磷脂在膜结构间的交换:温度和离子强度的影响

磷脂跨膜交换对生物膜功能与药学研究有重要意义.石英电子微天平及耗散系数测量仪被用于研究囊泡与支撑膜间磷脂的交换行为.研究表明:首先,在磷脂跨膜输运过程中,热力学环境和离子强度对支撑膜表面吸附囊泡的形变程度影响较小,囊泡与支撑膜的总接触面积直接取决于囊泡的吸附数量；其次,交换过程中膜结构间最大总接触面积随着温度的升高和离子强度的降低而增大,温度和离子引起的囊泡吸附速率和跨膜交换速率的变化在其中发挥着关键调节作用.本研究有助于加深对磷脂在生理条件下跨膜输运过程的理解,并为基于脂质体的药物载运体系研究提供参考.

Lipid exhange between membranes: effects of temperature and ionic strength

Transmembrane lipid exchange is critical to membrane function and pharmaceutical application. The exchange process is not fully understood and it is explored by quartz crystal microbalance with dissipation monitor method in this paper. It is found that the vesicle deformation discrepancy is not significant for the supported-lipid-bilayer-attached vesicles under different thermal and ionic strength conditions. And hence the total intermembrane contact area is determined by the vesicle adsorption amount. The maximum total intermembrane contact area decreases with the increase of temperature and the decrease of ionic strength. The changes of the vesicle adsorption rate and the transmembrane lipid exchange rate induced by temperature and ionic strength are elucidated to understand the observation above. The study helps explain some physiological phenomena and provides some guidelines for drug delivery researches.