Incubation of platelet-rich fibrin matrix with mesenchymal stem cells improves matrix stiffness

Objective: The platelet-rich fibrin matrix (PRFM) is condensed platelet-rich plasma (PRP) and should possess a comparable biomechanical property to the transplanted sites, for them to be physiologically functional. The aim of this study was to investigate the effect of human bone marrow mesenchymal stem cells (hBM-MSC) or human umbilical cord mesenchymal stem cells (hUC-MSC) on the biomechanical properties of PRFM. Methods: PRFM was prepared by the gelation of PRP using 25 mmol CaCl₂. The resulting coin-shaped PRFM pellets, 5 cm in diameter and 300 µm thick, were directly seeded with hUC-MSC or hBM-MSC at 2,000 cells cm^-2, followed by 24 h incubation at 37 °C in 5% (v/v) CO₂ in air. The samples were then observed by scanning electron microscopy to determine the morphology of the matrix surface. The PRFM biomechanical properties were determined at a 10 mm. min-1failure rate using an MCT 2150 universal testing machine (AandD Co. LTD). Results: SEM imaging of the surface of the PRFM seeded with hBM-MSC and hUC-MSC showed a cloudy layer that thickened over time. The elastin slope of the PRFM was significantly improved after seeding with hBM-MSC and hUC-MSC when compared with unseeded PRFM (p<0.002, R²=0.983). Both cell types elicited similar biomechanical effects (p=0.99). Conclusion: PRFM seeded with hBM-MSC or hUC-MSC showed significantly increased elasticity.