Carbon dots-bromoacetyl bromide conjugates as fluorescence probe for the detection of glutathione over cysteine and homocysteine

•The CDs were functionalized with bromoacetyl bromide molecules.•The functionalized CDs-Br were used to detect glutathione (GSH) via the halogen substitution cyclization.•CDs-Br could effectively immediate detect amino acids with thiols and it need not to be combined with metal ions.

A novel fluorescent sensor based on carbon dots (CDs) was synthesized for direct determination of glutathione (GSH), which bromoacetyl bromide was functionalized CDs (CDs-Br) sensing system for the first time. The bromoacetyl bromide functional groups (halogen moiety) can quench the fluorescence of CDs, which were substituted by the -SH group, could lead to a significant fluorescence increase of CDs-Br via the halogen substitution cyclization. This method could effectively immediately detect amino acids with thiols and it needn't to be combined with metal ions. Under optimum conditions, the probe has a good selectivity for GSH over other various biologically relevant species and even two other similar biothiols (Cys/Hcy) and could image GSH in living cells.

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