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Updated: Jan 15, 2026
ELIME Enzyme Linked Immuno Magnetic Electrochemical Method for Mycotoxin Detection
Published on: October 23, 2009
Breaking the Sensitivity-Convenience Trade-off: A Camelid HCAb-Based Immunoassay for Multi-Residue Detection of
Huijuan Yang1,2, Mengyao Chen1,2, Ruoxi Zhang1,2
1Key Laboratory of Digital-Intelligence and Dynamic Perception for Food Quality of China Light Industry, Beijing Technology and Business University, Beijing 100048, PR China.
Abstract:
The instability of conventional antibodies (ConAbs) in food matrix or target extraction reagents often limits the convenience or sensitivity of immunoassays. In this study, alpacas were immunized with water-soluble adjuvants to induce heavy chain antibodies (HCAbs) against antibacterial synergists (ASGs). Compared to ConAb C5, the HCAb H5 exhibited superior stability (binding activity >80% and IC50 change <2-fold) under harsh conditions (63 °C, pH 3.0-11.0, 6.0 mol L-1 NaCl, 30% methanol, 30% acetonitrile). An indirect competitive ELISA (icELISA) based on H5 showed IC50 values of 1.24, 1.44, 1.60, and 2.11 μg L-1 for trimethoprim (TMP), dimethoprim (DVD), ormetoprim (OMP), and baquiloprim (BQP), with cross-reactivity rates of 100%, 86.3%, 77.7%, and 56%, respectively. Sample preparation was simplified to minimal dilution steps─chicken, egg, pork, and milk samples were diluted only 2-, 4-, 4-, and 8-fold, respectively─and the entire pretreatment could be completed within 1-8 min. The limits of detection (LODs) ranged from 0.14 to 1.36 μg L-1/μg kg-1, with recoveries of 76.4-107.3%, and coefficients of variation (CV) below 14.1%. This is the first HCAb-based icELISA for ASGs, offering high sensitivity, robustness, and minimized pretreatment for complex food matrices.
