Rationally designed bioactive milk-derived protein scaffolds enhanced new bone formation

Area of Science:

• Biomaterials Science
• Regenerative Medicine
• Tissue Engineering

Background:

• Casein contains bioactive peptides that support bone homeostasis and fracture repair.
• These peptides, like casein phosphopeptide and β-casochemotide-1, bind calcium and influence macrophage activity.

Purpose of the Study:

• To investigate the potential of casein-based scaffolds for improving bone regeneration.
• To develop and evaluate a modified milk-derived protein scaffold (MDP-DOPA) for enhanced bone healing.

Main Methods:

• A physical-crosslinked scaffold (milk-derived protein; MDP) was created using casein and polyvinyl alcohol via freeze-thaw cycles.
• The MDP scaffold was surface-modified with 3,4-dihydroxy-l-phenylalanine (DOPA) to immobilize proteins and cytokines (MDP-DOPA).
• Macrophage migration and in vivo bone regeneration were assessed in a mouse calvarial defect model.

Main Results:

• Both MDP and MDP-DOPA scaffolds promoted macrophage migration, indicating the presence of bioactive peptides.
• The MDP-DOPA group exhibited significantly faster mineral deposition and higher bone density compared to the control and MDP groups.
• MDP-DOPA scaffolds attracted M2 macrophages and mesenchymal stem cells (MSCs), while MDP scaffolds primarily attracted M1 macrophages initially.

Conclusions:

• Surface-modified milk-derived protein scaffolds (MDP-DOPA) demonstrate enhanced bone regeneration capabilities.
• The DOPA modification facilitates the recruitment of beneficial M2 macrophages and MSCs, crucial for effective bone healing.
• These findings highlight the therapeutic potential of engineered casein-based biomaterials in regenerative medicine.