Test and evaluation of a new bioaerosol collector in a laboratory setting

Abstract

The aim of the project was to test a personal aerosol sampler based on electrostatic precipitation and electrowetting on dielectric (ESP-EWOD). A bioaerosol chamber trial was conducted to compare ESP-EWOD to two standard bioaerosol collectors (a SKC BioSampler and a 37 mm filter cassette hosting 0.8 μm polycarbonate filters). Three bacteria (Bacillus atrophaeus spores, Pantoea agglomerans, and Escherichia coli) were aerosolized, individually and in a mixture, into an aerosol chamber to introduce bacterial samples into the samplers simultaneously. The samples were collected and eluted for culture, endotoxin and quantitative polymerase chain reaction (qPCR) assays. The semi-quantitative comparison showed that ESP has comparable collection and elution efficiency as the BioSampler and filter cassette for E. coli and P. agglomerans, but reduced elution efficiency with B. atrophaeus spores. Sample concentration with the ESP was 1000x higher for E. coli and P. agglomerans and 33x higher than with the SKC BioSampler for B. atrophaeus spores. This first of a series of planned trials showed that ESP-EWOD is a promising technology for bioaerosol detector system integration. More work should be done to optimize ESP parameters to improve collection and elution efficiency and explore the effects of Tween detergent and different spore preparation methods on the ESP performance. Future test plans include field trials in easily accessible locations with complex environmental background, such as animal barns or wastewater treatment plants, and comparison to other low burden sampling systems would further demonstrate the use of the ESP-EWOD system.