Investigation of the vesicle-to-micelle transition of 11-amino undecanoic acid derived sulphonamide and a comprehensive study of its interaction with protein

In the present manuscript, an amphiphile sulphonamide based surfactant benzenesulphonyl-11-amino sodium undecanoate (BASU) is designed and synthesized. The surface activity of the amphiphile in the solutions is studied at neutral pH so that the resulting amphiphile self-organizes and transfers from large unilamellar vesicles to small micelles from dilute to concentrated solutions. During the aggregate transitions, the common surfactants tend to form the small aggregate at low concentrations; but BASU shows the large vesicle structure at low concentration of -3 mM and converts into the small micelle at -9 mM. Therefore, different techniques have been used, such as, tensiometry, conductometry, fluorimetry and DLS and some microscopic characterization, e. g., confocal fluorescence microscopy to reveal the aggregate assembly and transition mechanism. The isothermal titration calorimetry is used for quantitative measurement of thermodynamic properties of self-assembly formation and the process is found spontaneous and entropically favorable. The permeability of the vesicle membrane bilayer is explored by a kinetic study. Effects of salt and cholesterol on the aggregate of respective amphiphile are also investigated. The interaction of surfactant with both human and bovine serum albumin is analyzed through UV-visible and fluorescence techniques to draw a comparative study. Antibacterial activity is tested by both spectral and zone inhibition methods and its application for mixed amphiphiles (e.g., BASU/ CTAB) is found. Therefore, according to the ability of formation of unilamellar vesicles (ULV) and its stability, permeability and antibacterial activity, the amphiphile can have potential applications in the medicinal field.