Characterization of a micromachined planar patch clamp for cellular electrophysiology

We have fabricated planar patch-clamp substrates suitable for use in cellular electrophysiology. The substrates are a base component of a larger automated dose-response measurement system. Substrates with cell-patch-site apertures ranging from 0.5 /spl mu/m to 11 /spl mu/m were fabricated using standard MEMS techniques. The resistance of the cell-patch-site apertures and substrate capacitance were measured using impedance spectroscopy. The resistance of the cell-patch sites ranged from 0.2 M/spl Omega/ to 47 M/spl Omega/ for apertures ranging from 12 /spl mu/m to 0.75 /spl mu/m. The substrate capacitance was 17.2 pF per mm/sup 2/ of fluid contact area for substrates with a 2-/spl mu/m thick layer of silicon dioxide. It was found that the electrical properties of the substrates are acceptable for use in electrophysiological applications.