Students create Frankenstein's monster of bacteria to detect toxic chemicals
While the E.coli bacteria are more commonly associated with deadly outbreaks, a student team from Technion – Israel Institute of Technology – has come up with a way to harness them for good by using them in a chip to test for toxic substances. Their solution, called the Flash Lab, won them the gold medal at this year's iGEM synthetic biology competition held at MIT.
Like a lot of other bacteria, E. coli have whiplike appendages that enable them to move around in liquid environments. More specifically, the cells are able to swim toward substances they like, such as amino acids and sugars, and flee from those they don't. This chemical reaction is called chemotaxis. Now, imagine if the bacteria could react to toxic substances in our surroundings. This is the basis of the Technion team's product.
In nature, the bacteria make use of receptor proteins called chemoreceptors to sense their surroundings. The problem is that they have only a limited variety of such receptors, which means there aren't many substances they can detect. To get around this problem, the Technion team did two things:
1) They built a chimera receptor by combining half the E. coli protein with the genes of another bug, in this case Pseudomonas, which can detect the desired stimulants.
2) They created a receptor from scratch using a computational bioinformatics software suite called the Rosetta. This allows them to control the movement of the bacteria and detect drugs or compounds, such as antihistamines, that conventional E.coli bacteria can't.
Placing the engineered E.coli bug in the FlashLab chip enables users to test for toxic substances quickly and cost-efficiently. All they have to do is place the chip in said substance for an immediate response.
"In principle we can detect heavy metals, organic solvents, and other things. The chips can be taken to the field and within 30 minutes you have a yes/no answer for a substance," said the team's mentor Professor Roee Amit in an interview with Haaretz, likening FlashLab to a "pregnancy test." Apart from testing for hormones, pollutants and heavy metals, the chip can also be used in forensics kits, says the team.
This is the third consecutive year that a team from Technion has won the gold medal at the iGem competition, which aims to encourage the development of new biological systems that have a positive impact on communities amongst high school, undergraduate and graduate students.