抄録
The effects of ionic flow and organic matrices on the lengthwise and oriented growth of octacalcium phosphate (OCP), which is a potent precursor of apatite, was studied in model systems of tooth enamel apatite formation. In the model systems, cation selective membranes and dialysis membranes were used to control the ionic diffusion. The crystal size decreased in polyacrylamide gel, but the lengthwise growth along the c-axis direction of OCP took place in 5-20% gel, resulting in ribbon-like crystals with large aspect ratios. When a thin slice of Achilles tendon was used in place of the membrane (s), OCP crystals grew on the collagen fibril with the most preferred orientation direction of the c-axis of OCP which is parallel to the fiber axis of collagen. Thus, when the matrix has some correlation to the crystal, the lengthwise and oriented growth was regulated by the organic matrix, otherwise OCP tended to grow along the direction of the ionic flow.
