Team:METU Turkey/Project

The Project

Light controlled heavy metal carrying E. coli machine

Heavy metals are natural components of the Earth's crust. They cannot be degraded or destroyed. To a small extent they enter our bodies via food, drinking water and air. As trace elements, some heavy metals (e.g. copper, selenium, zinc) are essential to maintain the metabolism of the human body. However, at higher concentrations they can lead to poisoning. Heavy metal poisoning could result, for instance, from drinking-water contamination (e.g. lead pipes), high ambient air concentrations near emission sources, or intake via the food chain.

We designed a E.coli machine to control heavy metal concentration in water by using phototaxis induced tunable carrying system on E.coli membrane. In our system, there are two light sources. One of them is for the metal source and another is for the destination to where we want to carry metal atoms. And our machines have phototaxis ability. In addition to this, they have metal binding domain in outer surface and bacteriorhodopsin. When we open light at the metal source, they start to move toward source and catch the metal atoms. Then we open the light at the destination while closing the light at the source. So our machines move toward the destination. After the arrival our machines will be exposed to light with specific wavelength to activate bacteriorhodopsin leading to small local pH changing at the outer surface. This pH changing causes the release of metal atoms from the metal binding domain. Eventually, system starts from the beginning and so on.

As a result we will make E.coli cells act as trucks that carry metal ions on our medium from the metal uptake location to the release locations and also the path are illumintated by lights at specific wavelenghts.