A simple and facile strategy based on Fenton-induced DNA cleavage for fluorescent turn-on detection ofhydroxyl radicals and Fe2+

We provide a novel, simple, and general strategy based on a DNA–graphene oxide (GO)–Fenton hybrid system for fluorescence turn-on detection of hydroxyl radicals (HO˙) and Fe2+, in which GO as a nanoquencher is utilized for reducing the background signal and simplifying procedures. Fluorescence resonance energy transfer (FRET) between GO and dye units incorporated into DNA is switched off as a result of HO˙-induced strand breakage in the single-stranded DNAs, restoring the fluorescence of the quenched fluorophores. In our assay, HO˙ is generated by Fe2+ catalyzing decomposition of hydrogen peroxide through the Fenton reaction. Therefore, switching off FRET depends on the amounts of Fe2+ and HO˙. In vitro assays with Fe2+ and HO˙ demonstrated increases in fluorescence intensity with a linear range from 10 nM to1 μM and a detection limit as low as 2.4 nM.