Silica-encapsulated DNA tracers for measuring aerosol distribution dynamics in real-world settings

Aerosolized particles play a significant role in human health and environmental risk management. The global importance of aerosol-related hazards, such as the circulation of pathogens and high levels of air pollutants, have led to a surging demand for suitable surrogate tracers to investigate the complex dynamics of airborne particles in real-world scenarios. In this study, we propose a novel approach using silica particles with encapsulated DNA (SPED) as a tracing agent for measuring aerosol distribution indoors. In a series of experiments with a portable setup, SPED were successfully aerosolized, re-captured and quantified using quantitative polymerase chain reaction (qPCR). Position-dependency and ventilation effects within a confined space could be shown in a quantitative fashion achieving detection limits below 0.1 ng particles per m3 of sampled air. In conclusion, SPED show promise for a flexible, cost-effective and low-impact characterization of aerosol dynamics in a wide range of settings. PRACTICAL IMPLICATIONSFor the first time, silica particles with encapsulated DNA were used to characterize a confined indoor space regarding position- and ventilation-dependent effects of aerosol distribution. The method described here introduces SPED as a novel, non-toxic, low-impact, cost-effective and easy-to-use aerosol tracing platform that can be used to examine real-world environments. The mobile setup presented here as a proof of concept shows that SPED can be aerosolized and re-captured, followed by highly sensitive quantitative barcode-specific PCR analysis. The results revealed that this tracing method can detect position-dependent differences in exposure and ventilation effects influencing distribution dynamics. In the future, SPED could be engineered to exhibit custom-designed properties and be employed within a wide range of setups and high-capacity multi-tracing combinations.