Beveling of fine micropipette electrodes by a rapid precision method.

A technique has been developed for embedding alumina particles 0.05 micrometer in size in the surface of a polyurethane film laid on glass. This abrasive surface is used for rapid, precise, and reliable beveling of Pyrex micropipettes with tip diameters at least as small as 0.1 micrometer. In the snapping turtle retina the beveled electrodes give much better cell penetration and intracellular response stability than unbeveled electrodes of considerably higher proach to this problem.