Three-sided molded spikes help the success of Covid transmission

Overview

• Post By :


• Source: Okinawa Institute of Science and Technology (OIST) Graduate University


• Date: 16 Apr,2021

COVID-19 requires no introduction. This past year, the disease, which is caused by the virus SARS-CoV-2, reached every continent across the globe.

From the end of March 2021, there had been an estimated 128 million cases listed with nearly three million of these being deadly. As scientists’ race to produce vaccines and politicians coordinate their supply, basic research on what makes this virus so successful is also being carried out.

Previously they researched cholesterol molecules but when the pandemic hit, they realized that with the methods they had developed could be applied to the new virus.

They collaborated with investigators Mona Kanso and Professor Jeffrey Giacomin, from Queen’s University in Canada, to take a close look at SARS-CoV-2 and determine how the shape of the virus”spikes’ (which can be formally called peplomers) aid its success in spreading so prolifically. Their study was recently published in Physics of Fluids.

Rather, Dr. Chaurasia pointed out, the’spikes’ of the coronavirus particle are actually shaped like three small balls stacked together to form a triangular shape. This is an important consideration since the shape of a viral particle may influence its ability to disperse.

When one envisions a single coronavirus particle, it is common to think of a sphere with many spikes or smaller spheres distributed across its surface. This is the way the virus was originally modeled. But this model is a rough sketch and over the last year, we’ve come to learn much more about what the virus looks like.”

Dr. Vikash Chaurasia, Postdoctoral Researcher, Mathematics, Mechanics, and Materials Unit, Okinawa Institute of Science and Technology Graduate University

To understand this, imagine a ball moving through space. The ball will follow a curve but, as it does this, it will also rotate. The rate at which the ball rotates is called its rotational diffusivity. A particle of SARS-CoV-2 moves in a similar way to this ball although its suspended in fluid (specifically, tiny droplets of saliva).

The rotational diffusivity of the particle impacts how well it can align with and attach itself to objects (such as a individual’s cells or cells) and this has been key in its capability to successfully spread from person to person so rapidly.

A higher rotational diffusivity will indicate that the particle shakes and jitters as it follows a trajectory – and thus may have difficulty attaching to objects or efficiently bouncing off an object to continue to move through the atmosphere. Whereas a lower rotational diffusivity has the contrary effect.

Another consideration was that the fee of each spike.

The very same charges always repel each other so if there are only two spikes on a particle and they have equal charges, they will be situated at either pole (as far away from each other as possible). As more equally charged spikes are added, they get evenly distributed across the surface of the sphere. This supplied the investigators with a geometrical arrangement where they can calculate the rotational diffusivity.

For this new study, they used the exact same particle but changed out the single-bead spikes to the three-bead triangles. When they did this, the rotational diffusivity of the particle was found to decrease by 39%. Moreover, this trend was found to continue with the addition of more spikes.

This was an important finding – using a lower rotational diffusivity means that the virus particles can better align and attach themselves to objects and people. Thus, this study suggests that the triangular shaped spikes have contributed to the success of SARS-CoV-2.

“We know it’s more complex than this,” explained Dr. Chaurasia. “The spikes may not be equally charged. Or they may be flexible and able to twist themselves. Also, the’body’ of the particle might not be a sphere. Thus, we intend to do more research in this area.”

An additional interesting aspect of this study is its link to a question asked more than a century ago by physicist J. J. Thomson, who explored how a fixed amount of charges will be distributed across a sphere.

“I find it fascinating that a problem considered over 100 years ago has such significance for the situation we’re in today,” said Professor Eliot Fried. “Although this question was first posed primarily from a perspective of curiosity and intellectual interest, it has proven to be applicable in unexpected ways. This demonstrates why we mustn’t lose site of the value of basic research.”

The scientists at OIST and at Queen’s University intend to continue to collaborate on this sort of research to shed light on the success of SARS-CoV-2. The researchers at Queen’s University have just been given a Mitacs Globalink Research Award to allow for lead writer Mona Kanso to travel between Canada and Japan and work more closely with OIST.