“It is literally a programming language for bacteria,” says Christopher Voigt, an MIT professor of biological engineering. “You use a text based language, just like you’re programming a computer. Then you take that text and you compile it and it turns it into a DNA sequence that you put into the cell – and the circuit runs inside the cell.”
Prof Voigt, along with researchers from Boston University and the National Institute of Standards and Technology, has used the language to build circuits that can detect up to three inputs and respond in different ways. Potential applications are said to include designing bacterial cells that can produce a cancer drug when they detect a tumour.
While such circuits have been created during the last 15 years, their design is said to have been a laborious process that required great expertise and often a lot of trial and error. However, users of the new programming language are said to need no special knowledge of genetic engineering; anyone can write a program for the function they want, then generate a DNA sequence that will achieve it.
Using the language, the researchers have designed computing elements such as logic gates and sensors that can be encoded in a bacterial cell’s DNA. The sensors can detect different compounds, such as oxygen or glucose, as well as light, temperature, acidity and other environmental conditions. Users can also add their own sensors. “It’s very customisable,” Prof Voigt says.
In the language’s current version, the genetic parts are optimised for E. coli, but the team is working on expanding the language for other strains of bacteria, with the aim of allowing users to write one program, then compile it for different organisms.
Using the language, the researchers programmed 60 circuits with different functions and say 45 worked correctly the first time. One of the new circuits is said to be the largest biological circuit yet built, with seven logic gates and about 12,000 base pairs of DNA.
“Until now,” Prof Voigt concluded, “it would take years to build these types of circuits. Now you just hit the button and immediately get a DNA sequence to test.”
