Biophysical investigation of the interaction between cationic biodegradable Cm-E2O-Cm gemini surfactants and porcine serum albumin (PSA)

Abstract

The interaction of porcine serum albumin (PSA) with biodegradable, less cytotoxic C_m-E2O-C_m gemini surfactants was monitored using state-of-the-art techniques. The temperature variation fluorescence experiments were used to derive the thermodynamic parameters of non-covalent interaction in PSA-C_m-E2O-C_m gemini systems, which indicate an exothermic and a hydrogen bonding/Van der Waals force predominated binding process. Synchronous fluorescence spectra indicate that tryptophan fluorescence gets more quenched than the tyrosine fluorescence. The pyrene micropolarity assay signifies that pyrene is subjected to mild micropolarity changes. UV absorption spectra verify the ground state complexation between PSA and C_m-E2O-C_m geminis. Far-UV CD spectra reveal negligible changes in secondary structure with respect to PSA in its native state. These results indicate that the cationic C_m-E2O-C_m geminis, at lower concentrations, substantially bind to PSA but do not disrupt its secondary structure. These observations are favorable for the potential utilization of the concerned geminis in the field of drug delivery, especially in self-emulsifying drug delivery systems.

Keywords: Binding constant; C(m)-E2O-C(m) gemini surfactants; PSA (Porcine Serum Albumin).