▎ 摘　　要

A graphene oxide-based fluorescent nanosensor AGO has been designed and synthesized by covalent grafting allylamine onto GO surface. In aqueous media, AGO displays a highly selective and sensitive discrimination of Fe3+ from Fe2+ and other metal ions through electron transfer-induced fluorescence quenching. The quenching of AGO fluorescence is linearly proportional to Fe3+ concentration in a wide range of 0-120 mu M (correlation coefficient R-2=0.9994). Moreover, AGO can be used to construct a combinational three-input logic gate to discriminate Fe3+ and Fe2+. The logic gate works well in intracellular fluorescence imaging, which shows a potential as a promising platform for biosensing analysis. (C) 2015 Published by Elsevier B.V.