Researchers at Stanford University in California have taken the next step in genetically engineering a computer in a living cell’s DNA. Making cells smarter could have a wide range of medical and industrial applications.
Today’s electronic computers are built around vast numbers of transistors, etched into silicon wafers.
A transistor is basically a switch used to control the electrical current flowing through a wire. It can amplify the signal strength or turn it on or off.
Drew Endy and his Stanford colleagues have created what they call the transcriptor. Instead of electrical current, the device controls the flow of an enzyme, called R-N-A polymerase, along the DNA in a cell.
“If you imagine a DNA molecule like a wire, with this enzyme flowing along, what we’re going to do is we’re going to come in with a third signal, just like a transistor, and switch the DNA, such that the flow of the enzyme can either pass through the transcriptor or it gets blocked. And that’s it,” said Endy.
By using more than one transcriptor, the researchers were able to issue logical instructions, using concepts like “and” and “or,” concepts basic to silicon-based computers.
If biological computing has a future, Endy doesn’t see it embedded in a laptop or smart phone.
“We aren’t trying to replace silicon computers or mechanical computers, because they probably aren’t going to be as fast. They’re not going to be as raw-powerful. But they’re going to work in places that the existing computers we have don’t work. So it’s computing in a new space or a new place,” he said.
One place could be in agriculture. Endy gave an example of spirulina algae being grown in Thailand. It could be bio-engineered to change color if the water had heavy metals or other pollutants in it.
“And you’d get a warning saying, ‘you know that batch of food you’re making isn’t safe for people to eat.’”
Applications involving human health may be further in the future, because of the need for careful safety testing. Endy said he could imagine foods with computing power that could diagnose the status of the digestive tract.
Researchers also are looking at engineering human immune cells to give them a boost in the battle against cancer.
The research paper by Drew Endy and his colleagues is published online by the journal Science.