NAND gate built from bacteria

Posted by Emma Woollacott

Scientists have taken another step towards biological computing, with the creation of logic gates from gut bacteria and DNA.

While something similar's been done before, the team says its logic gates behave more like the standard electronic version. They're also modular, which means that they can be fitted together to make different types of logic gates, paving the way for more complex biological processors to be built in the future.

"Logic gates are the fundamental building blocks in silicon circuitry that our entire digital age is based on. Without them, we could not process digital information," says professor Richard Kitney of Imperial College London.

"Now that we have demonstrated that we can replicate these parts using bacteria and DNA, we hope that our work could lead to a new generation of biological processors, whose applications in information processing could be as important as their electronic equivalents."

In one experiment, the team  constructed an AND gate from E Coli - normally found in a rather unsavory spot. The team altered it with modified DNA, which reprogrammed it to perform the switching-on-and-off process when stimulated by chemicals.

The researchers were also able to connect the biological logic gates to form more complex components in a similar way to electronic components are made, combining a NOT gate with the AND gate to produce the more complex NAND gate.

Although it's all still a long way off, the team suggests that these biological logic gates could one day form the basis of microscopic biological computers.

Devices could include sensors that swim inside arteries, detecting the build up of harmful plaque and delivering medications. Other sensors could perhaps detect and destroy cancer cells inside the body.