Optimization of a Biomimetic Poly-(Lactic Acid) Ligament Scaffold 

Andrew F. Uehlin, Ph.D.

St.Jude Medical, Inc.

and

Derrick Dean, Ph.D.

University of Alabama-Birmingham 

Abstract:

The anterior cruciate ligament (ACL) is the most commonly injured ligament of the knee, often requiring orthopedic reconstruction using autograft or allograph tissue, both with significant disadvantages. As a result, tissue engineering an ACL replacement graft has been heavily investigated. This study attempts to replicate the morphology and mechanical properties of the ACL using a nanomatrix composite of highly-aligned poly(lactic acid) (PLA) fibers with various surface and biochemical modifications. Additionally, this study attempts to recreate the natural mineralization gradient found at the ACL enthesis onto the scaffold, capable of inducing a favorable cellular response in vitro. Furthering the development of the PLA nanomatrix composite, a bioinkjet printer was used to immobilize nanoparticulate hydroxyapatite (HANP) on the surface of the scaffold. The results of studies assessing the proliferation and differentiation response of human mesenchymal stem cells (hMSCs) in vitro with a variety of conditions and combinations of the PLA nanofiber scaffold surface modifications will be presented. 

Andrew F. Uehlin received his B.S. degree in Biomedical Engineering, and M.S. and Ph.D in Materials Engineering from theUniversity ofAlabama at Birmingham (UAB). Dr. Uehlin's research involved polymeric biomaterials, implant-tissue interactions, tissue engineering, and orthopaedic bioengineering. His current role is in cardiac rhythm management and elecrophysiology in the medical device industry as an agent for St. Jude Medical, Inc, based out ofBirmingham,Alabama. 

Derrick R. Dean is Associate Professor of Materials Science and Engineering at theUniversity ofAlabama at Birmingham (UAB). Dr. Dean received the B.S. and M.S. degrees in Chemistry fromTuskegeeUniversity and a Ph.D. in Materials Science and Engineering from theUniversity ofIllinois at Urbana-Champaign. Upon completing his doctorate, he served four years in the Air Force. He served as the Morphology Team Leader for the Polymer Branch in the Materials Directorate of the Air Force Research Laboratory.  Dr. Dean was also the leader of the Polymer Physics team in the Advanced Technology Group at BF Goodrich. Dr. Dean arrived at UAB in 2004, where the central theme of his research group is elucidating the structure-morphology-property relationships of polymers and polymer based composite materials, with specific emphasis on nanostructured polymer systems.