Decalcified bone scaffold with dynamic matrix stiffness prepared by mineralization improves bone defect repair

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Regenerative Medicine

Background:

• Bone matrix stiffness dynamically increases during maturation, regulating stem cell behavior.
• Dynamic stiffness scaffolds are crucial for simulating the bone's mechanical microenvironment for effective repair.
• Current scaffolds often lack the dynamic stiffening properties inherent in natural bone.

Purpose of the Study:

• To develop a novel scaffold with dynamically improving stiffness via mineralization for bone tissue engineering.
• To investigate the effect of mineralization-induced stiffening on scaffold properties and biological response.
• To evaluate the efficacy of the dynamic stiffness scaffold in promoting bone regeneration in vivo.

Main Methods:

• Fabrication of decalcified bone matrix (DBM)/collagen (Col)/silicon-substituted hydroxyapatite (SiHA) scaffolds.
• Assessment of scaffold stiffness changes upon contact with body fluid due to mineralization.
• In vitro evaluation of scaffold biocompatibility and promotion of osteogenic differentiation in mesenchymal stem cells.
• In vivo implantation of scaffolds in a rat calvarial defect model to assess bone regeneration.

Main Results:

• DBM/Col/SiHA scaffolds exhibited significant stiffness enhancement through mineralization (e.g., DBM/Col/SiHA from 40.54 ± 6.25 kPa to 69.40 ± 8.76 kPa).
• The DBM/Col/SiHA scaffold demonstrated good biocompatibility and promoted osteogenic differentiation of mesenchymal stem cells.
• In vivo studies showed enhanced bone regeneration and integration, with bone mineral density reaching 285.592 ± 19.611 mg HA/ccm at 12 weeks.

Conclusions:

• Mineralization-dependent stiffening scaffolds, like the DBM/Col/SiHA composite, offer a promising approach for bone tissue engineering.
• The dynamic mechanical properties achieved through mineralization mimic natural bone and enhance regenerative capacity.
• This strategy provides new insights for designing advanced biomaterials for bone repair and regeneration.