Potentiometric ion-selective silicon sensors for the on-line monitoring of blood electrolytes

Influence of the Composition of Plasticizer-Free Silicone-Based Ion-Selective Membranes on Signal Stability in Aqueous and Blood Plasma Samples

“…39,40 Even though silicone-based ISEs have been known for 50 years, the effects of polymer structure, polymerization catalysts, fillers, and curing conditions on longterm stability in biological samples have not been studied in much detail. The only long-term drifts reported to date are, for measurements in aqueous solution, for a conventional siliconebased ISE with valinomycin as ionophore (0.8 μV/h), 41 a Ca 2+ SC-ISE with ETH1001 as ionophore (200 μV/h), 42 a coated Ag wire K + ISE with a fluorosilicone membrane containing 10.5 wt % dioctyl sebacate (DOS) as plasticizer, and a Ag + salt redox modifier (10 μV/h), 43 and a K + ISE with a silicone membrane coated directly onto a Ag/AgCl electrode (<200 μV/h). 21 Although there has been a lot of work to characterize the properties of SC-ISEs in aqueous solution (with the exception of long-term drift), little attention has been paid to the effects of continuous long-term exposure of SC-ISEs to real samples like sweat or blood plasma.…”

Development of an Array of Ion-Selective Microelectrodes Aimed for the Monitoring of Extracellular Ionic Activities

“…In their pioneering work, Buck et al used a Kapton-based K + and pH sensitive microelectrode array for in-vivo monitoring of a beating heart during induced ischemia [6,7]. Other microfabricated arrays of ISEs have been developed for the detection of blood electrolytes [8,9,10,11,12]. In order to monitor the ionic concentration at the cellular level, the dimensions of the ISEs should ideally have cellular or subcellular sizes and the sensors should be organized in a dense array able to record ionic fluxes of neighboring cells.…”

“…7,8 Other microfabricated arrays of ISEs have been developed for the detection of blood electrolytes. [9][10][11][12][13] To monitor the ionic concentration at the cellular level, the dimensions of the ISEs should ideally have cellular or subcellular sizes and the sensors should be organized in a dense array able to record ionic fluxes of neighboring cells. Therefore, localized ion concentration change in a closer area around an electrode could be detected in response, for example, to local drug delivery.…”

“…In comparison, the development of ISE arrays is far less advanced. In their pioneering work, Buck et al used a Kapton-based K + - and pH-sensitive microelectrode array for in vivo monitoring of a beating heart during induced ischemia. , Other microfabricated arrays of ISEs have been developed for the detection of blood electrolytes. − To monitor the ionic concentration at the cellular level, the dimensions of the ISEs should ideally have cellular or subcellular sizes and the sensors should be organized in a dense array able to record ionic fluxes of neighboring cells. Therefore, localized ion concentration change in a closer area around an electrode could be detected in response, for example, to local drug delivery.…”

Continuous in vivo Monitoring of Blood Diffusible Calcium Using On-line Microdialysis Sampling Coupled with Flame Atomic Absorption Spectrometry

“…For these reasons, there is a growing interest in designing and developing various types of on-line techniques for rapid, easy, and reliable analysis of Ca concentration in blood. 2,7 Microdialysis, [8][9][10][11] a powerful sampling technique used to obtain protein-free samples, has become an important technique for continuous in vivo sampling of the extracellular fluid in discrete compartments of living systems. A microdialysis system is easy to automate and can be on-line coupled with many analytical techniques, such as liquid chromatography, 12 capillary electrophoresis, 13 mass spectrometry, 14 flow-injection analysis, [15][16][17][18] and electrochemical detection.…”