AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Development and Optimization of ATP Bioluminescence Method for Rapid Bioaerosol Quantification
TAEWON HAN, Srishty Subramanian, Gediminas Mainelis, Rutgers, The State University of New Jersey
Abstract Number: 436 Working Group: Health Related Aerosols
Abstract Measurement of Adenosine Tri-Phosphate (ATP) using bioluminescence method has been used in a variety of applications as a good indicator of microbial contamination. We recently explored application of the ATP method to rapidly obtain detailed information on the collection efficiency and losses of liquid-based samplers challenged with actual bioaerosols. However, the previous study did not investigate robustness of the ATP bioluminescence method. Thus, to widen the use of ATP-based bioluminescence in bioaerosol applications, we analyzed the effect of various factors affecting the intensity and consistency of the luminescence signal resulting from ATP reaction with bioaerosols: decay in reagent activity due to storage (e.g., BacTiter-Glo reagent needed to produce luminescence), microorganism culture period, bioaerosol sampling methods (e.g., filtering, liquid-based and electrostatic) and others.
A freshly received BacTiter-Glo reconstituted reagent was subdivided into equal portions and stored in the freezer (at -20°C) from 1 to 14 days. Every day a vial was thawed out, mixed with an ATP standard (10 micro-mol) at 0, 1, 2, 4, and 6 hours after thawing out, and the Relative Luminescence Units (RLU) of the reaction indicative of the total ATP content were measured. The results show that within 1 hour of thawing out the reagent its luminescence intensity decreased on average by 36%. However, the luminescence intensity did not change substantially for 5 hours after that indicting a time window when bioaerosol experiments should be performed. Reagent storage in a freezer for 14 days did not affect the reactions. Our results also show that microorganism species commonly used as test particles in bioaerosol work, such as E. coli, B. subtilis, and P. fluorescens, exhibit an optimum growth period producing strongest bioluminescence signal. Bioaerosol sampling method was also found to affect the intensity of ATP-based bioluminescence reactions, with inertia-based collection usually resulting in weaker bioluminescence signal.