Polymer-Rich Dense Phase Can Concentrate Metastable Silica Precursors and Regulate Their Mineralization

Abstract

Multistep mineralization processes are pivotal in the fabrication of functional materials and are often characterized by far from equilibrium conditions and high supersaturation. Interestingly, such 'nonclassical' mineralization pathways are widespread in biological systems, even though concentrating molecules well beyond their saturation level is incompatible with cellular homeostasis. Here, we show how polymer phase separation can facilitate bioinspired silica formation by passively concentrating the inorganic building blocks within the polymer dense phase. The high affinity of the dense phase to mobile silica precursors generates a diffusive flux against the concentration gradient, similar to dynamic equilibrium, and the resulting high supersaturation leads to precipitation of insoluble silica. Manipulating the chemistry of the dense phase allows to control the delicate interplay between polymer chemistry and silica precipitation. These results connect two phase transition phenomena, mineralization and coacervation, and offer a framework to achieve better control of mineral formation.

Silica Polymerization Driving Opposite Effects of pH on Aqueous Carbonation Using Crystalline and Amorphous Calcium Silicates

“…The silica species within the solutions were identified through in situ confocal Raman microscopy (HORIBA’s LabRAM HR Evolution, France). The experimental parameters for Raman analyses were 532 nm solid wavelength, 300 μm confocal pinhole, ×10 objective lens, 10 s exposure time, and scanning wavenumber range from 600 to 1500 cm –1 . For further quantification, the supernatants were isolated by using a centrifuge followed by a 200 nm syringe filtration.…”

The Role of Lysozyme in the Formation of Bioinspired Silicon Dioxide

“…A very intriguing model was suggested by Lenoci and Camp [5,6] indicating that polyamines and polycationic peptides undergo liquid‐liquid phase separation (LLPS) and then the polymerization occurs at the interface between the two liquid phases [7–9] . Two very recent papers by the group of Assaf Gal provided brilliant experimental verification of this model [10,11] . It is also well known that lysozyme and other polycationic proteins can perform the templating [4,12,13] .…”

“…[7][8][9] Two very recent papers by the group of Assaf Gal provided brilliant experimental verification of this model. [10,11] It is also well known that lysozyme and other polycationic proteins can perform the templating. [4,12,13] Also, in this case, the mechanism is unknown, and literature hosts competing views in which the protein is strongly distorted in the initial phases of the polymerization [14] and at the end the two components are completely independent from each other, [15] or that no distortion occurs during the polymerization [16] and the two components remain in intimate contact.…”