Removing electrodes from the protective box

To remove an electrode from the box, first, spread the slot in the foam and grasp the uninsulated shaft of the electrode with forceps or fingers, then gently lift it out. Fit into headstage or coupler (e.g. NL04).

It is advisable to use watchmaker’s forceps to handle the electrode, however avoid touching the glass as it can fracture if pressure is applied there by forceps.

You may also use fingers, but it is advised to operate with great care, minimising any damage to the electrode shank; in particular, the electrode tip is extremely delicate and easily damaged.

Avoid storing electrodes outside of boxes; the tip will be damaged, rendering the electrode unusable.

If you suspect tip damage, examine the electrode tip under light microscope with x200 or higher magnification and check the electrode impedance.

Fitting electrodes into tubing or NL04 holder

These microelectrodes easily fit into 25G, 26G or 27G hypodermic needle tubing. The uninsulated end of the electrode requires slight bending (e.g. 20deg, 5mm from the electrode end), and then can be carefully inserted into the tubing. This prevents the electrode from slipping out of the holder and ensures optimal electrical contact with the holder. We recommend electrode holder: NL04.

The microelectrodes can also be soldered into any of above stainless steel tubings. Soldering tungsten onto stainless steel can be a difficult process; it is strongly advised to use a professional soldering station and stainless steel flux.

The microelectrodes can be also crimped within any of above stainless steel tubings or within any commercially available type of pin holder. It is strongly recommended to use a professional crimping tool to avoid any personal accident/injury or electrode damage.

Optimal electrode use

Our short-tip electrodes are intended for single-unit spike recordings and have impedances of several MOhms this results in high selectivity. It is advised to use precise micropositioners with minimum advancing steps of 0.5-2µm for reliable cell isolation (smaller cells require finer searching step).

Best signal-to-noise ratio is obtained when using an electrode preamplifier (as close as possible to probing electrode) with an input impedance at least one order of magnitude higher than the electrode impedance. Moreover, consider avoiding shielding of concentric cables connecting electrode to preamplifier, which can significantly reduce the SNR due to its capacitive shunting effect.

It is strongly recommended to perform the experiment in shielded/grounded cabinets (e.g. sound booth, Faraday cage) with internal equipment being battery-powered to minimise the mains hum. Otherwise, recordings will be contaminated with mains frequency (50Hz/60Hz).

Cleaning electrodes

For longevity, it is best to clean electrodes immediately after removing from the tissue. The electrodes can be cleaned by sonication, e.g. in 30% sodium hypochlorite for 5 minutes, then should be thoroughly agitated in distilled water and then ethanol. Once cleaned, it is advised to check the condition of electrode tip under microscope and to measure its impedance. If tissue remains at the tip after cleaning, repeat the cleaning/testing procedure.

Dust particles from surrounding air easily adhere to electrode tips. Thorough rinsing with distilled water usually removes all dust deposits. However, electrodes stored for extended periods of time may need sonication cleaning in distilled water.

Disposing of used electrodes

Our electrodes are not harmful to the environment and can be disposed of as a sharp item.

Microelectrodes Ltd., Cambridge, UK
Monday-Friday: 9am to 5pm (UK time)
tel. +44 7503 311208