Label-Free Graphene Oxide Förster Resonance Energy Transfer Sensors for Selective Detection of Dopamine in Human Serums and Cells

A novel label-free Förster resonance energy transfer (FRET) sensor was developed from graphene oxide (GO) functionalized with doxorubicin (DOX) for selective and sensitive detection of dopamine (DA). Due to the competitive adsorption of DOX and DA onto GO, the addition of DA to the DOX–GO complex led to a significant fluorescence enhancement caused by replacing the GO-supported DOX with DA of a higher adsorption affinity to GO. The unique competitive adsorption interactions of DOX and DA toward GO, in conjugation with the fluorescence property of DOX, made the DOX–GO as an ideal label-free sensor to detect DA in human serums and cells