Fabrication and characterization of platelet-rich plasma scaffolds for tissue engineering applications.

Platelet-Rich Plasma (PRP), as a rich source of growth factor, can form a fibrin gel that recapitulates the extracellular matrix of the tissues. The aim of this study was to evaluate the effects of different concentrations of CaCl2 on the PRP scaffold structure which in turn could change the cell's behavior. PRP was mixed with 2.5, 5 and 10% (w/v) CaCl2. Then, the tensile strength, biodegradability and water content of the scaffolds were evaluated. We also performed immunostaining for assessment of the actin stress fiber orientation and SEM for detecting the cell phenotype and physical properties of the fibers. Cell viability, attachment and migration were also evaluated. The highest cell attachment and short term proliferation rate was observed on the scaffolds with 2.5% CaCl2. The cells cultured on the scaffold with higher CaCl2 concentration had fusiform phenotype with few cell processes and parallel arrangement of stress fibers while those cultured on the other scaffolds were fibroblast-like with more processes and net-like stress fibers. The scaffolds with 10% CaCl2 demonstrated the highest osmolarity (358.75±4.99mOsmole), fiber thickness (302.1±54.3nm), pore size (332.1±118.9nm2) and the longest clotting time (12.2±0.776min) compared with the other scaffolds. Water content, branching angle, porosity, orientation and tensile strength did not change by gelation with different CaCl2 concentrations. In conclusion, the cell shape, viability and proliferation were modified by culturing on the PRP scaffolds prepared with various concentrations of CaCl2, and as a result, the scaffolds showed different physical and biological properties.