Novel signal-on immunosensors for rapid and sensitive detection of Microcystin-LR

• Published in: Microchemical journal 2021-08, Vol.167, p.106295, Article 106295
• Main Authors: Zhang, Liqian, Dong, Hang, Li, Haimei, Li, Baowei, Zhao, Guangwei, Cai, Hongling, Chen, Limei, Dong, Jinhua
• Format: Article
• Language: English
• Subjects: Fluorescence; Immunosensor; Microcystin-LR; Quenchbody; Rapid detection
• ISSN: 0026-265X; 1095-9149
• DOI: 10.1016/j.microc.2021.106295

•Two novel signal-on immunosensors for detection of microcystin with leucine and arginine (MC-LR) were developed.•The assays can detect MC-LR in 3 min.•The combination of the two sensors achieved highly sensitive and wide-range detection of MC-LR.•The immunosensors successfully detected MC-LR in river water samples. Microcystins are a group of hepatotoxins produced by cyanobacteria present in surface water. We developed two Quenbodies (Q-bodies) as effective and reliable fluorescent sensors to detect microcystin with leucine and arginine (MC-LR) within 3 min. The designed single-chain variable region of antibody 3A8 was used to prepare Q-bodies by conjugating the fluorescent dye ATTO520 or tetramethylrhodamine (TAMRA) to its N-terminus. The fluorescence of Q-bodies was quenched by the internal tryptophan residues of antibody via photo-induced electron transfer, whereas it significantly increased upon the binding of MC-LR. The limit of detection and EC50 were 0.45 ng/mL and 20.43 ng/mL, respectively, for TMARA-labeled Q-body, and 8.6 ng/mL and 251.6 ng/mL for ATTO520-labeled Q-body. Combining the Q-bodies enabled sensitive and wide-range detection of MC-LR. The recovery rates for river water samples spiked with MC-LR ranged from 94.8% to 120.0%, suggesting their potential applications in MC-LR monitoring in nature.