Array of 3D permanent micromagnet for immunomagnetic separation

Immunomagnetic separation is the laboratory method used to separate targets from heterogeneous samples. It has been applied to separate or detect target entity existing rarely in the sample solution. In this study, a new type of microfluidic device with a 3D micromagnet array was designed, and it was demonstrated that this microfluidic device could be applied to immunomagnetic separation. As the 3D micromagnet is embedded in the microchannel, the height of the microchannel is extended to several hundred micrometers, and the magnetic field pulling the target can be confined to a limited region within the microchannel. Immunomagnetic separation using a microfluidic device was experimentally confirmed by fluorescence imaging. The capture efficiency was maximally 94.9% in the experimental study using the streptavidin-biotin binding of microbeads of the diameter of 1 µm. As a result, the microfluidic device with micromagnet arrays provides new solution for point-of-care device for immunomagnetic separation.