Development of a Novel Combined Scanning Electrochemical Microscope (SECM) and Scanning Ion-Conductance Microscope (SICM) Probe for Soft Sample Imaging

By incorporating a localized heating system within a scanning ion-conductance microscopy (SICM) system, we have performed stable ‘hopping-mode’ (HPICM) imaging for live cells maintained at temperatures ranging up to human body temperature. This allows the accurate study of cell volume and morphology variation versus temperature over extended periods of time. The integration of SICM with scanning electrochemical microscopy (SECM) provides the simultaneous mapping of electrochemical and topographic information for soft samples, such as live cells. This combined technique overcomes the limitations of resolution and topographical artifacts typically associated with SECM. However, previously reported SECM-SICM probe production required expensive and time-consuming focused ion beam (FIB) methods and produced pipettes that are typically hundreds of nanometers in diameter. We report a simple and rapid production method for SECM-SICM double-barrel probes with apertures down to 20 nm in diameter. The characterization of these SECM-SICM probes using scanning electron microscopy (SEM) imaging, cyclic voltammetry (CV) and Raman spectroscopy is also detailed. These SECM-SICM probes were subsequently used to study the morphology and electrochemical activity of several samples, ranging from hard metallic/insulating samples to live cells.