抄録
Formation of hydroxyapatite(HAP) via amorphous calcium phosphate(ACP) was studied by mixing CaCl2 with K2HPO4 in an aqueous phase in the presence of various sulfate compounds. Sodium sulfate and sodium chondroitin-6-sulfate did not show any effect on the formation of HAP up to ca. 1mM. Transformation of. ACP to HAP was retarded in the presence of potassium polyvinylsulfate(PVSK), while its mother compound, polyvinylalcohol, showed no specific effect over the same concentration range investigated. This result means that sulfate group on PVSK competes significantly with phosphate ion for the active growth sites on the HAP nuclei. Polyvinyl-pyrrolidone(PVP) accelerated the formation of HAP by virtue of its depletion effect. The induction time for the transformation was shortened in the presence of micelle of sodium dodecylsulfate(SDS) owing to its Ca2+ condensation effect. This micelle effect gradually diminished with the addition of PVP due to the formation of PVP-SDS complex, which behaved like a polyelectrolyte such as PVSK.
