Gemini amino acid-based surfactants

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]. 

Our group designed and synthesized a new elass of amino acid-based gemini surfactants of the bis(Quats) type (quaternary ammonium salt) (Scheme 2). These consist of 2 hydrophobic chains of 12 carbon atoms, 2 quaternary ammonium groups, and 1 spacer chain containing amide and disulfide bonds [63,64], They derived from the condensation of 7V-dodecyl-A, A -dimethylgly-cine (a well-known soft amphoteric surfactant) with amino acid derivatives containing disulfide bonds, i.e., cystine 1 and cystamine 2 (Scheme 2). 

FIG. 8 Structures of amino acid-based gemini surfactants as exemplified by lysine. 

More recently, we have developed an alternative chemoenzymatic route to the preparation of a variety of amino acid-based surfactants ranging from simple monoesters to more complex gemini amphiphiles [79], This approach was based on the observation that some lipases, notable immobilized Candida antartica and Rhizomucor miehei, readily accept N-Cbz amino acids as substrates and catalyze their esterification/amidation with a,(o-diols/a,to-diamines in excellent yields. The resulting alkanediyl-a,co-bis-(A -Cbz-amino acid) was further modified to obtain a range of amino acid-based gemini surfactants. Some examples of the products obtained in this work are shown in Fig. 8. 

VaUvety R, GUI IS Vulfson EN. 1998. AppUcation of enzymes to the synthesis of amino acid-based bola and gemini surfactants. Journal of Surfactants and Detergents 1(2) 177-185. van Rantwijk F, Woudenberg-van Oosterom M Sheldon RA. 1999. Glycosidase-catalyzed synthesis of alkyl glycosides. Journal of Molecular Catalysis B Enzymatic 6(6) 511-532. 

Figure 8.6 Enzymatic synthesis of amino acid-based surfactants (I) linear, (II) dimeric or gemini and (III) diacylglycerol amino acid conjugates. The amino acid can be coupled to an alkyl chain via an ester or an amide linkage.

Vahvety, R., Gill, I. S. and Vulfson, E. N. (1998) Application of enzymes to the S5mthesis of amino acid-based bola and gemini surfactants. J. Surfactants Deterg., 1, 177-185. 

Singh J, Yang P, Michel D, Verrall RE, Foldvari M, Badea 1, Amino acid-substituted gemini surfactant-based nanoparticles as safe and versatile gene delivery agents. Curr Drug Deliv 2011 8(3) 299-306. 

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