FABRICATION OF A METAL-CORED MULTI-BARRELED MICROIONTOPHORESIS ASSEMBLY

A method is described for fabrication of 7-barrelled microiontophoresis electrodes with a center barrel of platinum-coated tungsten. The electrodes require a minimum of expensive apparatus and can be fabricated in an hour or two. The electrodes have low recording impedance (typically 100 kΩ and low resistance iontophoresis barrels (typically 20-50 MΩ). Compared to electrodes with a micropipette recording barrel, these electrodes are practically noise-free and can pass ionotophoretic currents of up to 200 nA without an appreciable increase in recording noise. © 1990.