RNA-Based Computers Could Make House Calls on Cells

Oct. 17, 2008 -- Tiny biology-based computers could eventually check up on the health of individual cells, and, based on what they find, could then treat those cells. That's according to new research from scientists at the California Institute of Technology published in the current issue of Science.

"This is the first time that someone has showed a molecular computer that can respond to stimuli inside a living cell," said Ehud Shapiro, a professor of computer science and biology at the Weizmann Institute of Science.

Other scientists have created bio-based computers. Years ago Shapiro demonstrated a DNA-based computer in a test tube. The idea was that since computer code is based on 0s and 1s, DNA's four bases would significantly improve the amount of information a computer could process.

Most scientists have largely given up on challenging electronic computers in processing power, says Shapiro. Instead research has moved to producing a bio-computer that operates in areas where an electrical computer would find difficult.

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"DNA computing is all done outside of cells," said Christina Smolke, a coauthor of of the paper. "To make a computer work inside cells you have to use RNA."

As organic molecules go, RNA is pretty simple. Think of it as a piece of string dyed in four different colors. Each color corresponds to one of four nucleotides. Other molecules inside a cell read the colors on the RNA and use that information to build other molecules called proteins.

Proteins have a wide variety of functions. Some, like hemoglobin, deliver oxygen from the lungs to the far reaches of the body. Other proteins, like the one Smolke and coauthor Maung Win used for their RNA device, glow green when exposed to a laser.

The Caltech RNA device operates much like a normal computer in theory. Information goes in one end and, based on the data, the computer makes a decision. One big difference between normal computer and an RNA device is that a normal computer uses electrical information. A RNA device uses chemical information.