A Minimized Valveless Electromagnetic Micropump for Microfluidic Actuation on Organ Chips

In recent years, organ chips have become an ideal alternative for physiological and pathological studies as well as drug screening. To more realistically simulate the in vivo physiological environment, micropumps are often needed as power sources to achieve dynamic culture in organ chips. In this study, we present a valveless electromagnetic micropump that can be used in organ chips. Fluid flow is actuated by the vibration of a PDMS membrane through a varying magnetic field. This micropump uses a nozzle/diffuser structure instead of valves, which simplifies the structure. By reducing the volume of the coil and magnet, the size of the electromagnetic micropump is minimized so that it can be integrated on a microfluidic chip. The micropump and the chip can be portably packaged by using a small signal generation module and a dry battery to supply the coil with a square wave, reducing the dependence on external devices. In addition, multiple electromagnetic micropumps can be integrated on a single chip. These micropumps can be connected in series or in parallel, which can achieve complicated flow conditions and can simulate physiological fluid flow more realistically in different types of organ chips. The flow rate was measured to characterize the actuating performance of the micropump. We established the dynamic coculture of a liver and breast cancer model on the chip, with medium actuated by the electromagnetic micropump. Cell viability, albumin and IL-6 were analyzed. The results indicated that dynamic coculture, which was actuated by the electromagnetic micropump, was beneficial for cell growth and function compared with the static control group. (C) 2019 Elsevier B.V. All rights reserved.