Braided and Stacked Electrospun Nanofibrous Scaffolds for Tendon and Ligament Tissue Engineering

Abstract

Tendon and ligament injuries are a persistent orthopedic challenge given their poor innate healing capacity. Nonwoven electrospun nanofibrous scaffolds composed of polyesters have been used to mimic the mechanics and topographical cues of native tendons and ligaments. However, nonwoven nanofibers have several limitations that prevent broader clinical application, including poor cell infiltration, as well as tensile and suture-retention strengths that are inferior to native tissues. In this study, multilayered scaffolds of aligned electrospun nanofibers of two designs-stacked or braided-were fabricated. Mechanical properties, including structural and mechanical properties and suture-retention strength, were determined using acellular scaffolds. Human bone marrow-derived mesenchymal stem cells (MSCs) were seeded on scaffolds for up to 28 days, and assays for tenogenic differentiation, histology, and biochemical composition were performed. Braided scaffolds exhibited improved tensile and suture-retention strengths, but reduced moduli. Both scaffold designs supported expression of tenogenic markers, although the effect was greater on braided scaffolds. Conversely, cell infiltration was superior in stacked constructs, resulting in enhanced cell number, total collagen content, and total sulfated glycosaminoglycan content. However, when normalized against cell number, both designs modulated extracellular matrix protein deposition to a similar degree. Taken together, this study demonstrates that multilayered scaffolds of aligned electrospun nanofibers supported tenogenic differentiation of seeded MSCs, but the macroarchitecture is an important consideration for applications of tendon and ligament tissue engineering.

Living nanofiber yarn-based woven biotextiles for tendon tissue engineering using cell tri-culture and mechanical stimulation

“…Adequate mechanical properties are required for engineered tendon scaffolds, as tendons are subjected to dynamic mechanical forces in vivo [32]. Different human ligaments and tendons possess ultimate tensile strengths ranging from several to several hundred MPa and ultimate strain ranging 10 % to 50 %, depending on age, anatomy and measurement method [63–65].…”

Effect of scaffold morphology and cell co-culture on tenogenic differentiation of HADMSC on centrifugal melt electrospun poly (L‑lactic acid) fibrous meshes

“…In this study, we fabricated PLLA fibrous meshes with controlled fiber diameter, orientation, and thickness by the adjustment of the appropriate spinning parameters. PLLA was chosen as the biomaterial for the tendon regeneration application because it is a fully biocompatible, biodegradable, synthetic material which can undergo remodeling and ultimately be replaced by regenerated tissue in vivo [43, 44]. In addition, PLLA is thermoplastics and it can be heated to its melting point, cooled, and reheated again without significant degradation [45].…”

Hierarchically Structured Electrospun Scaffolds with Chemically Conjugated Growth Factor for Ligament Tissue Engineering

“…Two popular techniques are utilizing braided or twisted strands of material to increase stiffness and tensile strength, however encouraging cell infiltration can be challenging 13,[39][40][41][42] . A recent study comparing braided electrospun PCL sheets to stacked electrospun PCL sheets showed that the braided scaffolds possessed improved tensile strength which better mimicked the native ACL, however cell infiltration and proliferation was superior in stacked constructs 43 .…”