Engineering Multivalence Aptamer Probes for Amplified and Label-Free Detection of Antibiotics in Aquatic Products.

Excessive use of antibiotics in aquatic products is a serious problem for food safety and human health, and on-site detection of antibiotics is highly demanded. Herein, we proposed multivalence aptamer probes, allowing sensitive, label-free, and homogeneous detection of antibiotics in different aquatic products. Compared to commonly used aptamers, multivalence aptamer probes can provide multiple binding sites and a higher affinity for target molecules, and the iterative binding on different binding sites contributes to an amplified recognition effect, sharply increasing the response and sensitivity of aptamer probes. The 2-valence aptamer probes conferred a limit of detection of 0.097 nM for kanamycin detection, where it is estimated that their sensitivity is enhanced 12 times compared to 1-valence aptamer probes. Meanwhile, multivalence aptamer probes allowed us to specifically identify kanamycin among other antibiotics. It could detect kanamycin residual in aquatic products including river eel and puffer fish, as well as tap water with high precision. A multivalence design strategy of aptamer probes would significantly improve the detection performance of aptamers, facilitating the translation of aptamer for food safety control.