Interaction of cationic surfactants with DPPC membranes: effect of a novel Nα-benzoylated arginine-based compound

Cationic amino acid-based surfactants are known to interact with the lipid bilayer of microorganism resulting in cell death through a disruption membrane topology. To elucidate interaction cationic surfactant synthesized our lab, investigations involving Nα-benzoyl-arginine decyl amide (Bz-Arg-NHC10), and model membranes composed by 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) were done. Bz-Arg-NHC10was able penetrate into DPPC monolayers up critical pressure 59.6 mN m−1. Differential scanning calorimetry revealed that as concentration Bz-Arg-NHC10 increased, main transition temperature slightly decreased. Atomic force microscopy (AFM) situ experiments performed on supported bilayers mica allowed monitoring changes induced Bz-Arg-NHC10. patches partially removed, mainly borders defects for 50 µM solution. Increasing 100 resulted complete depletion bilayers. Surface plasmon resonance (SPR) experiments, carried out fully covered chips, showed net increase SPR signal, which can be explained adsorption. When patchy formed substrate, signal decrease was obtained, is consistent phospholipids’ removal observed AFM images. The results obtained suggest presence benzoyl group attached polar head compound would responsible increased antimicrobial activity against gram-negative bacteria when compared other arginine-based surfactants.