Branched Polymeric Prenucleation Assemblies Initiate Calcium Phosphate Precipitation

Autor(en)

Ertan Turhan, Ieva Goldberga, Christopher Pötzl, Waldemar Keil, Jean Michel Guigner, Martin F.T. Haßler, Herwig Peterlik, Thierry Azaïs, Dennis Kurzbach

Abstrakt

The formation of crystalline calcium phosphate (CaP) has recently gained ample attention as it does not follow the classic nucleation-and-growth mechanism of solid formation. Instead, the precipitation mechanisms can involve numerous intermediates, including soluble prenucleation species. However, structural features, stability, and transformation of such solution-state precursors remain largely undisclosed. Herein, we report a detailed and comprehensive characterization of the sequential events involved in calcium phosphate crystallization starting from the very early prenucleation stage. We integrated an extensive set of time-resolved methods, including NMR, turbidimetry, SAXS, cryo-TEM, and calcium-potentiometry to show that CaP nucleation is initiated by the transformation of “branched” polymeric prenucleation assemblies into amorphous calcium phosphate spheres. Such a mineralization process starts with the spontaneous formation of so-called nanometric prenucleation clusters (PNCs) that later assemble into those branched polymeric assemblies without calcium ion uptake from the solution. Importantly, the branched macromolecular species are invisible to many techniques (NMR, turbidity, calcium-potentiometry) but can readily be evidenced by time-resolved SAXS. We find that these polymeric assemblies constitute the origin of amorphous calcium phosphate (ACP) precipitation through an unexpected process: spontaneous dissolution is followed by local densification of 100-200 nm wide domains leading to ACP spheres of similar size. Finally, we demonstrate that the timing of the successive events involved in the CaP mineralization pathway can be kinetically controlled by the Ca²⁺/P_i molar ratio, such that the lifetime of the soluble transient species can be increased up to hours when decreasing it.

Organisation(en)

Institut für Biologische Chemie, Dynamik Kondensierter Systeme, Fakultätszentrum für Nanostrukturforschung, NMR Zentrum

Externe Organisation(en)

Université Paris VI - Pierre-et-Marie-Curie, Vienna Doctoral School in Chemistry

Journal

Journal of the American Chemical Society

Band

146

Seiten

25614-25624

Anzahl der Seiten

11

ISSN

0002-7863

DOI

https://doi.org/10.1021/jacs.4c07325

Publikationsdatum

2024

Peer-reviewed

Ja

ÖFOS 2012

103006 Chemische Physik, 104017 Physikalische Chemie, 105113 Kristallographie

ASJC Scopus Sachgebiete

Catalysis, Chemistry(all), Biochemistry, Colloid and Surface Chemistry

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/branched-polymeric-prenucleation-assemblies-initiate-calcium-phosphate-precipitation(5b599974-8601-427b-9e61-7dcce365ab02).html