Microstructure Manipulation of Polyurethane-Based Macromolecular Scaffold for Tendon/Ligament Tissue Engineering

In spite of improvements in tissue engineering approaches, tendon and ligament (T/L) regeneration is still a clinical challenge. The fabrication of functional scaffolds that possess the structural and biological properties of native T/L tissues is critical to a successful healing. Herein, the effect of scaffold microstructure on mesenchymal stem cells (MSCs) response is evaluated. Electrospun polyurethane (EPU) scaffolds with different alignment degrees of nanofibers are fabricated using five rotating speeds of the collector. Although the constructs display similarity in terms of porosity (85%), the increasing degree of alignment results in a notable reduction of fiber diameter. Accordingly, it also improves the tensile strength from 26.44 +/- 0.50 to 35.76 +/- 1.50 MPa and tensile modulus from 18.94 +/- 1.02 to 31.10 +/- 1.11 MPa. Furthermore, despite similarities of cell supporting behavior among all types of scaffolds in terms of cell attachment, spreading, proliferation, and infiltration, the aligned nanofibers noticeably direct cell orientation parallel to their alignment direction, resulting in significant upregulation of tendon-related markers expression. Taken together, the results highlight that the aligned EPU scaffolds are a promising candidate for T/L regeneration, which deserves to be further investigated with long-term studies.