基于金纳米颗粒信号放大ELISA检测食品中恩诺沙星

以金纳米颗粒（gold nanoparticles，AuNPs）为信号放大载体，利用辣根过氧化物酶（horseradish peroxidase，HRP）标记的二抗为信号探针，建立一种基于AuNPs的信号放大酶联免疫检测方法（AuNPs signal amplification enzyme-linked immunosorbent assay，AuNPs-HRP-IgG ic-ELISA），检测食品中恩诺沙星（enrofloxacin，ENR）。该方法对ENR的检测限（IC15）为5×10－4?ng/mL，半数抑制浓度（IC50）为0.24?ng/mL，检测范围为0.16～500?ng/mL，与建立的传统ELISA方法（IC50=8.76?ng/mL）相比，显著提高了检测灵敏度，并且该方法与环丙沙星、氧氟沙星、诺氟沙星交叉反应率均小于0.1%，具有良好的特异性。该AuNPs-HRP-IgG?ic-ELISA方法的实用性得到了样品添加回收实验和商业化ELISA检测试剂盒的验证，其在牛奶样品中的加标回收率可达80.52%～102.66%，适用于实际牛奶样本中ENR的快速灵敏检测，也为建立其他食品危害物质的精准检测技术开发提供参考。

Development and Application of a Gold Nanoparticle-Based Signal Amplification Enzyme Linked Immunosorbent Assay for the Detection of Enrofloxacin in Food Samples

In this study, a signal amplification enzyme-linked immunosorbent assay (AuNPs-HRP-IgG ic-ELISA) to detect enrofloxacin (ENR) in foods was established using gold nanoparticles (AuNPs) as a signal amplification carrier and horseradish peroxidase (HRP)-labeled secondary antibody as a signal probe. The detection limit (IC15) of this method for ENR was 5 × 10-4 ng/mL, the half maximal inhibitory concentration (IC50) was 0.24 ng/mL, and the detection range was 0.16–500 ng/mL. Compared with the traditional ELISA method (IC50 = 8.76 ng/mL), the sensitivity was significantly improved. The cross-reactivity of this method was less than 0.1% toward ciprofloxacin, ofloxacin, and norfloxacin, indicating good specificity. The feasibility of the AuNPs-HRP-IgG ic-ELISA was validated in terms of spiked recoveries in comparison with a commercial ELISA kit. The recoveries for spiked milk samples was 80.52%–102.66%, suggesting that this method could be suitable for the rapid and sensitive detection of ENR in actual milk samples. This study may also provide a new way to develop detection techniques for other related hazardous substances in foods.