Amino acid-based surfactants biological properties

The gemini-containing cationic [quaternary ammonium salts, called bis (Quats)], anionic (phosphate, sulfate, carboxylate), amphoteric and nonionic (polyether or sugar), polar groups have been a matter of numerous investigations [59]. Only few studies have been done on the physicochemical and biological properties of amino acid-based gemini surfactants [60-62]. 

Charged colloids in solution are ubiquitous in a wide variety of biological and technical systems. Some examples are proteins made by amino acids, micelles formed by charged surfactants or charged block copolymers, microemulsions formed by water, oil, and charged surfactants, silica particles made by silica oxide, and polystyrene based latex particles. In these systems, the physicochemical properties are to a large degree determined by electrostatic forces. Despite extensive studies of these forces for the last 50 years, the electrostatic interactions in such systems remain a central problem in colloidal science [1,2]. 

Sulphonic acids are water soluble, viscous liquids. Their acidity is akin to that of sulphuric acid feey form salts with bases but fail to undergo esterification with alcohols. Their properties vary according to the nature of R some are prone to thermal decomposition. They are used as surfactants and in the dye industry some have biological uses. 2-Amino-ethanesulphonic acid is the only naturally occurring sulphonic acid. 

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