Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS), Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, YICCAS, Yantai 264003, PR China.
Biosens Bioelectron. 2012 Oct-Dec;38(1):145-50. doi: 10.1016/j.bios.2012.05.020. Epub 2012 May 24.
Traditional potentiometric polyion-sensitive electrodes can only work effectively in samples with vigorous convection fulfilled by magnetic stirrer, electrode rotator, or other moving components. The dependence on complex moving parts prohibits the fabrication of compact, cost-effective, and energy-effective test devices from the commercial point of view. In this paper, a novel potentiometric sensing protocol without using any moving parts has been proposed for polycationic protamine. In contrast to traditional protamine-sensitive electrodes conditioned by discriminated ion (Na(+)), the proposed electrode is conditioned with primary ion (protamine). Upon a medium exchange from the conditioning solution into an unstirred sample solution without protamine, protamine loaded in the membrane is stripped into the aqueous phase via ion exchange with aqueous sodium ion, thereby inducing a large potential drop. Interestingly, when the sample solution initially contains protamine, the ion-exchange process has been found to be sensitively inhibited by the sample protamine, and thus the potential drop is suppressed, which forms the basis of the moving-part-free potentiometric polyion sensing strategy. Utilizing the digestion ability of protease to protamine, the electrode was employed to determine the activity of trypsin with a detection limit at least one order of magnitude lower than traditional potentiometric methods. The trypsin inhibitor in both buffer and plasma samples was also sensitively detected with the moving-part-free protamine-sensitive electrode. Finally, the ability of the proposed electrode to detect polyanionic heparin was demonstrated.
传统的电位型聚离子敏感电极只能在通过搅拌器、电极旋转器或其他运动部件实现剧烈对流的样品中有效工作。从商业角度来看，对复杂运动部件的依赖使得制造紧凑、经济高效和节能的测试设备变得不可能。本文提出了一种新颖的、无需任何运动部件的电位传感方案，用于阳离子聚合物鱼精蛋白。与传统的通过区分离子（Na(+））来调节的鱼精蛋白敏感电极不同，所提出的电极是通过主离子（鱼精蛋白）来调节的。在从中和溶液到没有鱼精蛋白的未搅拌样品溶液的介质交换后，通过与水溶液中的钠离子进行离子交换，将膜中负载的鱼精蛋白剥离到水相中，从而引起大的电位降。有趣的是，当样品溶液最初含有鱼精蛋白时，发现该离子交换过程会被样品鱼精蛋白敏感地抑制，从而抑制了电位降，这构成了无运动部件的电位型聚离子传感策略的基础。利用蛋白酶对鱼精蛋白的消化能力，该电极被用于测定胰蛋白酶的活性，其检测限比传统的电位法至少低一个数量级。该无运动部件的鱼精蛋白敏感电极还能灵敏地检测缓冲液和血浆样品中的胰蛋白酶抑制剂。最后，还展示了该电极检测阴离子聚合物肝素的能力。
