Calcium Phosphate Treatment Enhances Osteogenic Differentiation of Porcine Adipose-Derived Stem Cells on Fibrin Scaffolds

This study was designed to develop a fibrin scaffold for optimum in vitro osteogenic differentiation of porcine ASCs. Fibrin scaffolds physically and chemically modified to be stiffer or have higher concentrations of calcium and phosphate ions were hypothesized to enhance osteogenic differentiation compared to control fibrin scaffolds. Treatments during coagulation resulted in six scaffold types for comparison: whole blood controls, red blood cell lysis buffer, calcium chloride, calcium hydrogen phosphate, vacuum, and mechanical compression. Based on the results, fibrin supplemented with granules of calcium hydrogen phosphate (CaHPO4) was determined to be the most suitable formulation of those examined. Using calcium phosphate resulted in a fibrin scaffold that coagulated faster (p = 0.022), had a rougher surface, higher stiffness, and desirable properties for practical use during surgical operations and scaffolds used in bone tissue engineering. Further, osteogenic differentiation was enhanced on scaffolds treated with calcium phosphate. In addition, fibrin scaffolds treated with RBC lysis buffer were also stiffer than untreated controls. These results are partly explained by ASC attachment and fibrin polymerization during coagulation.