Real application of our device

In this section of the wiki, we present how we consider the design of our device and discuss realistic application. To learn more about the market expectations, we met a safety official of ARKEMA. Here are also some information about mecury toxicity.

Mercury poisoning.

Design of the device.

Meeting with ARKEMA.

Mercury poisoning.

Chemical forms

Mercury is a metal, liquid at room temperature. It easily become odorless and colorless vapor at room temperature. The exposure to mercury vapor can be really harmfull since mercury can easily reach the bloodstream by the lung, causing severe damage to kidney and brain.

Mercury pollution is an issue in air, soil and water. Here we focus on water pollution. Releases of mercury in the environment are mainly caused by the chemical and gold industry.

Mercury exists in water at different oxydation levels, mainly Hg and $Hg^{2+}$

References

• PhD thesis: Faïdjiba LOE-MIE, Développement de sels d'onium chélatants et fluorogéniques pour la détection des ions mercuriques en microsystèmes.
• www.epa.gov/hg/effects.htm

Design and use of Mercuro-Coli device

Design

Our objective is to design a device for the detection and quantification of heavy metal pollution in a given sample. Our final device is intended to sense mercury, but for practical reasons, we mainly work with a harmless molecule as a proof of concept: anhydrotetracyclin. One should notice that most of the elements in the design of our device and genetic network would not change whatever the chemical that we could want to quantify.

The device presented here take into account the information provided by modelling results. The device we conceived is rectangular shape, thin, light and very cheap. It is made of machined polycarbonate. Vertical channels are engraved in the plastic.

Each channel form a specific chemical environnement: they contain distincts concentration of IPTG, such that a gradient is obtained on the whole plate.

A graduation is etched below the channels to read the concentration corresponding to the channel where the red stripe appear. The graduation is not shown on the picture above. Experiments are made at the moment to know how to draw the graduation. Even if we have not all the data needed to get an experimental graduation, our modelling work gave us that answer.

Use: prepare the sample, read the result

Packaging

Collect, then prepare the sample

A preparation phase is needed before the sample can be spread on the plate. It consists of the mercury ionization since the ionic form is generally not found in nature: it is either complexed to others ions or it forms organometallic compounds. This is the reason why mercury is so poisonous: some bacteria metabolize Hg2+ into methyl-mercury, an organic compound eaten by fishes, which ones are subsequently eaten by humans.

Read the result

To use the device we just have to spread poluted water on it and wait for the result. Below is an illustration of how we observe results using the measurement device. One channel become red, the location give us the amount of mercury in the water.

Disposal of the device

The device is disposable. Once the test is performed, autoclave the device to sterilize it.

Meeting at ARKEMA and lab's visits