Shear Mechanics of Electrospun Scaffold for Annulus Fibrosus Tissue Engineering

INTRODUCTION Engineering functional replacements for the annulus fibrosus (AF) is contingent upon successful replication of anatomic form and mechanical function. Recently, our group and others have demonstrated the utility of electrospun scaffolds for AF tissue engineering [1]. These ordered, nanofibrous scaffolds direct cell alignment and deposition of a functional fibrocartilage matrix [1]. Previously, it has been shown that single lamellar engineered AF can be formed by seeding mesenchymal stem cells (MSCs) onto these scaffolds, and more recently we have applied this approach to generate nanofibrous biologic laminates that replicated the angle-ply architecture and uniaxial tensile modulus of native AF [2]. However, in vivo the disc is also subjected to torsion that causes shear loading [3]. Therefore, function of tissue-engineered constructs in shear is of primary importance. Despite its critical physiologic importance, shear testing has not been performed to assess the function of engineered AF. In this study, the effect of fiber orientation and culture duration on the shear modulus of MSC-seeded electrospun constructs was investigated.