Handheld, Biomimetic, Phase-Change Microsystems for Breath Condensate-Based Point-of-Use Diagnostic Assays

Herein, we report on a novel, biomimetic [Stenocara gracilipes (Namib desert beetle)]-based microsystem, for collecting exhaled breath for use in point-of-care (POC) settings. The overall platform consists of a $50\times 50$ mm 3-D printed microchamber, which is decorated with a polydimethylsiloxane (PDMS) micromolded breath condensate collection chip (BCCC) emulating the morphology of a beetle. The microchamber and BCCC are further treated with superhydrophobic coatings and oil infusion for enhancement in condensate collection and flow. Breath trials were conducted to determine optimum biomimetic design, conditions for ease of use, and efficient collection resulting in a maximum of ~82- $\mu $ L breath condensate recorded in 30 s. Breath condensate can be further analyzed for potential viruses or biomarkers with our established wireless, microfluidic, imaging platform. This microsystem exhibits the potential to be adapted to a variety of different point-of-use (POU) assays: agglutination, colorimetric, and bead-based. Furthermore, this diagnostic platform can be utilized to screen for a multitude of viruses/biomarkers present in exhaled breath.