TGF-beta1 exposure from bone surfaces by chemical treatment modalities

Growth factors are known to be sequestered to the mineralised matrix of bone. The aim of this study was to investigate the ability of citric acid, EDTA, calcium hydroxide and sodium hydroxide to release active growth factors from bone surfaces, able to promote osteoblast differentiation. All chemical treatments increased surface levels of TGF-beta1 (used as a biomarker of growth factor release), compared to control bone surfaces treated with PBS. Differences were observed in the kinetics of TGF-beta1 exposure at the surface and its subsequent release into the aqueous environment for the different chemical treatments. Surface levels of growth factor following chemical treatment were low, but of sufficient concentration to stimulate cell expansion and osteoblast differentiation of bone marrow stromal cells grown on EDTA and calcium hydroxide treated surfaces compared to PBS treated surfaces. The increased osteogenic potential on these surfaces may relate to an increase in growth factor availability and changes to the surface chemistry and topography.