Characterization of a Biodegradable Electrospun Polyurethane Nanofiber Scaffold Suitable for Annulus Fibrosus Tissue Engineering

The current study characterizes the mechanical and biodegradation properties of a polycarbonate polyurethane (PU) electrospun nanofiber scaffold intended for use in the growth of a tissue engineered annulus fibrosus (AF) intervertebral disc component. Both the tensile strength and initial modulus of aligned scaffolds were higher than those of random scaffolds and remained unaffected during a 4 week biodegradation study, suggesting a surface-mediated degradation mechanism. The resulting degradation products were non-toxic. Confined compressive mechanical force of 1kPa, was applied at 1Hz to in vitro bovine AF tissue grown on the scaffolds to investigate the influence of mechanical force on AF tissue production, which was found to decrease significantly at 72 hours relative to 24 hours, independent of any effects from mechanical forces. Overall, the consistent rate of PU degradation, along with mechanical properties comparable to those of native AF tissue, and the absence of cytotoxic effects, make this polymer suitable for further investigation for use in tissue-engineering the AF.