Chemically-modulated photoluminescence of graphene oxide for selective detection of neurotransmitter by "turn-on" response.

Designing artificial nanomaterials capable of selectively detecting targets without the use of expensive and fragile antibodies is of great interest in the applications of nanomedicine. Here, we show that the photoluminescence (PL) of graphene oxide (GO) was chemically modulated for the selective detection of a neurotransmitter without the use of antibodies. GO was functionalized with nitrotriacetic acid (NTA) on which four different metal ions were chelated (M-NTA-GO), which led to its different PL responses to neurotransmitters. In particular, the Cu-NTA-GO hybrid was able to selectively detect norepinephrine at nanomolar concentrations in a simple manner via its "turn-on" PL. Moreover, it was successfully applied to the selective detection of norepinephrine secreted from living PC-12 cells.