An immunoassay based on bio-barcode method for quantitative detection of semicarbazide

A functionalized gold nanoparticles bio-barcode technology was developed to detect semicarbazide. In the assay, the hapten CPSEM (4-[[2-(aminocarbonyl) hydrazinylidene] methyl]-benzoic acid) was first prepared and conjugated to bovine serum albumin as the coating antigen. Subsequently, gold nanoparticles dual-labeled with anti-CPSEM monoclonal antibodies and DNA oligonucleotide were synthesized via a one-step preparation method. Enzymatic signal was converted to DNA signal by combining polymerase chain reaction with indirect competitive ELISA (icELISA). The limit of detection of this method could reach 8 pg mL⁻¹ for detecting SEM, about 25 times more sensitive than conventional ELISA. The immunosorbent bio-barcode assay is a rapid high-throughput screening tool adapted for ultra-high sensitive detection.