Bacteria sensors for gene induction and coupled to optic fibers for sensitive detection

Water quality is one of the most important factors in preserving good health in any community. For that reason, care needs to be taken for monitoring of potential contaminants in water supplies. Not surprisingly, the infrastructure required to control water quality represents a worldwide investment of billions of dollars every year. Water contamination can occur in many ways, but can generally be classified as either biological, pertaining to infectious agents or chemical, pertaining to toxic compounds. Many contaminant detection methods exist, some very sensitive and accurate, others less so, but most of these require some level of expertise, specialized laboratories and time to perform the tests. Ideally, detection technologies should be portable, easy to use and widely accessible. Our multidisciplinary team is currently developing a detection platform based on an optical fiber sensor which has proven very efficient in detecting bacteria. Building on this success, we intend to radically increase the applicability of the platform with a new approach. This approach will integrate bacterial metabolism into the sensor components. In this approach, we will exploit the natural chemical detection capacity of bacteria by genetically engineering strains to signal when chemical contaminants reach dangerous levels. Contaminant detection will be accomplished by linking bacterial chemical sensing systems to green fluorescent protein (GFP) production. GFP fluorescence will provide the signal for the optical fiber sensor. "Bacteria sensors" capable of detecting contaminants such as lead, arsenic, cadmium and antibiotics will be developed. By approaching water quality analysis using both photonics and biotechnology we plan to optimize our optical fiber sensor platform for contaminant detection.

Our ability to use genetic engineering and knowledge on different types of gene regulation in bacteria can thus open the way to an approach that relies on the capability of bacteria to react to their environment in order to use them in a detection system. In parallel, the same expertise and the same genetic tools can be used to develop a system of induction in bacteria. Such an inducible system can thus be designed for the efficient production of useful proteins. The optimization of this gene control to have as good a modulation as possible will be done similarly for the development of a sensitive detection system.