Release date: 2017-12-20
Imagine that you have an incredibly powerful optical lens in front of you, through which you can see a small virus that is squatting on the surface of living cells -
Boldly, this is not an imagination, this lens has already been made!
Joshua Caldwell, associate professor of mechanical engineering at Vanderbilt University, published an article in the famous academic journal Nature Materials on December 11th, reporting this notorious "miracle."
Antony van Leeuwenhoek experimented with various light-transmissive materials such as glass, gemstones and diamonds, and finally grinds a lens that magnifies the material by nearly 300 times. Since then, humans have opened the observation journey of the tiny world, lighting up the new discoveries of the life sciences.
In this article, the researchers improved a natural crystalline optical material, hexagonal boron nitride (hBN). Previously, the minimum resolution for resolving objects using hBN was about 36 times smaller than that of infrared microscopes, which is almost the size of small bacteria (about 0.5-1 micron). The new article reports that the potential imaging power of the improved crystal is approximately 10 times higher than the previous highest level!
Typical commercial infrared microscope setup (left) and Cassegrain reflector objective (right) and central components of the infrared microscope
"We have shown that the inherent imaging efficiency limitations of hyperlenses can be overcome by isotopic engineering," said Alexander Giles, a physicist at the US Naval Research Laboratory. “The difficulty of manipulating and focusing light at the nanometer scale is absolutely beyond imagination, and it is almost impossible to achieve. However, through this research, we have found that isotope modification can improve material and device performance.â€
Over the years, scientists have developed a number of instruments with nanoscale resolution imaging capabilities such as electron microscopy and atomic force microscopy. However, they are not compatible with living organisms, samples need to be exposed to harmful radiation and various deadly conditions (such as freeze drying, etc.) and require high vacuum conditions.
Lens technology, unlike these high-resolution microscopy procedures, provides a very detailed picture of live cells by exposing the sample to natural conditions covered by low-energy light (such as infrared light).
For a long time, the resolution of an optical microscope is considered to not exceed half the wavelength of the light wave, which is called "Abbe resolution." If infrared light is used in the experiment, the "diffraction limit" is about 3250 nm. Previously, scientists have discovered that hBN can support mixed particles "surface phonon polaritons" composed of photons and vibration-coupled photons, so the actual wavelength of charged atoms in the crystal is much shorter than the incident wavelength. However, experiments have found that there is a problem with the use of polarized phonons, which dissipate too quickly.
In this latest study, researchers used isotopically separated purified boron to make hBN crystals. Natural boron has two isotopes, the difference between the two is about 10%, although it is not easy to detect, but after careful comparison, the researchers found that the optical properties of the crystal materials mixed with two kinds of boron are significantly reduced.
Through calculations, the researchers predicted that crystal lenses made with pure boron can capture images of objects up to 30 nanometers in principle. A hair has a diameter of about 80,000 to 100,000 nanometers, a human red blood cell of about 9 kilometers, and a known virus of about 20 to 400 nanometers. If the calculation is correct, it means that only through a single eyepiece, humans will be able to directly observe the activity of small as a virus!
In order to confirm the speculation, the researchers have now prepared a small piece of hBN crystals made of pure isotope boron (purity 99%). Compared with natural crystals, the optical loss of the crystal is significantly reduced. Unexpectedly, the polarization phonon lifetime is also improved. 3 times, the resolution has also been significantly improved. "We are now using small pieces of purified hBN. After we make bigger crystals, I believe the results will be better," Caldwell said.
Today, 363 years after Levin Hook handcrafted the first microscope, scientists have succeeded in raising the development of superlens to a new level. Levin under Jiuquan? If Hu Ke can know the news, he will certainly show a happy smile.
The 2014 Nobel Prize in Chemistry was announced on October 8th to American scientists Eric Betzig, William Moerner and German scientist Stefan Hell. In recognition of their contributions in the field of ultra-high resolution fluorescence microscopy. Will this next-generation optical lens, which uses isotope-purified boron as a raw material, be a major achievement at the Nobel Prize level?
Source: Biopass
Saccharomyces boulardii (S. boulardii) is a probiotic yeast that is a variety of Saccharomyces cerevisiae (also known as baker’s or brewer’s yeast).1 It has been isolated from lychee and mangosteen fruit.2
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This article discusses the uses, side effects, and precautions of S. boulardii. It also covers what to look for in an S. boulardii supplement.
Dietary supplements are not regulated like drugs in the United States, meaning the Food and Drug Administration (FDA) does not approve them for safety and effectiveness before products are marketed. Therefore, when possible, choose a supplement that a trusted third party, such as USP, ConsumerLabs, or NSF, has tested.
Saccharomyces boulardii
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