Biological supercomputer: don't laugh, he'll grow up
The largest computer made of DNA has been createdTape.
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Scientists have created the largest DNA computer to date. The authors described their "device" in an article in the journal Science (Lulu Qian and Erik Winfree, Scaling Up Digital Circuit Computation with DNA Strand Displacement Cascades).
A computer is a DNA chain in a liquid medium. DNA has the property of complementarity – strands of certain sequences can form strong pairs with each other. If the sequence of one thread is exactly complementary to the sequence of the other, then the connection is as strong as possible. If there is an incomplete match, the pair will be less stable and the thread that is better suited to one of the two chains of the "wrong" pair can displace the second chain, replacing it with itself. It is the process of sequential displacement of some strands by others that underlies computer calculations from DNA.
Scientists have created several logical circuits, the total number of DNA strands in which is 130. The largest contour includes 74 threads and is able to extract square roots from numbers up to 15. (The figure shows the schematic diagram of this block – VM.)
The computer is capable of performing logical operations AND or OR, and calculations take about 10 hours.
Since biochemical reactions do not take place with absolute accuracy, there is constant noise in the work of DNA computers. The authors of the new work were able to minimize it by "forcing" their device to amplify a signal with a probability of more than 80 percent, as well as inhibit all signals with a probability of less than 10 percent. This is clarified in a press release from the California Institute of Technology, where scientists work (Caltech Researchers Build the Largest Biochemical Circuit Out of Small Synthetic DNA Molecules).
While DNA computers are imperfect and work only in laboratories, however, scientists believe that such devices are promising for use inside the human body. For example, they can assess the concentration of a substance in the blood and, based on the result obtained, regulate the release of a drug contained in carrier capsules.
Portal "Eternal youth" http://vechnayamolodost.ru03.06.2011