Characterization of phosphatidylcholine/polyethylene glycol-lipid aggregates and their use as coatings and carriers in capillary electrophoresis

Maria V. Lindén, Kristoffer Meinander, Anne Helle, Gebrenegus Yohannes, Marja Liisa Riekkola, Sarah J. Butcher, Tapani Viitala, Susanne K. Wiedmer*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

22 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)852-862
Number of pages11
Issue number4
Publication statusPublished - Feb 2008
Externally publishedYes
MoE publication typeA1 Journal article-refereed


  • Disks
  • Fluorescein isothiocyanate-amino acids
  • Laser-induced fluorescence detection
  • Liposomes
  • Polyethylene glycol-lipids


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