Fast Nanoscale Surface Charge Mapping with Pulsed-Potential Scanning Ion Conductance Microscopy

摘要: A vast range of interfacial systems exhibit charge heterogeneities on the nanoscale. These differences in local surface density are challenging to visualize, but recent work has shown scanning ion conductance microscope (SICM) be a very promising tool spatially resolve and map topography via hopping potential sweep technique with single nanopipette probe, harmonic modulation bias applied between quasi-reference counter electrodes bulk solution, coupled lock-in detection. Although powerful, this is relatively slow process, limitations resolution size images that can collected. Herein, we demonstrate new routine for mapping SICM, which increases data acquisition rate by an order magnitude further gains. Furthermore, method simplified, eliminating need detection, utilizing potential-pulse, chronoamperometric approach, self-referencing calibration response at each pixel image. We application both model substrate living PC-12 cells under physiological (high ionic strength) conditions, where most (small Debye length). This contributes significantly emergence SICM as multifunctional simultaneously probing structure function nanometer resolution.