Some veterinary drug residues in food products and environment have been widely regarded as severe threats to human health. Rapid and simultaneous detection methods are crucial to monitor and control veterinary drug usage. Here, we propose a fluorescence biosensor utilizing immunomagnetic beads (IMBs) and quantum dots (QDs) for the rapid and simultaneous detection of 1-adamantylamine (ADA), enrofloxacin (ENR) and tilmicosin (TIL) in raw chicken meat. A pretreatment method using sodium phosphotungstate–magnesium as extraction reagent was developed to simultaneously extract ADA, ENR and TIL from chicken meat with minor interference in background or response. By adding the IMBs modified with three types of antibodies and the QD-antigens modified with three types of BSA-antigens to sample, IMBs competitively conjugated to target antigens in a sample or QD-antigens. After magnetic separation, the residual QD-antigens were adopted to collect signals using fluorescence spectroscopy. Using QDs with well separated emission peaks, the detection of one type of targets was minorly interfered by the others. Under the optimum conditions, the biosensor exhibited the limit of detection of 0.96, 3.32, and 3.17 ng/mL for ADA, ENR and TIL in chicken samples, respectively, as well as good specificity. Due to the way of direct collection of signals in extracts, the tedious and complicated multiple magnetic separation and signal amplification procedures in conventional methods were avoided, thus the procedures were significantly simplified, and the reduction of the operation time of 30 min for sample pretreatment and 40 min for detection part was achieved. The biosensor might be promising in the rapid, in-field and sensitive screening of multiple veterinary drugs to ensure agriculture and food safety.
Enriching small extracellular vesicles (sEVs) with undamaged structure and function is a pivotal step for further applications in biological and clinical fields. It has prompted researchers to explore a carrier material that can efficiently capture sEVs while also gently release the captured sEVs. Here, 1-adamantylamine (1-ADA) responsive immuno-affinitive supramolecular magnetic nanoparticles (ISM-NPs) incorporating ternary host-guest complexation structures mediated by CB[8] were proposed to achieved the goal. In particular, the ternary host-guest complexation was constructed by the host molecule (cucurbit[8]uril, CB[8]) mediated assembly of two guest molecules (naphthol and bipyridine), and served as a cleavable bridge to connect the magnetic core and peripheral antibody. These constructed ISM-NPs performed well in the applications of capturing sEVs with a high capture efficiency of 85.5%. Further, the CB[8]-mediated ternary host-guest complexation structures can be disassembled with addition of the 1-ADA. Thus, the sEVs recognized by the anti-CD63 were released competitively, with a decent release efficiency more than 82%. The released sEVs kept intact morphology and exhibited appropriate size distribution and concentration. This supramolecular magnetic system, with 1-ADA responsive ternary host-guest complexation structures, may contribute to efficient enrichment of any other biomarkers, likely cells, proteins, peptides, etc.
危险品化学品经营许可证（带存储）