Carboxymethyl chitosan-enhanced multi-level microstructured composite hydrogel scaffolds for bone defect repair

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Regenerative Medicine

Background:

• Critical-sized bone defects (CSBDs) pose significant challenges for bone regeneration, often requiring advanced interventions beyond the body's natural healing capabilities.
• Current bone graft and tissue engineering strategies aim to overcome these limitations by providing supportive structures for new bone formation.

Purpose of the Study:

• To fabricate and evaluate a multi-level microstructured composite hydrogel 3D scaffold for enhanced bone defect repair.
• To investigate the role of carboxymethyl chitosan (CMCS) in optimizing hydrogel properties and osteogenic activity.

Main Methods:

• Fabrication of a 3D-printed polylactic acid (PLA) scaffold treated with polydopamine and filled with a sodium alginate/nano hydroxyapatite/carboxymethyl chitosan (SA/nHA/CMCS) hydrogel.
• In vitro assessment of cell adhesion, proliferation, and differentiation of bone mesenchymal stem cells (BMSCs).
• In vivo evaluation using a rabbit tibial bone defect model to assess bone regeneration efficacy.

Main Results:

• The composite hydrogel scaffold demonstrated enhanced crosslinking, mineralization, and a regulated degradation rate.
• In vitro studies showed improved BMSC adhesion, proliferation, and differentiation on the scaffolds, especially those with CMCS.
• The DSHC scaffold significantly increased bone trabecular number (2.06-fold) in rabbit tibial defects compared to the control scaffold.

Conclusions:

• The developed composite hydrogel 3D scaffold is effective for bone tissue engineering and bone defect repair.
• CMCS plays a crucial role in tailoring hydrogel properties for optimal bone regeneration.
• This study offers a promising strategy for developing advanced hydrogel implant materials for bone regeneration.