Yang Hu, Morris Joseph J, Lopina Stephanie T
Department of Chemical Engineering and Biomedical Engineering, Olson, Room 301K, The University of Akron, Akron, OH 44325-0302, USA.
J Colloid Interface Sci. 2004 May 1;273(1):148-54. doi: 10.1016/j.jcis.2003.12.023.
Unimolecular dendritic micelles designed as solubility enhancers were obtained by coupling polyethylene glycol (PEG) to Starburst polyamidoamine (PAMAM) dendrimers. Micelles-750, -2000, and -5000 have a generation 3.0 dendrimer core (32 primary amine end groups) and PEG arms with molecular weights of 750, 2000, and 5000, respectively. The conjugate of dendrimer core and PEG was characterized by MALDI-TOF MS and 1H NMR. 1H NMR was also used to estimate the average number of PEG arms on each dendrimer molecule. A typical hydrophobic compound, pyrene, was sonicated in an excess amount together with micelles at 50 degrees C for 6 h to produce its saturated water solution. The change of the solubility of pyrene was monitored at 334 nm, its maximum adsorption wavelength, by UV-VIS spectra. Concentrated micelles tended to dissolve more pyrene. However, there is no obvious linear relationship between micelle type and the amount of pyrene entrapped within micelles. Micelle-2000 could solubilize more pyrene than micelle-750. It is hypothesized that micelle-5000 did not solubilize more pyrene than micelle-2000 because of the PEG shell disruption by adjacent interpenetration of individual micelles when PEG arm length increased.
通过将聚乙二醇（PEG）与星爆型聚酰胺-胺（PAMAM）树枝状大分子偶联，获得了设计用作溶解度增强剂的单分子树枝状胶束。胶束-750、-2000和-5000具有3.0代树枝状大分子核心（32个伯胺端基）和分子量分别为750、2000和5000的PEG臂。树枝状大分子核心与PEG的共轭物通过基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）和核磁共振氢谱（1H NMR）进行表征。1H NMR还用于估计每个树枝状大分子分子上PEG臂的平均数量。将一种典型的疏水性化合物芘与胶束一起在50℃下超声处理过量6小时，以制备其饱和水溶液。通过紫外-可见光谱在芘的最大吸收波长334nm处监测芘溶解度的变化。浓缩的胶束倾向于溶解更多的芘。然而，胶束类型与胶束中截留的芘量之间没有明显的线性关系。胶束-2000比胶束-750能溶解更多的芘。据推测，胶束-5000溶解的芘不比胶束-2000多，是因为当PEG臂长度增加时，单个胶束的相邻相互渗透导致PEG壳层破坏。
