AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
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A Microfluidic Inertial Aerosol Sampler for Continuous, Efficient Collection and near Real-Time Detection of Bioaerosols
LEAH CAROL, Andrea Timm, Ronald Jacak, Christopher Stiles, Brian Damit, Johns Hopkins University Applied Physics Laboratory
Abstract Number: 878 Working Group: Bioaerosols
Abstract Infectious bioaerosols pose a significant health threat. As transmission risks are better understood technologies for detection must advance by increasing collection efficiency and limit of detection. Existing aerosol sampling technologies require pre-analysis processing (not real-time) and use large volumes (mL). Among emerging sampling technologies are microfluidic systems, which can continuously operate, combine with approaches for rapid detection, and produce enriched samples due to low liquid-to-aerosol volume ratios (≤µL). Additionally, they offer low production and operating costs. In this study, we describe redesign of the MicroSampler (Choi et al., ACS Sensors), a microfluidic inertial aerosol sampler, for the purpose of viral aerosol collection. Two-phase stratified flow (sampling air and collection liquid) and inertial deposition provide efficient aerosol collection. As aerosols traverse the curved region of the sampler, centrifugal and drag forces result in the transfer of aerosols from sampling air to collection liquid. Physical collection efficiency (CE) was determined using salt particles (0.5-2 µm diameter) and an aerodynamic particle sizer, which measured particle concentration upstream and downstream of the sampler. CE for the MicroSampler-based design and two alternative designs were examined. For equivalent air and liquid flow rates, the MicroSampler-based design and alternative designs outperformed the MicroSampler – CE>99% for all particle sizes vs. CE>98% for particles ≥ 2 µm, respectively. In addition to experiments, modeling of the air-liquid interface was performed using COMSOL Multiphysics package. Initial models provided validation of the conditions required for stability of two-phase flow and the geometry observed at the water interface. Experimental results indicate the microfluidic sampler provides a cost-effective solution for continuous, efficient aerosol sampling, and, combined with suitable detection reagents, could offer near real-time detection of aerosolized pathogens.