Figure 5: Effect of the major PRF component, fibrin, on periodontal progenitor attachment and mineralization. Osteogenic lineage differentiation (a) and mineralized nodule formation (b) of dental follicle cells (DF), periodontal progenitors (PDL), and alveolar bone progenitors (AB) on fibrin-coated dishes, vacuum gas plasma-treated tissue culture dishes, and untreated Petri dishes as revealed by alkaline phosphatase (a) and alizarin red S (b). Alkaline phosphatase activity was determined after one week and alizarin red S staining was performed after three weeks.