FHC's Glass Coated Tungsten Electrodes

Features: Glass is a great insulator that provides a smooth, durable coating. In any electrode there are three main attributes to consider: Mechanical, Dielectric, and Biocompatible properties.

• Mechanical: Glass is very durable which is important especially for acute recordings from the same subject over long periods of time. The subject’s dura mater in these experiments tends to thicken as a result of exposure. When less durable electrodes are inserted, insulation can be lost which reduces the impedance of the electrode. Varnish coated electrodes are generally reliable for 1 or 2 recording sessions. Glass coated electrodes are reliable for ~10.

• Dielectric: Glass is a better insulator. The more tissue that surrounds an electrode (i.e. the deeper the structure that is recorded), the greater the possibility of having a noisy signal due to capacitance built up along the shank of the electrode.

• Biocompatible: Generally speaking, the current types of materials used to insulate electrodes don’t show many differences in tissue reaction. The completely smooth surface of the glass and polyimide, as opposed to surface irregularities along the shank in a varnished electrode, will have less physical effect on the tissue during positioning.

For ordering information, please see attached PDF: Standard Electrodes - Tungsten, Pt/Ir, Stainless Steel (PDF)