Upgrade for scanning ion-selective electrodes

离子选择性电极可用于测量生理离子（如钠、钾、钙、氯和氢）和毒素（如重金属镉、含氮废铵和有机阳离子四乙铵）的浓度。电极电压与离子浓度成正比。离子进出细胞的生物运输在细胞表面附近产生这些离子浓度的微小变化。扫描离子选择性电极技术（SIET）测量细胞表面附近两点的离子浓度变化，并计算相应的浓度差。 反过来，这种差异可以用来计算离子进出细胞的通量。 该技术是非侵入性的，因为细胞不被微电极接触，并且它允许在接近真实的时间内测量离子通量。这些测量使我们能够表征诸如肠道和昆虫的功能性肾脏等组织的离子运输。 因此，我们能够描述昆虫体内离子稳态的机制，以及激素对稳态的控制。这些知识是开发化合物如激素类似物的基础，这些化合物扰乱体内平衡，因此可以作为新的和环境友好的杀虫剂。此外，某些有机离子浓度的测量可用于评估昆虫如何排泄毒素，包括杀虫剂及其分解产物。 在这种情况下，这些知识也可以用来设计新的害虫物种控制策略。例如，这种测量允许鉴定本身无毒但干扰杀虫剂排泄的化合物。因此，施用这些化合物可以允许施用较低剂量的杀虫剂。

Ion-selective electrodes can be used to measure the concentrations of  physiological ions such as as sodium, potassium, calcium, chloride,  and hydrogen, and  toxins such as the heavy metal cadmium, the nitrogenous waste ammonium and the organic cation tetraethylammonium. The electrode voltage is proportional to the ion concentration. Biological transport of ions into or out of cells produces small changes in the concentrations of these ions near the surface  of the cells. The scanning ion-selective electrode technique (SIET) measures the changes in the concentrations of ions at two points near the surface of the cells and  permits calculation of the corresponding difference in concentration.  In turn, this difference can be used to calculate the flux of the ion into or out of the cells.  The technique is non-invasive, in that the cells are not touched by the microelectrode, and it permits measurements of ion fluxes in near real time. These measurements allow us to characterize the transport of ions by tissues such as the intestinal tract and the functional kidneys of insects.  We are thus able to characterize the mechanisms of ion homeostasis in insects, and the control of homeostasis by hormones. Such knowledge is the foundation for development of compounds such as hormone analogues which perturb homeostasis and can thus act as novel and environmentally benign insecticides. In addition, measurements of the concentrations of certain organic  ions can be used to assess how insects excrete toxins, including insecticides and their breakdown products.  In this case as well, such knowledge can be used to design novel control strategies for pest species. For example, such measurements permit  identification of compounds which are themselves non-toxic but interfere with insecticide excretion. Application of these compounds may thus allow lower doses of insecticides to be applied.