1
|
Georges T, Chèvre R, Cousin SF, Gervais C, Thureau P, Mollica G, Azaïs T. 43Ca MAS-DNP NMR of Frozen Solutions for the Investigation of Calcium Ion Complexation. ACS OMEGA 2024; 9:4881-4891. [PMID: 38313477 PMCID: PMC10831850 DOI: 10.1021/acsomega.3c08292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 12/11/2023] [Accepted: 12/26/2023] [Indexed: 02/06/2024]
Abstract
Calcium ion complexation in aqueous solutions is of paramount importance in biology as it is related to cell signaling, muscle contraction, or biomineralization. However, Ca2+-complexes are dynamic soluble entities challenging to describe at the molecular level. Nuclear magnetic resonance appears as a method of choice to probe Ca2+-complexes. However, 43Ca NMR exhibits severe limitations arising from the low natural abundance coupled to the low gyromagnetic ratio and the quadrupolar nature of 43Ca, which overall make it a very unreceptive nucleus. Here, we show that 43Ca dynamic nuclear polarization (DNP) NMR of 43Ca-labeled frozen solutions is an efficient approach to enhance the NMR receptivity of 43Ca and to obtain structural insights about calcium ions complexed with representative ligands including water molecules, ethylenediaminetetraacetic acid (EDTA), and l-aspartic acid (l-Asp). In these conditions and in combination with numerical simulations and calculations, we show that 43Ca nuclei belonging to Ca2+ complexed to the investigated ligands exhibit rather low quadrupolar couplings (with CQ typically ranging from 0.6 to 1 MHz) due to high symmetrical environments and potential residual dynamics in vitrified solutions at a temperature of 100 K. As a consequence, when 1H→43Ca cross-polarization (CP) is used to observe 43Ca central transition, "high-power" νRF(43Ca) conditions, typically used to detect spin 1/2 nuclei, provide ∼120 times larger sensitivity than "low-power" conditions usually employed for detection of quadrupolar nuclei. These "high-power" CPMAS conditions allow two-dimensional (2D) 1H-43Ca HetCor spectra to be readily recorded, highlighting various Ca2+-ligand interactions in solution. This significant increase in 43Ca NMR sensitivity results from the combination of distinct advantages: (i) an efficient 1H-mediated polarization transfer from DNP, resembling the case of low-natural-abundance spin 1/2 nuclei, (ii) a reduced dynamics, allowing the use of CP as a sensitivity enhancement technique, and (iii) the presence of a relatively highly symmetrical Ca environment, which, combined to residual dynamics, leads to the averaging of the quadrupolar interaction and hence to efficient high-power CP conditions. Interestingly, these results indicate that the use of high-power CP conditions is an effective way of selecting symmetrical and/or dynamic 43Ca environments of calcium-containing frozen solution, capable of filtering out more rigid and/or anisotropic 43Ca sites characterized by larger quadrupolar constants. This approach could open the way to the atomic-level investigation of calcium environments in more complex, heterogeneous frozen solutions, such as those encountered at the early stages of calcium phosphate or calcium carbonate biomineralization events.
