As described in Figure and detailed in the Experimental section, a portion of the purified l-GO dispersion was freeze-dried and weighed to determine its mass-based concentration, before reconstituting with endotoxin-free water to the original volume. This reconstituted dispersion was then split in 2 post-reaction treatment groups to be further processed in order to reduce the size of the sheets: i) exposure of l-GO to a sonication bath for 5 minutes followed by a centrifugal purification step to separate the small GO flakes (s-GO) from the larger flakes that deposited and formed a pellet (Figure , red arrows); ii) exposure of the aforementioned sonicated l-GO dispersions (without purification) to a sonication bath for an additional period of 4 hours, followed by a centrifugal purification step to enable the extraction of purified ultrasmall GO flakes (us-GO) in the supernatant (Figure , green arrows). In both cases, the temperature of the water bath employed in the sonication steps was controlled so that it did not exceed 40ºC (see Experimental section). As demonstrated in the following sections, this method of production resulted in the acquisition of three types of GO flakes, which differed only by their lateral dimensions whilst displaying a conserved surface chemistry.