A Novel Graphene Oxide-Based Aptasensor for Amplified Fluorescent Detection of Aflatoxin M(1) in Milk Powder

In this paper, a rapid and sensitive fluorescent aptasensor for the detection of aflatoxin M(1) (AFM(1)) in milk powder was developed. Graphene oxide (GO) was employed to quench the fluorescence of a carboxyfluorescein-labelled aptamer and protect the aptamer from nuclease cleavage. Upon the addition of AFM(1), the formation of an AFM(1)/aptamer complex resulted in the aptamer detaching from the surface of GO, followed by the aptamer cleavage by DNase I and the release of the target AFM(1) for a new cycle, which led to great signal amplification and high sensitivity. Under optimized conditions, the GO-based detection of the aptasensor exhibited a linear response to AFM(1) levels in a dynamic range from 0.2 to 10 μg/kg, with a limit of detection (LOD) of 0.05 μg/kg. Moreover, the developed aptasensor showed a high specificity towards AFM(1) without interference from other mycotoxins. In addition, the technique was successfully applied for the detection of AFM(1) in infant milk powder samples. The aptasensor proposed here offers a promising technology for food safety monitoring and can be extended to various targets.