Design and Synthesis of Peptide-Polyester Conjugates for Cell-Mediated Scaffold Degradation

Abstract

Biodegradable thermoplastic polyesters are promising biomaterials for tissue engineering due to their processability and mechanical properties. Polycaprolactone (PCL) is particularly attractive for load-bearing applications but does not degrade at the same rate as new tissue formation, which may compromise functional regeneration. This study presents a strategy for cell-mediated scaffold remodeling by incorporating a protease-cleavable peptide directly into the PCL backbone. Linear peptide-PCL conjugates were synthesized with poly(ethylene glycol) (PEG) spacers flanking the peptide to enhance protease access. A functional proteomics approach was used to identify a fast-degrading peptide sequence (Fast) selectively cleaved by multiple cell types. Conjugates containing Fast or its scrambled control (ScrFast) were combined with an RGDS-PCL conjugate and fabricated into scaffolds. Including Fast and ScrFast peptides did not impair cell adhesion to the scaffolds. Cy3 labeling enabled real-time quantification of scaffold degradation in the presence of collagenase or human mesenchymal stromal cells (hMSCs). Fast-PCL scaffolds degraded significantly faster than ScrFast-PCL in both conditions, demonstrating sequence-dependent and cell-directed resorption. Integrating protease-sensitive peptides into the polymer backbone is therefore an effective approach to fabricate solid scaffolds that degrade in response to cells. This platform can be adapted to couple cellular processes to scaffold remodeling to enhance tissue regeneration.