Some practical applications of magnetohydrodynamic pumping

Magnetohydrodynamic pumping provides a unique opportunity to mobilize fluids inside a channel using very low power and without employing any external moving parts. In this paper, we illustrate certain unique applications of these pumps such as sample injection, fluid flow in packed bed, and on-chip assay development, all of which are relevant to point-of-care diagnostic device design and fabrication. A linear flow velocity of 5 cm/min was obtained using four on-board pumps in a closed loop of circumferential track length of 10 cm (channel cross section of 0.5 mm × 0.5 mm), whereas it dropped to 1.8 mm/min in a packed bed column operated by a single pump. Finally, these pumps were integrated with silicon immunoassay chips to evaluate the feasibility of transporting electro active species with these pumps from source to electrochemical detection site.