Jump to main content
Jump to site search
Access to RSC content Close the message box

Continue to access RSC content when you are not at your institution. Follow our step-by-step guide.

Volume 159, 2012
Previous Article Next Article

A metastable liquid precursor phase of calcium carbonate and its interactions with polyaspartate

Author affiliations


Invertebrate organisms that use calcium carbonate extensively in the formation of their hard tissues have the ability to deposit biominerals with control over crystal size, shape, orientation, phase, texture, and location. It has been proposed by our group that charged polyelectrolytes, like acidic proteins, may be employed by organisms to direct crystal growth through an intermediate liquid phase in a process called the polymer-induced liquid-precursor (PILP) process. Recently, it has been proposed that calcium carbonate crystallization, even in the absence of any additives, follows a non-classical, multi-step crystallization process by first associating into a liquid precursor phase before transition into solid amorphous calcium carbonate (ACC) and eventually crystalline calcium carbonates. In order to determine if the PILP process involves the promotion, or stabilization, of a naturally occurring liquid precursor to ACC, we have analyzed the formation of saturated and supersaturated calcium carbonate–bicarbonate solutions using Ca2+ ion selective electrodes, pH electrodes, isothermal titration calorimetry, nanoparticle tracking analysis, 13C T2 relaxation measurements, and 13C PFG-STE diffusion NMR measurements. These studies provide evidence that, in the absences of additives, and at near neutral pH (emulating the conditions of biomineralization and biomimetic model systems), a condensed phase of liquid-like droplets of calcium carbonate forms at a critical concentration, where it is stabilized intrinsically by bicarbonate ions. In experiments with polymer additive, the data suggests that the polymer is kinetically stabilizing this liquid condensed phase in a distinct and pronounced fashion during the so called PILP process. Verification of this precursor phase and the stabilization that polymer additives provide during the PILP process sheds new light on the mechanism through which biological organisms can exercise such control over deposited CaCO3 biominerals, and on the potential means to generate in vitro mineral products with features that resemble biominerals seen in nature.

Back to tab navigation

Supplementary files

Article information

23 Apr 2012
06 Jun 2012
First published
07 Jun 2012

Faraday Discuss., 2012,159, 291-312
Article type

A metastable liquid precursor phase of calcium carbonate and its interactions with polyaspartate

M. A. Bewernitz, D. Gebauer, J. Long, H. Cölfen and L. B. Gower, Faraday Discuss., 2012, 159, 291
DOI: 10.1039/C2FD20080E

Social activity

Search articles by author