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translational science

Speeding COVID-19 Drug Discovery with Quantum Dots

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Viruses with nanoparticles attached
Credit: Ethan Tyler and Alan Hoofring/NIH Medical Arts

These round, multi-colored orbs in the illustration above may resemble SARS-CoV-2, the coronavirus responsible for COVID-19. But they’re actually lab-made nanocrystals called quantum dots. They have been specially engineered to look and, in some ways, act like the coronavirus while helping to solve a real challenge for many labs that would like to study SARS-CoV-2.

Quantum dots, which have been around since the mid-1980s, are designed with special optical properties that allow them to fluoresce when exposed to ultraviolet light. The two pictured here are about 10 nanometers in diameter, about 3,000 times smaller than the width of a human hair. The quantum dot consists of a semi-conductive cadmium selenide inner core (orange) surrounded by a zinc sulfide outer shell (teal). Molecules on its surface (yellow) allow researchers to attach the viral spike protein (purple), which SARS-CoV-2 depends on to infect human cells.

To the left is a human cell (gray) studded with the ACE2 receptors (blue) that those viral spike proteins bind to before SARS-CoV-2 enters and infects our cells. In the background, you see another spike protein-studded quantum dot. But human neutralizing antibodies (pink) are preventing that one from reaching the human cell.

Because SARS-CoV-2 is so highly infectious, basic researchers without access to specially designed biosafety facilities may be limited in their ability to study the virus. But these harmless quantum dots offer a safe workaround. While the quantum dots may bind and enter human cells just like the virus, they can’t cause an infection. They offer a quick, informative way to assess the potential of antibodies or other compounds to prevent the coronavirus from binding to our cells.

In work published in the journal ACS Nano, a team that included Kirill Gorshkov, NIH’s National Center for Advancing Translational Sciences (NCATS), Rockville, MD, along with Eunkeu Oh and Mason Wolak, Naval Research Laboratory, Washington, D.C., demonstrated how these quantum dots may serve as a useful new tool to speed the search for new COVID-19 treatments. The dots’ fluorescent glow enabled the researchers to use a microscope to observe how these viral mimics bind to ACE2 in real time, showing how SARS-CoV-2 might attach to and enter our cells, and suggesting ways to intervene.

Indeed, imagine thousands of tiny wells in which human cells are growing. Imagine adding a different candidate drug to each well; then imagine adding the loaded quantum dots to each well and using machine vision to identify the wells where the dots could not enter the cell. That’s not science fiction. That’s now.

With slightly different versions of their quantum dots, the NCATS researchers and their colleagues at the Naval Research Laboratory will now explore how other viral proteins are important for the coronavirus to infect our cells. They also can test how slight variations in the spike protein may influence SARS-CoV-2’s behavior. This work provides yet another stunning example of how scientists with widely varying expertise have banded together—using all the tools at their disposal—to forge ahead to find solutions to COVID-19.

Reference:

[1] Quantum dot-conjugated SARS-CoV-2 spike pseudo-virions enable tracking of angiotensin converting enzyme 2 binding and endocytosis. Gorshkov K, Susumu K, Chen J, Xu M, Pradhan M, Zhu W, Hu X, Breger JC, Wolak M, Oh E. ACS Nano. 2020 Sep 22;14(9):12234-12247.

Links:

What are Quantum Dots? (National Institute of Biomedical Imaging and Bioengineering/NIH)

Coronavirus (COVID-19) (NIH)

I Am Translational Science: Kirill Gorshkov (National Center for Advancing Translational Sciences/NIH)

U. S. Naval Research Laboratory (Washington, D.C.)

NIH Support: National Center for Advancing Translational Sciences


Wearable mHealth Device Detects Abnormal Heart Rhythms Earlier

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Zio patch

Caption: Woman wearing a Zio patch
Credit: Adapted from JAMA Network Summary Video

As many as 6 million Americans experience a common type of irregular heartbeat, called atrial fibrillation (AFib), that can greatly increase their risk of stroke and heart failure [1]. There are several things that can be done to lower that risk, but the problem is that a lot of folks have no clue that their heart’s rhythm is out of whack!

So, what can we do to detect AFib and get people into treatment before it’s too late? New results from an NIH-funded study lend additional support to the idea that one answer may lie in wearable health technology: a wireless electrocardiogram (EKG) patch that can be used to monitor a person’s heart rate at home.


Basic Research: Building a Firm Foundation for Biomedicine

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Benchtop Centrifuge

Credit: National Institute of Allergy and Infectious Diseases, NIH

A major part of NIH’s mission is to support basic research that generates fundamental knowledge about the nature and behavior of living systems. Such knowledge serves as the foundation for the biomedical advances needed to protect and improve our health—and the health of generations to come.

Of course, it’s often hard to predict how this kind of basic research might benefit human populations, and the lag time between discovery and medical application (if that happens at all) can be quite long. Some might argue, therefore, that basic research is not a good use of funds, and all of NIH’s support should go to specific disease targets.

To counter that perception, I’m pleased to share some new findings that underscore the importance of publicly supported basic research. In an analysis of more than 28 million papers in the PubMed.gov database, researchers found NIH contributed to published research that was associated with every single one of the 210 new drugs approved by the Food and Drug Administration from 2010 through 2016 [1]. More than 90 percent of that contributory research was basic—that is, related to the discovery of fundamental biological mechanisms, rather than actual development of the drugs themselves.


Clinical Trials Bring Hope to Kids with Spinal Muscular Atrophy

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Faith Fortenberry

More than a decade ago, the NIH’s National Institute of Neurological Disorders and Stroke (NINDS) launched a special project to accelerate the translation of basic scientific discoveries into new treatments for a rare and often fatal disease. Five-year-old Faith Fortenberry whom you see above is among the kids who may benefit from the success of this pioneering endeavor.

Faith was born with spinal muscular atrophy (SMA), a hereditary neurodegenerative disease that can affect movement, breathing, and swallowing. When the NIH project began, there was no treatment for SMA, but researchers had discovered that mutations in the SMN1 gene were responsible for the disorder. Such mutations cause a deficiency of SMN protein, leading to degeneration of neurons in the brain and spinal cord, and progressive muscle weakness throughout the body. The NIH effort supported research to discover ways of raising SMN levels in cells grown in lab dishes, and then worked closely with patient advocates and pharmaceutical companies to move the most promising leads into drug development and clinical testing.

Given the desperate need for SMA treatments and all of the scientific energy that’s been devoted to pursuing them, I’ve been following this field closely. So, I was very encouraged to learn recently about the promising results of human tests of not just one—but two—new treatments for SMA [1, 2].


Cool Videos: The Ghost in the Lab Dish?

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As Halloween approaches, lots of kids and kids-at-heart will be watching out for ghosts and goblins. So, to help meet the seasonal demand for scary visuals, I’d like to share this award-winning image that’s been packaged into a brief video.

The “ghoul” you see above is no fleeting apparition: it’s a mouse cell labelled to reveal its microtubules, which are dynamic filaments involved in cellular structure, transport, and motility. Graduate student Victor DeBarros captured this image a couple of years ago in the NIH-supported lab of Randall Duncan at the University of Delaware, Newark, as part of research on the rare skeletal disorder metatropic dysplasia (MD).


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