Cellulose Nanofiber-Reinforced Chitosan Hydrogel Composites for Intervertebral Disc Tissue Repair

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Regenerative Medicine

Background:

• Intervertebral disc (IVD) degeneration affects millions, leading to pain and mobility issues.
• Current treatments for annulus fibrosus (AF) defects are limited in promoting regeneration.
• Non-cellularized biomaterials offer a promising avenue for IVD repair.

Purpose of the Study:

• To develop and characterize novel chitosan (CHI) hydrogel composites reinforced with cellulose nanofibers (CNFs).
• To evaluate the potential of these CNF-filled CHI hydrogels as implants for AF tissue repair and regeneration.
• To assess the structural, mechanical, and biological properties of the developed biomaterials.

Main Methods:

• Fabrication of CNF-filled CHI hydrogels via neutralization of aqueous suspensions.
• Microtensile testing under controlled humidity to assess mechanical reinforcement.
• Ex vivo evaluation using spine pig models to assess suitability for IVD tissue engineering.

Main Results:

• Successfully developed non-cellularized CHI hydrogels physically reinforced by CNFs.
• Demonstrated that CNFs enhance the mechanical properties of the CHI matrix.
• Ex vivo studies indicated suitability for implantation in AF defects, restoring biomechanics and preventing disc nucleus protrusion.

Conclusions:

• CNF-filled CHI hydrogels represent a viable biomaterial for intervertebral disc annulus fibrosus repair.
• These hydrogel composites can restore IVD biomechanics and serve as a scaffold for tissue regeneration.
• The developed implants offer a potential solution for treating degenerated intervertebral discs.