Figure 1.

s-graphene oxide (s-GO) reduced basal synaptic activity in a dose-response fashion without inducing cell death in organotypic ventral horns. In (A), low magnification confocal micrograph of a spinal cord slice culture (14 days in vitro, DIV) immune-labeled for neurofilament H (SMI-32; in green) and nuclei (DAPI; in blue). Scale bar 500 μm. The arrow head indicates the ventral fissure, localizing the ventral horns, while the arrows the co-cultured dorsal root ganglias (DRGs). In (B), sketch of the experimental setting for ventral interneuron single cell recordings (modified with permission from Usmani et al., 2016). In (C), tracings represent spontaneous synaptic activity recorded from ventral interneurons in Control (top) and s-GO treated slices (bottom; 50 μg/mL). On the right panel, isolated fast and slow postsynaptic currents (PSCs) are shown superimposed (electronic average trace superimposed in white) for the control (top) and s-GO treated (bottom) recordings (same cells as above). In (D), the plots summarize the average PSCs frequency (left) and amplitude (right) values; note the reduction in PSC frequency upon s-GO treatments (25 and 50 μg/mL; *P < 0.05 and **P < 0.01). In (E), confocal micrographs visualize caspase-3 positive cells (in red) in the ventral horns, counter-stained for β-tubulin III (in green, to visualize neurons) in Control (left) and s-GO (50 μg/mL; right) treated slices. Nuclei are visualized by DAPI (blue). Scale bar: 50 μm. The column plot summarizes the density of caspase and β-tubulin double positive cells; note the absence of statistical significant differences between the two conditions.