Topographical and Compositional Gradient Tubular Scaffold for Bone to Tendon Interface Regeneration

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Regenerative Medicine

Background:

• The enthesis, a crucial tendon-bone interface, is prone to injury due to its inherent stiffness gradient.
• Current surgical reconstructions for enthesis injuries often face recurrence, highlighting the need for advanced regenerative strategies.

Purpose of the Study:

• To design and develop a novel tubular scaffold composed of pullulan (PU) and chitosan (CH) to enhance enthesis repair.
• To incorporate a topographical gradient of nanofibers (random to aligned) and hydroxyapatite (HAP) nanoparticles within the scaffold.
• To evaluate the scaffold's potential when loaded with chondroitin sulfate (CS) for improved wound healing.

Main Methods:

• Fabrication of a tubular scaffold with a continuous gradient of random, mineralized fibers (bone-like) and aligned fibers (tendon-like).
• Incorporation of hydroxyapatite (HAP) nanoparticles in the bone-like region and evaluation of scaffold integrity after hydration using Micro CT and SEM.
• In vitro assessment of human adipose stem cell (hASC) behavior, differentiation, and extracellular matrix (ECM) production on the scaffold, with and without chondroitin sulfate (CS).

Main Results:

• The scaffold exhibited a continuous topographical and compositional gradient, confirmed by Micro CT and SEM analysis, even after prolonged hydration.
• Human adipose stem cells cultured on the scaffold successfully differentiated, producing tendon-specific ECM in the aligned zone and bone-specific ECM in the random mineralized zone.
• Chondroitin sulfate demonstrated a synergistic effect, significantly enhancing cell adhesion and proliferation on the scaffold surface.

Conclusions:

• The developed tubular scaffold, featuring a gradient structure and loaded with chondroitin sulfate, shows significant promise for supporting enthesis repair.
• This biomaterial could serve as a powerful tool to improve surgical outcomes for tendon-bone injuries.
• The scaffold's ability to guide cell differentiation towards specific tissue types offers a new avenue for regenerative therapies at the tendon-bone interface.