基于超顺磁性纳米粒子的食品中塑化剂快速传感检测方法

The co-precipitation and thermal decomposition method will be used for controllable synthesis of magnetic nanomaterial in this project. Through modification techniques, the surface functional group on the magnetic nanoparticles will be conjugated with antibody and biotin, respectively. The parameters for synthesis of magnetic nanoparticles, labeling conditions will be optimized, and high performance magnetic nanoprobe will be obtained. Based on the prepared nanoprobe, the detection will be performed in immunoassay formats in microplate, including antigen coating, washing steps, etc., through magnetic nanoparticles catalyzed tetramethylbenzidine chromogenic reaction, and we will finally achieve rapid, highly sensitive detection of plasticizing agent. At the same time, the developed nanoprobe can also be used as magnetic resonance nanoprobe for magnetic resonance relaxation detection. The developed magnetic nanoparticle sensor detection will be compared with horseradish peroxidase, and the advantages of the method, repeatability, stability will be evaluated.

本项目采用共沉淀法和热分解法可控合成磁纳米材料，利用磁纳米粒子表面的功能性基团结合修饰技术，利用抗体和生物素两种方法对磁性纳米粒子进行偶联标记。通过控制纳米合成参数，标记条件优化，得到高性能的磁性纳米探针。利用制备的纳米探针，在微孔板中进行免疫反应，洗涤等步骤，利用磁纳米粒子的催化四甲基联苯胺显色反应，实现对塑化剂快速，高灵敏检测.该磁性纳米探针可同时作为磁共振探针，进行磁共振弛豫探针传感检测，同时与辣根过氧化物酶进行对比，对方法的优越性、重复性、稳定性进行评价。

食品接触材料中的塑化剂成分如双酚A等通过食物进入人体内，发挥类似于激素的作用，严重危害了食用者的健康。本项目围绕纳米粒子磁分离、核磁共振、等离子共振三种增敏效应与生物识别材料相结合：a）利用化学共价偶联法将包被原表面修饰于纳米粒子表面，制备得到功能化磁纳米粒子。b）基于功能化磁纳米粒子建立核磁共振免疫传感器检测双酚A，成功的应用于牛奶测定。c)利用一抗和二抗具有抗体的多价识别性质，放大了信号响应。通过化学偶联方法将双酚A包被原修饰在磁纳米粒子表面，得到功能化磁纳米粒子，此功能化磁纳米粒子在抗体的多价性质诱导下进行三维自组装。相反，随着免疫传感器体系中目标物双酚A的加入，抗双酚A抗体竞争性的识别双酚A和功能化磁纳米粒子，从而使磁纳米粒子保持分散的状态，并且导致对应的横向弛豫时间T2的变化。检测灵敏度达到0.1 fM，检测限为3.9pg/ml，同时提高了检测的特异性。上述检测方法满足了双酚A高灵敏检测的需求，也满足了对多个样品同时进行测定的需求。进而发展了应用新型纳米技术在食品安全检测领域的高通量高灵敏检测的新原理。