We have heard of supercomputers, quantum computers, but there is a special computer that is also a major direction for future computer development, that is, DNA computers. A DNA computer is a biological form of a computer. In the DNA computer, the calculation is no longer the physical properties of the symbol transformation, but the chemical nature of the symbol transformation, the traditional sense of "plus", "and" the operation has become a chemical nature of the cutting and paste, Insert and delete.
For many years, there is a technology giant has been on the DNA molecular computer prospects show a strong interest, that is, Microsoft.
In 2016, Microsoft researchers set a record of DNA data storage (this record was broken by the Harvard team this year). Today, Microsoft has turned its research goal to another important branch of the DNA molecular computer. & Mdash;
Microsoft and the University of Washington research team together to find a substantial increase in DNA molecular computing methods, which will accelerate the use of DNA computer gene mutation or cancer detection and monitoring of footsteps. Experiments show that the new DNA computer in just seven minutes to complete the run with three input chain with the door, and the previous equipment takes four hours to complete the same amount of work.
The results were published on July 24, "Nature - Nanotechnology" (Nature Nanotechnology) on.
The title of this paper
In fact, the DNA computer is composed of DNA molecular circuits, and the input of the RNA, proteins and other chemicals in the cytoplasm, and the output is easy to distinguish between the molecular signals. As with the traditional computer, the DNA molecular circuit also has the same thing as the "logic gate is the basic component of the integrated circuit".
Figure A variety of logic gates in the computer
The researchers said in the paper, they use DNA origami to form a DNA hairpin structure (hairpin) of the spatial arrangement of the organization to build a row of DNA molecular logic and signal transmission lines. The so-called card structure, that is, if the sub-chain and the parent chain of the two DNA strand base complementary pairs, there will be some areas can not be paired and protruding parts, that is, we said the card structure. It makes the arrangement of DNA molecules more orderly, more modular, and each DNA molecule is also relative to the fixed "rssquo" down, like a fixed molecular circuit board.
Figure 丨 DNA domino circuit design process
Different from the computer on weekdays, these nano-level computer circuits are made of artificial DNA, called "DNA domino circuit" and "mdash;" by the different DNA strands. This DNA molecular circuit in the course of work, the circuit adjacent to the DNA chain through the chain of the card structure of the link to connect, and one by one and then react with each other, like a domino collapse, until the reaction is completed, the target DNA chain.
Figure 丨 information in the transmission of DNA between the hairpin
The results show that, whether in different lengths or different directions of the transmission line, this structure of the DNA molecular circuit has a good signal transmission capacity. In addition, the logic gate through the modular way can be combined into a conventional circuit mode, also greatly improve the DNA molecules between the information transmission speed and stability.
Figure 5 Andrew Phillips, Head of Bio Computing, Microsoft
Andrew Phillips, head of Microsoft's bio-computing group, gave a further explanation of the details of the study in an interview. In one device, the constituent molecules were spatially aligned together, and for our study, as a component Of the DNA molecular chain through the origami technology is relatively fixed in the entire system of space structure, looks like a molecular circuit board. & Rdquo;
The results of this research are very different from those of the past DNA computers. Most of the previous DNA computer is the DNA solution dissolved in the chemical solution. The disadvantage of doing so is that DNA molecules can walk freely in the chemical solution, prone to connect or react, thus affecting the efficiency.
Phillips introduced the improvement of the new DNA molecular computer: "For us, the DNA molecules that make up the device are tightly aligned, and their position is fixed by the DNA molecular circuit board." , They will first react with adjacent DNA molecules, rather than free to walk to other places with other locations of DNA molecules. & Rdquo;
This approach effectively reduces the interaction between DNA molecules. Although our equipment also relies on the principle of diffusion to operate, but because most of the molecules are fixed in the DNA space structure, travel around is the transmission of information on the fuel chain, the operating speed is much higher than the original. & Rdquo;
In this way, these devices will have a high degree of flexibility, because the new DNA molecular computer can be self-assembled, that is, molecules can be self-organized. In this regard, Phillips said, "DNA molecular chain will be in the DNA molecular circuit board as a whole, and we will use its self-assembly ability to calibrate the location of DNA molecules." & Rdquo;
For researchers, the next step is to expand the size of DNA molecular circuit boards, but this requires more advanced DNA origami technology.
The reason why the DNA can be folded, pasted, or attributed to its unique double helix structure: two parallel, reverse single chain in accordance with the principle of precision base complementary, A and T, G and C, like a key with a lock, has a unique and highly specific (A is adenine, T is thymine, G is guanine, C is cytosine). The chemical composition of these bases makes it possible to design two DNA single strands of ATGC sorting, to find each other in the vast sea, and to form the shape of the researchers.
Phillips also said that we are also ready to link new devices with biomarkers such as RNA markers, so that computer logic can be used to accurately diagnose viral diseases and cancers in the human body. Initially detected from the blood, but with the development of science and technology, we will achieve from any living cells in the detection of disease ideas. & Rdquo;
The DNA computer established with the encoded DNA sequence as a computing object has the characteristic information of all activities such as real-time detection and monitoring of gene mutations, and to determine the function of cancer cells and other diseased cells. In the future, scientists are more hope that the use of DNA computing logic to determine the ability to calculate the ability to "r & d"; "will be thinking" smart DNA computer equipment, making the development of personalized "smart drug" will become a reality The
In this regard, the field of gene editing scholar, Stanford University Department of Biological Engineering and Department of Chemistry and Systems Biology Professor Qi Lei recently also said that genetic editing is expected to make the human body can be a gene can be read, predicted and rewritten "DNA computer "It can not only act as a monitoring device, find potential pathogenic changes, but also in the human body to synthesize the necessary drugs, treatment of cancer, heart disease, atherosclerosis and other difficult conditions, even in the restoration of blind vision will Show their talents.
Although Microsoft's results for the DNA computer has taken a big step, but the current DNA computer is still in a very early stage of research. Due to the current level of biotechnology, DNA computing process, the early creation of DNA molecular chain and the late selection of DNA molecular chain, to spend a considerable amount of work.
For example, Adlerman's "test-tube computer" in a few seconds to get the results, but he spent several weeks to pick the correct results. In addition, in the field of mathematics in the famous travel salesman problem (TSP problem), if the number of cities in the experiment increased to 200, then the required DNA weight will exceed the weight of the Earth. And hundreds of millions of DNA molecules are very complex, in the reaction process is prone to deterioration and damage, and even test tube wall adsorption residue may be fatal error.
Therefore, DNA computer really into the real life still need time, we from the construction of a mature DNA computer also has a long way to go.