QUANTITATIVE ASSESSMENT OF APATITE FORMATION VIA A BIOMIMETIC METHOD USING QUARTZ-CRYSTAL MICROBALANCE

Quantitative assessment of hydroxyapatite formation on a gold surface via the biomimetic method, composed of a nucleation step in a simulate d body fluid (SBF) containing glass powders and a subsequent apatite g rowth step in glass powder-free SBF, was made using a quartz crystal m icrobalance (QCM) technique. The frequency change of the QCM linearly increased with increasing soaking time, and largely depended on the nu cleation period. The growth rates, defined as daily increase in thickn ess, increased monotonicly with an increasing nucleation period of up to 96 h, thereafter being constant at 2.0 mu m/day. The growth rate of the apatite layer increased with increasing temperature of the SBF: 0 .9, 2.0, and 3.8 mu m/day at 25, 37, and 50 degrees C, respectively. T he Arrhenius-type activation energy for the growth of apatite was 47.3 kJ/mol. The QCM method was found to be a very powerful tool for quant itative, in situ measurement of precipitation and growth of apatite in real time. (C) 1996 John Wiley & Sons, Inc.