Fully automated immunoassay system of endocrine disrupting chemicals using monoclonal antibodies chemically conjugated to bacterial magnetic particles

The development of a rapid and high-throughput detection system for endocrine disrupting chemicals (EDCs) has been required in the recent years. A fully automated immunoassay system was described for the detection of EDCs, such as alkylphenol ethoxylates (APEs), bisphenol A (BPA) and linear alkylbenzene sulfonates (LASs), using monoclonal antibodies chemically conjugated to bacterial magnetic particles (BMPs) and alkaline phosphatase (ALP)-conjugated EDCs. EDC concentrations were evaluated by the decrease in luminescence based on the competitive reaction of EDCs and ALP-conjugated EDCs. Full automation of the BMP-based immunoassay was achieved by using an automated eight-way pipet moving at X-, Y- and Z-direction and a B/F separation unit. B/F separation was performed on the tip surface of eight-way pipet with a retractable magnet mounted close to the pipet tip. Immunoreactions were saturated after 10min, and the assay was completed within 15min. The detection ranges for APE, BPA and LAS were 6.6ppb-66ppm, 2.3ppt-2.3ppm, and 35ppt-35ppm, respectively. This BMP-based immunoassay system has advantages due to its high sensitivity and rapid measurement of samples.