An ultracompliant glass microelectrode for intracellular recording

Area of Science:

• Biomedical Engineering
• Electrophysiology
• Cardiovascular Research

Background:

• Stable impalement of cardiac preparations is crucial for electrophysiological studies.
• Existing microelectrodes can cause damage and have limited impalement durations.
• Contractile nature of cardiac cells presents unique challenges for electrode stability.

Purpose of the Study:

• To describe the fabrication of a novel glass microelectrode.
• To enhance the stability and duration of impalement for contracting cardiac preparations.
• To investigate the mechanical properties contributing to electrode performance.

Main Methods:

• Fabrication of long-shanked glass microelectrodes using a standard pipette puller.
• Incorporation of a stepped design at specific angles (70 degrees) near the electrode tip.
• Mechanical testing and comparison of stepped electrodes with straight electrodes.

Main Results:

• The stepped microelectrodes exhibited marginally higher resistance (34.9 MΩ vs. 26.0 MΩ).
• The stepped design significantly reduced electrode stiffness in both vertical and horizontal planes.
• Impalement duration was significantly longer with stepped electrodes compared to straight ones, allowing indefinite periods with minimal damage.

Conclusions:

• The described stepped glass microelectrode offers a simple and effective solution for stable cardiac cell impalement.
• The unique mechanical properties of the stepped design minimize damage to delicate, contractile cardiac tissues.
• This fabrication method provides a valuable tool for long-term electrophysiological recordings of cardiac preparations.