ATTACHMENT, MORPHOLOGY, AND PROTEIN EXPRESSION OF RAT MARROW STROMAL CELLS CULTURED ON CHARGED SUBSTRATE SURFACES

Although surface charge has been shown to affect the adhesion and morp hology of a variety of cell types, the interactions of bone marrow str omal cells with charged surfaces still remain unclear. A novel electri cal stimulation system was used to investigate the interactions betwee n rat bone marrow stromal cells and charged substrates in this study. A conductive and transparent indium tin oxide (ITO) coating was used a s an electret substrate. Rat marrow stromal cells were cultured on pos itive, negative, and uncharged ITO surfaces. Cell attachment, morpholo gy, alkaline phosphatase activity, and expression of osteopontin and c ollagen type III were assessed using histochemical staining, immunolab eling, and fluorescence microscopy. Voltages of 0.7, 0.8, 0.9, and 1.0 V applied to the substrates created surface potentials but were insuf ficient to decompose the media. On positively charged ITO, cell attach ment was enhanced in serum-supplemented and serum-free media. Furtherm ore, decreases in cell spreading, alkaline phosphatase activity, and o steopontin were observed in cells grown on the positively charged ITO. These data indicate that positively charged surfaces enhance cell att achment but suppress cell spreading and differentiation of rat marrow stromal cells. (C) 1998 John Wiley & Sons, Inc.