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Characterization of phosphatidylcholine/polyethylene glycol‐lipid aggregates and their use as coatings and carriers in capillary electrophoresis
Author(s) -
Lindén Maria V.,
Meinander Kristoffer,
Helle Anne,
Yohannes Gebrenegus,
Riekkola MarjaLiisa,
Butcher Sarah J.,
Viitala Tapani,
Wiedmer Susanne K.
Publication year - 2008
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200700651
Subject(s) - popc , quartz crystal microbalance , chemistry , dynamic light scattering , polyethylene glycol , membrane , peg ratio , analytical chemistry (journal) , molar mass , chromatography , chemical engineering , small angle x ray scattering , lipid bilayer , organic chemistry , adsorption , polymer , scattering , biochemistry , finance , nanoparticle , engineering , economics , physics , optics
Abstract PEG‐stabilized lipid aggregates are a promising new class of model membranes in biotechnical and pharmaceutical applications. CE techniques, field‐flow fractionation, light scattering, quartz crystal microbalance (QCM), and microscopic techniques were used to study aggregates composed of 1‐palmitoyl‐2‐oleyl‐ sn ‐glycero‐phosphatidylcholine (POPC) and PEG‐lipid conjugates. The PEG‐lipids, with PEG molar masses of 1000, 2000, and 3000, were 1,2‐diacyl‐ sn ‐glycero‐3‐phosphoethanolamine‐ N ‐[methoxy‐(PEG)] derivatives with either dimyristoyl (DM, 14:0) or distearoyl (DS, 18:0) acyl groups. The 80/20 mol% POPC/PEG‐lipid dispersions in HEPES at pH 7.4 were extruded through 100 nm size membranes. Asymmetrical flow field‐flow fractionation (AsFlFFF), photon correlation spectroscopy (PCS), and dynamic light scattering (DLS) were used to determine the sizes of POPC and the PEGylated aggregates. All methods demonstrated that the DSPEG‐lipid sterically stabilized aggregates were smaller in size than pure POPC vesicles. The zeta potentials of the aggregates were measured and showed an increase from −19 mV for pure POPC to −4 mV for the POPC/DSPEG3000 aggregates. Atomic force microscopy (AFM), electron cryo‐microscopy (EM), and multifrequency QCM studies were made to achieve information about the PEGylated coatings on silica. Lipid aggregates with different POPC/DSPEG3000‐lipid ratios were applied as capillary coating material, and the 80/20 mol% composition was found to give the most suppressed and stable EOFs. Mixtures of low‐molar‐mass drugs and FITC‐labeled amino acids were separated with the PEGylated aggregates as carriers (EKC) or as coating material (CEC). Detection was made by UV and LIF.