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Surface Stability and Morphology of Calcium Phosphate Tuned by pH Values and Lactic Acid Additives: Theoretical and Experimental Study.
- Source :
-
ACS applied materials & interfaces [ACS Appl Mater Interfaces] 2022 Feb 02; Vol. 14 (4), pp. 4836-4851. Date of Electronic Publication: 2022 Jan 19. - Publication Year :
- 2022
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Abstract
- The ubiquitous mineralization of calcium phosphate (CaP) facilitates biological organisms to produce hierarchically structured minerals. The coordination number and strength of Ca <superscript>2+</superscript> ions with phosphate species, oxygen-containing additives, and solvent molecules played a crucial role in tuning nucleation processes and the surface stability of CaP under the simulated body fluid (SBF) or aqueous solutions upon the addition of oligomeric lactic acid (LAC <subscript> n </subscript> , n = 1, 8) and changing pH values. As revealed by ab initio molecular dynamics (AIMD), density functional theory (DFT), and molecular dynamics (MD) simulations as well as high-throughput experimentation (HTE), the binding of LAC molecules with Ca <superscript>2+</superscript> ions and phosphate species could stabilize both the pre-nucleation clusters and brushite (DCPD, CaHPO <subscript>4</subscript> ·2H <subscript>2</subscript> O) surface through intermolecular electrostatic and hydrogen bonding interactions. When the concentration of Ca <superscript>2+</superscript> ions ([Ca <superscript>2+</superscript> ]) is very low, the amount of the formed precipitation decreased with the addition of LAC based on UV-vis spectroscopic analysis due to the reduced chance for the LAC capped Ca <superscript>2+</superscript> ions to coordinate with phosphates and the increased solubility in the acid solution. With the increasing [Ca <superscript>2+</superscript> ] concentration, the kinetically stable DCPD precipitation was obtained with high Ca <superscript>2+</superscript> coordination number and low surface energy. Morphologies of DCPD precipitation are in plate, needle, or rod, depending on the initial pH values that were tuned by adding NH <subscript>3</subscript> ·H <subscript>2</subscript> O, HCl, or CH <subscript>3</subscript> COOH. The prepared samples at pH ≈ 7.4 with different Ca/P ratios exhibited negative zeta potential values, which were correlated with the surface electrostatic potential distributions and potential biological applications.
Details
- Language :
- English
- ISSN :
- 1944-8252
- Volume :
- 14
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- ACS applied materials & interfaces
- Publication Type :
- Academic Journal
- Accession number :
- 35043625
- Full Text :
- https://doi.org/10.1021/acsami.1c18727