Capturing live cell dynamics at the nanoscale by sweeping laterally at a fixed standoff

Scanning ion conductance microscopy (SICM) offers non-contact, label-free imaging of live cells with nanometer-scale resolution. However, its conventional imaging mode is inherently slow due to repeated vertical scanning, limiting temporal resolution and causing inertial issues. Here, we present Scanning Counter Ion Conductance Microscopy (SCICM), which enables a new mode, Sweep mode, by simply introducing a polyelectrolyte gel-filled (PGF) nanopipette into the SICM. This modification allows continuous lateral scanning without vertical feedback, greatly improving imaging speed and pixel density with simplifying operation. The high conductivity of the polyelectrolyte gel, combined with ion concentration polarization (ICP) near the tip, enhances distance sensitivity, yielding a gradual approach curve essential for Sweep mode operation. SCICM enables high signal-to-noise imaging at a pixel rate of 8,000 Hz, beyond the temporal limitation of SICM, allowing visualization of dynamic morphological changes in live hippocampal neurons and establishing SCICM as a powerful platform for high-fidelity, label-free imaging.