Novel detection platform for insulin based on dual-cycle signal amplification by Exonuclease III

A novel detection platform based on Exonuclease III dual-cycle signal amplification with graphene oxide as quenching agent and DNA labelling as recognition element has been developed for the fluorometric determination of insulin. Specific DNA sequences were cut by Exo III to control the fluorescence recovery of the system. Fluorescence intensity analysis was carried out by fluorescence spectrophotometer to obtain the fluorescence intensity corresponding to different concentrations of insulin. When insulin is added to the system, insulin binds to the adaptor and the fluorescence is quenched, whereas in the absence of insulin the fluorescence is restored. The sensor platform achieved multiple signal amplification affording rapid and sensitive detection of insulin with a detection range of 0.048–2.15 U/ml. The methodology is rapid, sensitive, of low cost and convenient to perform and has potential for routine screening of insulin in blood, and also has prospects for the detection of other proteins and biomolecules.