磷酸二钙二水合物CaHPO₄·2H₂O（DCPD）的体外形成

In vitro formation of dicalcium phosphate dihydrate, CaHPO4 . 2H2O (DCPD).

作者信息

LeGeros R Z, Lee D, Quirolgico G, Shirra W P, Reich L

出版信息

Scan Electron Microsc. 1983(Pt 1):407-18.

Abstract

Dicalcium phosphate dihydrate, CaHPO4 . 2H2O (DCPD) crystals were grown in solutions and in different types of gels (silica, agar, collagen) at different pH's, in the presence of other ions, and on different Ca-bearing substrates (enamel, dentine, bone, calcite). Hydrolysis of DCPD to other calcium phosphates and calcium oxalates were made in solutions containing different ions at 37 degrees C, 24h. Results showed that the type of media (solution or gel), type of gel, pH, presence of other ions affect the morphology (size/shape) and growth of DCPD. In systems of changing pH, the more basic calcium phosphate (e.g., apatite, OCP) formed in the first zone, DCPD in the last zone, regardless of the initial Ca/P of the system. Growth of DCPD was suppressed in the presence of F-(which favored growth of apatite), of Cd2+, Pb2+ (which favored OCP). Hydrolysis of DCPD to apatite was promoted in solutions containing Ca2+, F-, CO3=, and inhibited by Mg2+, P2O74-. Hydrolysis of DCPD to calcium oxalate occurs in presence of C2O4=. Results indicate that the variation in morphology of DCPD occurring in various human tissue calcinosis and the co-existence of DCPD with other calcium phosphates and oxalates in urinary and dental calculi are due to variations in pH, and presence of different ions in the media.

摘要

二水磷酸氢钙（CaHPO₄·2H₂O，DCPD）晶体在不同pH值的溶液以及不同类型的凝胶（二氧化硅、琼脂、胶原蛋白）中生长，在其他离子存在的情况下，在不同的含钙底物（牙釉质、牙本质、骨、方解石）上生长。在37℃下，将DCPD在含有不同离子的溶液中水解24小时，使其转化为其他磷酸钙和草酸钙。结果表明，介质类型（溶液或凝胶）、凝胶类型、pH值、其他离子的存在会影响DCPD的形态（尺寸/形状）和生长。在pH值变化的体系中，无论体系的初始钙磷比如何，在第一个区域会形成碱性更强的磷酸钙（如磷灰石、OCP），在最后一个区域形成DCPD。在F⁻（有利于磷灰石生长）、Cd²⁺、Pb²⁺（有利于OCP生长）存在的情况下，DCPD的生长受到抑制。在含有Ca²⁺、F⁻、CO₃²⁻的溶液中，DCPD向磷灰石的水解得到促进，而受到Mg²⁺、P₂O₇⁴⁻的抑制。在C₂O₄²⁻存在的情况下，DCPD会水解为草酸钙。结果表明，在各种人类组织钙化中DCPD形态的变化以及在尿路结石和牙结石中DCPD与其他磷酸钙和草酸盐的共存是由于pH值的变化以及介质中不同离子的存在。