Integration of dual-barrel membrane patch-ion channel probes (MP-ICPs) to scanning ion conductance microscopy (SICM) holds promise of providing a revolutionized approach of spatially-resolved chemical sensing. However, to fully exploit the MP-ICP platforms for concurrent topography and chemical sensing, a comprehensive characterization of the analytical performance of this newly-developed platform is needed.  A series of experiments were performed to further our understanding of the system and to answer some fundamental questions, in preparation for future developments of this approach.  First, we constructed MP-ICPs that contained different types of ion channels including TRPV1 channels and BK channels to establish the generalizability of the methods. Next, we proved the capability of the MP-ICP platforms in single ion channel activity measurements, and demonstrated that the channel behaviors can be faithfully obtained with this approach. In addition, we studied the interplay between the SICM barrel and the ICP barrel. An interesting phenomenon that’s related to the charge of the ligand molecules was discovered, for ion channels gated by uncharged ligands, channel activity at the ICP barrel is unaffected by the SICM barrel potential; whereas for ion channels that are gated by charged ligands, enhanced channel activity can be obtained by biasing the SICM barrel at potentials with opposite polarity to the charge of the ligand molecules. Finally, a proof-of-principle experiment was performed and site-specific molecular flux sensing was demonstrated at single-ion-channel level.<br/>

Coupling ion channels to mobile nanofluidic devices (nanopipettes)

254th National Meeting (2017)

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