Sensitive and multiplexed detection of antibiotics using a suspension array platform based on silica-agarose hybrid microbeads

A multiplex suspension array detection platform of antibiotics has been developed based on silica-agarose hybrid microbeads (SAHMs). Chloramphenicol (CAP), sulfamethoxazole (SMX), metronidazole (MTZ) and amoxicillin (AMX) were employed as model analytes. The antigens (the antibiotics conjugated with BSA) were immobilized on the surface of four different types of SAHMs. Based on an indirect competition immunoassay, the selected antibiotics are detected through the competition of the specific monoclonal antibodies between the multiple antibiotics and the antigens. Due to high resistance to nonspecific protein absorption of SAHMs, the proposed method exhibited wide linear ranges (0.4˜72.9 ng/mL for CAP, 2.0˜108.5 ng/mL for SMX, 2.6˜142.2 ng/mL for MTZ, 1.0˜63.3 ng/mL for AMX) and low detection limits of 0.09˜0.8 ng/mL. Recoveries for spiked tap water samples were from 82% to 113%, with relative standard deviation lower than 14%, demonstrating the accuracy of the measurements performed with the developed method. This work offered a high-throughput, flexible and accurate tool, which provides a good platform for simultaneous detection of antibiotics.