Nature Methods: new fluorescent dyes make biological imaging as colorful as rainbow

The rainbow after rain always attracts many people's attention In the field of chemistry, there are also the "Rainbow" that attracts much attention Recently, researchers reported a new dye rhodamine on nature methods These fluorescent molecules are colorful and can achieve almost all colors through structural adjustment The new research provides scientists with a way to adjust the properties of dyes, making them more eye-catching, more colorful and more permeable The coauthor, Luke Levis of the Howard Hughes Medical Institute (HHMI), said expanding the dye's color could help researchers better understand the mechanism of action within cells His team used a new dye to light up the nucleus, the brain of the fly larvae, and the neurons in the visual cortex of mice with tiny glass windows on their skulls Until about 20 years ago, scientists relied on chemical fluorescent dyes to achieve biological imaging At that time, cell observation, organelle staining and other biological imaging experiments were all done by chemical fluorescent dyes, which were called "kings" After that, green fluorescent protein (GFP) came out, biomarkers were widely used, and "King" stepped down Sources of Aequorea victoria jellyfish with green fluorescent protein in vivo: in the 1960s, Osamu Shimomura and others isolated green fluorescent protein (GFP) from jellyfish In 1994, E coli and C elegans reported on science that using gene technology can fix green fluorescent protein into other cell proteins, making proteins become "fluorescent rods" Instead of expensive synthetic dyes, the new technology provides a simpler way for researchers to track the movement of proteins under a microscope, thus illuminating the field of biological imaging In 2007, Jeff W Lichtman and Joshua R SANEs mixed green fluorescent protein and two other fluorescent proteins to paint vivid colors on mouse neurons This technology is called "brainbow" A year later, the discovery and application of GFP won the Nobel Prize for three scientists, including the late HHMI investigator and Chinese American chemist Qian Yongjian However, GFP has some defects It's a large molecule of natural amino acids, sometimes not bright enough to see everything you want to see So researchers turned their attention to chemistry Scientists have developed cutting-edge microscopes and new labeling techniques, but the dye that marks molecules is still in the 19th century, Lavis said His team specializes in rhodamine, because the molecule is particularly bright and the cells are permeable, so it's easy to get into the cells and make them glow Despite more than 100 years of research on Rhodamine, chemists have created only a few dozen colors, most of them green or orange Source of core structure of rhodamine: it is not easy for Wikipedia to synthesize new rhodamine molecules The traditional condensation method is that different chemical components are refluxed in sulfuric acid, and different new dyes can be obtained by changing the substrate structure This method has a great limitation on the reaction substrate, because the reaction condition of sulfuric acid bath reflux is too strong, and the stable molecular selectivity under this condition is not much Brightening up in 2011, Levis team developed a new method of modifying molecular structure of rhodamine under mild conditions Using palladium as catalyst, researchers can avoid using sulfuric acid bath and build more complex structural units than before This gentler approach opens the door to a new world of dyes, and the team is still working on it Four years later, janelia fluor dye with heterocyclic butane structure came into being Its fluorescence brightness is 50 times that of other dyes, and it is more stable Moreover, this structure can only be realized by Levis's new chemical method Scientists can use various strategies to connect bright dye molecules to the proteins they want to study Then, their oscillations and interactions with other molecules are observed, free from background blur Janeliafluor dye fluoresces under UV irradiation (Credit: Jonathan B Grimm) source: Phys Org "for us, this is a revolution in the field of single molecule imaging." Xavier darzacq, a molecular biologist at the University of California, Berkeley Before using the janelia fluor dye, his team studied fluorescent labeled transcription factor proteins that were too dark to capture clear images Researchers had to open the camera shutter for 10 milliseconds to collect enough light Although it's a short time, it's enough for protein movement, which makes the image blurry like a crawling baby Darzacq said the janelia fluor dye was bright enough to solve the problem, allowing researchers to capture molecules in a millisecond Such a quick snapshot made the team's experiments "unimaginable a few years ago." Now, Lavis's team has figured out how to further fine tune the fluorescent dye by adjusting the structure of rhodamine Rhodamine has basic quaternary ring structure and substituents on the ring In the previous work, scientists developed the strategy of coarse adjustment dye: to get green dye by subtracting here, and to get red dye by adding silicon atom there Levis found that the introduction of several new atoms into the dye structure can fine tune the color and chemical properties of the dye, making the same skeleton show many kinds of green It's like using a few colors on a palette to get the colors you want Source of general synthesis method of rhodamine containing Si atom: ACS Central Science published in another article of ACS central science on August 9, 2017 The team introduced the method of modifying dye structure bottom ring "The key is to use modular and reasonable methods." Choosing the right atoms, Levis explained, allows chemists to design almost any dye they want Levis's team attached different chemical groups to rhodamine and analyzed the properties of the new dye "No one has seen this systematic synthesis of rhodamine before." Jonathan Grimm, a senior scientist at janelia who wrote the first paper, said Lavis showed that these dyes were obtained by one-step reaction of cheap raw materials, which made rhodamine dyes cheaper than other commercial fluorescent dyes, which only cost 1p per bottle Low cost allows teams to share their work with scientists around the world Lavis, Grimm and colleagues have now shipped bottles of dye to hundreds of different laboratories "These dyes are completely game changer," said Ethan Garner, a Harvard bacterial cell biologist who used these new dyes to track single molecular pathways Previously, scientists could not choose multiple colors, while rhodamine could expand the selection to the entire spectrum " Paper link: http:// HTML? Foxtrotcallback = true