title: A simple novel device for air sampling by electrokinetic capture.
abstract: BACKGROUND
  A variety of different sampling devices are currently available to acquire air samples for the study of the microbiome of the air. All have a degree of technical complexity that limits deployment. Here, we evaluate the use of a novel device, which has no technical complexity and is easily deployable.
  
  
  RESULTS
  An air-cleaning device powered by electrokinetic propulsion has been adapted to provide a universal method for collecting samples of the aerobiome. Plasma-induced charge in aerosol particles causes propulsion to and capture on a counter-electrode. The flow of ions creates net bulk airflow, with no moving parts. A device and electrode assembly have been re-designed from air-cleaning technology to provide an average air flow of 120 lpm. This compares favorably with current air sampling devices based on physical air pumping. Capture efficiency was determined by comparison with a 0.4 μm polycarbonate reference filter, using fluorescent latex particles in a controlled environment chamber. Performance was compared with the same reference filter method in field studies in three different environments. For 23 common fungal species by quantitative polymerase chain reaction (qPCR), there was 100 % sensitivity and apparent specificity of 87 %, with the reference filter taken as "gold standard." Further, bacterial analysis of 16S RNA by amplicon sequencing showed equivalent community structure captured by the electrokinetic device and the reference filter. Unlike other current air sampling methods, capture of particles is determined by charge and so is not controlled by particle mass. We analyzed particle sizes captured from air, without regard to specific analyte by atomic force microscopy: particles at least as low as 100 nM could be captured from ambient air.
  
  
  CONCLUSIONS
  This work introduces a very simple plug-and-play device that can sample air at a high-volume flow rate with no moving parts and collect particles down to the sub-micron range. The performance of the device is substantially equivalent to capture by pumping through a filter for microbiome analysis by quantitative PCR and amplicon sequencing.
authors.affiliation: Inspirotec LLC, 3307 Meadow Lane, Glenview, IL, 60025, USA. jgordon@inspirotec.com.
authors.forename: Julian
authors.initials: J
authors.lastname: Gordon
authors.affiliation: Inspirotec LLC, 3307 Meadow Lane, Glenview, IL, 60025, USA. pgandhi@inspirotec.com.
authors.forename: Prasanthi
authors.initials: P
authors.lastname: Gandhi
authors.affiliation: Department of Materials Science and Engineering, McCormick School of Engineering and Applied Science, Northwestern University, 2220 Campus Drive, #2036, Evanston, IL, 60208, USA. g-shekhawat@northwestern.edu.
authors.forename: Gajendra
authors.initials: G
authors.lastname: Shekhawat
authors.affiliation: Genomic and Systems Biology, Bioscience Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439, USA. angel.frazier@gmail.com.
authors.forename: Angel
authors.initials: A
authors.lastname: Frazier
authors.affiliation: Genomic and Systems Biology, Bioscience Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439, USA. jarrad.marcell@gmail.com.
authors.forename: Jarrad
authors.initials: J
authors.lastname: Hampton-Marcell
authors.affiliation: Genomic and Systems Biology, Bioscience Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, 60439, USA. gilbertjack@gmail.com.|Department of Ecology and Evolution, University of Chicago, 1101 E 57th Street, Chicago, IL, 60637, USA. gilbertjack@gmail.com.|Department of Surgery, University of Chicago, 5841 South Maryland Avenue, MC 5029, Chicago, IL, 60637, USA. gilbertjack@gmail.com.|Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA, 02543, USA. gilbertjack@gmail.com.|College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China. gilbertjack@gmail.com.
authors.forename: Jack A
authors.initials: JA
authors.lastname: Gilbert
mesh_terms: D000336:Aerosols; D000393:Air Pollutants / Q000032:analysis*; D004784:Environmental Monitoring / Q000295:instrumentation*; D004867:Equipment Design; D010316:Particle Size
chemical_list: D000336:Aerosols; D000393:Air Pollutants