School of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland.
Sci Rep. 2020 Jul 30;10(1):12876. doi: 10.1038/s41598-020-69757-7.
Micromagnetic arrays (MMAs) have proven to be powerful tools for controlling the transport and separation of bioanalytes, i.e., they allow bioanalyte-superparamagnetic (SPM) bead complexes of specific size and magnetization to be moved in a synchronized manner that is precisely controlled with the orientation of an external magnetic field. This article presents a laser-photodetector system for the simple detection of individual SPM beads moving on a specific region of an MMA. This system detects the SPM beads through the change in intensity of reflective light as they move from the highly reflective micromagnetics to the supporting substrate. We demonstrate that this opti-MMA system allowed the size, number, and magnetic and optical properties of the SPM beads to be rapidly determined for regions > 49 µm in size. The response of the opti-MMA system was characterized in several optical configurations to develop a theoretical description of its sensitivity and dynamic range. The speed, low-cost, and sensitivity of this system promises to allow MMAs to be readily applied in in vitro diagnostics and biosensing.
微磁体阵列 (MMAs) 已被证明是控制生物分析物输运和分离的强大工具，即它们允许具有特定大小和磁化强度的生物分析物-超顺磁 (SPM) 珠复合物以与外部磁场方向精确控制的同步方式移动。本文介绍了一种用于简单检测 MMA 上特定区域上单个 SPM 珠的激光光电探测器系统。该系统通过 SPM 珠从高反射微磁体移动到支撑基底时反射光强度的变化来检测 SPM 珠。我们证明，该 opti-MMA 系统允许快速确定尺寸 > 49 µm 的区域中 SPM 珠的尺寸、数量以及磁和光学性质。为了开发其灵敏度和动态范围的理论描述，对 opti-MMA 系统的几种光学配置进行了响应特性表征。该系统的速度、低成本和灵敏度有望使 MMAs 能够在体外诊断和生物传感中得到广泛应用。
