Detection of airborne bacteria with disposable bio-precipitator and NanoGene assay

Abstract

We demonstrated the detection of airborne bacteria by a disposable bio-precipitator and NanoGene assay combination. The bio-precipitator employed micro corona discharge at 1960 V and at less than 35 mu A to simultaneously charge, capture and lyse the airborne bacteria. This was enabled by the use of a 15 mu L. liquid anode. Using a custom exposure setup, the target bacterium Bacillus subtilis in the atomization solution was rendered airborne. After exposure, the liquid anode in the bio-precipitator was subsequently measured for DNA concentration and analyzed with the NanoGene assay. As the bacterial concentration increased from 0.0104 to 42.6 g-DCW/L the released DNA concentration in the liquid anode increased from 2.10 +/- 1.57 to 75.00 +/- 7.15 ng/mu L. More importantly, the NanoGene assay showed an increase in normalized fluorescence (gene quantification) from 18.03 +/- 1.18 to 49.71 +/- 1.82 as the bacterial concentrations increased from 0.0104 to 42.6 g-DCW/L. the electrical power consumption of the bioprecipitator was shown to be amenable for portable use. In addition, the detection limit of bio-precipitator and NanoGene assay combination in the context of environmentally relevant levels of airborne bacteria was also discussed. (C) 2016 Elsevier B.V. All rights reserved.