A handheld, wide-range pressure pump for portable microfluidic applications

Pumping is an indispensable operation in microfluidic applications. Numerous simple pumps have been developed to improve the portability of microfluidic systems, but they generally have poor controllability, short duration working time, and narrow pressure range, which compromises the functionality of portable microdevices. To address these limitations, we present a novel handheld, wide-range pressure pump that utilizes a disposable mini gas cylinder as a pressure source and a porous PDMS film as a flow-rate regulator. Specifically, by incorporating a set of parallel porous PDMS films with varying porosity, sectional area, and thickness into the pump system, and selectively switching between the branch flow circuits containing these porous PDMS films, we are able to finely regulate the flow rate of air released from the mini gas cylinder. This capability enables precise control of the pumping pressure applied to microfluidic devices over a wide range, thereby governing the fluid flow rate to accommodate different applications. The compact and lightweight nature of our pressure source renders this pump system particularly advantageous for field-portable microfluidic applications. Additionally, we demonstrate its capabilities through the performance of well-established microfluidic experiments, including concentration gradient generation and emulsion droplet production. We firmly believe that the compactness, operational simplicity, and disposability of our pump will greatly facilitate the widespread adoption of microfluidic technologies, particularly in point-of-care diagnostics and resource-limited settings.