In some ways, humans are complex living computers composed of individual cells. The creation of such an artificial “living” computer is still only a subject of science fiction, but several groups of scientists, including scientists from the Helmholtz-Zentrum Dresden-Rossendorf Institute, Germany, have been working in this direction for quite some time. And not so long ago, a group led by Bezu Teschome and Artur Erbe managed to find a way to apply a gold coating to nanoconductors made of pieces of DNA molecules. And in the future, using such tiny conductive elements, it will be possible to assemble the most complex circuits of a genetic computer, consisting of one or a weave of several long DNA molecules.
“The main advantage of using DNA is that it can be used to quickly create very complex circuits at the nanoscale,” says Arthur Erbe. The creation of complex circuits is made possible by a technology called DNA-origami, which allows the creation of complex spatial structures through a controlled and programmed self-assembly process. The technology was developed by U.S. scientists more than a decade ago and uses an unraveled reference DNA molecule, along which a second molecule is formed from a set of short sections.
The sequence of assembly of the long DNA molecule from the short sections is controlled by adding ions of certain chemical elements to the solution and adjusting the temperature of the solution. The use of precise control of the above and other process parameters makes it possible to create two- and three-dimensional objects of any complex shape from DNA.
“In this case, we created a kind of nanotube from DNA,” says Bezu Teshome. These nanotubes are quite tiny, no more than 30 nanometers long. By comparison, a red blood cell, the red blood cell, is 7,000 nanometers in size, while the Ebola virus is 1,500 nanometers long and 50 nanometers wide.
Then, using molecules of certain chemical compounds, the scientists placed gold nanoparticles along the nanotubes, which were “welded” to each other using gold ions. This step of the work was quite easy because gold combines very well with molecules of many organic compounds, including DNA molecules. But coating DNA with gold was half the problem. It was much more difficult to connect it all with external electrodes, through which the resulting nanoconductor could be electrically energized.
Using a high-precision microscope, the scientists determined the position of the ends of the nanoconductor. Using another technique, they attached electrodes, which are tens of nanometers in size, to the ends of this nanoconductor. In the process of connecting to the ends of the nanoconductor by depositing additional material on them, these electrodes increased in size to the micron scale, making it many times easier to connect measuring equipment to them.
After conducting measurements, scientists determined that gold DNA nanowires are capable of conducting electric current of sufficiently large strength for their size. And in the future these same scientists are going to develop technology to create conductors with a complex structure, having several branches, with which it will be possible to connect a large number of components made from the same DNA molecules.