Semi-permeable vesicles composed of natural clay

Abstract

We report a simple route to form robust, inorganic, semi-permeable compartments composed of montmorillonite, a natural plate-like clay mineral that occurs widely in the environment. Mechanical forces due to shear in a narrow gap assemble clay nanoplates from an aqueous suspension onto air bubbles. Translucent vesicles suspended in a single-phase liquid are produced when the clay-covered air bubbles are exposed to a variety of water-miscible organic liquids. These vesicles of clay are mechanically robust and are stable in water and other liquids. The formation of clay vesicles can be described by a physical mechanism that recognizes changes in the wetting characteristics of clay-covered air bubbles in organic liquids. The clay vesicles are covered with small pores and so intrinsically exhibit size-selective permeability, which allows spontaneous compartmentalization of self-assembling molecules in aqueous environments. The results we report here expand our understanding of potential paths to micro-compartmentalization in natural settings and are of relevance to theories of colloidal aggregation, mineral cycles, and the origins of life.Comment: 42 pages, 10 figure

Artificial cells: from basic science to applications

“…Subramaniam et al [107] reported a simple method to construct a robust, semi-permeable protocell model by using the clay montmorillonite, which is a soft phyllosilicate type mineral that is abundant on the Earth. Montmorillonite is believed to be possibly involved in the process of the origin of life.…”

Role of Clay Minerals in Chemical Evolution and the Origins of Life

“…It is conceivable that the small spaces behave like cells. Further, when clay minerals are dispersed in water, bubbles form in water or the surface of water, while the clay particles gather at the boundary between water and air, as shown in Figure 7 [57]. In such a case, clay minerals make a cell-like spherule.…”

Chemical Signaling and Functional Activation in Colloidosome‐Based Protocells

“…Significantly, the as‐prepared silica‐stabilized emulsion droplets can be exploited as membrane‐bounded microcompartments for enhanced enzyme‐mediated transformations, or cross‐linked and transferred into a continuous water phase for use as colloidosome‐based protocell models for integrating various biomimetic or biological processes, including cytoskeletal‐like hydrogel assembly, capsule growth and division, synthesis of RNA and proteins via cell‐free gene expression pathways, and membrane gating of encapsulated enzyme reactions . Water‐in‐water clay colloidosomes have also been prepared using unmodified montmorillonite particles by applying wetting procedures to clay‐coated air bubbles suspended in water …”