Light Shrinking Material Lets Ordinary See In
Electrical engineers at the University of California, San Diego, came up with a way to improve the resolution of a regular light microscope. This makes it possible to see more details and finer structures in living cells.
With this technology, a regular light microscope can be turned into what is called a “super-resolution microscope.” It uses a special made-material that shortens the wavelength of light as it shines on the sample. It is this shorter wavelength of light that lets the microscope take better pictures.
Zhaowei Liu, a professor of electrical and computer engineering at UC San Diego, said, “This material changes low-resolution light into high-resolution light.” “It’s easy to understand and use. Just put a sample on the material and then look at the whole thing through a regular microscope.”
The work, which was published in Nature Communications, gets around a big problem with traditional light microscopes, which is that they don’t have very good resolution. Live cells can be seen under a light microscope, but you can’t see anything smaller. Conventional light microscopes have a resolution limit of 200 nanometers, which means that objects closer than this distance cannot be seen as separate objects. There are also more powerful tools like electron microscopes that can see subcellular structures, but they can’t be used to take pictures of living cells because the samples have to be put in a vacuum chamber.
- “Finding a technology that has a very high resolution and is safe for living cells is the biggest problem,” said Liu.
Both of these things are in the technology that Liu’s team made. With it, a regular light microscope can be used to take pictures of live subcellular structures with a resolution of up to 40 nanometers.
The technology is made up of a microscope slide that is covered with a hyperbolic metamaterial, which is a type of material that makes light smaller. It is made of very thin layers of silver and silica glass that are only a few nanometers thick. As light passes through, its wavelengths shorten and scatter, making a series of random, high-resolution speckled patterns. When a sample is put on the slide, these different patterns of light shine on it in different ways. This makes a bunch of low-resolution images, which are then all taken and put back together by an algorithm to make a high-resolution image.
The researchers used a commercial inverted microscope to test their technology. They were able to take pictures of fine details, like actin filaments, in fluorescently labeled Cos-7 cells. These details are hard to see with just a microscope. Researchers were also able to clearly tell the difference between small fluorescent beads and quantum dots that were 40 to 80 nanometers apart.
Researchers said that there is a lot of potentials for super-resolution technology to be used at high speeds. Their goal is to make a system for imaging living cells that has high speed, high resolution, and low phototoxicity all in one.
The technology is now being improved by Liu’s team so that high-resolution imaging can be done in three dimensions. This paper shows that the technology can make two-dimensional images with a high resolution. Liu’s team has already shown in a paper that this technology can also be used to take pictures with very high axial resolution (about 2 nanometers). Now, they are working to put the two together.
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