Adhesion, growth and osteogenic differentiation of human bone marrow mesenchymal stem cells on positively and negatively charged and uncharged ferroelectric crystal surfaces

The cell-material interaction is significantly influenced by the physicochemical properties of the material surface, including its electrical charge. In this study, the effect of the surface polarity of ferroelectric LiNbO3 single crystals on the adhesion, growth and osteogenic differentiation of human bone marrow mesenchymal stem cells was investigated. The cells were cultured on the normal-to-plane poled and in-plane poled plates resulting in positive, negative and zero surface charge. The number of initially adhering cells on day 1 after seeding, their spreading, shape, and their metabolic activity, production of type I collagen, activity of alkaline phosphatase and mineralization in the following days of cultivation (days 6 and 20) were comparable on all three tested surfaces. However, significant differences were found in the expression of mRNA for type I collagen, alkaline phosphatase and osteocalcin, i.e. an early, medium-term and late arkers of osteogenic cell differentiation, respectively. On day 20, the expression of type I collagen was significantly lower in cells on negatively-charged than on non-charged surfaces. Moreover, the expression of alkaline phosphatase and osteocalcin was higher in cells on positively-charged than on negatively-charged surfaces. These differences were generally more pronounced in standard cell culture medium than in osteogenic medium, which could, at least partly, mask the influence of the material surface properties on the cell behaviour. Thus, positively-charged LiNbO3 surfaces seemed to be more suitable for the osteogenic differentiation of bone marrow mesenchymal stem cells than the negatively-charged surfaces.