基于磁弛豫开关的免疫传感器检测自来水和脱脂牛奶中的雌二醇

A magnetic relaxation switch immunosensor for the detection of estradiol in tap water and skimmed milk

中文关键词:  磁弛豫开关  免疫传感器  雌二醇  自来水  脱脂牛奶

英文关键词:magnetic relaxation switch  immunosensor  estradiol  tap water  skimmed milk

中文摘要:

      目的 建立磁弛豫开关(magnetic relaxation switch, MRS)免疫传感器检测自来水和脱脂牛奶中雌二醇(estradiol, E2)残留的方法。方法 通过1-(3-二甲基氨基丙基)-3-乙基碳化二亚胺[1-(3-dimethy laminopropyl)-3-ethylcarbodiimide hydrochloride, EDC]和N-羟基丁二酰亚胺(n-hydroxysuccinimide, NHS)反应将雌二醇抗体(E2-Ab)和雌二醇全抗原(E2-BSA)分别偶联在磁纳米粒子(magnetic nanoparticles, MNP)表面, 利用透射电子显微镜和动态光散射法等方法对偶联前后状态进行表征, 之后添加游离E2于检测体系中与E2-BSA竞争反应1 h, 将反应溶液转移到核磁共振管中, 使用核磁共振交联密度分析测量仪器对横向弛豫时间(T2)进行测定, 进而对E2定量分析。结果 在磁珠偶联抗体(MNP-Ab)浓度为5 μg/mL, 磁珠偶联全抗原(MNP-E2-BSA)为50 μg/mL及孵育时间为90 min的优化条件下, 该传感方法的横向弛豫时间变化(△T2)与E2浓度的对数在0.01~100 ng/mL的范围内呈良好的线性关系, 检出限为0.01 ng/mL。对自来水样品和脱脂牛奶在0.5、5和50 ng/mL添加水平的回收率分别为93.55%~118%和91.25%~107.32%, 相对标准偏差(relative standard deviation, RSD)小于4.82%。结论 该方法快速、准确、灵敏, 为食品安全风险因子快速检测提供一种更为有效的手段。

英文摘要:

      Objective To establish a method for the determination of estradiol (E2) residues in tap water and skimmed milk by magnetic relaxation switch (MRS) immunosensor. Methods The estradiol antibody (E2-Ab) and estradiol total antigen (E2-BSA) were coupled to the surface of magnetic nanoparticles (MNP) by 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride-n-hydroxysuccinimide (EDC-NHS) reacting. Secondly, the state before and after coupling of MNP was characterized by transmission electron microscopy and dynamic light scattering methods. Then, free E2 was added to the detection system to compete with E2-BSA for 1 h, the reaction solution was transferred to nuclear magnetic resonance tube, and the transverse relaxation time (T2) was measured using nuclear magnetic resonance crosslinking density analysis measuring instrument, and E2 was quantitatively analyzed. Results The concentration of magnetic nanoparticles conjugated antibody (MNP-Ab) was 5 μg/mL, the magnetic nanoparticles conjugated estradiol-bovin serum albumin (MNP-E2-BSA) was 50 μg/mL, and the incubation time was 90 min. The change of transverse relaxation time (△T2) had a good linear relationship with the Log of concentration of E2 in the range of 0.01-100 ng/mL, and the limit of detection was 0.01 ng/mL. The recoveries of tap water samples and skim milk were ranged from 93.55% to 118% and 91.25% to 107.32% for the E2 residues with 3 spiked levels of 0.5, 5, and 50 ng/mL, and the relative standard deviations (RSD) were less than 4.82%. Conclusion The proposed method is fast, accurate and sensitive, so as to provide a more effective means for rapid detection of food safety risk factors.