Ultrahigh Resolution On-Chip Separation System Using Negative Magnetophoresis

A high-resolution magnetic separation microfluidic system used for the negative magnetophoretic separation of nanoparticles is presented in this paper. The chip can generate an ultrahigh gradient magnetic field greater than 10
⁵
T/m in the separation channel by integrating two on-chip magnetic pole arrays. A label-free separation of nanoparticle is achieved by this microfluidic system with a mixed sample of 0.2 µm and 1 µm polystyrene particles, where the recovery rate of 0.2 µm particles is 91.20%, and the purity reaches 94.72%. The experimental results show that the chip can efficiently separate nano-scale particles with ultrahigh resolution, and in future, it may develop into a versatile and robust tool for the separation and purification of nano-biological samples.