| The anterior cruciate ligament (ACL) is frequently injured and fails to mount an intrinsic healing response. Currently available biological grafts for surgical reconstruction are not ideal, leading to the search for alternative materials for ACL reconstruction. Tissue engineering is an approach combining resorbable scaffolds with viable cells and/or cell signals to induce new tissue generation at sites of limited or compromised healing. The scaffolds are designed to promote tissue in-growth, and gradually degrade, transferring load from the scaffold to newly synthesized host tissue. This results in tissue remodeling and functional new tissue formation.; This dissertation describes the development of a resorbable collagen fiber scaffold, crosslinked with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC), for ACL reconstruction. It was hypothesized that this scaffold could be used to guide neoligament formation in an ACL reconstruction model, and that neoligament formation could be enhanced by seeding the scaffold with viable autogenous fibroblasts prior to implantation.; To test the hypothesis of this thesis project, preliminary studies were performed to develop an EDC crosslinking protocol for collagen fibers, and to characterize the properties of these fibers and scaffolds prepared from them. The scaffolds were found to be strong, relatively resistant to proteolytic degradation, and were also found to support cell attachment and proliferation in vitro. ACL reconstruction surgeries were performed in rabbits with acellular and autogenous dermal fibroblast seeded EDC crosslinked collagen fiber scaffolds, and their relative ability to guide neoligament formation was assessed. The results were found to refute the first part of the hypothesis. EDC crosslinked collagen fiber scaffolds failed prematurely when used for ACL reconstruction in a rabbit model. The second part of the hypothesis, that neoligament formation could be enhanced by seeding the scaffold with viable autogenous fibroblasts prior to implantation, could not be definitively supported or refuted due to the premature scaffold failures. Seeded cells survived for at least 4 weeks in vivo and appeared to enhance tissue in-growth into the midsubstance of the scaffold, but may also have accelerated scaffold mechanical degradation and rupture. Further studies with a stronger, more durable scaffold are required to definitively determine the effect of seeded cells on neoligament formation. |
