A microfluidic suction pump using a super absorbent polymer*

We propose a portable, non-powered suction pump driven by hydrogel for microfluidic devices. The development of portable microfluidic devices has often been limited by the need for external pumps. We have developed a microfluidic suction pump by enclosing a super absorbent polymer in a housing with an extended surface area for water absorption. The pump has a remarkably high flow rate of ~100 μl/min and an absorption volume of ~15 ml, thus far superior to the previously reported non-powered pumps. We constructed a portable energy harvesting system by combining the hydrogel pump with a reverse electrodialysis (RED) device. This portable system, powered by saltwater only, has successfully delivered enough power to operate small LEDs by generating an output density of ~ 100 μW / cm² for an hour. Our hydrogel pump would make a breakthrough in developing portable microfluidic systems.