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Concentrating Bacterial Spores from Milk and Juices using Dielectrophoresis-Based Microfluidic Capture Systems

Award No.: 
Principal Investigator: 
Suresh Pillai
PI Organization: 
Texas A & M University
A microscale prototype device that can be ultimately scaled up for concentrating bacterial spores from large volumes of milk and apple juice is developed. Dielectrophoresis (DEP) is utilized to concentrate Clostridium sporogenes as surrogates of Bacillus anthracis and Clostridium botulinum spores from suspending medium in a microfabricated channel. Effectiveness of the DEP as functions of the applied electric field frequency and amplitude, and the conductivity of the ionic solution is validated both experimentally and theoretically. First set of experiments are conducted utilizing interdigitated electrode geometry that amplify positive DEP. Experimental results are correlated with the theory using a scaling analysis that considered the relative magnitudes of dielectrophoresis, electrophoresis, ACelectroosmosis, gravity and Brownian motion. Using simple electrode designs that amplify the negative DEP effectively, DEP is successfully utilized for concentrating spores from milk and apple juice. The prototype device allows fast and effective concentration of biological species in high conductivity media. (Revised 2007)
Analytic Methods Utilized: