A sensitive immunosorbent bio-barcode assay combining PCR with icELISA for detection of gonyautoxin 2/3

In the current study, we developed a nanosphere bio-barcode technology to detect trace gonyautoxin 2/3 (GTX 2/3). GTX 2/3–glucose oxidase (GOX) conjugates were first prepared as the coating antigen in a periodate reaction. Subsequently, gold nanoparticles (NP) dual-labeled with anti-GTX 2/3 monoclonal antibodies (Mab) and DNA oligonucleotides were synthesized via a one-step preparation method. Combining PCR with indirect competitive ELISA (icELISA), a novel immunosorbent bio-barcode assay was established utilizing the Mab–NP–dsDNA complex to convert enzymatic signals to DNA signals. Importantly, the limit of detection of the method was lower than 0.74 μg mL−1. Thus, the immunosorbent bio-barcode assay is a rapid and high-throughput screening tool to detect GTX 2/3 in aquatic products.