Controlled synthesis of dicalcium phosphate dihydrate (DCPD) from metastable solutions: insights into pathogenic calcification

Abstract

Calcium phosphate (CaP) compounds may occur in the body as abnormal pathogenic phases in addition to their normal occurrence as bones and teeth. Dicalcium phosphate dihydrate (DCPD; CaPO4·2H2O), along with other significant CaP phases, have been observed in pathogenic calcifications such as dental calculi, kidney stones and urinary stones. While other studies have shown that polar amino acids can inhibit the growth of CaPs, these studies have mainly focused on hydroxyapatite (HAp; Ca10(PO4)6(OH)2) formation from highly supersaturated solutions, while their effects on DCPD nucleation and growth from metastable solutions have been less thoroughly explored. By further elucidating the mechanisms of DCPD formation and the influence of amino acids on those mechanisms, insights may be gained into ways that amino acids could be used in treatment and prevention of unwanted calcifications. The current study involved seeded growth of DCPD from metastable solutions at constant pH in the presence of neutral, acidic and phosphorylated amino acid side chains. As a comparison, solutions were also seeded with calcium pyrophosphate (CPP; Ca2P2O7), a known calcium phosphate inhibitor. The results show that polar amino acids inhibit DCPD growth; this likely occurs due to electrostatic interactions between amino acid side groups and charged DCPD surfaces. Phosphoserine had the greatest inhibitory ability of the amino acids tested, with an effect equal to that of CPP. Clustering of DCPD crystals giving rise to a “chrysanthemum-like” morphology was noted with glutamic acid. This study concludes that molecules containing an increased number of polar side groups will enhance the inhibition of DCPD seeded growth from metastable solutions.

Anionic Polysaccharide Cryogels: Interaction and In Vitro Behavior of Alginate–Gum Arabic Composites

“…For the Alg-26GA sample, the XRD pattern after 21 days of immersion indicates the formation of crystalline phases of NaCl, with pronounced diffraction peaks at approximately 2θ = 26.42, 36.94, and 51.64 being identified (Figure S1b). The same reflections can be observed for the Alg-16GA sample but with lower crystallinity [47][48][49].…”

Synthesis and characterization of calcium phosphate (tricalcium phosphate/calcium pyrophosphate) from snail shells (Achatina fulica)

“…Specific FTIR spectra of calcium phosphate sample is shown in Figure 1. Compared with TCP [25] and CPP [26], it shows two main functional groups i.e., OH and PO4. The OH group was detected at a wavenumber of 3446.32 and 725.78 cm -1 , while the phosphate group (PO4) was strongly detected at a wavenumber of 938.50 cm -1 .…”

Synthesis of Natural Nano-Hydroxyapatite from Snail Shells and Its Biological Activity: Antimicrobial, Antibiofilm, and Biocompatibility

“…The most common type of CaPs used in dental applications appears to be apatites (HA, CDHA, and FA). Because nano-dimensional and nano-crystalline apatites are often regarded as model compounds for dental enamel due to chemical and phase similarities [21], their use in restorative dentistry has a number of promising benefits, including intrinsic radio-opaque response, enhanced polishability, and improved wear performance. They also have a hardness that is comparable to that of actual teeth [22].…”