Controlled bending of high-resistance glass microelectrodes.

The short working distance of compound microscope lenses in many cases prevents microelectrode penetrations of cells perpendicular to the cell surface. Bending electrodes very near their tips removes this constraint. A method is described for bending glass microelectrodes with a hot filament while their tips are immersed in a water drop. Immersion protects the fine electrode tips from the heat and provides control over the angle through which the electrodes are bent.