Power efficient self-cleaning hydrophilic condenser surface for portable exhaled breath condensate (EBC) metabolomic sampling

摘要

In this work, we present a hydrophilic self-cleaning condenser surface for collection of biological and environmental aerosol samples. The condenser is installed in a battery-operated, hand-held breath sampling device. The device performance is characterized with collection and analysis of exhaled breath samples from a group of volunteers. The exhaled breath condensate is collected on a sub-cooled condenser surface, transferred into a storage vial, and its chemical content is analyzed with mass spectrometric methods. The engineered surface supports a continuous condensation cycle on it, and this allows collection of liquid samples exceeding the saturation mass/area limit of a plain hydrophilic surface. The condenser surface employs two constituent parameters: a low surface energy barrier to enhance nucleation and condensation efficiency, and a network of surface microstructures to create a self-cleaning mechanism for fluid aggregation into a reservoir. Removal of the liquid condensate from the condenser surface prevents formation of a thick liquid layer, and thus keeps a continuous condensation cycle with a minimum decrease in heat transfer efficiency as condensation occurs on the surface. The self-cleaning condenser surfaces may have a number of applications in collection of biological, chemical, or environmental aerosol samples. Sample phase conversion to liquid can facilitate sample manipulation and chemical analysis of matrices with low concentrations. Here, we demonstrate the use of a self-cleaning microcondenser for collection of exhaled breath condensate with a hand-held portable device. All breath collections with the two devices were performed with the same group of volunteers under UC Davis IRB protocol 63701-3.