Non-CTAB synthesized gold nanorods-based immunochromatographic assay for dual color and on-site detection of aflatoxins and zearalenones in maize

Abstract

New developing gold nanorods (AuNRs) are promising alternatives of gold nanospheres in the immunochromatographic assay (ICA) for the rapid screening of mycotoxins in cereals because of their unique three-dimensional structure. Nevertheless, cetyltrimethylammonium bromide (CTAB) was used to prepare of AuNRs without exception in previous reports, resulting in poor biocompatibility, cytotoxicology and difficulty for further functionalization. In this study, we used non-CTAB synthesized AuNRs with different colors as labels on ICA for the screening of four aflatoxins and total zearalenones. The results showed the non-CTAB synthesized AuNRs was more stable and easier for further functionalization than CTAB-based AuNRs. The visual detection limits of developed AuNR-ICA were 0.5 ng/mL for AFB1 and 1 ng/mL for ZEN, and the quantitative detection limits were 0.05 ng/mL for AFB1 and 0.27 ng/mL for ZEN, respectively. The assay could accomplish qualitative detection and quantitative analysis within 20 min. The results of the AuNR-ICA were comparable to those of HPLC-MS/MS for naturally contaminated maize samples, indicating the feasibility of the AuNR-ICA in practical use. Given these performances, the non-CTAB synthesized AuNRs showed great potential for use as an effective label in the ICA development.