Strip biosensors based on broad-spectrum aptamers and cationic polymers for the on-site rapid detection of tetracycline antibiotics residues in milk

A lateral flow chromatography strip (LFS) is a chromatography-based biosensor with advantages of convenient carrying, simple operation and rapid detection. In this study, a novel rapid detection technique of aptamer-based chromatography strip was developed and used for the first time for the residue detection of tetracycline antibiotics (TCs) in various milk samples. In this method, gold nanoparticles (AuNPs) modified by TCs specific aptamers were used as probes, and cationic polymers as a capture molecule in a test line (T-line). Meanwhile, the analysis of the gray value of the T-line enabled a linear detection range of 1–300 nM and a limit of detection (LOD) of 0.33 nM for quantitative analysis. The biosensor demonstrated specificity, stability, and successfully detected tetracyclines in milk samples with recovery between 93.60 %–106.20 %. This method sets a basis for multi-residue antibiotics detection in diverse samples, showing potential for on-site applications.