Schematic representation of the proposed mechanism taking place during GO (a) and rGO (b) stimulation and of the consequent cellular response. b, In the case of rGO, charge accumulation occurs at the cellsolution interface, inducing depolarization of the cell membrane at the electrolytcell interface (1) which might stimulate directly electrically/mechanically the endoplasmic reticulum 58 (2) causing the release of INT-Ca 2+ from the stores. 3, The above-mentioned electric field might repulse cations at the cellelectrolyte interface, thus hampering the EXT channel in mediating Ca 2+ influx. Lower panels: the potential drop across the substrate (GO, a, and rGO, b), and the direction of electric fields created by the potential applied to the substrate (E sub). The electric fields created on the cell walls by the membrane potential (E mem), pointing inside the cell, are also shown. Bottom panel: the scheme of the equivalent electric circuit, as described in the text.
