Engineering Anisotropic 2D and 3D Structures for Tendon Repair and Regeneration

Tendon injuries and degenerative conditions constitute an unmet clinical need with pharmacological strategies and tissue grafts failing to recapitulate native tendon function. Advancements in bioengineering have enabled the development of various scaffold fabrication technologies, using natural or synthetic in origin polymers that closely imitate the native tendon anisotropic architecture. Anisotropic collagen sponges, extruded collagen fibers, isoelectric focused collagen fibers, and electrospun polymeric fibers have been extensively investigated as tendon prosthesis with data-to-date demonstrating adequate mechanical properties, physiological cell morphology, and protein/gene expression in vitro and bidirectional neotissue formation in vivo. Imprinted substrates, although can maintain tenogenic phenotype or differentiate stem cells toward tenogenic lineage in vitro, are not suitable for implantation. Foreign body response has also been reported, when harsh collagen cross-linkers and/or polymers were used to induce mechanical resilience proportional to the native tissue. We envisaged that development of more biological friendly cross-linkers and/or polymers, along with advancements in scalability would bring these technologies to clinic.