Next Generation Biological Surrogate Particles to Test Aerosol Dispersion

Project Overview

DNA tagged reagents for aerosol experiments (DNATrax) are harmless biological aerosol simulant materials designed to mimic bacterial spores. The original DNATrax, which uses a food-safe sugar (maltodextrin) as the carrier for short synthetic DNA oligomers, has been implemented to study the spread of biological agents in both indoor and urban environments through aerosol studies sponsored externally. However, key fundamental scientific and practical challenges still exist for applying DNATrax to new application spaces, thus, our approach towards formulating the next generations of DNATrax. This feasibility study focused on developing low-solubility particles for use in very humid/wet environments and a liquid version of DNATrax to emulate respiratory aerosols.

Using a specific form of non-naturally derived, yet safe polymer, we developed a formulation of particles that are at least 5000x less soluble than the current maltodextrin particles in the same 1-5 micron-scale size range. These robust particles can be synthesized in bulk both with and without the DNA barcode. We demonstrated the feasibility of aerosolizing and subsequently detecting the DNA barcode by polymerase chain reaction (PCR) analysis. It is important to note that this new formulation did not alter the detection method.

To mimic respiratory aerosols, we found two types of aqueous, safe surfactant mixtures that can be used with our already established analysis techniques. Liquid particles were successfully aerosolized and collected using two different matrices. PCR analysis confirmed that our unique DNA barcodes were detected in the aerosolized liquid particles. Collectively, these significant results will help enable future opportunities for these next generation DNAtrax particles to be used for aerosol studies in densely humid and inclement outdoor climates, as well as for emulating the spread of infectious liquid-droplet respiratory aerosols.

Mission Impact

This work is highly relevant to the Lab's Bio-Resilience Mission Focus Area and the Bioscience and Bioengineering Core Competency. Developing robust biological surrogates for use in experimental studies and model validations in real-world environments will help better inform how we can mitigate the health impacts of current and emerging threats, thus, improving current bio-resilience efforts.