Young Colin C, Blackley Benjamin W, Porter Marc D, Granger Michael C
Department of Chemical Engineering, University of Utah , Salt Lake City, Utah 84112, United States.
Nano Institute of Utah, University of Utah , 36 S. Wasatch Dr., SMBB Rm. 5531, Salt Lake City, Utah 84112, United States.
Anal Chem. 2016 Feb 16;88(4):2015-20. doi: 10.1021/acs.analchem.5b04271. Epub 2016 Jan 26.
In this work, we describe an approach to determine the distance separating a magnetic address from a scanning magnetoresistive sensor, a critical adjustable parameter for certain bioassay analyses where magnetic nanoparticles are used as labels. Our approach is leveraged from the harmonic ratio method (HRM), a method used in the hard drive industry to control the distance separating a magnetoresistive read head from its data platter with nanometer resolution. At the heart of the HRM is an amplitude comparison of a signal's fundamental frequency to that of its harmonics. When the signal is derived from the magnetic field pattern of a periodic array of magnetic addresses, the harmonic ratio contains the information necessary to determine the separation between the address array and the read head. The elegance of the HRM is that there is no need of additional components to the detection platform to determine a separation distance; the streaming "bit signal" contains all the information needed. In this work, we demonstrate that the tenets governing HRM used in the hard drive industry can be applied to the bioanalytical arena where submicrometer to 100 μm separations are required.
在这项工作中，我们描述了一种确定磁地址与扫描磁阻传感器之间距离的方法，对于某些使用磁性纳米颗粒作为标记的生物分析而言，这是一个关键的可调参数。我们的方法借鉴了谐波比率法（HRM），该方法在硬盘行业中用于以纳米分辨率控制磁阻读取头与其数据盘片之间的距离。HRM的核心是信号基频与其谐波频率的幅度比较。当信号源自磁性地址周期性阵列的磁场模式时，谐波比率包含确定地址阵列与读取头之间距离所需的信息。HRM的精妙之处在于，无需在检测平台上添加额外组件来确定分离距离；流动的“位信号”包含所需的所有信息。在这项工作中，我们证明了硬盘行业中使用的HRM原理可应用于需要亚微米至100μm分离距离的生物分析领域。
