PFSSTKT(PFS)-functionalized Hierarchical Porous ECM Scaffolds Facilitate Articular Cartilage Regeneration through the Recruitment of Endogenous Stem Cells and Chondrogenic Induction.

Abstract

Injury to articular cartilage remains a major clinical challenge owing to its limited self-healing capacity. Current cell-based therapies are limited by issues such as dedifferentiation and regulatory hurdles, whereas existing scaffold systems often lack the essential biochemical signals necessary for effective tissue regeneration. Consequently, biomimetic acellular strategies capable of recruiting endogenous stem cells while establishing a conducive biochemical microenvironment to direct their chondrogenic differentiation are needed. In this study, we developed a bioactive, hierarchical porous extracellular matrix (ECM) scaffold fabricated via low-temperature deposition manufacturing (LDM) and functionalized with the bone marrow-homing peptide PFS (amino acid sequence PFSSTKT) to increase in situ cartilage regeneration. The scaffold preserves the native biochemical characteristics of ECM while enabling stable functionalization with the chemoattractant peptide PFS. In vitro studies demonstrated that the PFS-functionalized ECM scaffold exhibited favorable biocompatibility and supported cell adhesion, migration, and proliferation. In vivo studies using a rabbit full-thickness cartilage defect model further showed enhanced endogenous stem cell recruitment and hyaline-like cartilage regeneration in the PFS-ECM group compared with the ECM and control groups. The regenerated tissue exhibited improved matrix composition, biomechanical properties, and histological scores. Collectively, this work presents a cell-free, biofunctional ECM-based scaffold strategy that promotes endogenous repair of articular cartilage, providing a promising approach for cartilage regeneration without exogenous cell transplantation. STATEMENT OF SIGNIFICANCE: Articular cartilage repair remains a significant clinical challenge. While current cell-based therapies face limitations such as dedifferentiation, conventional scaffolds often lack essential bioinductive signals. To address this challenge, we have developed a bioactive extracellular matrix scaffold functionalized with the chemotactic peptide PFS. In this design, the PFS peptide enhances endogenous stem cell recruitment, while the ECM provides a chondrogenic microenvironment. Experimental results confirmed that this scaffold significantly promotes stem cell migration and chondrogenic differentiation. Animal studies demonstrated that the PFS-ECM group outperformed control groups in cell recruitment, hyaline cartilage regeneration, and mechanical properties, offering a promising cell-free solution with translational potential for clinical cartilage repair.