Flux-Biased, Energy-Efficient Electromagnetic Micropumps Utilizing Bistable Magnetic Latching and Energy-Storage Springs

On-platform pumping systems are a potentially critical technology for microphysiological systems (MPS) to control the pressure and flow of growth media. Supporting sufficient physiological tissue quantity in culture requires fluid flow rates on the order of microliters per second, which is larger than for typical microfluidic systems. Thus, a need exists for new types of pumping systems operating in this flow range while maintaining stringent sterility of the culture as well as enabling tight temperature control at ${37}^{\circ } {\rm C}$. Flow rates and pressure also need to be readily computer-controlled, with a manageable set of connections into the culture incubator environment. This article describes a novel mesoscale electromagnetically driven pumping system designed to meet all these requirements. Our design achieves a very low energy dissipation of ${0.65}\,{\rm mJ}$ per switching event, which allows one pumping channel to operate at ${0.45}\,{{\rm {\mu } L} /{\rm s}}$ with an average power dissipation of 1.3 mW and ${0.04}\,{{^\circ } {\rm C}}$ temperature rise in each actuator. The actuator operates in a bistable, teeter-totter configuration with a latching force of ${4.5}\,{\rm N}$, and a relatively large stroke of ${400}\,{{\mu } {\rm m}}$ at the actuator pole face. Preliminary operational pumping test results show the potential of this type of electromagnetic actuator for fluidic pumping. Due to their compact configuration and very high energy efficiency, these pumps can provide the foundation for multichannel, on-platform pumping for MPS platforms, as well as for a range of sterile, temperature-sensitive microflow devices such as portable, battery-operated insulin pumps.