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

0926970

Freeman

Bone 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.