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“Nanobots” are frequent visitors to movies and science fiction, and show off their stunts again and again. In the minds of many people, they are Transformers that have shrunk countless times.

With the “nano robot” as the key word, the search results appear, the style is the sauce:

“Epic” “Epoch-making” “Technology Revolution”, blessing in “Nano Robots” So many names on the list, how many points are true, how many points? How many gaps does reality and science fiction have? In order to answer these questions, today we will talk about the “real body” of nano-scale robots!

What about nanobots? How to make it?

About nano-robots, originally defined from the perspective of “size”: “Micro-machines within 0.1-10 microns.” Later, scientists extended this concept to define nano-robots as “functionality” for nano-scale objects.Operating machine”. Regardless of how it is defined, manufacturing nanobots is a very difficult task. First, we need some small parts – quite small, maybe only one thousandth of the diameter of the hair. The 2016 Nobel Prize in Chemistry was awarded to three scholars who specialize in “design molecular machines.” Their main job is to use chemical synthesis to make many molecular-scale parts, such as switches, pumps, and shafts [1].

▲Chemical methods can synthesize a range of molecular-scale parts: a typical nanoswitch schematic that controls specific molecules to move by changing pH | References [1]

There are also some hard technologies that can be used to make nano parts, such as lithography.

The lithography technology is mainly used to manufacture chips, and is one of the few processing technologies that humans can master to achieve nanometer-level precision. Scientists at the California Institute of Technology use lithography to create complex 3D metal geometries with resolutions of 25-100 nm [2]. In 2019, scientists at the Lawrence Livermore National Laboratory in the United States developed a “femtosecond projection two-photon lithography” technology that can increase the processing speed of conventional techniques by a factor of 1000, requiring only 8 minutes and 20 seconds. A sesame-sized micro-nano structure was printed, and the processing accuracy was maintained at the nanometer level [3].

▲Complex 3D microstructures fabricated by femtosecond projection two-photon lithography | References [3]

Neither chemical or photolithographic methods produce nano-parts that need to be further assembled into robots. How to achieve micro-scale assembly is another difficulty in the research of “nano-robots”.

As early as the 1980s, people realized control of single atoms. In 2005, the Chinese Academy of Sciences successfully moved a 4 micron long, 100 nanometer thick carbon nanotube into an engraved groove [4]. However, how to perform nanoassembly on a large scale is still a problem.

In 2015, a research team at the French National Academy of Sciences successfully synthesized a long polymer chain that combines thousands of nanomachines through supramolecular bonds, each of which can produce about 1 Linear stretching motion of nanometers. With the accumulation of less, the movement of these tens of thousands of small nanomachines can make the polymer chain produce 10 micron contraction and relaxation, just like in muscle tissue [5].

▲ 积少成多: The coordinated movement of tens of thousands of nano-parts can produce large-scale changes | References [5]

Evenly, these studies have only realized the simple aggregation of “nano-parts”. If you really want to assemble the kind of universal machine like a needle in the movie, humans still have a lot to go.

How do you get the nanobots moving?

In addition to how to “make it”, there is a key question, how to make nano-robots “moving up”? The most direct way is to install an engine. Scientists at the University of Texas at Austin have created the world’s smallest and fastest micro-engine. The engine is 500 times smaller than a salt and converts electrical energy into mechanical motion at speeds of up to 18,000 rpm, which is equivalent to the speed of the engine on a jet and can be rotated for 15 hours [8].

▲Sperm drilled into the nanotube as a power source | References [10]

The researchers used bovine sperm. In the macro world, cattle can be used to pull carts. I never imagined that in the microscopic world, their sperm would still be “the ox cart in the nanosphere.”

What can the current nanobots do?

The ultimate goal of nanobots is to improve ourselves. In the 2014 film Transcendence, the actor used nano-robots to repair his seriously ill body. In 2015, Google’s technical director Ray Kurzweil also put forward a point: “In 2020, the human immune system will be taken over by nano-robots; in 2030, nano-robots can correct a series of immunitys such as pathogens and tumors. System problems”. However, 2020 is close at hand, and it is not accurate at this time. The nano-robots in the movie, “One-shot cure”, did not appear. How to adapt nano-robots to complex body fluids from blood to stomach acid? How to position or drive a nano-robot like a dust in an intricate blood vessel? How do nanobots identify the sick one in millions of cells? It is true that disease treatment is the most important and most invested research direction of nano-robots, but the difficulties in practice make this field falter. Of course, advances in technology have provided some possible solutions to these problems. In 2019, scientists at the California Institute of Technology put nanobots in a gluey/kyjz/200504/t20050410_1032191.shtml

[5] Du, G., Moulin, E., Jouault, N., Buhler, E., & Giuseppone, N. (2012). Muscle‐like Supramolecular polymers: Integrated motion from thousands of molecular machines. Angewandte Chemie International Edition, 51(50), 12504-12508.

[6] Castro, CE, Kilchherr, F., Kim, DN, Shiao, EL, Wauer, T., Wortmann, P., … & Dietz, H (2011). A primer to scaffolded DNA origami. Nature methods, 8(3), 221.

[7] Li, S., Jiang, Q., Liu, S., Zhang, Y., Tian, ​​Y., Song, C., … & Chang, Y. (2018). A DNA nanorobot functions as a cancer therapeutic in response to a molecular trigger in vivo. Nature biotechnology, 36(3), 258.

[8] Kim, K., Xu, X., Guo, J., & Fan, DL (2014). Ultrahigh-speed rotating nanoelectromechanical system devices assembled from Nanoscale building blocks. NatUre communications, 5, 3632.

[9] https://new.qq.com/omn/20190504/20190504A06FRH.html

[10]Magdanz, V., Sanchez, S., & Schmidt, OG (2013). Development of a sperm‐flagella driven micro‐bio‐robot. Advanced Materials, 25(45), 6581-6588.

[11] Wu, Z., Li, L., Yang, Y., Hu, P., Li, Y., Yang, SY, … & Gao , W. (2019). A microrobotic system guided by photoacoustic computed tomography for targeted navigation in intestines in vivo. Science Robotics, 4(32), eaax0613.

[12] Castelvecchi, D. (2017). Drivers gear up for world’s first nanocar race. Nature News, 544(7650), 278.< /p>

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