Sensitive and Matrix-Tolerant Lateral Flow Immunoassay Based on Fluorescent Magnetic Nanobeads for the Detection of Clenbuterol in Swine Urine

The lack of sensitivity and poor matrix tolerance are the main bottlenecks of the lateral flow immunoassay (LFIA). Here, a sensitive and matrix-tolerant method that integrated immunomagnetic separation and fluorescent lateral flow immunoassay (IMS-FLFIA) based on fluorescent magnetic nanobeads was developed to detect the clenbuterol (CLE) residue in swine urine. The limit of detection (LOD) of IMS-FLFIA is 4 times lower than that of traditional colloidal gold LFIA. This method, which exhibits similar LOD and linearity range in both phosphate-buffered saline and urine swine, is highly correlated with liquid chromatography-tandem mass spectrometry for the detection of real swine urine samples. The result indicated that IMS-FLFIA has a universal resistance to the swine urine matrix. The merits of this assay, high sensitivity, matrix tolerance, accuracy, and specificity, ensure a promising future in detection of veterinary drug residues.

灵敏度低和基质耐受性差是侧向流免疫测定（LFIA）的主要瓶颈。在此，开发了一种基于荧光磁性纳米珠的灵敏且耐基质的方法，该方法整合了免疫磁分离和荧光侧向流免疫测定（IMS - FLFIA），用于检测猪尿液中的克伦特罗（CLE）残留。IMS - FLFIA的检测限（LOD）比传统胶体金LFIA低4倍。该方法在磷酸盐缓冲盐水和猪尿液中均表现出相似的检测限和线性范围，并且与液相色谱 - 串联质谱法在检测实际猪尿液样本时高度相关。结果表明，IMS - FLFIA对猪尿液基质具有普遍的耐受性。这种检测方法的优点，即高灵敏度、基质耐受性、准确性和特异性，确保了其在兽药残留检测方面有良好的应用前景。