Interaction of an arginine based-surfactant with model lipid membranes

MELISA HERMET; ROMINA F. VAZQUEZ; MATÉ, SABINA M.; DAZA MILLONE, MARÍA A.; MARIA ELENA VELA; BAKÁS, LAURA S.

Congreso; XLVII Reunión Anual de la Sociedad Argentina de Biofísica.; 2018

Interaction of an arginine based-surfactant with model lipid membranesHermet M, Vázquez R, Maté S, Daza Millone MA, Vela ME, Morcelle S, Bakás LThe stratum corneum is a major barrier to drug penetration across the skin in transdermal delivery. To overcome this barrier, skin penetration enhancers are commonly used. Lipoaminoacids derived from arginine consist of a family of nontoxic biodegradable cationic surfactants with antifungal and antimicrobial properties. They meet four crucial requirements for the industrial development of new surfactants: low toxicity, high biodegradability, multifunctionality and use of renewal sources of raw materials for their synthesis. The interaction of a novel arginine-based cationic surfactant, Nα-benzoyl-arginine decyl amide (Bz-Arg-NHC10) with DPPC monolayers was studied at different initial surface pressures (πo) of the lipid films. For all the πo assayed, the injection of the lipoaminoacid into the subphase bulk produced a rapid increase in π reaching a maximum within the first 5 min followed by a decrease in π which stabilized after ~20 min. Bz-Arg-NHC10 was able to penetrate into these lipid monolayers up to a critical pressure of 35 mN/m. Differential scanning calorimetry was used to assess the effect of Bz-Arg-NHC10 upon DPPC membranes. As the concentration of Bz-Arg-NHC10 increased, the main transition temperature of DPPC slightly decreased. AFM in situ experiments performed on supported DPPC bilayers on mica allowed to follow the changes induced by Bz-Arg-NHC10. DPPC bilayer patches were partially removed, mainly in borders and defects for 0.05 mM Bz-Arg-NHC10 solution. Increasing the concentration to 0.10 mM resulted in a complete depletion of the supported bilayers. SPR measurements allowed to quantitatively assess the DPPC removal by Bz-Arg-NHC10. Experiments carried out with fully DPPC bilayers covered chips showed a net increase of the SPR signal, which can be assigned to Bz-Arg-NHC10 adsorption. When patchy DPPC bilayers were formed on the substrate, a net decrease of SPR signal was obtained. This is consistent with the DPPC removal observed in AFM images.