A biological computer controlled by DNA offers a cheap and simple way to test the concentration of contaminants in drinking water. And experiments show that logical operations borrowed from computer science can be engineered into the DNA to make future biological computers far more powerful at detecting contaminants. Julius Lucks at Northwestern University in Illinois and his colleagues created a biosensor in 2020 that can detect contaminants in a single drop of water. It contains proteins that react to the presence of certain chemicals by producing fluorescent molecules. This easily spotted reaction acts as a warning that a water sample is polluted with these chemicals. The reactions involved were inspired by mechanisms that evolved naturally within bacteria. Lucks say that scientists initially tried engineering the bacteria to carry out the tests, but that it was a challenge to keep them alive and stop them from spreading into the environment. This led to research into a cell-free, synthetic biological version, where the protein-based mechanisms are removed from the bacteria and used in isolation.
A simple test for water pollution involving engineered strands of DNA can report levels of contamination, and this biological system can carry out logical operations like those done by computers TECHNOLOGY 17 February 2022. The DNA computer – although not set up for formal analysis, Julius Lucks/Northwestern University A biological computer controlled by DNA offers a cheap and simple way to test the concentration of contaminants in drinking water. And experiments show that logical operations borrowed from computer science can be engineered into the DNA to make future biological computers far more powerful at detecting contaminants. Julius Lucks at Northwestern University in Illinois and his colleagues created a biosensor in 2020 that can detect contaminants in a single drop of water. It contains proteins that react to the presence of certain chemicals by producing fluorescent molecules. This easily spotted reaction acts as a warning that a water sample is polluted with these chemicals. The reactions involved were inspired by mechanisms that evolved naturally within bacteria. Lucks say that scientists initially tried engineering the bacteria to carry out the tests, but that it was a challenge to keep them alive and stop them from spreading into the environment. This led to research into a cell-free, synthetic biological version, where the protein-based mechanisms are removed from the bacteria and used in isolation. New Scientist Live is going hybrid, with a live in-person event in Manchester, UK, that you can also enjoy from the comfort of your own home.
“In synthetic biology, we’re trying to repurpose those molecular machines that detect toxins and re-engineer them, so they work how we want them to, maybe rewire them, so they do different things,” says Lucks. “You don’t really want to be releasing an engineered microbe into the water that you’re trying to measure the quality of.” Now, the team has created a more advanced version of the system that cannot only warn of the presence of dangerous chemicals, but also report on the amounts present so that proportionate steps can be taken. The system, dubbed ROSALIND 2.0, has eight small test tubes, each containing a biosensor with a different sensitivity to contaminants. If only one tube glows, then the water sample has just trace levels of contamination. But as more tubes glow, the water is shown to be increasingly more polluted.
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