抄録
It was previously reported that when hydroxyapatite (HAP) synthesized with an increased Ca/P molar ratio was heated to precipitate CaO on the HAP matrix, the HAP remained alkaline even when immersed in physiological saline. Alkaline HAP may cause cell toxicity, so heated HAP with a high molar ratio should be neutralized after being immersed in distilled water.
In this study, spherical HAP (average size of 35 μm) with a Ca/P molar ratio of 1.70 was prepared. The HAP samples were heated at 900℃ for 180 min. The heated HAP was soaked in distilled water for one week and the soak tests were repeated four times. The dissolution of Ca and pH value in distilled water were measured each week.
The X-ray diffraction pattern of HAP and the strength of fibronectin adsorption of 1.70-90 (HAP of molar ratio 1.70 heated at 900℃) and 1.70-90 W (HAP of molar ratio 1.70 heated at 900℃ and soaked four times) were measured, and the following results were obtained.
The pH value and the amount of dissolved Ca of 1.70-90 were highest, but they decreased as the frequency of soaked times increased. The results of X-ray diffraction analysis confirmed precipitated CaO on the surface of 1.70-90, but 1.70-90 W and other HAP were not confirmed. The pH of 1.70-90 W was 7.85. 1.70-90 W showed a higher strength of fibronectin adsorption than 1.70-90. The biological reaction will be researched in the future.
