BONE-GROWTH ON SOL-GEL CALCIUM-PHOSPHATE THIN-FILMS IN-VITRO

Thin, sub-micron, films of calcium phosphate were fabricated on either glass or quartz supports by a colloidal suspension sol-gel method. Th ese films, which varied in both surface chemistry and topography were then employed as culture substrata for osteogenic rat bone marrow cell s. During an 18 day culture period, the cells elaborated a morphologic ally 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 ob served by scanning electron microscopy. Particular attention was paid to the morphologies of the interface between the sol-gel layer and the underlying support, and that between the sol-gel layer and the elabor ated bone tissue. The mechanical disruption of both tissue and thin fi lms resulting from critical point drying affected the morphology of bo th interfaces dependent upon the film processing conditions. The inter facial bone matrix, which was a cement-line like matrix interdigitated with the surface of the films. This mechanical interdigitation create d a bond which remained intact during tissue processing. With films pr ocessed at 1000 degrees C on quartz supports, but not with those proce ssed at lower temperatures on glass, fracture of the interface reveale d pitting in the quartz surface which was associated with areas of adh erence of the overlying calcium phosphate film. These preliminary stud ies demonstrate the intimate relationship which can be established bet ween such thin calcium phosphate thin films and bone matrix.