On the formation of glass microelectrodes

Glass microelectrodes are used widely in experimental studies of the electrophysiology of biological cells and their membranes. However, the pulling of these electrodes remains an art, based on trial and error. Following Huang et al. (SIAM J. Appl. Math., 63 (2003), pp. 1499-1519], we derive a one-dimensional model for the stretching of a hollow glass tube that is being radiatively heated. Our framework allows us to consider two commonly used puller designs, that is, horizontal (constant force) and vertical (variable force) pullers. We derive explicit solutions and use these solutions to identify the principal factors that control the final shape of the microelectrodes. The design implications for pullers also are discussed. © 2007 Society for Industrial and Applied Mathematics.