A novel concentric double-barrelled calcium-selective microelectrode for small cells

Area of Science:

• Electrochemistry
• Analytical Chemistry
• Biomedical Engineering

Background:

• Accurate measurement of intracellular calcium ions (Ca2+) is crucial for understanding cellular processes.
• Existing microelectrode designs face challenges in sensitivity, noise, and applicability to small cells.

Purpose of the Study:

• To develop and describe a novel concentric double-barreled Ca2+-selective microelectrode.
• To optimize the electrode design for improved performance and broader applicability.

Main Methods:

• Fabrication using concentric capillaries and a horizontal pipette puller.
• Selection of Corning 1724 glass for the inner barrel to ensure protrusion.
• Preferential silanization of the inner barrel and back-filling with Ca2+ ionophore (ETH 1001) and CaCl2 solution.
• Filling the reference barrel with KCl solution buffered to pCa 7.

Main Results:

• Achieved a linear response for Ca2+ concentrations between 10(-3) M and 10(-7) M with a slope of approximately 30 mV.
• Demonstrated low noise levels due to the external concentric KCl electrode.
• The electrode design is mechanically simple and suitable for various small cell applications.

Conclusions:

• The novel concentric double-barreled Ca2+-selective microelectrode offers a significant advancement in Ca2+ measurement technology.
• Its design provides enhanced performance characteristics, including low noise and versatility.
• This microelectrode is well-suited for precise Ca2+ determination in small biological cells.