Gold nanoparticles enhanced chemiluminescence - a novel approach for sensitive determination of aflatoxin-B1

The present paper describes the effect of gold nanoparticles on the enhancement of chemiluminescence, widely known as metal enhanced chemiluminescence. Here for the first time we have studied the effect of gold nanoparticles on two enhanced chemiluminescence systems, alkaline phosphatase-disodium 2-chloro-5-(4-methoxyspiro{1,2-dioxetane-3,2'-(5'-chloro)tricyclo[3.3.1.1(3,7)]decan}-4-yl)-1-phenylphosphate and luminol-urea hydrogen peroxide-horseradish peroxidase. In both the systems, up to 100% enhancement of chemiluminescence was observed in the presence of citrate capped gold nanoparticles. On the other hand cetyl trimethyl ammonium bromide capped gold nanorods did not exhibit much effect on chemiluminescence. Based on the results, a dipstick based enhanced chemiluminescence based method was developed for the sensitive detection of aflatoxin-B1 in water samples. The minimum detectable limit for aflatoxin-B1 was 0.1 ng mL(-1) with a linearity in the range of 0.5-20 ng (R-2 = 0.994). The results were well correlated with those obtained by HPLC analysis (linearity 3-200 ng, R-2 = 0.99). This enhanced chemiluminescence based immunodipstick method can be used for the development of a quantitative test kit for the determination of aflatoxins.