A low-energy-consumption electroactive valveless hydrogel micropump for long-term biomedical applications

Stimuli-responsive hydrogels have attracted considerable interest in the field of microfluidics due to their ability to transform electrical energy directly into mechanical work through swelling, bending, and other deformations. In particular, electroactive hydrogels hold great promise for biomedical micropumping applications such as implantable drug delivery systems. In such applications, energy consumption rate and durability are key properties. Here, we developed a valveless micropump system that utilizes a hydrogel as the main actuator, and tested its performance over 6 months of continuous operation. The proposed micropump system, powered by a single 1.5 V commercial battery, expended very little energy (less than 750 μWs per stroke) while pumping 0.9 wt% saline solution under a low voltage (less than 1 V), and remained fully functional after 6 months. CFD simulations were conducted to improve the microchannel geometry so as to minimize the backflow caused by the valveless mechanism of the system. Based on the simulation results, an asymmetric geometry and a stop post were introduced to enhance the pumping performance. To demonstrate the feasibility of the proposed system as a drug delivery pump, an anti-cancer drug (adriamycin) was perfused to human breast cancer cells (MCF-7) using the pump. The present study showed that the proposed system can operate continuously for long periods with low energy consumption, powered by a single 1.5 V battery, making it a promising candidate for an implantable drug delivery system.