Giant Magenetoresistive Sensors. 2. Detection of Biorecognition Events at Self-Referencing and Magnetically Tagged Arrays
Giant Magenetoresistive Sensors. 2. Detection of Biorecognition Events at Self-Referencing and Magnetically Tagged Arrays
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DOI：
10.1021/ac800967t
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发表时间：
2008-11-01
影响因子：
7.4
通讯作者：
Granger, Michael C.
中科院分区：
文献类型：
--
作者：
Millen, Rachel L.;Nordling, John;Granger, Michael C.
由厚度为数百纳米的磁性和非磁性材料交替层形成的微加工器件表现出一种称为巨磁阻效应的现象。基于这种效应的器件被称为巨磁阻 (GMR) 传感器。 GMR 的电阻取决于外部磁场的强度，这导致此类平台在高速、高数据密度存储驱动器中得到广泛使用。相同的属性（即灵敏度、小尺寸和速度）也是许多类型的生物分析传感器的重要体现，这表明通过整合 GMR 技术、磁性标记策略和生物识别元件（例如抗体）会带来有趣的机会。本文描述了利用 GMR 检测链霉亲和素包被的磁性颗粒，这些颗粒被 2 x 0.3 cm 样品棒上的生物素化金地址选择性捕获。 GMR 传感器网络以开始模拟“刷卡”系统的方式读取样本棒上的地址。这项研究还利用了样本上的磁性地址，该地址可作为 GMR 响应内部校准的参考，并作为一种简便的方法来解释样本棒和传感器之间间隙的微小变化。检测极限处的磁性颗粒表面覆盖率被确定为类似于 2%，这相当于 200 x 200 μm 捕获地址上的 800 个结合事件。讨论了这些发现，以及链霉亲和素包被的磁性颗粒作为抗原检测的通用标记的潜在用途，例如在异质测定中。
Microfabricated devices formed from alternating layers of magnetic and nonmagnetic materials at combined thicknesses of a few hundred nanometers exhibit a phenomenon known as the giant magnetoresistance effect. Devices based on this effect are known as giant magnetoresistive (GMR) sensors. The resistance of a GMR is dependent on the strength of an external magnetic field, which has resulted in the widespread usage of such platforms in high-speed, high-data density storage drives. The same attributes (i.e., sensitivity, small size, and speed) are also important embodiments of many types of bioanalytical sensors, pointing to an intriguing opportunity via an integration of GMR technology, magnetic labeling strategies, and biorecognition elements (e.g., antibodies). This paper describes the utilization of GMRs for the detection of streptavidin-coated magnetic particles that are selectively captured by biotinylated gold addresses on a 2 x 0.3 cm sample stick. A GMR sensor network reads the addresses on a sample stick in a manner that begins to emulate that of a "card-swipe" system. This study also takes advantage of on-sample magnetic addresses that function as references for internal calibration of the GMR response and as a facile means to account for small variations in the gap between the sample stick and sensor. The magnetic particle surface coverage at the limit of detection was determined to be similar to 2%, which corresponds to similar to 800 binding events over the 200 x 200 mu m capture address. These findings, along with the potential use of streptavidin-coated magnetic particles as a universal label for antigen detection in, for example, heterogeneous assays, are discussed.