Synthesis of oriented hydroxyapatite crystals: Effect of reaction conditions in the presence or absence of silk sericin

The purpose of this study was to investigate the effect of silk sericin (SS) on the morphology and crystallinity of hydroxyapatite (HAp) crystals synthesized at the pH 7.4-12 and 50 degrees C via a biomimetic method. Using X-ray diffraction (XRD), transmission electron microscope (TEM) and high-resolution transmission electron microscope (HRTEM), it was revealed that a homogeneous assembly could be obtained in the presence of SS, which held a highly ordered microstructure and poor crystallinity. But in the absence of SS, an oriented aggregate could be prepared at 50 C and pH 10, which held more confused crystal lattice lines. The results proved that the biomimetic structure of HAp could be constructed under the controlled reaction conditions, which may offer a new clue on the understanding of the process of biomineralization. (C) 2010 Elsevier B.V. All rights reserved.