title: Interaction of antimicrobial arginine-based cationic surfactants with liposomes and lipid monolayers.
abstract: The present work examines the relationship between the antimicrobial activity of novel arginine-based cationic surfactants and the physicochemical process involved in the perturbation of the cell membrane. To this end, the interaction of these surfactants with two biomembrane models, namely, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) multilamellar lipid vesicles (MLVs) and monolayers of DPPC, 1,2-dipalmitoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] sodium salt (DPPG), and Escherichia coli total lipid extract, was investigated. For the sake of comparison, this study included two commercial antimicrobial agents, hexadecyltrimethylammonium bromide and chlorhexidine dihydrochloride. Changes in the thermotropic phase transition parameters of DPPC MLVs in the presence of the compounds were studied by differential scanning calorimetry analysis. The results show that variations in both the transition temperature (Tm) and the transition width at half-height of the heat absorption peak (deltaT1/2) were consistent with the antimicrobial activity of the compounds. Penetration kinetics and compression isotherm studies performed with DPPC, DPPG, and E. coli total lipid extract monolayers indicated that both steric hindrance effects and electrostatic forces explained the antimicrobial agent-lipid interaction. Overall, in DPPC monolayers single-chain surfactants had the highest penetration capacity, whereas gemini surfactants were the most active in DPPG systems. The compression isotherms showed an expansion of the monolayers compared with that of pure lipids, indicating an insertion of the compounds into the lipid molecules. Owing to their cationic character, they are incorporated better into the negatively charged DPPG than into zwitterionic DPPC lipid monolayers.
authors.affiliation: Institute for Chemical and Environmental Research CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain.
authors.forename: José A
authors.initials: JA
authors.lastname: Castillo
authors.forename: Aurora
authors.initials: A
authors.lastname: Pinazo
authors.forename: Josep
authors.initials: J
authors.lastname: Carilla
authors.forename: M Rosa
authors.initials: MR
authors.lastname: Infante
authors.forename: M Asunción
authors.initials: MA
authors.lastname: Alsina
authors.forename: Isabel
authors.initials: I
authors.lastname: Haro
authors.forename: Pere
authors.initials: P
authors.lastname: Clapés
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000031:analogs & derivatives* / Q000737:chemistry; D000890:Anti-Infective Agents / Q000737:chemistry*; D001120:Arginine / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D002412:Cations / Q000737:chemistry; D002457:Cell Extracts / Q000737:chemistry; D004926:Escherichia coli / Q000737:chemistry; D007700:Kinetics; D008081:Liposomes / Q000737:chemistry*; D008563:Membrane Lipids / Q000737:chemistry*; D008954:Models, Biological; D008956:Models, Chemical; D044367:Phase Transition; D010715:Phosphatidylglycerols / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*; D013696:Temperature
chemical_list: C476507:1,2-dipalmitoyl-sn-glycero-3-ethylphosphocholine; D000890:Anti-Infective Agents; D002412:Cations; D002457:Cell Extracts; D008081:Liposomes; D008563:Membrane Lipids; D010715:Phosphatidylglycerols; D013501:Surface-Active Agents; D015060:1,2-Dipalmitoylphosphatidylcholine; D001120:Arginine; C030345:1,2-dipalmitoylphosphatidylglycerol