Double-barrell ion-sensitive microelectrodes with extra thin tip diameters for intracellular measurements

Area of Science:

• Biomedical Engineering
• Neuroscience
• Analytical Chemistry

Background:

• Intracellular ion activity and membrane potential are critical physiological parameters.
• Accurate measurement requires high-resolution microelectrodes.
• Existing methods may have limitations in simultaneous measurements or resolution.

Purpose of the Study:

• To describe a method for producing double-barrel ion-sensitive microelectrodes.
• To enable simultaneous intracellular measurement of cell membrane potential and ion activity.
• To characterize the performance of these novel microelectrodes.

Main Methods:

• Fabrication of double-barrel microelectrodes with a 0.1-micron tip diameter.
• Utilizing ion exchangers and neutral ion carriers for ion selectivity (potassium, calcium, chloride).
• Electrophysiological characterization including steepness, drift, and response time.

Main Results:

• Microelectrodes achieved a mean tip diameter of 0.1 micron.
• Successful measurement of potassium, calcium, and chloride ion activity.
• Electrodes exhibited mean steepness values of 50.16 mV (K+), 24.7 mV (Ca2+), and 39 mV (Cl-).
• Drift ranged from 2-4%/h, with response times of 170 ms (K+), 350 ms (Ca2+), and 250 ms (Cl-).

Conclusions:

• A viable method for producing high-resolution double-barrel ion-sensitive microelectrodes has been established.
• These electrodes facilitate simultaneous intracellular measurement of membrane potential and specific ion activities.
• The characterized performance metrics indicate suitability for advanced cellular electrophysiology research.