Lopes António, Edwards Katarina, Feitosa Eloi
ITQB - Inst. Tecn. Química e Biológica, Univ. Nova de Lisboa, Oeiras, Portugal.
J Colloid Interface Sci. 2008 Jun 15;322(2):582-8. doi: 10.1016/j.jcis.2008.03.015. Epub 2008 Mar 18.
Combined dynamic and static light scattering (DLS, SLS) and cryogenic transmission electron microscopy (cryo-TEM) were used to investigate extruded cationic vesicles of dioctadecyldimethylammonium chloride and bromide (DODAX, X being Cl(-) or Br(-)). In salt-free dispersions the mean hydrodynamic diameter, D(h), and the weight average molecular weight, M(w), are larger for DODAB than for DODAC vesicles, and both D(h) and M(w) increase with the diameter (varphi) of the extrusion filter. NaCl (NaBr) decreases (increases) the DODAB (DODAC) vesicle size, reflecting the general trend of DODAB to assemble as larger vesicles than DODAC. The polydispersity index is lower than 0.25, indicating the dispersions are rather polydisperse. Cryo-TEM micrographs show that the smaller vesicles are spherical while the larger ones are oblong or faceted, and the vesicle samples are fairly polydisperse in size and morphology. They also indicate that the vesicle size increases with phi and DODAB assembles as larger vesicles than DODAC. Lens-shaped vesicles were observed in the extruded preparations. Both light scattering and cryo-TEM indicate that the vesicle size is larger or smaller than phi when phi is smaller or larger than the optimal phi approximately 200 nm.
结合动态和静态光散射（DLS、SLS）以及低温透射电子显微镜（cryo-TEM）来研究挤出的二辛基二甲基氯化铵和溴化铵（DODAX，X为Cl(-)或Br(-)）阳离子囊泡。在无盐分散体中，DODAB囊泡的平均流体动力学直径D(h)和重均分子量M(w)比DODAC囊泡的更大，并且D(h)和M(w)都随着挤出过滤器的直径（φ）增加。NaCl（NaBr）会减小（增加）DODAB（DODAC）囊泡的尺寸，这反映了DODAB比DODAC更容易组装成更大囊泡的总体趋势。多分散指数低于0.25，表明分散体的多分散性相当高。低温透射电子显微镜照片显示，较小的囊泡是球形的，而较大的囊泡是长方形或多面体形的，并且囊泡样品在尺寸和形态上的多分散性相当高。它们还表明，囊泡尺寸随着φ增加，并且DODAB比DODAC更容易组装成更大的囊泡。在挤出制剂中观察到了透镜状囊泡。光散射和低温透射电子显微镜都表明，当φ小于或大于约200 nm的最佳φ时，囊泡尺寸大于或小于φ。
