Graphene sheets with lateral dimens

Graphene sheets with lateral dimensions less than 100 nm are known as GQDs, which have very low toxicity and exhibit high stability, excellent solubility, stable photoluminescence, and good biocompatibility. A fluorescence “off-to-on” mechanism of bright blue fluorescent glutathione (GSH)-functionalized GQDs (GQDs@GSH) for assaying adenosine triphosphate (ATP) was proposed