A portable and integrated traveling-wave electroosmosis microfluidic pumping system driven by triboelectric nanogenerator

The lab-on-a-chip system can simultaneously complete the preparation, reaction, separation, and detection of samples on a centi-scale platform by manipulating trace fluids. Traveling-wave electroosmosis (TWEO) technology, with the merit of electric signal-based flexible control over the fluid behavior, can achieve precise driving of fluids, which is an important requirement of the lab-on-a-chip system. However, the peripheral power equipment such as the function generator required for TWEO limits the application in some occasions lacking power supply facilities, due to its large size and high cost. In this paper, we have developed a brand-new portable and integrated TWEO microfluidic pumping system, wherein a front-end module of triboelectric nanogenerator (TENG) is in serial connection with the back-end microfluidic pumping chip, which greatly improves portability and reduces costs. The TENG can output stable four consecutively 90 degrees-phase-shifted alternating current voltage signals in a continuous rotational motion originated by its novel electrode structure. And the four-phase traveling potential waves are applied to four sets of electrode strips alternately distributed in the microchannel, thereby inducing nonlinear electroosmotic slip on the electrode surface, achieving stable pumping of fluids in the microchannel. Compared with traditional fluid-driven methods, this system features high safety for the operator and chip but also realizes the almost instantaneous start, stop, and directional switching in response to a turn on, turn off, and turn in reverse of TENG, respectively. Finally, this system is integrated into a droplet microfluidic chip for the efficient generation of single emulsion droplets. This study presents a promising solution for the miniaturization, integration, and commercialization of lab-on-a-chip system.