Department of Chemistry, William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology , Clear Water Bay, Kowloon, Hong Kong, China.
Langmuir. 2011 Mar 15;27(6):2528-35. doi: 10.1021/la104449y. Epub 2011 Feb 4.
Understanding how the composition and environmental conditions of membranes influence their interactions with guest species is central to cell biology and biomedicine. We herein study the nonspecific adsorption of charged quantum dots (QDs) onto a supported zwitterionic lipid bilayer by using quartz crystal microbalance with dissipation (QCM-D). It is demonstrated that (1) the adsorption of charged QDs is charge-dependent in a way similar to but much stronger than that of the capping molecules by reason of size effect; (2) the adsorption behavior of charged QDs is dominated by electrostatic interaction, which can be well described by an "adsorption window"; (3) the "adsorption window" can be broadened by exploiting the bridge role of Ca(2+) ions; and (4) by introducing a cationic lipid into the zwitterionic lipid bilayer, one can achieve preferential adsorption of anionic QDs but suppression of the cationic QD adsorption. Our QCM-D data also indicates that these different adsorption traits effect different changes in the dissipation of supported lipid bilayers (SLBs) after adsorption of the charged QDs. The different adsorption propensities of cationic and anionic QDs on SLBs have reinforced the picture of electrostatic interactions. We believe that these findings provide important information on QD-lipid membrane interactions, which will help to develop new drug molecules and efficient drug delivery systems, and to predict and unravel their potential toxicities if any.
了解膜的组成和环境条件如何影响其与客体物种的相互作用，是细胞生物学和生物医学的核心。本文通过石英晶体微天平耗散（QCM-D）研究了带电荷的量子点（QD）在负载的两性离子脂质双层上的非特异性吸附。结果表明：（1）由于尺寸效应，带电荷的 QD 的吸附与带电分子的吸附相似，但强度要大得多，这是一种电荷依赖性吸附；（2）带电荷的 QD 的吸附行为主要由静电相互作用主导，这可以通过“吸附窗口”很好地描述；（3）通过利用 Ca（2+）离子的桥接作用，可以拓宽“吸附窗口”；（4）通过在两性离子脂质双层中引入阳离子脂质，可以实现阴离子 QD 的优先吸附，但抑制阳离子 QD 的吸附。我们的 QCM-D 数据还表明，这些不同的吸附特性会导致带电荷的 QD 吸附后支撑脂质双层（SLB）的耗散发生不同的变化。阳离子和阴离子 QD 在 SLB 上的不同吸附倾向强化了静电相互作用的图像。我们相信这些发现为 QD-脂质膜相互作用提供了重要信息，这将有助于开发新的药物分子和有效的药物递送系统，并预测和阐明其潜在的毒性（如果有的话）。
