On-chip particle sorting into multiple channels by magnetically driven microtools

This paper presents a new type of sorting system by magnetic microtools (MMT) separating particles into multiple channels. Two nickel-based MMTs are activated by commercially available permanent magnets below the biochip to lead particles to certain channels via fluid force. The horizontally assembled permanent magnet drive we developed shows that the MMT positioning accuracy had been improved 5 times in 2 degrees of freedom. The channel and the MMT shape are determined based on FEM analysis to ensure that particles flow smoothly. We have successfully achieved to sort 100 μm diameter microbeads into 7 branched channels. The noncontact drive and disposable chip provide a less invasive environment for the cell with low cost.