Cells and Materials


Thin, sub-micron, films of calcium phosphate were fabricated on either glass or quartz supports by a colloidal suspension sol-gel method. These films, which varied in both surface chemistry and topography were then employed as culture substrata for osteogenic rat bone marrow cells. During an 18 day culture period, the cells elaborated a morphologically distinguishable bone matrix on all substrata which was similar to that reported earlier on tissue culture polystyrene. Selected samples of the culture substrata were fractured, critical point dried, and observed by scanning electron microscopy. Particular attention was paid to the morphologies of the interface between the so1-gellayer and the underlying support, and that between the sol-gel layer and the elaborated bone tissue. The mechanical disruption of both tissue and thin films resulting from critical point drying affected the morphology of both interfaces dependent upon the film processing conditions. The interfacial bone matrix, which was a cement-line like matrix, interdigitated with the surface of the films. This mechanical interdigitation created a bond which remained intact during tissue processing. With films processed at 1000°C on quartz supports, but not with those processed at lower temperatures on glass, fracture of the interface revealed pitting in the quartz surface which was associated with areas of adherence of the overlying calcium phosphate film. These preliminary studies demonstrate the intimate relationship which can be established between such thin calcium phosphate thin films and bone matrix.