Whole Cell Biosensing of Bacterial Chemotaxis

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DESCRIPTION (provided by applicant): The U.S. faces an enormous task in cleaning up hazardous wastes. Bioremediation via wild-type (Wt) and genetically engineered microorganisms (GEMs) has the potential of completely degrading waste material with little or no toxic byproducts. Bacterial adhesion and movement towards contaminants (termed "Chemotaxis") are two important factors that may affect the role of bacteria in the biodegradation of pollutants. However, the fundamental mechanisms governing these factors for wild type (Wt) and genetically engineered microorganisms (GEMs) are still poorly understood and have not been well defined because of the inability to measure basic physico-chemical properties of bacterial chemotaxic behaviors in the presence of chemoattractants. In this project, we propose to develop a whole cell biosensing system to measure chemotaxic behaviors of bacteria in real-time based on a novel design of dual mode electric impedance measurements. The specific aims are: 1) integrated whole cell biochip design and microfabrication that is capable of measuring electric impedance (ECIS) and acoustic impedance (AIA) responses; 2) real-time and simultaneous measurement of adhesion and chemotaxic behaviors of Wt and genetically engineered Pseudomonas putida KT 2440 on the integrated microfabricated working electrode; measurements of morphological (by ECIS), viscoelastic (by AIA), and velocity (by time-lapse video microscopy) properties of Wt and the GEM. 3) comparison of the proposed whole cell biosensing system with currently available chemotaxis detection techniques in terms of sensitivity and versatility; 4) quantification of the chemotaxic behaviors of Wt and GEM (alteration of various chemotaxis genes) in the presence of various chemotaxic substances, and comparison of parameter responses by analysis of the proposed biosensing system; 5) enhancement of the Biological Engineering program at Utah State by addressing the goals of the NIH AREA grant program.