Nano Research & Applications

Abstract

Controlling the flow of fluids at a high precision has been a technological challenge in microfluidics. There is an increasing need in the market for pumps that can be integrated on lab-on-chips. We report on a design of an integratable, wireless micropump made that from the magnetic shape memory (MSM) alloy Ni-Mn-Ga. The working principle of the MSM pump is based on the magnetic field-induced deformation of Ni-Mn-Ga alloy by a rotating magnetic field [1-3]. The pump is a piece of MSM alloy placed inside a plastic housing with inlet and outlet holes, with an elastic sealing between the MSM material and the housing. The MSM pump can also be placed in a fluid channel of the lab-on-a-chip. When actuated by a rotating magnet, the MSM material shrinks forming a cavity that transports a portion of fluid, similarly to peristaltic pumps. Pumping volume per cycle is largely scalable, from ca. 0.1 to 100 nL, and is dependent on the MSM element size and the magnetic field strength. MSM pump provides highly repeatable and reversible cycling flow thus allowing precise fluid dosing. With a permanent cylindrical magnet connected to a servo motor, we ran the pump at speeds up to hundreds of cycles per second. We demonstrated pumping of high-viscous fluids and pressure up to 10 bar. As an example of high accuracy, we pumped water with a resolution of about 0.2 nL per cycle.