Planar bio/magnetic bead separator with microfluidic channel

A new micromachined planar bio/magnetic bead separator that can separate magnetic beads from suspended liquid solutions has been realized on a silicon wafer as a bio-sampling component for miniaturized biological detection systems. The requisite magnetic field gradients are generated by an embedded serpentine conductor coil and electromagnet under the bottom of a microfluidic channel, which yields several advantages in design flexibility, compactness, electrical and optical monitoring, and integration feasibility. Applying 10 ≈ 35 mA of DC current, the fabricated device has been successfully tested for magnetic beads separation on the top of the inductive components. The maximum flow rate and fluid velocity in which the DC current can hold the beads without losing them has been also measured. The realized bio/magnetic bead separator can hold the separated beads in the fluid flow whose average velocity is up to 1 mm/s when a 30 mA of DC current is applied. The separated magnetic beads are also easily released when the applied current is removed, achieving the primary purpose of a separator. The test results show that the microfabricated bio/magnetic bead separator has a high potential in biological or biomedical applications, especially in separating or manipulating small amounts of cells, enzymes, or DNA that are marked with magnetic beads