TRANSDUCTION IN MICROBIAL BIOSENSORS USING MULTIPLEXED BIOLUMINESCENCE

The enormous diversity of genetic responses in living microbes to thei r environment is an attractive resource on which to base biosensor des igns. In particular, there is much interest in microbial sensors for e nvironmental monitoring where toxicity can be ascertained directly by its action on cellular physiology. However, due to the complexities of living systems, the utility of genetic-based microbial sensors has be en limited by the ability to accurately transduce the activities of sp ecific genetic sensing systems into readily measurable signals. We pre sent here a strategy for employing an additional signal in the sensor design, to provide an internal baseline control upon which to reliably interpret sensor responses. The strategy relies on using beetle lucif erases capable of emitting optical signals of different wavelengths; t he optical signals are a sensitive real-time indicator of genetic acti vity within the cells. The different wavelengths allow both a target a nd control signal to be incorporated into each cell, providing a means of differentiating between specific effects of a genetic sensing syst em and other non-specific interfering influences.