To develop a method for the detection of dexamethasone (DMS) in milk by colloidal gold lateral flow assay (CG-LFA).
In this study, active groups were introduced from the hydroxyl groups of DMS to prepare haptens, and complete antigens were prepared by coupling carrier proteins. After animal immunization and cell fusion screening, 3 monoclonal antibodies (mAbs)—mAb 2H1, mAb 1B6 and mAb 2B6—were produced. Finally, the CG-labeled antibodies were immobilized as probes using electrostatic adsorption, establishing a colloidal gold method for detecting DMS in milk.
After evaluation, mAb 1B6 was selected as the optimal antibody to establish CG-LFA, with a cut-off value of 0.20 ng/mL and a half maximal inhibitory concentration (IC50) of 0.07 ng/mL. Moreover, the cross-reactivity with 3 kinds of structurally similar betamethasone(BTM), fluorohydrocortisone (FDC) and hydrocortisone (HDC) ranged from 3.9% to 13.4%, and there was no cross-reactivity with the other common hormones. The recoveries of real samples spiked with DMS were in the range of 92.4%–102.8%, and the limit of detection (LOD) was 0.05 μg/kg.
The DMS established in this study is characterized by simplicity of operation and high sensitivity, which is capable of meeting the requirements for rapid on-site detection of DMS in milk.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |