Dry Aerosol Deposition Device (DADD): An Instrument for Depositing Microbial Aerosols onto Surfaces (PREPRINT)

摘要

Contamination of infrastructure and equipment with biowarfare agents has led to the development of antimicrobial surfaces/coatings that are designed to 'self-sterilize'. Surfaces will likely be contaminated via an aerosol exposure and thus antimicrobial efficacy measurements should also be performed using biological aerosols. Standard tests that use microbial agents suspended in aqueous buffers may provide misleading results that overestimate the performance of the surface. A settling chamber is the most common instrument for applying biological aerosols to surfaces. However, settling chambers have some drawbacks that make them undesirable for all applications (i.e., slow loading times, large footprint, variable loading, etc.). We developed a Dry Aerosol Deposition Device (DADD) that uses impaction rather than settling for loading surfaces with biological aerosols. The use of impaction allows for rapid and highly reproducible loading of microorganisms onto surfaces. We demonstrated that the DADD can deliver both Bacillus atrophaeus spores and Staphylococcus aureus vegetative cells to glass coupons at concentrations exceeding 1x10,000 CFU/sq cm. The coefficient of variation (CV) for sample-to- sample loading within an experiment was 13.6% for spores and 6.1% for S. aureus cells.