Tiny Biocomputers Move Closer to Reality

Scientific American Magazine/ By Tim Requarth and Greg Wayne

 

Image: Illustration by Thomas Fuchs

Researchers in nanomedicine have long dreamed of an age when molecular-scale computing devices could be embedded in our bodies to monitor health and treat diseases before they progress. The advantage of such computers, which would be made of biological materials, would lie in their ability to speak the biochemical language of life.

Several research groups have recently reported progress in this field. A team at the California Institute of Technology, writing in the journal Science, made use of DNA nanostructures called seesaw gates to construct logic circuits analogous to those used in microprocessors. Just as silicon-based components use electric current to represent 1’s and 0’s, bio-based circuits use concentrations of DNA molecules in a test tube. When new DNA strands are added to the test tube as “input,” the solution undergoes a cascade of chemical interactions to release different DNA strands as “output.” In theory, the input could be a molecular indicator of a disease, and the output could be an appropriate therapeutic molecule. A common problem in constructing a computer in a test tube is that it is hard to control which interactions among molecules occur. The brilliance of the seesaw gate is that a particular gate responds only to particular input DNA strands.  More >>