Engineering the hard–soft tissue interface with random-to-aligned nanofiber scaffolds

Abstract

Tendon injuries can be difficult to heal and have high rates of relapse due to stress concentrations caused by scar formation and the sutures used in surgical repair. Regeneration of the tendon/ligament-to-bone interface is critical to provide functional graft integration after injury. The objective of this study is to recreate the tendon-to-bone interface using a gradient scaffold which is fabricated by a one-station electrospinning process. Two cell phenotypes were grown on a poly-ε-caprolactone nanofiber scaffold which possesses a gradual transition from random to aligned nanofiber patterns. We assessed the effects of the polymer concentration, tip-to-collector distance, and electrospinning time on the microfiber diameter and density. Osteosarcoma and fibroblast cells were seeded on the random and aligned sections of scaffolds, respectively. A random-to-aligned cocultured tissue interface which mimicked the native transition in composition of enthesis was created after 96 h culturing. The results showed that the microstructure gradient influenced the cell morphology, tissue topology, and promoted enthesis formation. This study demonstrates a heterogeneous nanofiber scaffold strategy for interfacial tissue regeneration. It provides a potential solution for mimicking transitional interface between distinct tissues, and can be further developed as a heterogeneous cellular composition platform to facilitate the formation of multi-tissue complex systems.

Tissue Engineering for the Insertions of Tendons and Ligaments: An Overview of Electrospun Biomaterials and Structures

“…After 4 days of cellular growth, the fibroblasts resulted to be aligned and elongated along the nanofibers’ direction, while the osteosarcoma cells resulted to be randomly oriented. Moreover, a cell migration was observed forward the mixed region ( Nowlin et al, 2018 ). Samavedi et al (2011) focused on the ligament–bone regeneration.…”

“…The mats cut along the gradient direction, and analyzed via X-ray diffraction, confirmed a continuous gradation both in fiber organization and in the materials’ composition. Nowlin et al (2018) realized a random to aligned mat to improve the tendon–bone enthesis regeneration. The PCL mats were electrospun on 2 parallel aluminum bars to obtain random (on the bar surface) and aligned (in the gap) nanofibers.…”

A Textile Platform Using Continuous Aligned and Textured Composite Microfibers to Engineer Tendon‐to‐Bone Interface Gradient Scaffolds

“…Moreover, gradient scaffolds were not able to uniformly support preosteoblast cells adhesion . Comparably, Nowlin et al produced random‐to‐aligned nanofiber scaffolds to mimic the microtopology of tendon‐to‐bone interface. Even though a transitional region was obtained, authors seeded terminally cells (fibroblasts and osteosarcoma cells) on the different regions and did not demonstrate the ability of cells to differentiate toward specific lineages due to the influence of fibers topology and composition.…”

A Physiology-Inspired Multifactorial Toolbox in Soft-to-Hard Musculoskeletal Interface Tissue Engineering

“…scaffolds ( Figure 3B). Interestingly, tailoring the surface topography of scaffolds by increasing either the roughness or the use of nano-scaled matrices has been shown to allow a better cell adhesion to the matrix, followed by subsequent tenogenic, osteogenic, and chondrogenic commitment of stem cells when in contact with oriented groove materials or just by creating dense or fibrous topologies in scaffolds, respectively [10,18,[44][45][46][47].…”