Lindén Maria V, Meinander Kristoffer, Helle Anne, Yohannes Gebrenegus, Riekkola Marja-Liisa, Butcher Sarah J, Viitala Tapani, Wiedmer Susanne K
Laboratory of Analytical Chemistry, Department of Chemistry, University of Helsinki, Helsinki, Finland.
Electrophoresis. 2008 Feb;29(4):852-62. doi: 10.1002/elps.200700651.
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.
聚乙二醇（PEG）稳定的脂质聚集体是生物技术和制药应用中一类很有前景的新型模型膜。采用毛细管电泳（CE）技术、场流分级法、光散射、石英晶体微天平（QCM）和显微镜技术来研究由1-棕榈酰-2-油酰基-sn-甘油-磷脂酰胆碱（POPC）和PEG-脂质缀合物组成的聚集体。PEG-脂质的聚乙二醇摩尔质量分别为1000、2000和3000，是1,2-二酰基-sn-甘油-3-磷酸乙醇胺-N-[甲氧基-（PEG）]衍生物，其酰基基团为二肉豆蔻酰基（DM，14:0）或二硬脂酰基（DS，18:0）。将pH 7.4的HEPES中80/20摩尔百分比的POPC/PEG-脂质分散体通过100 nm孔径的膜挤出。采用不对称流场流分级法（AsFlFFF）、光子相关光谱法（PCS）和动态光散射法（DLS）来测定POPC和聚乙二醇化聚集体的大小。所有方法均表明，DSPEG-脂质空间稳定的聚集体尺寸比纯POPC囊泡小。测量了聚集体的ζ电位，结果显示从纯POPC的-19 mV增加到POPC/DSPEG3000聚集体的-4 mV。采用原子力显微镜（AFM）、冷冻电子显微镜（EM）和多频QCM研究来获取有关二氧化硅上聚乙二醇化涂层的信息。将具有不同POPC/DSPEG3000-脂质比例的脂质聚集体用作毛细管涂层材料，发现80/20摩尔百分比的组成能产生最受抑制且最稳定的电渗流（EOF）。以聚乙二醇化聚集体作为载体（EKC）或作为涂层材料（CEC），分离低摩尔质量药物和异硫氰酸荧光素（FITC）标记的氨基酸混合物。通过紫外和激光诱导荧光（LIF）进行检测。
