Luffa cylindrica-inspired powerless micropump: long-term, high-flow operation and energy-generation application†

Powerless micropumps are in increasing demand for applications requiring portability, simplicity, and long-term operation. However, several existing passive pumps have limitations such as sustained high flow rates and extended operational periods. Inspired by the unique structural characteristics of Luffa cylindrica, this study aims to develop a biomimetic micropump capable of long-term and high-flow operation. By examining the water transport mechanisms in a hierarchical porous structure, we designed and fabricated micropumps that replicate these mechanisms. A key aspect of this design is the integration of flow resistors, which enables precise control over the absorption rates and extend the pumping duration. The cone-shaped agarose aerogel (AAG) micropump operates for over 930 min with an average flow rate of 5.6 μl min⁻¹, demonstrating significant longevity. The agarose superabsorbent polymer aerogel (ASAG) micropump, while having a shorter operational duration of approximately 620 min, exhibited a significantly higher average pumping rate of 13.2 μl min⁻¹. This study highlights the potential of bio-inspired designs for advancing efficient and powerless pumping systems. The proposed micropump shows promise for applications in microfluidic devices and reverse electrodialysis systems, where continuous and sustainable fluid transport is essential.