Technological conception of an optical biosensor with a disposable card for use with bioluminescent bacteria

The detection of pollutants in the environment by chemical, physical or biological methods is a necessary part of European policy and biosensors should play a role in the monitoring of such pollution. A portable optical biosensor, namely Lumisens 2, is described for the on line detection of pollutants. Lumisens 2 features three main parts: (I) a central unit, (II) a disposable card where bacteria are immobilized and inserted into unit 1, and (III) an acquisition unit to control the device. The first card used in this study (TBTcard) included the bioluminescent Escherichia coli strain TBT3 harboring the truncated luxAB genes from Vibrio harveyi. TBT3 specifically detects organotin compounds (tributyltin or dibutyltin).Lumisens 2 was validated according to the on line measurement of bioluminescence with a continuous flow of sample. The biosensor was able to detect 2 μM of TBT on line in 400 min and after a contact time of 1 h with the pollutant, the accumulation effect of the matrix allowed us to detect 1 nM of this toxic biocide.Because any bioluminescent bacteria can be immobilized in the cards, Lumisens 2 could become a multipurpose optical biosensor for the detection of either the overall toxicity of a sample or one particular pollutant.