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 10 min, and the assay was completed within 15 min. The detection ranges for APE, BPA and LAS were 6.6 ppb-66 ppm, 2.3 ppt-2.3 ppm, and 35 ppt-35 ppm, respectively. This BMP-based immunoassay system has advantages due to its high sensitivity and rapid measurement of samples. (C) 2002 Elsevier Science B.V. All rights reserved.