Zeng Lin, Chen Xi, Du Jing, Yu Zitong, Zhang Rongrong, Zhang Yi, Yang Hui
Laboratory of Biomedical Microsystems and Nano Devices, Bionic Sensing and Intelligence Center, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 518055 Shenzhen, China.
Center for Medical AI, Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, 518055 Shenzhen, China.
Nanoscale. 2021 Feb 25;13(7):4029-4037. doi: 10.1039/d0nr08383f.
The need for fast and accurate analysis of low-concentration species is ubiquitous nowadays. The separation and purification techniques restrict the highly sensitive detection of low-abundance nanoparticles. On the other hand, the commonly used separation techniques of labeling procedures limit their implementation in various applications. We report a microfluidic system with ultrahigh magnetic field for the label-free separation of nanoscale particles. Using high-permeability alloys and on-chip integrated magnetic micro-pole arrays, the external strong magnetic field can be conducted into the microfluidic device to form a magnetic field of high intensity and gradient, therefore separating particles of nanometer size with high efficiency. An ultrahigh gradient magnetic field greater than 105 T m-1 can be generated in the separation channel. Moreover, a negative magnetophoretic technique to separate nanoparticles is established in this device. Then, the label-free separation of nanoparticles is achieved in this microfluidic system perfused by a ferrofluid with an extremely low concentration (0.01%). A mixture of 0.2 μm and 1 μm particles is used to verify the performance of the device, where the recovery rate of 0.2 μm particles is 88.79%, and the purity reaches 94.72%. Experimental results show that the device can efficiently separate nanoscale particles with ultrahigh resolution, and in future, it may develop into a versatile and robust tool for the separation and purification of the biological samples of nanometer size.
如今，对低浓度物质进行快速准确分析的需求无处不在。分离和纯化技术限制了对低丰度纳米颗粒的高灵敏度检测。另一方面，标记程序常用的分离技术限制了它们在各种应用中的实施。我们报道了一种具有超高磁场的微流控系统，用于纳米级颗粒的无标记分离。利用高磁导率合金和片上集成磁微极阵列，可以将外部强磁场引入微流控装置，形成高强度和高梯度的磁场，从而高效分离纳米尺寸的颗粒。在分离通道中可以产生大于105 T m-1的超高梯度磁场。此外，在该装置中建立了一种用于分离纳米颗粒的负磁泳技术。然后，在由极低浓度（0.01%）的铁磁流体灌注的该微流控系统中实现了纳米颗粒的无标记分离。使用0.2μm和1μm颗粒的混合物来验证该装置的性能，其中0.2μm颗粒的回收率为88.７９%，纯度达到94.72%。实验结果表明，该装置能够以超高分辨率高效分离纳米级颗粒，并且在未来，它可能发展成为一种用于分离和纯化纳米尺寸生物样品的通用且强大的工具。
