The electron microscope is perhaps the most powerful resolution in the microscope, it can even distinguish a single atom. However, electron microscopy cannot be used for the observation of living cells because electrons can damage the observed sample. The research team led by Professor Mehmet Fatih Yanik of MIT has proposed a new plan to overcome this problem. Yani et al. Wrote in the October Physical Review A-Rapid Communications magazine that the use of quantum mechanics measurement technology can allow electrons to sense the observed object at a long distance, thus avoiding damage to the electronic sample. This non-invasive electron microscope can reveal the basic problems of life and matter. It enables researchers to observe the molecules in a living cell. If successful, this microscope can overcome the basic flaw of the electron microscope proposed by Nobel Prize winner Dennis Gabor in 1956: the medium observed damaged the sample.
Electron microscopes use electron beams instead of beams to image samples. The resolution of the electron microscope image is 0.2-10 nm, which is 10-1000 times that of the traditional optical microscope. The electron microscope can magnify the sample two million times, while the maximum magnification of the optical microscope is 2000 times.
However, biologists have been unable to observe living specimens with such a powerful electron microscope. Because the electron beam will destroy the sample. When imaging with an electron microscope, a sample received a radiation dose equivalent to the amount of radiation released by a 100,000-ton equivalent hydrogen bomb exploding 30 meters away. When exposed to this high-energy electron beam, the structure of biological specimens will quickly collapse, some chemical bonds will be modified or other structures will be destroyed.
Although there is currently a special container that can store the sample in a high-vacuum water environment, it has also reached the demand of electron microscope observation, but before using the existing electron microscope to observe biological samples, the sample needs to be stored or frozen by chemical methods These methods can kill cells.
In the initially envisaged quantum mechanical device, the electron beam does not directly hit the object under observation. Instead, an electron beam can fly around one of the two rings arranged one above the other. The two rings are placed close enough so that electrons can easily jump between them. However, if an object (such as a cell) is placed in the middle of two rings, then it will prevent electrons from jumping and the electrons will be confined to one ring. This device can scan one pixel (pixel) of the sample at a time, and combine these pixels to make an image of the entire sample. But whenever the electron is captured, the system will display a black pixel in that place.
Although there are still some technical difficulties (such as preventing the interaction of imaging electrons with electrons in the microscope metal) that requires breakthroughs, Yanik believes that the resolution of this new microscope can eventually reach a few nanometers. This level of resolution allows scientists to observe the situation of molecules in living cells, such as the activity of enzymes in living cells, or even construct a single nucleic acid molecule map of DNA.
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