Collapse
Affiliation(s)
- Tristan Georges
- Sorbonne
Université, CNRS, Laboratoire de Chimie de la Matière
Condensée de Paris (LCMCP), 4 Place Jussieu, 75005 Paris, France
| | - Romain Chèvre
- Aix
Marseille Univ, CNRS, ICR, 13397 Marseille, France
| | | | - Christel Gervais
- Sorbonne
Université, CNRS, Laboratoire de Chimie de la Matière
Condensée de Paris (LCMCP), 4 Place Jussieu, 75005 Paris, France
| | | | | | - Thierry Azaïs
- Sorbonne
Université, CNRS, Laboratoire de Chimie de la Matière
Condensée de Paris (LCMCP), 4 Place Jussieu, 75005 Paris, France
| |
Collapse
|
2
|
Gindele MB, Vinod-Kumar S, Rochau J, Boemke D, Groß E, Redrouthu VS, Gebauer D, Mathies G. Colloidal pathways of amorphous calcium carbonate formation lead to distinct water environments and conductivity. Nat Commun 2024; 15:80. [PMID: 38167336 PMCID: PMC10761707 DOI: 10.1038/s41467-023-44381-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 12/12/2023] [Indexed: 01/05/2024] Open
Abstract
CaCO3 is the most abundant biomineral and a major constituent of incrustations arising from water hardness. Polycarboxylates play key roles in controlling mineralization. Herein, we present an analytical and spectroscopic study of polycarboxylate-stabilized amorphous CaCO3 (ACC) and its formation via a dense liquid precursor phase (DLP). Polycarboxylates facilitate pronounced, kinetic bicarbonate entrapment in the DLP. Since bicarbonate is destabilized in the solid state, DLP dehydration towards solid ACC necessitates the formation of locally calcium deficient sites, thereby inhibiting nucleation. Magic-angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy of poly-aspartate-stabilized ACC reveals the presence of two distinct environments. The first contains immobile calcium and carbonate ions and structural water molecules, undergoing restricted, anisotropic motion. In the second environment, water molecules undergo slow, but isotropic motion. Indeed, conductive atomic force microscopy (C-AFM) reveals that ACC conducts electrical current, strongly suggesting that the mobile environment pervades the bulk of ACC, with dissolved hydroxide ions constituting the charge carriers. We propose that the distinct environments arise from colloidally stabilized interfaces of DLP nanodroplets, consistent with the pre-nucleation cluster (PNC) pathway.
Collapse
Affiliation(s)
- Maxim B Gindele
- Institute of Inorganic Chemistry, Leibniz University Hannover, Callinstr. 9, 30167, Hannover, Germany
| | - Sanjay Vinod-Kumar
- Department of Chemistry, University of Konstanz, Universitätsstr. 10, 78464, Konstanz, Germany
| | - Johannes Rochau
- Institute of Inorganic Chemistry, Leibniz University Hannover, Callinstr. 9, 30167, Hannover, Germany
| | - Daniel Boemke
- Institute of Inorganic Chemistry, Leibniz University Hannover, Callinstr. 9, 30167, Hannover, Germany
| | - Eduard Groß
- Institute of Inorganic Chemistry, Leibniz University Hannover, Callinstr. 9, 30167, Hannover, Germany
| | | | - Denis Gebauer
- Institute of Inorganic Chemistry, Leibniz University Hannover, Callinstr. 9, 30167, Hannover, Germany.
| | - Guinevere Mathies
- Department of Chemistry, University of Konstanz, Universitätsstr. 10, 78464, Konstanz, Germany.
| |
Collapse
|
3
|
Karafiludis S, Scoppola E, Wolf SE, Kochovski Z, Matzdorff D, Van Driessche AES, Hövelmann J, Emmerling F, Stawski TM. Evidence for liquid-liquid phase separation during the early stages of Mg-struvite formation. J Chem Phys 2023; 159:134503. [PMID: 37787132 DOI: 10.1063/5.0166278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 09/15/2023] [Indexed: 10/04/2023] Open
Abstract
The precipitation of struvite, a magnesium ammonium phosphate hexahydrate (MgNH4PO4 · 6H2O) mineral, from wastewater is a promising method for recovering phosphorous. While this process is commonly used in engineered environments, our understanding of the underlying mechanisms responsible for the formation of struvite crystals remains limited. Specifically, indirect evidence suggests the involvement of an amorphous precursor and the occurrence of multi-step processes in struvite formation, which would indicate non-classical paths of nucleation and crystallization. In this study, we use synchrotron-based in situ x-ray scattering complemented by cryogenic transmission electron microscopy to obtain new insights from the earliest stages of struvite formation. The holistic scattering data captured the structure of an entire assembly in a time-resolved manner. The structural features comprise the aqueous medium, the growing struvite crystals, and any potential heterogeneities or complex entities. By analysing the scattering data, we found that the onset of crystallization causes a perturbation in the structure of the surrounding aqueous medium. This perturbation is characterized by the occurrence and evolution of Ornstein-Zernike fluctuations on a scale of about 1 nm, suggesting a non-classical nature of the system. We interpret this phenomenon as a liquid-liquid phase separation, which gives rise to the formation of the amorphous precursor phase preceding actual crystal growth of struvite. Our microscopy results confirm that the formation of Mg-struvite includes a short-lived amorphous phase, lasting >10 s.
