The increased threat of bio-warfare agents both domestically and abroad has created a critical need for quick and accurate methods of detecting and characterizing airborne biological materials. Methods for the detection and characterization of airborne biological materials such as bacteria, using their DNA or organic composition are fairly well developed [1-9] but do not provide the type of immediate results necessary during an attack. In this study, an inductively coupled plasma mass spectrometer (ICP-MS) will be used for the inorganic chemical characterization of biological materials by direct injection ICP-MS, a method already developed and published by Towson undergraduate students working in the NSF funded Nanotechnology Laboratory and Materials Research Laboratory at Towson (MRLT) (DMR-MRI # 0116619) (Gikunju et al., 2003a and b). ICP-MS has the advantage of sub-nanogram/gram detection limits for most elements making it a sensitive tool for the detection and characterization of aerosolized biological material. Suspended, microgram-sized samples of Bacillus subtilis spores (BG), Bacillus subtilis vegetative cells (Bg) and Bacillus thuringiensis spores (Bt) cultured under different conditions (using intra- and inter- laboratory comparisons) will be analyzed via direct injection and their inorganic chemical signatures will be determined reflecting the processing history of each organism. The development of a unique chemical fingerprint as a means to detect the presence of a bio-warfare agent and potentially distinguish the type of organism, its state (i.e. vegetative vs. spore), and how and/or where it was processed makes for a powerful and precise detection system.

The methods used to detect and characterize the bacterial samples will also be used to study the adhesive forces of biological particles using a laminar flow cell. In a series of experiments, the detachment strength required to remove spores from various substrates will be calculated using both optical image analysis methods and a calibrated instrumental response using the particle detection capabilities of the ICP-MS. Undergraduate students currently working in the MRLT and the Nanotechnology Laboratory have already developed preliminary methods for these flow cell experiments. Undergraduates play a critical role in the Materials Research program at Towson and this proposed REU program would allow us to maximize the impact of our previously funded NSF laboratories. Dr. Gail Gasparich, a molecular biologist in the Towson University Biology department, will provide biological support of this project. She will supervise the cultivation of microbes and processing of cultures used in these experiments.

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