The biological transistor could be used to create living computers.
These cellular building blocks could be used to do anything from monitoring their environment to turning processes on and off in the cells.
“Transcriptors are the key component behind amplifying genetic logic,” lead author Jerome Bonnet, a bioengineer at Stanford University, said in a statement. On their own, these devices do not represent a computer, but they allow for logical operations, such as “if this-then that” commands, one of three basic functions of computers (the other two being storing and transmitting information).
To make the transcriptors the researchers took
A group of natural proteins
The workhorses of cells
and used them to control how the enzyme known as RNA polymerase zipped along a DNA molecule. The team used these transcriptors to create the mathematical operators that perform computations using Boolean logic of 0’s and 1’s.
1s and 0s
Boolean logic, named for the 19th-century mathematician George Boole, refers to a branch of math in which variables can have a true or false value (a 1 or a 0). In a Boolean circuit, the logic gates are like traffic conductors, deciding which of these values gets transmitted.
The “AND” gate takes in two values as input, and only outputs 1 (a true value) if both inputs are 1.
An “OR” gate, by contrast, outputs a 1 if either of its inputs is 1. Combining these simple gates in different ways gives rise to even the most complex forms of computing.
The scientists created biological versions of these logic gates, by carefully calibrating the flow of enzymes along the DNA (just like electrons inside a wire). They chose enzymes that would be able to function in bacteria, fungi, plants and animals, so that biological computer might be made with a wide variety of organisms, Bonnet said.
Like the transistor, one main function of the transcriptor is to amplify signals. Just as transistor radios amplify weak radio waves into audible sound, transcriptors can amplify a very small change in the production of an enzyme to produce large changes in the production of other proteins. Amplification allows signals to be carried over large distances, such as between a group of cells.
The new technology offers some electric possibilities:
Sensing when a cell has been exposed to sugar or caffeine and storing that information like a value in computer memory. Or telling cells to start or stop dividing depending on stimuli in their environment.
The researchers have made their biological logic gates available to the public to encourage people to use and improve them.