Design and Development of a High-Throughput Multipattern Aerosol Deposition Device for Respiratory Toxicity and Health-Risk Assessment (MARTHA)

In vitro toxicity assessments of aerosols are often limited by their physiological relevance. Conventional aerosol exposure systems provide uniform particle deposition, whereas in vivo deposition is inherently heterogeneous across lung regions. To address this, we have developed a high-throughput Multipattern Aerosol deposition device for Respiratory Toxicity and Health-risk Assessment (MARTHA). MARTHA employs laminar-flow, water-based condensation technology to efficiently grow nanoparticles from as small as 5 nm to > 3 μm while maintaining physiological conditions in the lungs (37 °C, ≥95% humidity). A key innovation is its ability to generate both uniform and non-uniform deposition patterns using three distinct nozzle configurations (3-jets, slit, and 7-jets). Deposition validation using aerosolized sodium fluorescein demonstrated consistent particle dose distribution across nozzle types, with a low coefficient of variation (CoV <15%) among wells. Experimental results demonstrated that MARTHA achieved high collection efficiency (>95%) for particle number concentrations ranging from 2000 to 200,000 #/cm3 and enabled simultaneous exposure of cells at the air-liquid interface (ALI) in 12 Transwell inserts. As proof-of-concept functional validation of the platform, exposure of aerosolized e-liquid to A549 cells at the ALI resulted in significant differences in trans-epithelial electrical resistance (TEER), underscoring the impact of deposition patterns. Overall, MARTHA is an advanced in vitro platform that more realistically mimics pulmonary aerosol deposition than existing systems and enables high-throughput, pattern-controlled ALI exposure studies.