New test detects protein secretion by cells

We have recently witnessed the stunning views of distant galaxies revealed by the James Webb Telescope, which were previously only visible as blurry spots. Researchers at Washington University in St. Louis have developed a new method to visualize proteins secreted by cells with astonishing resolution, making it the James Webb variation for visualizing single-cell protein secretion.

The researchers, led by Srikanth Singamaneni, Lilyan & E. Lisle Hughes Professor of Mechanical Engineering and Materials Science at the McKelvey Faculty of Engineering, and Anushree Seth, former postdoctoral researcher in Singamaneni’s lab, developed the take a look at FluoroDOT, which they introduced in an August 5 report 2022 in the journal Cell Reviews Solutions. The very wise examination is able to see and measure the proteins secreted by a single cell in approximately 30 minutes.

En collaboration with researchers from the Washington University College of Drugs and other universities, they found that the take a look at FluoroDOT is versatile, inexpensive, and adaptable to any laboratory environment and has the potential to provide insight more comprehensive of these proteins than the widely used examination. existing assays. Biomedical researchers look to these secreted proteins for insights into cell-to-cell conversation, cell signaling, activation, and inflammation, among other actions, but existing methods have limited sensitivity and can take up to at 24 hours to be processed.

What differentiates the FluoroDOT examination from existing examinations is that it uses plasmonic fluorine, a plasmon-enhanced nanolabel developed in Singamaneni’s lab which is 000 000 times brighter than conventional fluorescence markers and has a signal-to-noise ratio nearly 30 times higher..

“Plasmonic fluorides are composed of metallic nanoparticles that serve as an antenna to attract light and enhance the fluorescence emission of molecular fluorophores, making it an ultra-bright nanoparticle e,” said Singamaneni.

This ultra-bright plasmonic fluorine emission allows the user to see very small amounts of secreted proteins, which they are unable to do in existing assays, and digitally measure high-resolution signals using the number of particles, or pattern of factors, per cluster, or spot, using a custom algorithm. Moreover, it does not require any special equipment. Singamaneni and collaborators first published their work on plasmonic fluoride in Nature Biomedical Engineering in 2020.

The Technology patent-pending Plasmonic Fluoride is licensed from the Office of Know-how Administration at Washington University in St. Louis to Auragent Bioscience LLC.

“Using an easy fluorescence microscope, we are able to simultaneously image a cell as well as the spatial distribution of the proteins secreted around it,” said said Seth, who worked on this project as a postdoctoral researcher in Singamaneni’s lab and continues to work on it as a principal investigator (cellular programs) for Auragent Bioscience. “We observed interesting secretion patterns for different cell styles. This examination also allows the simultaneous visualization of two types of proteins from single cells. When several cells are subjected to the same stimuli, we can distinguish the cells which secrete two proteins at the same time. time of those who secrete only one protein or who do not secrete at all.”

To validate the technology, the team used proteins secreted by human cells and mice, including immune cells infected with Mycobacterium tuberculosis.

One of the collaborators and co-authors, Jennifer A. Philips, MD, PhD, Professor Theodore and Bertha Bryan in the Departments of Medicine and Molecular Microbiology and Co-Director of the Division of Infectious Diseases in the School of Medicine, used the FluoroDOT test in her lab.

“When Mycobacterium tuberculosis infects immune cells, these cells respond by secreting important immune proteins, called cytokines,” Philips said. “But not all cells react to infection in the same way. The FluoroDOT test allowed us to see how individual cells in a population respond to infection – to see which cells are secreting and in which direction. This was not possible with the old technology. “

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