Quantitative Chemical Sensing Using Genetically Engineered Bacterial Bioreporters

We present a generic quantitative chemical sensing methodology for assessing the concentration of a target material (TM) in an aqueous solution by using bioluminescent microbial bioreporters as the core sensing elements. Such bioreporters, genetically engineered to respond to the presence of a TM in their microenvironment by emitting bioluminescence, have previously been mostly designed to report the presence or absence of the TM in the sample. We extend this methodology to also assess the TM concentration, by exploiting the dose-dependency of the TM-induced luminescence. To overcome luminescence intensity variations due to bacterial batch differences and the ambient temperature, simultaneous measurements were carried out on sample solutions containing known concentrations of the TM. A “standard ratio” parameter, defined as the ratio between the two measurements, is shown to be independent of the bacterial batch and the temperature, and hence provides the conceptual basis for a generic quantitative chemical sensing methodology. Assessment of 2,4-dinitrotoluene (DNT) concentration in solutions is demonstrated with an accuracy of 2.5% over a wide dynamic range.