China National Tobacco Quality Supervision & Test Center, Zhengzhou 450001, PR China.
Anal Chim Acta. 2010 Jan 11;657(2):204-9. doi: 10.1016/j.aca.2009.10.036.
A novel piezoelelctric biosensor has been developed for cholera toxin (CT) detection based on the analyte-mediated surface-agglutination of ganglioside (GM1)-functionalized liposomes. To achieve a CT-specific agglutination at the surface, the gold electrode is modified by a GM1-functionalized supported lipid membrane via spontaneous spread of the liposomes on a self-assembled monolayer of a long-chain alkanethiol. In the presence of CT, the GM1-incorporated liposomes in assay medium will rapidly specifically agglutinate at the electrode surface through the binding of CT to GM1 on the electrode surface and the liposome interface. This results in an enormous mass loading on the piezoelelctric crystal as well as a significant increase of density and viscosity at the interface, thereby generating a decrease in frequency of the piezoelelctric crystal. The combination of mass loading with interfacial change in the surface-agglutination reaction allows the developed piezoelelctric biosensor to show substantial signal amplification in response to the analyte CT. The detection limit can be achieved as low as 25 ng mL(-1) CT. This is the first demonstration on CT detection based on specific surface-agglutination of GM1-modified liposomes. The supported lipid layer based sensing interface can be prepared readily and renewably, making the developed technique especially useful for simple, reusable and sensitive determination of proteins.
一种新型的压电生物传感器已经被开发出来，用于霍乱毒素（CT）的检测，其基于分析物介导的神经节苷脂（GM1）功能化脂质体的表面聚集。为了在表面上实现 CT 的特异性聚集，金电极通过脂质体在长链烷硫醇自组装单层上的自发扩散来修饰 GM1 功能化的支撑脂质膜。在 CT 存在的情况下，在检测介质中的 GM1 掺入的脂质体将通过 CT 与电极表面和脂质体界面上的 GM1 的结合而迅速地在电极表面特异性聚集。这导致在压电晶体上产生巨大的质量负载，以及在界面处的密度和粘度的显著增加，从而产生压电晶体的频率降低。质量负载与表面聚集反应中的界面变化的结合使得开发的压电生物传感器能够对分析物 CT 表现出显著的信号放大。检测限可低至 25ng mL(-1) CT。这是首次基于 GM1 修饰的脂质体的特异性表面聚集来检测 CT。基于支撑脂质层的传感界面可以容易地和可重复地制备，使得所开发的技术特别适用于蛋白质的简单、可重复使用和灵敏的测定。
