Humans can make smaller machines with small machines, and finally they will arrange atoms one by one to make products. This is the earliest dream of the famous physicist Nobel Laureate richard feynman for nanotechnology in 1959. Since then, mankind has begun to explore the nano-world. Scientists at Rice University in the United States have recently made the world's smallest car using nanotechnology. Like a real car, this nano car has wheels that can turn. It's just that they are so small that even if there are 2, nano-cars running side by side on one hair, there will be no traffic jam.
Although the car body is small, the parts are complete
The diagonal length of the whole nano car is only 3 to 4 nanometers, which is slightly wider than a single strand of DNA, and the diameter of a hair is about 8, nanometers.
however, although the nano car is small, it also has basic components such as chassis and axle. Its wheel is a football-shaped single molecule composed of 6 carbon atoms. This makes the nano car look like a dumbbell in appearance. It uses a triad as the shaft, and the shaft connecting each wheel can rotate independently, so that the car can travel on the uneven atomic surface.
According to experts, people have made nano-subminiature "cars" before. However, this new "car" is very different from its predecessors: this nano-car is the first nano-structured material in the world to move forward by rolling, and the so-called nano-car used to move forward only by sliding. This technology was developed under the leadership of Professor James Thor of Rice University for eight years. Thor said, "This is it. You can't build any smaller atomic transport." Kevin kelly, his colleague, said, "It is no longer a difficult problem to build a nano tool that can slide on a plane. It is the most difficult part of this project to prove that nano-objects are rotating and rolling, not sliding or sliding. Therefore, this breakthrough is the most important achievement in the micro field recently. "
Nano refers to one billionth of a meter, while nano-materials are composed of dozens to thousands of molecules. Because of its small size, this gives them some characteristics, such as the nano-car is not affected by friction, and its wheel is a single molecule with a tight structure, which is difficult to disperse into individual carbon atoms.
the wheels roll forward at high temperature
95% of the weight of the nano car is carbon, in addition to some hydrogen and oxygen atoms. The whole manufacturing process is roughly similar to the steps of molecular synthesis of drugs, which is divided into 2 steps. After manufacturing, it is placed in toluene gas and placed on the surface of gold sheet.
At room temperature, the wheels of the nano-car will be closely combined with the surface of the gold sheet. When the surface of the gold metal is heated to a high temperature of 2℃, the nano-car placed on it will start to move due to denaturation. It is not known whether they will move forward or backward when there is no external force, but once they start, they will not stop or change direction until they stop heating.
But the researchers found that by applying a magnetic field, they could change the direction of the nano-car. In addition, scientists can also grab the nano-car through subtle tips and drag it forward. Scientists have also built the world's smallest motor for the nano car, which is made up of 3 carbon atoms and some sulfur atoms and is driven by light. However, when placed on a gold surface, the nano-motor can't get enough power because the metal molecules absorb most of the light.
It will take some time for practical application
One gram of this nano-car can carry about 1 milligrams of drug molecules, and because of its small size, it can freely pass through organs and blood vessels. It looks like a "hollow ball" full of regular holes, which contains drugs. When the nano-drug delivery vehicle reaches the affected area under the action of external magnetic field, and then the pH or ionic strength of the affected area is adjusted, the "coat" of the nano-drug delivery vehicle will be taken off and the drugs loaded on the vehicle will be released. The researchers hope that this special vehicle can be used in the field of molecular structure. The improved nano-car can carry a molecular "cargo" and transport atoms and molecules between nano-factories. In the future, people can use a large number of such micro-machines to build new materials.
However, some people question that molecular manufacturing is unrealistic, and it may also bring unpredictable risks to the environment, such as a large number of nano-machines being flooded by self-replication. But scientists generally believe that such a situation can only appear in science fiction. Professor Thor said that at present, he does not intend to apply for a patent for nano-car technology, because he thinks it will take at least a generation to solve many technical problems in molecular manufacturing. He said: "By the time you use this technology to develop practical industries, the patent right will have expired long ago."
The sponsors of this research are Zyvex, a nanotechnology company in Texas, the National Science Foundation of the United States and Honda of Japan.