A Graphene Oxide-based Covalent Resorufin-Conjugated Fluorescence "OFF-ON" Probe for Detection of Hydrazine.

The unique properties of graphene oxide (GO), such as good water solubility, non-toxicity, biocompatibility and cell permeability, make GO well suited for a number of biological applications. In this study, we explore the application of GO as an efficient fluorescent quencher for a highly fluorescent organic dye, resorufin (RF). The quenching effect of GO on resorufin is studied by noncovalent and covalent bonding of resorufin, respectively. The fluorescence is completely quenched when resorufin is covalently linked to GO; while resorufin's fluorescence could be still observed through noncovalent bonding to GO sheet. Interestingly, addition of hydrazine into RF-GO complex causes the fluorescence recovered, providing a potential ''OFF-ON'' fluorescence responsive probe for detecting hydrazine in vitro and in living cells.