A label free exonuclease III-aided fluorescence assay for adenosine triphosphate based on graphene oxide and ligation reaction

Abstract

A label free exonuclease III (Exo III)-aided fluorescence assay for adenosine triphosphate (ATP) was developed based on the ATP-dependent enzymatic reaction and graphene oxide (GO). This strategy relies on the principle that Exo III shows different cleavage capacity for a DNA substrate in the absence and presence of ATP and the preferential binding of GO to single-stranded DNA over double-stranded one. By combining the unique properties of SYBR Green I and GO adsorption, this sensor displays an improved sensitivity and a wide linear range within the ATP concentration from 1 nM to 200 nM with a low detection limit of 0.2 nM. The proposed method is simple, cost-effective and convenient, which might create a new methodology for developing a sensitive ATP biosensor.