Chemical Engineering Department, Stanford University, Stanford, California 94305, USA.
Langmuir. 2011 Sep 20;27(18):11444-50. doi: 10.1021/la2016879. Epub 2011 Aug 25.
Interactions between amphiphilic block copolymers and lipids are of medical interest for applications such as drug delivery and the restoration of damaged cell membranes. A series of monodisperse poly(ethylene oxide)-poly(butylene oxide) (EOBO) block copolymers were obtained with two ratios of hydrophilic/hydrophobic block lengths. We have explored the surface activity of EOBO at a clean interface and under 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) monolayers as a simple cell membrane model. At the same subphase concentration, EOBO achieved higher equilibrium surface pressures under DPPC compared to a bare interface, and the surface activity was improved with longer poly(butylene oxide) blocks. Further investigation of the DPPC/EOBO monolayers showed that combined films exhibited similar surface rheology compared to pure DPPC at the same surface pressures. DPPC/EOBO phase separation was observed in fluorescently doped monolayers, and within the liquid-expanded liquid-condensed coexistence region for DPPC, EOBO did not drastically alter the liquid-condensed domain shapes. Grazing incidence X-ray diffraction (GIXD) and X-ray reflectivity (XRR) quantitatively confirmed that the lattice spacings and tilt of DPPC in lipid-rich regions of the monolayer were nearly equivalent to those of a pure DPPC monolayer at the same surface pressures.
两亲性嵌段共聚物与脂质的相互作用在药物输送和受损细胞膜修复等应用中具有医学意义。我们获得了一系列具有两种亲水/疏水嵌段长度比的单分散聚（氧化乙烯）-聚（氧化丁烯）（EOBO）嵌段共聚物。我们已经探索了 EOBO 在清洁界面和 1,2-二月桂酰基-sn-甘油-3-磷酸胆碱（DPPC）单层膜（简单的细胞膜模型）下的表面活性。在相同的亚相浓度下，与裸界面相比，EOBO 在 DPPC 下达到了更高的平衡表面压力，并且表面活性随着聚（氧化丁烯）嵌段的延长而提高。对 DPPC/EOBO 单层膜的进一步研究表明，与纯 DPPC 相比，在相同的表面压力下，组合膜表现出相似的表面流变学特性。在荧光掺杂的单层膜中观察到 DPPC/EOBO 相分离，并且在 DPPC 的液体膨胀-液体凝聚共存区域内，EOBO 没有明显改变液体凝聚区域的形状。掠入射 X 射线衍射（GIXD）和 X 射线反射率（XRR）定量证实，在相同表面压力下，单层膜中富含脂质区域内 DPPC 的晶格间距和倾斜与纯 DPPC 单层膜几乎相同。
