Development of a Colloidal Gold Immunochromatographic Assay Strip Using a Monoclonal Antibody for the Rapid Detection of Ofloxacin

The livestock industry uses ofloxacin, an antibiotic, to prevent several animal diseases; however, the overdose of ofloxacin used in animal farming treatments may appear in food products and cause some adverse human health effects. Hence, there is an immediate need to develop a method suitable for on site large-scale detection of ofloxacin residues in animal-derived foods. This study aimed to prepare a monoclonal antibody with high sensitivity and affinity for ofloxacin by re-synthesizing the ofloxacin hapten and synthesizing the corresponding complete antigen. The IC₅₀ of the enzyme-linked immunosorbent assay (ic-ELISA) was 0.13 ng/mL, and the detection limit was 0.033 ng/mL. The visual detection limit of the established colloidal gold immunochromatographic test strip, for the visual detection of actual samples, was 1 ng/g. In summary, this work establishes a rapid detection method of ofloxacin residues on the basis of colloidal gold immunochromatography that is suitable for actual detection.