Mineralization of Calcium Phosphate Crystals in Starch Template Inducing a Brushite Kidney Stone Biomimetic Composite

Abstract

Dicalcium phosphate dihydrate (brushite) and octacalcium phosphate (OCP) crystals are precursors of hydroxyapatite (HAp) for tooth enamel, dentine, and bones formation in living organisms. Here, we introduce a new method for biomimicking brushite and OCP in starch using single and double diffusion techniques. Brushite and OCP crystals were grown by precipitation in starch after gelation. The obtained materials were analyzed by infrared spectroscopy (IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and confocal laser scanning microscopy (CLSM). IR spectra demonstrate starch inclusion by peak shifts in the 2900−3500 cm −1 region. SEM showed two different morphologies: plate-shaped and needle-like crystals. Calcium phosphate/starch aggregates bear strong resemblance to prismatic brushite kidney stones. This may open up a clue to understand the mechanism of kidney stone formation.

Biomineralization‐Inspired Green Synthesis of Zinc Phosphate‐Based Nanosheets in Gelatin Hydrogel

“…We observed similar results for calcium hydrogen phosphate crystals produced in starch hydrogel . The reflection positions of nanocomposite sheets clearly show that the use of gel growth method for crystallization as well as the local pH in gel is very important for producing ZP with different lattice textures . This observation clearly indicates the differences in the morphology of crystallites due to gel pH.…”

“…At ambient temperature, the gelation of gelatin established a template for diffusion of zinc cations. Thus, subsequent precipitation reaction took place in hydrogel between Zn 2+ and HPO 4 −2 ions, inducing the nucleation and growth of ZP/gelatin nanocomposite sheets . We can finally express that different adsorption of macromolecular chains on crystal surfaces probably changed the crystal morphology and stacks arrangement.…”

“…The PO stretches in the PO 4 −3 fragment of ZP are characterized by three strong bands at 1113, 1022, and 939 cm −1 . The P‐O bending of the PO 4 −3 fragment is indicated by the bands at about 550–650 cm −1 …”

“…This observation clearly confirmed that gelatin is entrapped between ZP sheets and nanocomposite powders are produced. In our previous study, we showed that the entrapment of gelatin between the calcium phosphate sheets occurs by preferential interaction of gelatin functional domains with atomic arrangement on the crystal planes . It is well‐known that collagen macromolecules have charged amino acid groups including negatively charged aspartic and glutamic acids, and positively charged lysine and arginine.…”

Powdered Ca‐activated zeolite for phosphate removal from treated waste‐water

“…However, little work has been done to prepare a reactive material to: (a) efficiently remove phosphate from waste‐water effluents in the form of relatively soluble phosphates (e.g. brushite (logK so = 6.59)) compared with Hap (Ca 5 (PO 4 ) 3 OH(s), logK so = 116.8); and (b) to achieve suitable properties for use as a synthetic fertiliser.…”