Strontium hydroxyapatite/chitosan nanohybrid scaffolds with enhanced osteoinductivity for bone tissue engineering

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Nanotechnology

Background:

• Bone tissue engineering requires scaffolds with excellent biocompatibility and osteoinductivity for effective bone defect repair.
• Mesenchymal stem cells (MSCs) are crucial for bone regeneration, necessitating scaffolds that support their adhesion, proliferation, and differentiation.

Purpose of the Study:

• To fabricate and characterize strontium hydroxyapatite [SrHAP]/chitosan (CS) nanohybrid scaffolds for bone tissue engineering.
• To evaluate the effect of varying strontium content on the cytocompatibility and osteoinductivity of these nanohybrid scaffolds.

Main Methods:

• Fabrication of SrHAP/CS nanohybrid scaffolds using a freeze-drying method with varying strontium (Sr) concentrations (x=0, 1, 5, 10).
• Characterization of scaffold microstructure, pore size, and nanocrystal dispersion.
• In vitro assessment of human bone marrow mesenchymal stem cells (hBMSCs) adhesion, spreading, proliferation, and osteogenic differentiation on the scaffolds.

Main Results:

• SrHAP/CS nanohybrid scaffolds exhibited a 3D interconnected macroporous structure (100-400μm) with uniformly dispersed SrHAP nanocrystals.
• All scaffolds showed excellent cytocompatibility, supporting hBMSC adhesion, spreading, and proliferation.
• The Sr5HAP/CS scaffold demonstrated significantly enhanced hBMSC proliferation and osteogenic differentiation compared to other groups.
• Released Sr2+ ions from SrHAP/CS scaffolds boosted alkaline phosphatase (ALP) activity, extracellular matrix (ECM) mineralization, and osteogenic gene expression (COL-1, ALP).

Conclusions:

• SrHAP/CS nanohybrid scaffolds possess excellent cytocompatibility and osteogenic properties, suitable for bone tissue engineering.
• The Sr5HAP/CS scaffold exhibits the most promising osteoinductivity due to a synergistic effect between Ca2+ and Sr2+ ions.
• These findings highlight the potential of Sr5HAP/CS nanohybrid scaffolds for accelerating bone defect repair.