Fig. 1

 Intra-spinal delivery of s-GO and dfG does not alter zebrafish development, neuronal survival or the electrophysiological basic properties of motor neurons. (a) Experimental setting for injections of nanomaterials in the spinal cord of 2 dpf zebrafish. Left: Lateral view of a 2 dpf zebrafish larva; the rectangle indicates the region of the body targeted by injection. Middle: Bright field image at higher magnification of the dorsal part of fish where solutions are delivered through a tiny glass pipette. Right: Fluorescence field of the previous image, showing that the injected solutions, added with a fluorescent dye, are delivered precisely in the spinal cord. (b) Schematic representation of the anatomical traits measured in zebrafish to analyse their development. (c) Bright field images of control, dfG-injected and s-GO-injected fish two days after injection. (d) Plots reporting the values of fish length and height, eye and yolk diameters. (e) Confocal images (Z-stack reconstructions) of the spinal cord of control, dfG-injected and s-GO-injected fish. Green signal is GFP expressed in motor neurons. (f) Plots reporting the number of motor neurons in the two segments of spinal cord around the site of injection. (g) Experimental setting for in vivo patch clamp recordings from motor neurons in zebrafish spinal cord: on the left a schematic representation of the patch clamp pipette inserted in the spinal cord (in red) of a larva, on the right bright field image of spinal neurons during recordings. A patch clamp pipette targeting the cell body of a motor neuron is visible. (h) Plots reporting the capacitance, the input resistance and the resting membrane potential of primary motor neurons. Dots superimposed to bars correspond to single fish or single neuron values.