Surface characterizations of, and protein adsorption to, synthetic and sintered apatite plates

Abstract

We investigated the surface characterizations of apatite plates synthesized by the method of Abe, and of sintered apatite plates, and examined adsorption isotherms of protein to these plates. An x-ray refraction apparatus showed the sintered apataite plate to have high crystallinity. Chemical analysis by electron spectrometer for chemical analysis showed that the peaks for calcium, phosphorous, oxygen and carbon were in the same positions for the apatite plate as they were for powdered hydroxyapatite. Scanning electron microscopy and atomic force microscopy showed that the surface structure in the sintered apatite plate was flat because of polishing, and that the synthetic apatite plate was comprised of overlapping layers. The zeta potential of the surface of the apatite plate in protein solution (human serum albumin and salmon protamine) increased with increasing protein concentration, and the plateau value of the sintered apatite plate was closer to the charge of protein than was that of the synthetic apatite plate. We found the sintered apatite plate useful for experiments on the adhesion o f protein and bacteria.