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How to use electron beams to uncover cell structures? Explore the mysteries of electron microscopy!
The electron microscope, an outstanding achievement of this technology, allows scientists to observe the mysteries of the microscopic world in depth with its resolution dozens of times higher than that of optical microscopes. By illuminating a sample with an electron beam, the technology reveals details of cellular structure, playing a key role in fields ranging from biology to materials science.
With the wavelength of electrons up to 100,000 times smaller than visible light, electron microscopes have a resolution as high as 0.1 nanometers, becoming the gold standard for studying microstructures.
In the history of electron microscopy, the efforts of many scientists have allowed us to utilize this technology today. From the earliest cathode ray tubes to today's high-resolution electron microscopes, the journey has been filled with discoveries and breakthroughs.
Types of electron microscopes
There are several main types of electron microscopes, including transmission electron microscopes (TEM), scanning electron microscopes (SEM), and scanning transmission electron microscopes (STEM). Each microscope has unique applications and features. For example:
Transmission electron microscopy (TEM) uses a high-voltage electron beam to penetrate a thin sample to produce high-resolution images.
Scanning electron microscopy (SEM) scans the sample surface with a focused electron beam, captures the reflected electrons, and provides the three-dimensional structure of the sample.
Different microscopes have many differences in resolution, imaging mode and sample requirements, making them unique in different scientific research.
How electron microscopes work
The core of an electron microscope lies in the generation and manipulation of its electron beam. Unlike optical microscopes, which use glass lenses, electron microscopes use electromagnetic lenses to focus the electron beam. As these electrons travel through the sample, they interact with the sample's atomic structure and produce various images through different mechanisms, such as electron diffraction and secondary electron emission.
High-resolution transmission electron microscopy can reveal the arrangement of atoms and the details of genetic organization before our eyes.
Sample preparation and processing
Processing the sample for observation is a crucial step when operating an electron microscope. Different materials and research purposes require different processing techniques, such as:
- Chemical fixation: used to stabilize the structure of biological samples.
- Cryofixation: Immediately freeze at low temperatures to maintain the original state of the sample.
- Embedding: Biological samples and other materials are embedded in resin and then sectioned for observation.
Each step in sample preparation has a significant impact on the quality of the final image obtained, affecting our insights into cellular structure.
Applications and future prospects
Electron microscopes are currently widely used in life sciences, materials science and other fields. Its high resolution can help scientists observe structural changes inside cells, characteristics of pathogens, and even the atomic structure of materials. In the future, with the further development of technology, electron microscopes will be more accurate, not only able to image with higher resolution, but also perform real-time analysis and observe sample changes in real time.
The electron microscope is not only an observation tool, but also a window for scientific exploration, taking us into an unprecedented microscopic world.
However, the expensive and running costs of electron microscopes, as well as the special requirements for samples, remain challenges in technology development. How will future research overcome these obstacles to further explore the microscopic world of life and matter?
