A rapid and non leaky way for preparation of the sharp intracellular recording microelectrodes

To fill microelectrodes using backfilling method needs excessive time approximately 4-6 h. It is often difficult to fill microelectrodes without damage or leakage. A main problem is bubble formation in microelectrodes which has an impact on the electrical properties of the electrode and thus it influences the quality of the recording. Based on Archimede's principle there is a force within a solution which pushes insoluble material with a lower specific gravity upward and outside of the solution. Centrifugation can increase the force to eliminate the bubbles. We designed a microelectrode holder to protect microelectrode sensitive tips from mechanical damage due to the gravity tensions; it can help to eliminate the bubbles easily and simultaneously in 10 min or less. The tests were performed for 2000, 4000, and 8000 rpm centrifugation each one for 3, 6 and 12 min duration respectively, it was found that the bubbles were completely eliminated at 8000 rpm for 6-12 min and there were no significant differences for resistance, and the number of leaky or damaged electrodes between the two methods. In the new design of devices, the materials used and the design of the holder are simple and the approach is applicable to many laboratories worldwide.