Anionic Effects on the Size and Shape of Aptite Crystals Grown From Physiological Solutions

Published

June 1, 2000

Author(s)

E D. Eanes, A W. Hailer

Abstract

Comparatively little is known of the role tissue fluid electrolytes have in establishing the size and shape of apatite crystals deposited in skeletal tissues. In vitro accretion experiments using synthetic apatite seed crystals comparable in size to bone apatite were performed to assess the extent these crystalline features may be affected by direct electrolyte/mineral interactions. A constant composition method was used to maintain the accretion reactions under physiological-like solution conditions (1.33 mmol/L Ca2+, 1.0 mmol/L total inorganic phosphate, 0 or 26 mmol/L carbonate, 270 mmol/kg osmolality, pH 7.4, 37 C). When new accretions equaled the initial seed mass, the solids were harvested and net crystal growth was assessed by x-ray diffraction line broadening analysis. All the electrolytes examined in this study inhibited the accretion rate. The order of effectiveness was phosvitin > polyaspartate, polyglutamate > 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) > bovine serum albumin (BSA) > citrate. Citrate and BSA also suppressed growth of the seed crystals in favor of the proliferation of new crystals. In contrast, the other electrolytes stimulated seed crystal growth. These growth changes, however, were anisotropic, with the anions affecting primarily crystal width/thickness. The effects were also more pronounced in the presence of carbonate. These findings suggest that adsorbed electrolytes may be a significant factor in controlling the size of apatite crystals in skeletal tissues by inducing proliferative growth of new crystals and/or affecting crystal shape by selectively modifying growth of the lateral dimensions.

Citation

Calcified Tissue International

Volume

66

Issue

No. 6

Pub Type

Journals

Keywords

albumin, apatite, calcifiction, calcium phosphates, citrate, crystal texture, hydroxyapatite, mineralization

Citation

Eanes, E. and Hailer, A. (2000), Anionic Effects on the Size and Shape of Aptite Crystals Grown From Physiological Solutions, Calcified Tissue International (Accessed July 26, 2024)