Testing of Brushite (CaHPO₄·2H₂O) in Synthetic Biomineralization Solutions and In Situ Crystallization of Brushite Micro‐Granules

Abstract

Conventional flat plate-shaped brushite, dicalcium phosphate dihydrate, CaHPO 4 ·2H 2 O), produced by reacting Ca-chloride and alkali phosphate salt solutions, were found to undergo a maturation process (changing their Ca/P molar ratio from 0.8 to the theoretical value of 1) similar to those seen in biological apatites. Water lily (WL)-shaped brushite crystals were produced in nonstirred aqueous solutions at room temperature in 24 h, by using precipitated calcite and NH 4 H 2 PO 4 as the starting chemicals. The hydrothermal transformation of WLtype brushite into octacalcium phosphate (OCP) or Ca-deficient hydroxyapatite (CDHA) was tested at 37°C by using four different biomineralization solutions, including Tris-buffered SBF (synthetic body fluid) and sodium lactate-buffered SBF solutions. All four solutions used in this study consumed the starting brushite in 1 week and caused transformation into a biphasic mixture of nanocrystalline OCP and CDHA of high surface area. WL-type brushite crystals when synthesized in the presence of small amounts of Zn 2+ ions resulted in the formation of, for the first time, spherical micro-granules of brushite.

Composite of porous starch-silk fibroin nanofiber-calcium phosphate for bone regeneration

“…Various factors such as charged surface, type of functional groups, pH, and supersaturation degree of aqueous medium (IP/K 0 ) affect the nature and crystallinity of the deposited CaP on the surface of materials [33][34][35]. It has been reported that brushite precipitates in aqueous solution containing Ca 2+ and HPO 4 2-in pH values between 2 to 6.5 [27,36]. In this study, the pH value of the CaCl 2 solution decreased from 7.4 to 5.02, presumably due to the ionization of hydroxyl and carboxyl groups.…”

Morphology control of brushite prepared by aqueous solution synthesis

“…Therefore, elucidating the effects of DCPD crystallization parameters is very important. In recent studies of calcium phosphate bioceramics, various crystallization conditions (e.g., calcium and phosphorous concentrations, temperature, ionic strengths, and solution pH) were investigated [29][30][31][32][33][34][35][36]. We previously reported the effects of both acetate anion and pH on the morphology of DCPD crystallization [37].…”

PEG hydrogel containing calcium-releasing particles and mesenchymal stromal cells promote vessel maturation

“…For this reason, we measured the release of calcium from GC8 particles for several days. Also, since the type of media can influence degradation rate of bioglasses/glass-ceramics, we used CCM and buffered MilliQ water [66–68]. Despite achieving a sustained release for several days, calcium release was slower in CCM.…”