Collapse
Affiliation(s)
- Stephanos Karafiludis
- Federal Institute for Materials Research and Testing (BAM), Richard-Willstatter-Straße 11, 12489 Berlin, Germany
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Ernesto Scoppola
- Biomaterials, Hierarchical Structure of Biological and Bio-inspired Materials, Max Planck Institute of Colloids and Interfaces, Potsdam 14476, Germany
| | - Stephan E Wolf
- Friedrich-Alexander University Erlangen-Nürnberg (FAU), Department of Materials Science and Engineering, Institute for Glass and Ceramics, Martensstr. 5, 91058 Erlangen, Germany
| | - Zdravko Kochovski
- Helmholtz-Zentrum Berlin for Materials and Energy, Hahn-Meitner Platz 1, 14109 Berlin, Germany
| | - David Matzdorff
- Helmholtz-Zentrum Berlin for Materials and Energy, Hahn-Meitner Platz 1, 14109 Berlin, Germany
| | - Alexander E S Van Driessche
- Instituto Andaluz de Ciencias de la Tierra (IACT), CSIC - Universidad de Granada, Av. De las Palmeras 4, 18100 Armilla, Spain
| | - Jörn Hövelmann
- REMONDIS Production GmbH, Brunnenstraße 138, 44536 Lünen, Germany
| | - Franziska Emmerling
- Federal Institute for Materials Research and Testing (BAM), Richard-Willstatter-Straße 11, 12489 Berlin, Germany
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Tomasz M Stawski
- Federal Institute for Materials Research and Testing (BAM), Richard-Willstatter-Straße 11, 12489 Berlin, Germany
| |
Collapse
|
4
|
Diao Y, Bai J, Sun C, Huang J, Yang C, Hu Q. A Simplified Model for Shear Behavior of Mortar Using Biomimetic Carbonate Precipitation. MATERIALS (BASEL, SWITZERLAND) 2023; 16:5613. [PMID: 37629904 PMCID: PMC10456397 DOI: 10.3390/ma16165613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 07/27/2023] [Accepted: 08/05/2023] [Indexed: 08/27/2023]
Abstract
As a common molecule in biomineralization, L-aspartic acid (L-Asp) has been proven to be able to induce in vitro CaCO3 precipitation, but its application in sand reinforcement has never been studied. In this study, L-Asp was employed in sand reinforcement for the first time through the newly developed biomimetic carbonate precipitation (BCP) technique. Specimens with different number of BCP spray cycles were prepared, and a series of direct shear tests were conducted to investigate the impact of spray number on shear strength, critical displacement, and residual strength. Then a simplified power model for shear stress-displacement behavior was established and calibrated with the measured data. The results show that BCP can significantly improve the shear strength of sand. As the number of spray cycles increases, both the shear strength and residual strength increase, while the critical displacement decreases. Such variations can be described with two sigmoid models and a linear model, respectively. The simplified power model performs well in most cases, especially at higher spray numbers. This study is expected to provide a practical model for the shear behavior of BCP-treated mortar.
Collapse
Affiliation(s)
- Yu Diao
- School of Civil Engineering, Tianjin University, Tianjin 300072, China
| | - Jitao Bai
- School of Civil Engineering, Tianjin University, Tianjin 300072, China
| | - Changyou Sun
- 3rd Construction Co., Ltd. of China Construction 5th Engineering Bureau, Changsha 410021, China
| | - Jianyou Huang
- School of Civil Engineering, Tianjin University, Tianjin 300072, China
| | - Chao Yang
- China State Construction Engineering Corporation, Beijing 100029, China
| | - Qingsong Hu
- School of Civil Engineering, Tianjin University, Tianjin 300072, China
| |
Collapse
|