Carbendazim (CBZ) pesticide residues in food products have become a growing concern in recent years. Herein, a sensitive biosensor for detecting CBZ was developed based on luminescent resonance energy transfer (LRET) from aptamer labeled upconversion nanoparticles (UCNPs, donor) to manganese dioxide (MnO 2 , acceptor) nanosheets. The strong overlap between the absorption spectrum of MnO 2 and the UCNPs fluorescence emission allowed the luminescence quenching. With the addition of CBZ, it tended to bind with specific aptamers, which culminated in the UCNPs-aptamer dropping off MnO 2 nanosheets and restoring the fluorescence. A linear calibration plot between logarithmic CBZ concentration and fluorescence intensity was acquired in the range of 0.1–5000 ng·mL −1 , with a limit of detection 0.05 ng·mL −1 , indicating that the UCNPs- MnO 2 aptasensor is a rapid, sensitive and specific quantitative detection platform for CBZ. Furthermore, the precision and accuracy of the developed LRET biosensor was validated by HPLC method with no significant differences.
To overcome limitations with respect to the low sensitivity of rapid immunoassay methods due to dilution of the extract in extraction solution, ultra-sensitive antibodies are needed. The linker-tethering site between the target and carrier protein , the length of the spacer arm , and the atomic charge of the linker-tethering site between the target and spacer arm in haptens design play a pivotal role in the preparation of ultra-sensitive antibodies. In this study, carbendazim (CBZ), a systemic broad-spectrum fungicidal pesticide, was used as model compound. 2-Aminobenzimidazole was chosen as the common skeletal structure and reacted with different groups, such as alkanes and urine groups, to form haptens H1 (previously reported), H2 (novel), and H3 (novel), respectively. Subsequently, eight monoclonal antibodies (mAbs) were generated using these three haptens , which exhibited notable variation in sensitivity. The half maximal inhibitory concentration (IC 50 ) value of mAb 4B11 based on hapten H3 against CBZ was 0.04 ng/mL, which was seven times better than that of mAb 5B10 (IC 50 value of 0.28 ng/mL) prepared using hapten H2 and 129 times better than that of mAb 6D5 (IC 50 value of 5.15 ng/mL) prepared using hapten H1. Finally, the optimal antigen–antibody combination was employed to establish a sensitive colloidal gold lateral flow immunoassay (CG-LFA) for CBZ detection in vegetables and fruits with convenient sample pretreatment . The developed CG-LFA shows promising practical utility and prospects for application due to its low limit of detection (0.10–0.18 ng/mL) and high recovery ratios (76.0%–96.1%) in six different samples.
危险品化学品经营许可证（带存储）