Biodegradable poly(ε-caprolactone)/poly(silyl fumarate) shape memory scaffolds.

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Tissue Engineering

Background:

• Biodegradable shape memory scaffolds are crucial for craniomaxillofacial (CMF) defect repair.
• Poly(ε-caprolactone) diacrylate (PCL-DA) scaffolds exhibit slow degradation, limiting neotissue formation.
• Previous attempts using siloxane macromers (PDMS-DMA, PMHS-DMA) improved degradation but lacked hydrolytic instability.

Purpose of the Study:

• To synthesize and evaluate poly(silyl fumarate) (PSF) as a novel, hydrolytically unstable siloxane macromer for biodegradable scaffolds.
• To create and characterize PCL/PSF co-network scaffolds for CMF defect healing.
• To assess the impact of PSF incorporation on scaffold degradation, mechanical properties, and shape memory behavior.

Main Methods:

• Poly(silyl fumarate) (PSF) was synthesized with a hydrolytically unstable backbone.
• PCL/PSF co-network scaffolds were fabricated using solvent-casting particulate leaching (SCPL) with varying PCL-DA to PSF weight ratios (90:10, 75:25, 60:40, 50:50).
• Scaffold properties including shape memory behavior, mechanical modulus, and in vitro degradation were evaluated.

Main Results:

• All PCL/PSF scaffolds maintained excellent shape memory properties.
• Scaffolds with 10% and 25% PSF retained the modulus of PCL-only and PCL/siloxane scaffolds.
• In vitro degradation increased with PSF content, with 25% PSF degrading faster than PCL/PDMS scaffolds, attributed to PSF's hydrolytic instability rather than phase separation.

Conclusions:

• PSF is a promising biodegradable siloxane macromer for developing advanced shape memory scaffolds.
• PCL/PSF scaffolds demonstrate tunable degradation rates and maintained mechanical integrity and shape memory function.
• The hydrolytic instability of PSF offers a novel strategy for accelerating scaffold degradation and promoting neotissue formation in CMF defect repair.