A North Carolina
State University
chemist has found a way to give DNA-based computing better control over logic
operations. His work could lead to interfacing DNA-based computing with
traditional silicon-based computing.
The idea of using DNA molecules to perform computations is not new;
scientists have been working on it for over a decade. DNA has the ability to
store much more data than conventional silicon-based computers, as well as the
potential to perform calculations in a biological environment—inside a live
cell, for example. But while the technology holds much promise, it is still
limited in terms of the ability to control when and where particular
computations occur.
Alex Deiters, PhD, associate professor of chemistry at NC State, developed a
method for controlling a logic gate within a DNA-based computing system. Logic
gates are the means by which computers “compute,” as sets of them are combined
in different ways to enable the computer to ultimately perform tasks like
addition or subtraction. In DNA computing, these gates are created by combining
different strands of DNA, rather than by a series of transistors. The drawback
is that DNA computation events normally take place in a test tube, where the
sequence of computation events cannot be easily controlled with spatial and
temporal resolution. So while DNA logic gates can and do work, no one can tell
them when or where to work, making it difficult to create sequences of
computational events.
In a paper published in the Journal of
the American Chemical Society, Deiters addressed the control problem by
making portions of the input strands of DNA logic gates photoactivatable, or
controllable by ultraviolet (UV) light. The process is known as photocaging.
Deiters successfully photocaged several different nucleotides on a DNA logic
gate known as an AND gate. When UV light was applied to the gate, it was
activated and completed its computational event, showing that photoactivatable
logic gates offer an effective solution to the “when and where” issues of
DNA-based logic gate control.
Deiters hopes that using light to control DNA logic gates will give
researchers the ability not only to create more complicated, sequential DNA
computations, but also to create interfaces between silicon and DNA-based
computers.
“Since the DNA gates are activated by light, it should be possible to
trigger a DNA computation event by converting electrical impulses from a
silicon-based computer into light, allowing the interaction of electrical
circuits and biological systems,” Deiters says. “Being able to control these
DNA events both temporally and spatially gives us a variety of new ways to
program DNA computers.”
