1. Development of Biosensors to Detect Biological Agents in Water Melissa Bui Mentor: Dr. Christopher Choi Agricultural and Biosystems Engineering College of Agriculture and Life Sciences University of Arizona/NASA Space Grant 2007-2008 Statewide Symposium April 19, 2008

2. Presentation Outline The Issue at Hand Benefits of using biosensors Methods Key Findings

3. The Issue at Hand Arizona’s water distribution network is comprised of a grid of pipes Entry points of the grid make it easy for contaminants to pollute the water There is currently no real-time method for detecting contaminants in Arizona’s water supply

4. Benefits of using biosensors Microfluidic device provides a faster method of detecting microbes than current methods (assays) Uses less materials than traditional culture plate method Faster detection  Eliminating the problem before it affects the masses Can be used to prevent bioterrorism

5. Methods E. Coli was the microbe being detected Salt injected in 8.5 m pipe at a flow rate of 0.4 L/m for 10 seconds 1 mL of E. Coli (concentration greater than 10 9 CFU/mL) in 1 L dechlorinated water is injected Samples taken in set time intervals with a fraction collector at downstream end of pipe Samples taken at critical time points were analyzed using biosensor and cell culturing

6. Comparison of optical signals to cell counts and salt tracer data Turbulent flowLaminar flow Jin-Hee Han, PhD Student, University of Arizona

7. E. Coli counts and microfluidic signals Jin-Hee Han, PhD Student, University of Arizona

8. Key Findings Microfluidic signals showed same trends as E. Coli counts and salt tracer data Data from culture counts and sensors signals corresponded after normalizing data Detection limit of biosensor as low as 10 CFU/mL Sensors detected sample concentration in 5 minutes, while culturing samples took at least 2 days

9. Acknowledgements Support provided by: Dr. Christopher Choi, Dr. Jeong-Yool Yoon, Jin-Hee Han, and Dr. Ryan Sinclair Figures courtesy of Jin-Hee Han