禽流感病毒快速检测中的纳米磁珠分离器设计及试验

为实现禽流感病毒快速检测中的纳米级免疫磁珠分离,该文设计了一种便携式环形六孔纳米磁珠分离器,通过瓦型钕铁硼永磁体的合理布局,采用高导磁率的坡莫合金制作导磁片并贴合离心试管外壁锥度,实现了满足试验要求的6个局部强磁场区域,实测分离器分离空间磁感应强度达1166.2 mT,最大磁场梯度达152.7 T/m。为考核磁分离器分离效率,分别开展了多点磁感应强度测量、磁珠分离效率初步观察、透射电镜辅助观察等定性试验,并从定性和定量角度分别采用灭活的禽流感H5N1病毒和大肠杆菌E.coli O157:H7,结合Dot-ELISA和平板菌落计数方法进行了30、100和180 nm磁珠分离效率考核试验。试验结果表明:对于30、100和180 nm磁珠,当分离时间分别大于等于60min、60和40s时,磁珠分离器对3种磁珠捕获效率均在96.5%以上,分离上清液中均无残留磁珠,磁分离系统稳定可靠。

Design and experiment of magnetic nanobead separator for rapid detection of avian influenza virus

Abstract: An impedance immunosensor was developed recently for the rapid detection of a H5 subtype avian influenza virus (AIV). The important step was to have a magnetic nanobead separator (MNS) to separate and concentrate the streptavidin-coated magnetic nanobeads which were captured with the avian influenza virus H5N1. This paper describes a compact and portable magnetic nanobead separator designed for the rapid detection of an avian influenza virus and the series of experiments for confirming the separation efficiency. These ideas came from several tries of different MNS separator designs and experiments. There were six separation holes constructed by tile-shaped NdFeBs in this MNS. It was built up of a cylinder shell with 6 cylinder containers, pairs of tile-shaped magnets, a piece of metal magnetizer, and 6 separation holes. The design was aided by Pro/Engineer software to simulate and analyze. From the measurements, the maximum magnetic induction intensity of each separation area (hole) reached 1166.2mT and its maximum grads reached 152.7T/m. Also, the ingenious configuration of MNS could be suitable for other requirements by minor amendment. The experiments on separating H5N1 virus and E. coli O157:H7 were conducted to confirm the separation efficiency of the MNS with the nanobeads in different sizes. The results showed that the MNS could separate 30, 100, and 180nm nanobeads entirely, while the separation duration was no less than 60min, 60, and 40s respectively, and the separation efficiency was higher than 96.5% under the controlled experimental condition, without any residual bead in supernatant liquid. The experiments for separation efficiency of the MNS included: a multi-point magnetic induction intensity measurement, a preliminary separation observation, a transmission electron microscope observation, a Dot-ELISA experiment, and an enumeration by a plate count experiment. All the repeatable experimental data showed that the MNS system was stable and efficient. The relative standard deviation (RSD) of the magnetic induction intensity measurement was around 3%.