趣。

0926970FreemanBone loss due to trauma or disease is prevalent in the U.S. Over 3 million orthopaedic procedures are performed every year; approximately 500,000 of these are bone grafting procedures making bone second only to blood as the most transplanted material. Bone loss is usually treated using autografts or allografts. Although they do have their benefits, each of these materials has a set of drawbacks which limit the extent of their use. With this in mind, the objective of this project is to use tissue engineering to create new scaffolds as practical and functional alternatives for bone replacement and regeneration. The new scaffolds will have a nanofibrous structure and be structurally similar to natural bone, containing both cortical and trabecular areas and microvascularization. To accomplish this task we will complete the following objectives: 1) Perform a finite element analysis to discover the nanofiber orientation necessary for the scaffold to bear the appropriate load. 2) Construct fully mineralized, porous, nanofibrous scaffolds for trabecular bone by combining techniques for nanofiber mineralization, pore creation, and sintering. 3) Creating cortical bone like structures with vascular channels using electrospinning techniques with microfibers and nanofiber mineralization. 4) Creating a full thickness, porous load bearing scaffold by combining the trabecular and cortical scaffolds with sintering techniques. The resulting structure will be engineered from mineralized poly (L-lactic acid) nanofibers and will be designed to withstand the forces experienced in load bearing bones while having enough porosity to allow for full thickness cellular and tissue infiltration. Intellectual Merit: Although many studies have created scaffolds to replace bone, most of these seek to only replace trabecular bone. No currently available scaffold or technique seeks to mimic the structure and properties of both trabecular and cortical bone, including correctly placed vasculature. The creation of this scaffold would also lead to a solution to the problem of cell movement in nanofiber scaffolds. Typically the pores in nanofibrous scaffolds are too small to allow significant cellular infiltration. The method of micro-porous nanofibrous scaffold fabrication described in this project would solve this problem and could be used for the other tissue engineering applications. Broader Impacts: The proposed research will advance the field of tissue engineering through the creation of nanofibrous scaffolds that do not hinder cell motility and the production of a full thickness bone graft. This research will provide an opportunity for many students to gain experience in experimental design, data analysis, engineering, and the ability to work in a group environment. Dr. Freeman is devoted to establishing outreach programs to recruit students from underrepresented groups into engineering and science. Currently, he mentors graduate students from all segments of underrepresentation. Since arriving at Virginia Tech over 2 years ago he has also mentioned 3 undergraduates of underrepresented groups. Dr. Freeman is involved in the Multicultural Academic Opportunities Program (MAOP) and the Center for the Enhancement of Engineering Diversity (CEED) at Virginia Tech. Students will be chosen from these programs to conduct research based on this project. He will use aspects from this project in his presentations to encourage student interest in math, science, and engineering.