DNA‐bridged double gold nanoparticles‐based immunochromatography for dual‐mode detection of ochratoxin A

Abstract

AbstractA novel immunochromatography strip (ICS) based on the DNA‐bridged double gold nanoparticles was established and evaluated for the dual‐mode detection of ochratoxin A (OTA). For this purpose, the streptavidin was coupled with the big size of gold nanoparticle (40 nm, AuNP), the OTA monoclonal antibody and biotinylated DNA‐SH were simultaneously immobilized on the small size of AuNP (20 nm), and then the enhanced ICS was self‐assembled and evaluated. The dual‐mode detection of semi‐quantification and quantification had been achieved and performed by the proposed ICS. The LOD for semi‐quantification (semi‐Q‐LOD) was 0.06 ng/mL by the directly naked eye (eightfold enhanced than conventional ICS). By the on‐site reader, the LOD for quantification (Q‐LOD) was 0.03 ng/mL (threefold enhanced), with the detection range between 0.03 and 1.2 ng/mL. The specificity, reliability, and practicability had been well represented. Furthermore, the OTA‐positive results of the enhanced ICS method correlated well with those obtained by the referenced HPLC–MS/MS for the market samples. This study provided a new ICS pattern of semi‐quantification and quantification for OTA contamination, which could be used as a valuable reference for improving the ICS technology and enhancing the sensitivity.