Underwater contact adhesion and microarchitecture in polyelectrolyte complexes actuated by solvent exchange

Polyelectrolyte complexation is critical to the formation and properties of many biological and polymeric materials, and is typically initiated by aqueous mixing followed by fluid-fluid phase separation, such as coacervation. Yet little to nothing is known about how coacervates evolve into intricate solid microarchitectures. Inspired by the chemical features of the cement proteins of the sandcastle worm, here we report a versatile and strong wet-contact microporous adhesive resulting from polyelectrolyte complexation triggered by solvent exchange. After premixing a catechol-functionalized weak polyanion with a polycation in dimethyl sulphoxide (DMSO), the solution was applied underwater to various substrates whereupon electrostatic complexation, phase inversion, and rapid setting were simultaneously actuated by water-DMSO solvent exchange. Spatial and temporal coordination of complexation, inversion and setting fostered rapid (???25 s) and robust underwater contact adhesion (Wad ??? 2 J m-2) of complexed catecholic polyelectrolytes to all tested surfaces including plastics, glasses, metals and biological materials.close

Chemical exchanges and actuation in liposome-based synthetic cells: Interaction with biological cells

The development of new synthetic biology frontiers has led to scenarios where the embodied information-processing capability of biological organisms are implanted, in minimalistic version, in liposome-based synthetic cells. These are cell-like systems of minimal complexity resembling biological cells. Although not yet alive, synthetic cells are useful for generating basic biological understanding, and can become interesting biotechnological tools. In 2012 we devised a research program aimed at the design and construction of synthetic cells capable of exchanging chemical signals with biological micro-organisms (in particular bacteria). Here we review the fundamental steps leading to this innovative research field and comment on the most relevant experimental results obtained by us and others