Small‐Molecular‐Weight Additives Modulate Calcification by Interacting with Prenucleation Clusters on the Molecular Level**

Abstract

Small-molecular-weight (MW) additives can strongly impact amorphous calcium carbonate (ACC), playing an elusive role in biogenic, geologic, and industrial calcification. Here, we present molecular mechanisms by which these additives regulate stability and composition of both CaCO 3 solutions and solid ACC. Potent antiscalants inhibit ACC precipitation by interacting with prenucleation clusters (PNCs); they specifically trigger and integrate into PNCs or feed PNC growth actively. Only PNC-interacting additives are traceable in ACC, considerably stabilizing it against crystallization. The selective incorporation of potent additives in PNCs is a reliable chemical label that provides conclusive chemical evidence that ACC is a molecular PNC-derived precipitate. Our results reveal additive-cluster interactions beyond established mechanistic conceptions. They reassess the role of small-MW molecules in crystallization and biomineralization while breaking grounds for new sustainable antiscalants.

Surface Passivation by Embedment of Polyphosphate Inhibits the Aragonite-to-Calcite Thermodynamic Pump

“…Our data therefore suggest that surface embedment of SHMP during the initial dissolution−recrystallization of aragonite and calcite yields surfaces where the thermodynamic forces that drive the aragonite-to-calcite pump no longer prevail. This mode of action of P-species embedment is consistent with our earlier study 14 that identified that strong phosphate•••carbonate interactions (Ca 2+ -mediated) impeded CaCO 3 nucleation in solution, and their persistence in the amorphous calcium carbonate (ACC) solid also prevented its crystallization. 13 Aragonite-to-calcite conversion in aqueous environments is a widespread phenomenon.…”

Efficient Assessment of ‘Instantaneous pK’ Values from Molecular Dynamics Simulations

“…Apart from the interface model discussed in the present work, current studies aim at the pH-dependent characterization of prenucleation species and their interplay with antiscalant additives. [32]…”

“…Indeed, solute‐rich domains featuring poly‐ionic chains that exchange ion‐ion and ion‐water contacts on the 10 ps scale appear as the key field of application of the presented method. Apart from the interface model discussed in the present work, current studies aim at the pH‐dependent characterization of prenucleation species and their interplay with antiscalant additives [32] …”

Inhibition of Crystal Nucleation and Growth: A Review

“…They found that the remaining additives did not inhibit nucleation, but they could form polycrystals by preferentially adsorbing to cluster-related structures. Recently, Duchstein et al 53 investigated the regulation of mineralization by small molecular weight additives at the molecular level by interacting with prenucleated clusters. Amorphous calcium carbonate (ACC) is a transient precursor of crystalline calcium carbonate, so the production of crystalline calcium carbonate can be prevented if ACC can be stabilized.…”