Dual Micropores in Glass Substrates for Ion Channel and Gap Junction Recording

Abstract

Despite the commercial success of automated high-throughput patch clamp technologies, instruments on the market typically cannot match the quality of single-channel recordings obtained by traditional patch clamp experiments with glass micropipettes. In automated approaches that use suction to position a cell to a micropore, the inner surface of the pore can be contaminated with proteins in solution prior to seal formation. Traditional patch clamping avoids this problem by applying a positive pressure to the micropipette prior to contacting the cell membrane, which enables significantly higher electrical seal resistances. This research aims to develop a universal platform for high-quality transport assays on glass chips that circumvents the problem of surface contamination and takes advantage of the high seal resistances and low capacitive current noise realized with glass substrates. Femtosecond laser ablation is used to fabricate a pair of micropores in close proximity to each other (distance < 5 µm) in glass, while the access channels to these pores are kept separate. This configuration makes it possible to use one pore for automated positioning of a cell by suction, while the other pore is kept clean by applying positive pressure. Once the cell is pre-positioned onto the first pore, suction may be applied to the second pore to establish a high quality seal that could be used to interrogate individual transmembrane transporter proteins and single ion channel proteins. In addition, this dual micropore configuration may enable the first automated gap junction recordings, bypassing the difficulties of manually positioning two micropipettes.