Fabrication and Characterization of a K+-Selective Nanoelectrode and Simultaneous Imaging of Topography and Local K+ Flux Using Scanning Electrochemical Microscopy

A nanopipette containing a solution of bis(benzo1S-crown-S) dissolved in 1,6-dichlorohexane was used as an ionselective electrode (ISE) to probe KT' for shear force-based constant-distance scanning electrochemical microscopy (SECM). In a previous study, the ISE responded only at low Kr concentrations ([1(+] < 1 mM), due to the depletion of the bis(benzo-1S-crown-5) at the oil/water interface at high IC+ concentrations and the unstable response of the tip at the oil/ water interface for shear force and current detection. In the present 10 study, a nanopipette reshaped by heating and with the hydrophobic layer removed was used as the ISE. This modified ISE enabled a rapid response to changes in IC flux at a physiological concentration of K(+)force-based SECM. Topography and K+ flux images were obtained simultaneously at a pm pores and human embryonic kidney 293 cells (HEK293). Several areas containing a were found in the SECM images of the HEK293 cells, which indicated the existence polycarbonate membrane filter with K+ flux larger than the surrounding of Kf channels. and allowed SECM imaging on a nanometer scale. The fabricated nano-ISE was used as a probe for polycarbonate membrane filter with K+ flux larger than the surrounding of Kf channels.