Halochromic modulation of amorphous calcium carbonate crystallization driven by pH-responsive bioinspired pigments
Abstract Colors in biominerals often arise from the occlusion of low-molecular-weight organic pigments within calcium carbonate (CaCO 3 ) mineral phases during biomineralization processes; however, the physicochemical origin of these colors has been overlooked. Here, inspired by the growth of colored sea urchin spines that occurs through amorphous CaCO 3 (ACC) precursors, we show an in-vitro halochromic modulation of ACC crystallization. In this mechanism, the deprotonation of a natural red pigment naphthazarin (NZ) is driven by pH variations during mineral formation and subsequently stabilized within CaCO 3 - hybrid pigments. The latter show lavender-blue to violet-blue hues upon crystallization. Deprotonated NZ has a minimal impact on ACC formation and crystallization, which occurs through local dissolution and reprecipitation mechanisms; however, it limits the formation of vaterite, and calcite distorted nanodomains. Deprotonated NZ nano-inclusions that interact with calcite through water are thus formed. Overall, this study brings insights into the processes behind the coloration of biomineralized organisms.
Authors
- Shahrouz Amini (ORCID: https://orcid.org/0000-0002-1928-2760)
- Nadine Nassif (ORCID: https://orcid.org/0000-0002-4094-4909)
- Thierry Azaı̈s (ORCID: https://orcid.org/0000-0002-9031-872X)
- Iryna Polishchuk (ORCID: https://orcid.org/0000-0003-3003-1580)
- Boaz Pokroy (ORCID: https://orcid.org/0000-0003-0480-7250)
- Mathieu Frégnaux (ORCID: https://orcid.org/0000-0002-3915-3982)
- Peter Fratzl (ORCID: https://orcid.org/0000-0003-4437-7830)
- Vaskar Sardhalia (ORCID: https://orcid.org/0000-0002-7468-4498)
- Clemens N. Z. Schmitt (ORCID: https://orcid.org/0000-0002-7646-4739)
- Anne Vallée (ORCID: https://orcid.org/0000-0002-0171-2080)
- M. de Frutos (ORCID: https://orcid.org/0000-0002-9053-1723)
- Guillaume Laurent (ORCID: https://orcid.org/0000-0002-8127-5326)
- Zhaoyong Zou (ORCID: https://orcid.org/0000-0003-2427-2812)
- Mohamed Selmane
- Marie Albéric (ORCID: https://orcid.org/0000-0002-5322-9904)
- Andrew N. Fitch (ORCID: https://orcid.org/0000-0002-9768-5688)
- Xiaoyan Li (ORCID: https://orcid.org/0000-0003-2332-2523)
- Claudio dos Reis Ferreira (ORCID: https://orcid.org/0009-0001-3751-2726)
Institutions
- Centre National de la Recherche Scientifique (FR)
- Technion – Israel Institute of Technology (IL)
- Université de Versailles Saint-Quentin-en-Yvelines (FR)
- Wuhan University of Technology (CN)
- Université Paris-Saclay (FR)
- Laboratoire de physique des Solides (FR)
- European Synchrotron Radiation Facility (FR)
- Sorbonne Université (FR)
- Max Planck Institute of Colloids and Interfaces (DE)
- Chimie de la Matière Condensée de Paris (FR)
- Institut Parisien de Chimie Moléculaire (FR)
- Laboratoire de Réactivité de Surface (FR)
- Institut Lavoisier de Versailles (FR)
- Fédération de Chimie et Matériaux de Paris-Centre (FR)
Publication Details
- Journal
- Nature Communications
- Published
- 2026-08-03
- DOI
- https://doi.org/10.1038/s41467-026-75888-8
- Primary Topic
- Calcium Carbonate Crystallization and Inhibition
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- European Commission
- Deutscher Akademischer Austauschdienst
- Agence Nationale de la Recherche
- European Synchrotron Radiation Facility
- Technische Universität Dresden
- Conseil Régional, Île-de-France
- Centre National de la Recherche Scientifique
- Technion-Israel Institute of Technology
- Université Paris-Saclay
- Sorbonne Université