In situ measurement of crystal growth rate on the hap coating by quartz crystal microbalance method

摘要

The measurement for bonelike apatite crystal growth rate on biomaterials in a simulated body fluid is very important. The crystal growth has been measured with scanning electron microscopic (SEM) observation. It is difficult to measure a dynamic behavior of crystal growth by using ex-situ measurement, such as a SEM observation. On the other hand, a quartz crystal microbalance (QCM) method is an in-situ measurement, which is suitable for the precise measurement of the crystal growth. A resonant frequency of quartz crystal is measured in the QCM method. This resonant frequency change corresponds to a mass change of a substance accumulated on the quart crystal. An amorphous calcium phosphate was deposited on the quartz crystal covered with gold using rf-magnetron sputtering. Then the calcium phosphate was annealed under water vapor pressure in an autoclave at 200 deg C for 24 h, in order to obtain a high crystalline HAp. The crystal growth on this substrate in a SBF was measured with QCM method. From this measurement, the mass change on the substrate was obtained. The deposited compounds was assigned to bonelike apatite from x-ray diffraction method and Fourier transform infrared spectroscopy. Using this substrate, the mass change directly corresponding to the crystal growth on HAp was precisely measured.