Analog DNA Circuit Performs Math Calculations In A Test Tube


DNA contains the genetic code that makes humans different from other species of animals and even from each other. Researchers, however, have discovered other uses for the so-called blueprint of life.

In a new study published in the journal ACS Synthetic Biology, researchers have developed a DNA-based circuit that may one day prove useful in the field of science and medicine.

Study researcher John Reif, from Duke University, and colleagues developed strands of synthetic DNA that can form an analog circuit when mixed in a test tube. The circuit is capable of performing what calculators do: add, subtract and multiply when the strands break or form bonds.

Other DNA-based circuits are also capable of solving math problems but most of these are digital and involve encoding the information in a sequence of zeroes and ones. The new device, however, does math calculation in an analog fashion by measuring the different concentrations of DNA molecules sans converting them to zeroes and ones. The device also uses concentration of specific DNA strands as signals and not voltage.

"We propose an architecture for the systematic construction of DNA circuits for analog computation based on DNA strand displacement," the researchers wrote in their study.

"The input and output of these gates are analog, which means that they are directly represented by the concentrations of the input and output DNA strands, respectively, without requiring a threshold for converting to Boolean signals."

Reif acknowledged that the analog DNA circuit they developed is way behind silicon-based circuits that are currently used in modern-day electronics when it comes to commercial application. One reason is that test tube calculations tend to be very slow.

The DNA circuits though are far tinier compared with those made of silicon. They can also work in wet environments, which can make them useful DNA calculators swimming in the bloodstream or cells.

Researchers hope that in the future, these devices can be used to sense if blood chemicals are within the range of normal values and release a DNA or RNA to provide treatment.

The researchers are also starting to work on DNA-based devices that can detect cancer cells and release substances that can boost the ability of the immune system to fight back, capabilities that can make them very useful and potentially life-saving.

Reif said that even with its limitations, simple DNA computing may still have important impacts in the field of medicine or science.

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