Effect of the Components of Biological Environment on the Formation of Hydroxyapatite

Using the modified procedure of the synthesis of non-stoichiometric hydroxyapatite species at the physiological pH and solution temperature, we obtained the solid phases with the Ca/P atomic ratios within the range from 1.58 +/- 0.01 to 1.67 +/- 0.01. According to the data of X-ray phase analysis, these samples are composed of hydroxyapatite. The effect of inorganic additives (phosphate, oxalate, carbonate anions, magnesium cations) and organic ones (amino acids) on the crystallization of hydroxyapatite was studied. The electrokinetic properties of the sol of synthesized hydroxyapatites of different stoichiometric composition were studied. It was established that the charge and the value of o potential of hydroxyapatite particles depend on the Ca/P atomic ratio. It was discovered that the character of amino acid interaction with non-stoichiometric hydroxyapatite differs from that with the stoichiometric one. It was shown that adsorption observed on the samples of synthesized hydroxyapatite is described within Langmuir and Freundlich models.