Grenoble 2011, Mercuro-Coli iGEM

Mercuro-Coli: A new way to quantify heavy metals.

Our project aims at constructing an easy to use, transportable sensor capable of quantifying the concentration of mercury, in an aqueous sample.

Our system is based on a comparison between an unknown mercury concentration and a known IPTG concentration. A linear IPTG gradient is present on a test-strip containing the engineered bacteria. When the mercury solution is added, the regulatory network will switch to one of two states depending on the IPTG/mercury ratio.

Bacteria become either “sender” or “receiver”. The bacteria sensing a predominance of mercury over IPTG, the “senders”, will release a quorum sensing molecule which is detected by the nearby “receivers”. The reception of quorum sensing molecules will induce the expression of a red dye in the “receivers”. In this way, a red line emerges at a position in the IPTG gradient from which the unknown mercury concentration can be deduced.