Zinc Ions Modify Calcium Oxalate Growth by Distinct Transformation of Crystal Surface Termination

Abstract

Calcium oxalate crystals are ubiquitous minerals in biogenic, geological, and synthetic systems. It has been shown that the most naturally abundant form of these crystals, calcium oxalate monohydrate (COM), grows via a classical pathway that can be regulated by crystal growth modifiers. One of the most important occurrences of COM is during human kidney stone disease where the role of zinc in pathological stone formation is not fully understood. There are conflicting claims in the literature that zinc functions either as a promoter or inhibitor of COM stone formation. Here, we examine the role of zinc ions in COM crystal growth using a combination of experimental and modeling techniques to elucidate ion−crystal interactions at macroscopic to atomic length scales. From this, we show that zinc reduces the rate of crystal growth and also induces morphological transformations via the introduction of intergrowths that can potentially accelerate crystal growth. Density functional theory calculations indicate high energetic barriers for zinc incorporation in COM crystals, suggesting that changes in crystal growth are related to zinc interactions with COM crystal surfaces. This was confirmed by in situ atomic force microscopy measurements showing a unique ability of zinc ions to truncate the height of layers on the (100) face, which concomitantly affects both the morphology of surface features and the kinetics of layered growth. Collectively, our study suggests that the role of zinc in pathological crystallization is potentially bimodal, consistent with opposing theories in the literature.

Opposing Effects of Impurity Ion Sr2+ on the Heterogeneous Nucleation and Growth of Barite (BaSO4)

“…Impurities are known to change growth rates and growth habits of crystals. − Impurity ions adsorbed at surface sites, including monomolecular steps or kink sites on those steps result in retardation of the step advance. Both adsorption of Sr 2+ on barite and precipitation of a (Ba,Sr)­SO 4 solid solution could decrease the growth rate.…”

Elucidating the role of hyaluronic acid in the structure and morphology of calcium oxalate crystals

“…The COD form is often present in the urine of healthy subjects while COM calculi are more prevalent in the urine of recurrent stone formers compared with urine from healthy subjects [14,15]. Thus, recent reports focused on how natural and synthetic additives, for example, amino acids [16][17][18][19], polymers [20,21], lipids [22], proteins [23,24], peptides [25,26], metal ions [27][28][29], and carboxylic acids [30,31], affect the formation of the different forms of CaOx and how they can be leveraged to prevent or treat kidney stones. Various additives show specific binding with different surfaces of the CaOx crystals and can inhibit their growth via various mechanisms [32].…”

Manipulation of amorphous precursors to enhance zeolite nucleation

“…13,54,55 In biomineralization, metals are also prevalent and can function as crystal growth modifiers. 56–58 This was recently demonstrated in calcium carbonate by De Yoreo and coworkers, 59 who showed that ACC infused with Mg 2+ ions modifies precursor hydration and inhibits its evolution, which impacts the kinetics of CaCO 3 crystallization and crystal size.…”

“…13,54,55 In biomineralization, metals are also prevalent and can function as crystal growth modiers. [56][57][58] This was recently demonstrated in calcium carbonate by De Yoreo and coworkers, 59 who showed that ACC infused with Mg 2+ ions modies precursor hydration and inhibits its evolution, which impacts the kinetics of CaCO 3 crystallization and crystal size. 3 (A) Induction time of zeolite L (LTL) syntheses with three as-received silicon sources (potassium silicate, fumed silica, and colloidal silica) and a modified fumed silica incubated in 2 M KBr (aq) solution at room temperature for 7 days.…”