In Vitro Characterization of Sustained Drug Release from Tissue-Engineered ACL Scaffolds

Introduction: Rupture of the anterior cruciate ligament (ACL) is one of most common ligament injuries of the knee. Because of limitations associated with the use of autografts and allografts, as well as advances in regenerative medicine, there is an increasing interest in developing a tissue engineered substitute for biologic ACL grafts. Our group has developed an electrospun biodegradable polymer scaffold that has favorable mechanical properties for ligament replacement. The focus of this study was to examine the feasibility of sustained release of growth factor from our electrospun scaffold for enhanced cellular response. It is well accepted that cell proliferation, extracellular matrix elaboration, neovascularization, as well as mechanical properties, can be dramatically influenced by the presence of growth factors. As such, there has been a great deal of interest in the use of growth factors to augment tissue engineered constructs for ACL replacement. For in vivo studies in particular, it would be advantageous to introduce growth factors steadily over a sustained period, without an initial burst release. In this study, fluorescein-isothiocyanate labeled bovine serum albumin (FITC-BSA) was used as a protein surrogate for growth factor to compare three methods of growth factor release from an electrospun scaffold for use in ligament tissue engineering.