Synthesis of unsymmetrical saturated or diacetylenic cationic bolaamphiphiles

Supramolecular Hydrogelators and Hydrogels: From Soft Matter to Molecular Biomaterials

In this review we intend to provide a relatively comprehensive summary of the work of supramolecular hydrogelators after 2004 and to put emphasis particularly on the applications of supramolecular hydrogels/hydrogelators as molecular biomaterials. After a brief introduction of methods for generating supramolecular hydrogels, we discuss supramolecular hydrogelators on the basis of their categories, such as small organic molecules, coordination complexes, peptides, nucleobases, and saccharides. Following molecular design, we focus on various potential applications of supramolecular hydrogels as molecular biomaterials, classified by their applications in cell cultures, tissue engineering, cell behavior, imaging, and unique applications of hydrogelators. Particularly, we discuss the applications of supramolecular hydrogelators after they form supramolecular assemblies but prior to reaching the critical gelation concentration because this subject is less explored but may hold equally great promise for helping address fundamental questions about the mechanisms or the consequences of the self-assembly of molecules, including low molecular weight ones. Finally, we provide a perspective on supramolecular hydrogelators. We hope that this review will serve as an updated introduction and reference for researchers who are interested in exploring supramolecular hydrogelators as molecular biomaterials for addressing the societal needs at various frontiers.

Bolaform surfactants with polyoxometalate head groups and their assembly into ultra-small monolayer membrane vesicles

Surfactants are indispensable in established technologies as detergents or emulsification agents, and also in recent studies for controlling the growth of nanoparticles or for creating nanocarriers. Although the properties of conventional, organic surfactants are thoroughly explored, strong interest persists in surfactants that possess unique features inaccessible for ordinary systems. Here we present dipolar, bolaform surfactants with a head group comprising of 11 tungsten atoms. These novel compounds are characterized by an exceptionally low critical self-organization concentration, which leads to monolayer vesicles with a diameter of only 15 nm, that is, substantially smaller than for any other system. The membrane of the vesicles is impermeable for water-soluble and oil-soluble guests. Control over release kinetics, which can be followed via the quantitative fluorescence quenching of confined fluorophores, is gained by means of pH adjustments.