Design an aptamer-based sensitive lateral flow biosensor for rapid determination of isocarbophos pesticide in foods

Rapid, sensitive, point-of-care detection of isocarbophos is extremely important in food safety. Herein, a new aptamer-based lateral flow biosensor (LFB) has been designed and developed for isocarbophos detection. The SS2-55 aptamer serves as alternative recognition element instead of antibodies in this LFB, and it was conjugated to the surface of gold nanoparticles (AuNPs) to achieve a highly sensitive and specific isocarbophos probe. The SS2-55 aptamer can interact with isocarbophos pesticide and desorb from the surface of AuNPs in the probe, leading to the capture of free AuNPs by cysteamine that immobilized on the test (T) line of the LFB. The designed LFB has a detection limit as low as 2.48 μg L−1, and shows high selectivity for isocarbophos over other control pesticides. Notably, the designed LFB can distinguish whether isocarbophos exceeds the permissible level in less than 1 min even by the naked eyes. The detection results in actual samples show that the designed LFB has good accuracy and practicability, indicating its bright application prospects in the rapid analysis of pesticide residues.