Self-enhanced electrochemiluminescence of luminol induced by palladium-graphene oxide for ultrasensitive detection of aflatoxin B1 in food samples

In this work, a novel and credible electrochemiluminescence immunoassay (ECLIA) was constructed for the ultrasensitive and highly selective detection of aflatoxin B-1 (AFB(1)). Amino-functionalized 3D graphene hydrogel (NGH) served as the ECL platform with the self-enhanced ECL of luminol-palladium-graphene oxide (lum-Pd-GO) acting as a marker for the antibodies against AFB(1). Pd-GO was synthesized by a self-redox method; it promotes the formation of reactive oxygen species, which are important to the ECL of luminol, from dissolved oxygen. The pi-pi conjunction between luminol and GO shortens their electron transfer distance, resulting in an amplified ECL signal (similar to 8.5 times larger than conventional luminol ECL). Moreover, 3D NGH, with its good conductivity, large surface area, and sufficient amino groups, was used to anchor gold nanoparticles (AuNPs), which subsequently immobilized bovine serum albumin (BSA)-AFB1 through Au-S bonds. The resultant, competitive ECLIA gave a relative low detection limit of 5 x 10(-3) mu g kg(-1) and exhibited a broad linear relationship over the range of 0.05-50 mu g kg(-1). Finally, the proposed ECLIA was successfully used to analyze AFB(1) contents in food samples. ECLIA: electrochemiluminescence immunoassay; AFs: Aflatoxins; HPLC: high-performance liquid chromatography.

Automated summary

In this study, a novel and credible electrochemiluminescence immunoassay (ECLIA) was developed for the ultrasensitive and highly selective detection of aflatoxin B-1 (AFB(1)). The combination of amino-functionalized 3D graphene hydrogel (NGH) and self-enhanced ECL of luminol-palladium-graphene oxide (lum-Pd-GO) served as the platform and marker, respectively. The developed ECLIA exhibited low detection limit and broad linear relationship, and was successfully applied for the analysis of AFB(1) contents in food samples.