SERS sensor based on an optimized specific aptamer by Capture-SELEX screening for rimantadine detection

Rimantadine (RIM), as a commonly used antiviral drug, is often illegally used in the aquaculture industry due to its remarkable therapeutic effect and low price, resulting in the accumulation of RIM in the environment and eventually threatening human health. Therefore, the realization of specific detection and monitoring of RIM has become an important topic in food safety and other fields. In this work, we screened an aptamer RIM-17 with high specificity and affinity for RIM based on Capture-systematic evolution of ligands by exponential enrichment (Capture-SELEX) technology. The binding mechanism and key sites of RIM and RIM-17 was studied by molecular docking technology. According to the molecular binding site, the optimal aptamer RIM-172 with a length of 50mer was obtained by truncation optimization strategy, and its affinity K-d value for RIM was 46.84 +/- 11.33 nM. Based on the optimized aptamer, a surface-enhanced Raman spectroscopy (SERS) aptasensor with Fe3O4@UIO-66@AuNS as the Raman report substrate was established for the detection of RIM. Under the optimal preparation conditions, the linear range of the SERS-based aptasensor to detect RIM was 0.5 similar to 25 ng/mL and the limit of detection (LOD) was 0.27 ng/mL. In the test of added standard recovery, the recovery rate was 96.00%similar to 101.20%. Moreover, the aptasensor exhibited accepted stability and specificity. The discovery of RIM aptamer provides an effective way for the specific capture and detection of RIM, and helps to monitor the illegal abuse of RIM.