Surface thermodynamics of osteoblasts: relation between hydrophobicity and bone active biomaterials

Surface tensions of rat calvaria osteoblasts were determined by measuring the cell–liquid–vapor contact angle with sessile drops of water on the cell monolayer. The results indicated the hydrophobic character of osteoblastic cells with a contact angle of 26.89° (0.29°). This value could explain the ability of osteoblasts to specifically attach onto hydrophobic surfaces like titanium or hydroxyapatite. The first cellular step of bone healing requires the presence of osteoblasts and their adhesion to biomaterial surfaces is the crucial phase of the osteointegration process. The presence of a monolayer of a newly discovered hydrophobic bacterial exopolysaccharide on coverglass slides appeared to strongly encourage adhesion of osteoblastic cells. In that, providing surfaces with this hydrophobic material induced a selective adsorption of osteoblast cells and might enhance osteointegration.