High-Resolution Imaging Reveals Makeup of Virus Particles

At the Lawrence Berkeley National Laboratory (Berkeley Lab), laser and biology specialists have teamed up to create a new platform and experiments to analyze the components and structure of viruses, such as the one causing the current COVID-19 infection.

The experts will also explore how these viruses communicate with their surrounding environment. The experiments could offer a better understanding of how to decrease the infectious potency of viruses.

The novel platform will build upon the world-leading research and development efforts of Berkeley Lab in laser-based plasma acceleration, where an extremely hot and exotic state of matter—called plasma—is produced by a laser pulse. This plasma, in turn, quickly speeds up charged particles—that is, ions and electrons.

The previous year, Berkeley Lab researchers beat their own world record in speeding up the electrons to high energies in a span of 20 cm.

In the latest setup, X-rays produced by the accelerated electrons will serve as tiny strobes to record the images of droplets containing the virus and dripped into the pathway of the X-rays.

A second laser beam, synchronized within quadrillionths of a second, will simultaneously hit the virus-laden droplets to capture more information about the virus particles and their biological makeup, and also about the presence of other matter in the droplets.

The idea is to learn about the virus and what’s around it. How does it behave inside a droplet and what binds to it? How long is the virus viable in a droplet?

Thomas Schenkel, Acting Director of the Accelerator Technology and Applied Physics Division, Lawrence Berkeley National Laboratory

Schenkel is also a part of the group that is planning the experiments.

The aim is to examine the virus in specific biofluids, such as saliva, and how it responds to compounds added to the droplets. At Berkeley Lab, biosciences experts will prepare the samples and take part in the data studies.

In this pilot work, the scientists will employ surrogate viruses, the properties of which are similar to that of the SARS-CoV-2 virus that is responsible for causing the COVID-19 infection but can be safely used by laboratory staff.

“These droplets aren’t just mini sacks of water, but a complex mixture of proteins and salt that affects viral stability,” stated Antoine Snijders, a staff scientist and chair of the department of BioEngineering and BioMedical Sciences in the Biological Systems and Engineering Division of Berkeley Lab.

The virus-laden droplets are meant to replicate the setting of the body’s respiratory system.

What’s exciting about this study is that it will lead to a better understanding of the chemical characteristics of respiratory droplets and the virus contained within them. Once we understand the chemical characteristics, and the mechanism of viral inactivation within these droplets, we may be able to reduce efficiency of airborne disease transmission.

Antoine Snijders, Chair, Department of BioEngineering and BioMedical Sciences, Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory

The study is funded by Berkeley Lab’s Laboratory Directed Research and Development (LDRD) program, via which the Berkeley Lab directs the funding to certain areas of studies. Similar to the other national laboratories of the U.S. Department of Energy, Berkeley Lab is giving priority to COVID-19 research.

The experiments will integrate two methods—X-ray imaging for structural data and mass spectrometry to understand the details of the chemical composition of samples down to the level of individual molecules and proteins.

Within the experiments, the secondary laser will offer the spectroscopic data by charging up and then breaking down the matter present in the samples. Such bits and parts, like the separate protein components of a virus, can be later quantified and examined chemically by a detector.

Perhaps, this kind of setup can potentially be modeled or used as a testing platform for the COVID-19 disease.

Schenkel observed that with prevalent capabilities available at the Berkeley Lab Laser Accelerator (BELLA) Center, approximately five droplets can be imaged and measured per second. That rate could be increased up to 1,000 droplets every second through a recommended BELLA Center upgrade, known as kBELLA.

According to Eric Esarey, BELLA Center director, the ultimate aim of creating laser-plasma acceleration methods is to decrease the cost and size of particle accelerators that may serve in an array of capacities for the research, industrial, and medical communities.

In principle, this could be a compact, powerful, and low-cost device that could be put in lots of laboratories and lots of hospitals.

Eric Esarey, Director, BELLA Center

At the BELLA Center, novel types of X-ray sources based on laser-plasma accelerators are actively being researched and they continue to be enhanced. Such enhancements are required to offer high-resolution imaging of extremely small viruses in their setting.

Although the BELLA Center is currently offline because of lockdown orders, Schenkel informed that planning has been initiated for the latest experimental setup, with the aim to perform the first experiments later this summer.

At the BELLA Center, an association with biologists is ongoing and already mass spectroscopy equipment is available that can be adjusted for the latest experiments.

Schenkel informed that the team can continue to alter a computer code developed by Berkeley Lab. This code models the electron and laser beams to improve them for the latest studies.

“We are excited to use our tools to advance our understanding of COVID and contribute to future pandemic prevention,” added Schenkel.

“There are many analytical techniques that have originated from research with atom-smashers and particle beams years ago and that have since become workhorse tools in biomedical science,” he further added.

“When we discussed this new idea, there was a strong sense of urgency and excitement. This project is one example where we can immediately adapt our capabilities in response to the current crisis and advance our arsenal for the prevention of future pandemics. We want to show that this works so that we can establish it as a new capability for the community,” Schenkel concluded.

Source: https://www.lbl.gov/