Interaction of an arginine based-surfactant with model lipid membranes

HERMET, M.; VÁZQUEZ, R.F.; MATÉ, S.; DAZA MILLONE, M.A.; VELA, M.E.; MORCELLE, S.R.; BAKÁS, L.

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

The stratum corneum is a major barrier to drug penetration across the skin intransdermal delivery. To overcome this barrier, skin penetration enhancers arecommonly used. Lipoaminoacids derived from arginine consist of a family of nontoxicbiodegradable cationic surfactants with antifungal and antimicrobialproperties. They meet four crucial requirements for the industrial development ofnew surfactants: low toxicity, high biodegradability, multifunctionality and use ofrenewal sources of raw materials for their synthesis.The interaction of a novel arginine-based cationic surfactant, Nα-benzoyl-argininedecyl amide (Bz-Arg-NHC10) with DPPC monolayers was studied at different initialsurface pressures (πo) of the lipid films. For all the πo assayed, the injection of thelipoaminoacid into the subphase bulk produced a rapid increase in π reaching amaximum within the first 5 min followed by a decrease in π which stabilizedafter ~20 min. Bz-Arg-NHC10 was able to penetrate into these lipid monolayers upto a critical pressure of 35 mN/m.Differential scanning calorimetry was used to assess the effect of Bz-Arg-NHC10upon DPPC membranes. As the concentration of Bz-Arg-NHC10 increased, the maintransition temperature of DPPC slightly decreased.AFM in situ experiments performed on supported DPPC bilayers on mica allowed tofollow the changes induced by Bz-Arg-NHC10. DPPC bilayer patches were partiallyremoved, 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 thesupported bilayers. SPR measurements allowed to quantitatively assess the DPPCremoval by Bz-Arg-NHC10. Experiments carried out with fully DPPC bilayerscovered chips showed a net increase of the SPR signal, which can be assigned toBz-Arg-NHC10 adsorption. When patchy DPPC bilayers were formed onthe substrate, a net decrease of SPR signal was obtained. This is consistent withthe DPPC removal observed in AFM images.