A Novel Graphene Oxide-Based Aptasensor for Amplified Fluorescent Detection of Aflatoxin M1 in Milk Powder

Abstract

In this paper, a rapid and sensitive fluorescent aptasensor for the detection of aflatoxin M1 (AFM1) 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 AFM1, the formation of an AFM1/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 AFM1 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 AFM1 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 AFM1 without interference from other mycotoxins. In addition, the technique was successfully applied for the detection of AFM1 in infant milk powder samples. The aptasensor proposed here offers a promising technology for food safety monitoring and can be extended to various targets.

A Review of the Use of Carbon Nanotubes and Graphene-Based Sensors for the Detection of Aflatoxin M1 Compounds in Milk

“…Due to the enhanced electrical, mechanical and thermal characteristics, graphene in its pure, oxide and composite forms has achieved the required performances. Biomedical sensing applications have also been used to detect biomolecules [ 111 , 112 , 113 ] to their high surface-to-volume ratio, excellent electrical conductivity and tunable optical properties. This helps the sensors to achieve high sensitivity, low LOD and detection without any chemical mediators [ 111 ].…”

Aptamer-Based Biosensor for Detection of Mycotoxins

“…However, complicated instruments and procedures were required in this aptasensor. In order to overcome these difficulties, a rapid fluorescent aptasensor was developed for AFM1 determination in further studies [93], which combined the advantages of fluorescence quenching ability of graphene oxide and target-cycled signal amplification induced by DNase (Figure 9). In optimized conditions, this amplified aptasensor showed a good detection range of 0.2-10 μg kg −1 for AFM1, and the detection limit was calculated at 0.05 μg kg −1 .…”

Aptamer-Based Biosensor for Detection of Mycotoxins

“…However, complicated instruments and procedures were required in this aptasensor. In order to overcome these difficulties, a rapid fluorescent aptasensor was developed for AFM1 determination in further studies (Guo et al, 2019), which combined the advantages of fluorescence quenching ability of graphene oxide and target-cycled signal amplification induced by DNase (Figure 9). In optimized conditions, this amplified aptasensor showed a good detection range of 0.2-10 µg kg −1 for AFM1, and the detection limit was calculated at 0.05 µg kg −1 .…”

“…Schematic illustration of fluorescent aptasensor for detection of AFM1 by using graphene oxide signal amplification. Reprinted fromGuo et al (2019) with permission.…”