Department of Electrical and Computer Engineering, Tufts University, Medford, MA 02155, USA.
Nanotechnology. 2011 Feb 25;22(8):085501. doi: 10.1088/0957-4484/22/8/085501. Epub 2011 Jan 17.
A novel multiplexed sensing scheme based on the measurement of the magnetic susceptibility of the affinity captured target molecules on magnetic nanoparticles in liquid suspension is proposed. The AC magnetic susceptibility provides a measurement of Brownian relaxation behavior of biomolecules bound to magnetic nanoparticles (MNPs) that is related to its hydrodynamic size. A room temperature, compact AC susceptometer is designed and developed to measure complex AC magnetic susceptibility of such magnetic nanoparticles. The AC susceptometer exhibits high sensitivity in magnetic fields as low as 10 µT for 1 mg ml(-1) concentration and 5 µl volume, and is fully software programmable. The capability of biological sensing using the proposed scheme has been demonstrated in proof of principle using the binding of biotinylated horseradish peroxidase (HRP) to streptavidin-coated MNPs. The proposed technique and instrument are readily compatible with lab-on-chip applications for point-of-care medical applications.
提出了一种基于测量悬浮在液体中的磁性纳米粒子上亲和捕获目标分子的磁化率的新型多重传感方案。交流磁化率提供了与结合到磁性纳米粒子 (MNP) 的生物分子的流体动力尺寸相关的布朗松弛行为的测量。设计并开发了一种室温紧凑型交流磁化率计，用于测量此类磁性纳米粒子的复杂交流磁化率。交流磁化率计在低至 10 µT 的磁场中具有很高的灵敏度，对于 1 mg ml(-1)浓度和 5 µl 体积，且完全可编程。使用所提出的方案进行生物传感的能力已通过生物素化辣根过氧化物酶 (HRP) 与链霉亲和素涂覆的 MNP 的结合进行了原理验证。所提出的技术和仪器与用于即时医疗应用的芯片实验室应用非常兼容。
