Fig. 2

a Schematic view of the cell surface fluctuation setting by SICM. To investigate fluctuation levels, the nano-pipette was positioned on the apex of the single cell. b Typical ion current–distance curves of the solid substrate (black), a fixed cell (red), a 1% PFA treated cell (green), a 0.1% PFA treated cell (blue) and a live cell (sky blue). For the solid substrate (petri dish), there was no change. In the fixed cell, a much broader curve range was observed. For the live cell, the broadness of the curve range was greatest