Microfluidics Based Impinger for Air Sampling Available to Purchase

Capturing particles from the air into the liquid is critical for the development of analysis systems for bio-particles such as virus, toxins and spores. We report a miniaturized airborne particle sampling (collection) device that relies on a bubbling process formed in a small chamber where air (to be sampled) is flown through a microchannel array into the liquid in the chamber. The airborne particles trapped in the tiny bubbles (diameter: 80 microns) are diffused into liquid and captured into the liquid and analyzed. The whole device is fabricated on a glass slide using soft-lithography method with Polydimethylsiloxane (PDMS) as the structural material. To prevent the air leakage at the connections, a special sealing process depending on PDMS only without the use of any glue was successfully developed. Hydrophobicity of channel surface was found to be critical for generating continuous and stable bubble lines in the bubbling process. The collection efficiency is measured by collecting polystyrene latex particles (diameter: ∼1 micron) on polycarbonate membrane filters at the inlet and outlet of the device. It was found that a collection efficiency of 90% from the microfluidics based impinger is achieved, which is much higher than that of conventional impinger device. Furthermore, a collection time of 10 minutes is needed for this device compared to a few hours for a conventional impinger.