A Biomimetic Fibrous Composite Scaffold with Nanotopography-Regulated Mineralization for Bone Defect Repair

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Nanotechnology

Background:

• Regenerating large bone defects via bone tissue engineering is challenging due to difficulties in creating an osteogenic microenvironment.
• The natural extracellular matrix's fibrillar architecture inspires strategies for enhanced bone regeneration.

Purpose of the Study:

• To develop nanoscale composite scaffolds mimicking natural bone fibrils for enhanced osteogenic capability.
• To investigate the effect of nanotopography on hydroxyapatite deposition and bone marrow mesenchymal stem cell (BMSC) behavior.
• To evaluate the efficacy of these scaffolds in promoting bone regeneration in a rat calvarial defect model.

Main Methods:

• Fabrication of poly(ε-caprolactone) (PCL) electrospinning scaffolds with self-adaptive ridge-like nanolamellae via surface-directed epitaxial crystallization.
• Assessment of hydroxyapatite deposition under stimulated physiological conditions.
• In vitro culture of BMSCs on scaffolds to evaluate adhesion, proliferation, and osteogenic differentiation.
• In vivo evaluation of bone regeneration in a rat calvarial defect model using micro-CT, histological, and immunofluorescence staining.

Main Results:

• The developed bone fibril-like scaffolds exhibited a nanotopography with a significantly increased specific surface area.
• Hydroxyapatite deposition was 5-fold greater on the engineered scaffolds compared to pristine PCL scaffolds.
• Enhanced BMSC adhesion, proliferation, and osteogenic differentiation were observed in vitro.
• The scaffolds significantly accelerated bone regeneration in the rat calvarial defect model.

Conclusions:

• The nanoscale bioengineering strategy successfully created bone fibril-like scaffolds with enhanced osteogenic capability.
• The unique nanotopography promotes hydroxyapatite nucleation and improves BMSC osteogenic differentiation.
• These scaffolds show significant potential for recapitulating the osteogenic microenvironment for effective bone repair in tissue engineering.