Sodium-selective liquid ion-exchanger microelectrodes for intracellular measurements

Area of Science:

• Electrochemistry
• Ion-selective electrodes
• Cellular physiology

Background:

• Accurate measurement of intracellular ion concentrations is crucial for understanding cellular processes.
• Existing methods for measuring intracellular sodium activity face challenges with selectivity and stability.

Purpose of the Study:

• To develop and validate novel sodium-selective microelectrodes for intracellular measurements.
• To assess the performance of these microelectrodes in terms of response time, stability, and selectivity.

Main Methods:

• A new sodium-selective ligand, 1,1,1-tris[1(1)-(2(1)-oxa-4(1)-oxo-5(1)-aza-5(1)-methyl)dodecanyl]propane, was synthesized and incorporated into microelectrodes.
• The microelectrodes utilized a liquid ion-exchanger formulation with tetrachlorophenyl borate in 3-nitro-o-xylene.
• Electrode performance was evaluated by measuring sodium activity under conditions mimicking the intracellular environment.

Main Results:

• The developed microelectrodes exhibited rapid and stable responses.
• Electrode responses showed a linear relationship with the logarithm of sodium activity.
• Significant interference from intracellular potassium was not observed, indicating high selectivity for sodium.

Conclusions:

• The novel sodium-selective microelectrodes are effective tools for measuring intracellular sodium activity.
• These electrodes offer a reliable and selective method for physiological research, particularly in complex biological samples.
• The findings support the use of these microelectrodes for in vivo and in vitro studies of cellular sodium homeostasis.