Catanionic vesicles formed with arginine-based surfactants and 1,2-dipalmitoyl-sn-glycero-3-phosphate monosodium salt.
We report on mixing an anionic diacyl phospholipid (1,2-dipalmitoyl-sn-glycero-3-phosphate monosodium salt, DPPA) with either monoacyl and diacyl arginine-based surfactants. These mixtures are part of the rich family of pseudo-triple-chain and pseudo-tetra-chain catanionic mixtures, respectively. Vesicle size and zeta-potential were measured at several mixing ratios. Additional information on counterion binding, vesicle size, and integrity was obtained from ion selective electrode and Cryo-TEM measurements. Addition of positively charged surfactants to DPPA results in an increase of vesicle size. However, zeta-potential shows different trends, depending on whether water or acid media are used as solvent. In the latter, zeta-potential values progressively approach 0 upon addition of amino acid based surfactants. In water, surprisingly, zeta-potential values become more negative. The results are discussed in terms of modifications in counterion binding and vesicle size.
Lozano
Neus
N
Departament de Tecnologia Quimica i de Tensioactius, Institut de Quimica Avancada de Catalunya (IQAC), CSIC, Jordi Girona 18-26, E-08034 Barcelona, Spain.
Pinazo
Aurora
A
La Mesa
Camillo
C
Perez
Lourdes
L
Andreozzi
Patrizia
P
Pons
Ramon
R
D000838:Anions; D001120:Arginine / Q000737:chemistry*; D002412:Cations; D020285:Cryoelectron Microscopy / Q000379:methods; D010316:Particle Size; D010712:Phosphatidic Acids / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*
D000838:Anions; D002412:Cations; D010712:Phosphatidic Acids; D013501:Surface-Active Agents; C031599:dipalmitoylphosphatidic acid; D001120:Arginine