Bioactive Siloxane-Containing Shape-Memory Polymer (SMP) Scaffolds with Tunable Degradation Rates

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Regenerative Medicine
• Tissue Engineering

Background:

• Cranial defect regeneration requires scaffolds with conformal fit, bioactivity, and appropriate resorption rates.
• Previous poly(ε-caprolactone) diacrylate (PCL-DA) scaffolds showed shape-memory properties but lacked bioactivity and degraded slowly.
• Polydimethylsiloxane (PDMS) can enhance bioactivity and modify degradation in polymer networks.

Purpose of the Study:

• To develop novel poly(ε-caprolactone)/polydimethylsiloxane (PCL/PDMS) shape-memory polymer (SMP) scaffolds.
• To investigate the effect of varying PDMS content and cross-link density on scaffold properties.
• To evaluate the bioactivity and degradation characteristics of the new PCL/PDMS scaffolds for cranial defect healing.

Main Methods:

• PCL/PDMS SMP scaffolds were synthesized using different macromers (linear PDMS-dimethacrylate, star PDMS-tetramethacrylate, triblock copolymer) at varying weight ratios.
• Scaffold morphology, shape-memory behavior, degradation rates, and mechanical properties were characterized.
• Mineralization potential was assessed by exposing scaffolds to simulated body fluid (SBF).

Main Results:

• PCL/PDMS scaffolds maintained excellent shape-memory behavior with interconnected pores.
• Degradation rates increased with higher PDMS content and lower cross-link density.
• All PCL/PDMS scaffolds mineralized to form carbonated hydroxyapatite (HAp) in SBF, enhancing mechanical properties.

Conclusions:

• Incorporating PDMS into PCL-DA scaffolds successfully introduced bioactivity and tunable degradation.
• The PCL/PDMS scaffolds demonstrated mineralization and improved mechanical properties post-mineralization.
• These PCL/PDMS SMPs show significant potential as advanced materials for cranial bone regeneration.