Ion-selective electrode for transmembrane pH difference measurements

Area of Science:

• Electrochemistry
• Biophysics
• Analytical Chemistry

Background:

• Measuring transmembrane pH gradients is crucial for understanding cellular processes.
• Existing methods may have limitations in sensitivity or applicability to diverse biological systems.

Purpose of the Study:

• To develop a sensitive and reliable electrode for determining pH differences across cell membranes.
• To utilize the electrode for in situ monitoring of pH gradients in biological samples.

Main Methods:

• Construction of a triethylammonium-sensitive electrode using a PVC membrane matrix with specific ion-exchanger and solvent mediator.
• Monitoring pH gradient-induced uptake of triethylammonium.
• Calibration and validation of the electrode using buffer solutions and liposomes.

Main Results:

• The electrode demonstrated a near-Nernstian response to triethylammonium over a wide concentration range (5 x 10(-6)-1 x 10(-2) M) with a detection limit of 1 microM.
• Quantitative induction of triethylammonium uptake was observed, correlating with the pH difference across liposomal membranes.
• Successful determination of transmembrane pH differences in Escherichia coli cells and Halobacterium halobium vesicles.

Conclusions:

• The developed triethylammonium-sensitive electrode is effective for quantifying transmembrane pH differences.
• The method provides a valuable tool for studying cellular bioenergetics and membrane transport.
• The electrode's performance in biological systems highlights its potential for diverse research applications.