Developing bioaerosol samplers for indoor air quality control requires overcoming key challenges, including efficient particle collection, accurate size-based sorting, preservation of pathogen viability, and real-time microbiological analysis. Current samplers are often costly, lack portability, and perform poorly in size-resolved bioaerosol collection. Moreover, they frequently compromise pathogen viability during sampling, limiting their utility in applications requiring detailed characterization of airborne pathogens. In this study, we present a modular microfluidic platform capable of sorting particles in the 0.3–20 μm range—covering the typical sizes of environmental bioaerosols that carry viruses, bacteria, and fungi. The system integrates Spiral Inertial Focusing (SIF) to preconcentrate samples by removing the continuous liquid phase, thereby enriching pathogen concentration above detection thresholds and enhancing analytical sensitivity. This step is critical for detecting pathogens present at low concentrations that might otherwise remain undetected. Following preconcentration, the sample passes through an array of Deterministic Lateral Displacement (DLD) microchannels, which use micropillar arrays to physically sort particles into 16 distinct size bins while maintaining pathogen viability. This size-resolved sorting capability enables high-resolution pathogen load measurements and is compatible with downstream assays such as qPCR for species-level identification. Overall, this platform offers a powerful new approach to studying airborne disease transmission and improving risk assessment in indoor environments.
