赭曲霉毒素A和诺氟沙星荧光双适配体生物传感器

ptamers have been widely used in the preparation of various biosensors to recognize small molecules and proteins due to their high specificity and efficiency. However, the specificity of aptamers has been regarded as an intrinsic property and has not been systematically investigated. Our research group found that aptamers have promiscuous binding phenomenon through large-scale spatial virtual screening and have a high potential for false positives when identifying targets. By studying the aptamer OBA3 of ochratoxin A (OTA), we found that the aptamer actually binds more strongly to norfloxacin, so we constructed a logic gate (NOR) for the simultaneous detection of OTA and norfloxacin at the molecular level based on the principles of target-induced conformational change, chain displacement and fluorescence resonance energy transfer, achieving high specificity for both targets single detection and interference-free hybrid detection. The linear detection range is from 25 to 400 nM with a detection limit of 8 nM for OTA and from 25 to 100 nM with a detection limit of 53 nM for norfloxacin in single detection, and 31 nM with a detection limit of from 25nM to3μM for OTA and 33 nM with a detection limit of from 25 to 400 nM for norfloxacin in mixed detection. The sensor is highly sensitive, specific and rapid,it was applied to milk samples with OTA spiked recoveries ranging from 94.06% to 100.25% and norfloxacin spiked recoveries ranging from 96.26% to 100.93%. This study could facilitate the practical application of the aptamer to reduce the risk of human health from mycotoxin and antibiotic residues in animal-derived foods.