When they exposed the virus to 100 MHz ultrasound excitations, the virus' natural vibrations were initially undetectable. The team started with vibrations of 100 megahertz, or 100 million cycles per second, which they estimated would be the shell's natural vibrating frequency, based on what's known of the virus' physical properties. To answer that question, the researchers introduced acoustic vibrations into the simulations and observed how the vibrations rippled through the virus' structure across a range of ultrasound frequencies. 'The question is, what are the stresses and strains that will cause the virus to rupture?' 'We feel confident that this elastic model is a good starting point,' Wierzbicki says.

So this modeling requires a lot of assumptions.' 'Even more unknown is what's inside the virus, which is not empty but filled with RNA, which itself is surrounded by a protein capsid shell. 'We don't know the material properties of the spikes because they are so tiny - about 10 nanometers high,' Wierzbicki says. As the virus' exact physical properties are uncertain, the researchers simulated the behavior of this simple structure across a range of elasticities for both the shell and the spikes. With this geometry in mind, the team modeled the virus as a thin elastic shell covered in about 100 elastic spikes. This structure consists of a smooth shell of lipid proteins, and densely packed, spike-like receptors protruding from the shell. They used simple concepts of the mechanics and physics of solids to construct a geometrical and computational model of the virus' structure, which they based on limited information in the scientific literature, such as microscopic images of the virus' shell and spikes.įrom previous studies, scientists have mapped out the general structure of the coronavirus - a family of viruses that s HIV, influenza, and the novel SARS-CoV-2 strain. Wierzbicki's team set out to simulate the novel coronavirus and its mechanical response to vibrations. With this perspective, he wondered what could be learned about the virus' fracture potential. His group's focus is in solid and structural mechanics, and the study of how materials fracture under various stresses and strains. Wierzbicki's co-authors are Wei Li, Yuming Liu, and Juner Zhu at MIT.Īs the Covid-19 pandemic took hold around the world, Wierzbicki looked to contribute to the scientific understanding of the virus. The team's results appear online in the Journal of the Mechanics and Physics of Solids. 'The hope is that our paper will initiate a discussion across various disciplines.' 'We've proven that under ultrasound excitation the coronavirus shell and spikes will vibrate, and the amplitude of that vibration will be very large, producing strains that could break certain parts of the virus, doing visible damage to the outer shell and possibly invisible damage to the RNA inside,' says Tomasz Wierzbicki, professor of applied mechanics at MIT. How exactly ultrasound could be administered, and how effective it would be in damaging the virus within the complexity of the human body, are among the major questions scientists will have to tackle going forward. Nevertheless, the researchers say their findings are a first hint at a possible ultrasound-based treatment for coronaviruses, including the novel SARS-CoV-2 virus. The results are preliminary, and based on limited data regarding the virus' physical properties.

This effect was seen in simulations of the virus in air and in water. They found that vibrations between 25 and 100 megahertz triggered the virus' shell and spikes to collapse and start to rupture within a fraction of a millisecond. Through computer simulations, the team has modeled the virus' mechanical response to vibrations across a range of ultrasound frequencies. A new study by researchers in MIT's Department of Mechanical Engineering suggests that coronaviruses may be vulnerable to ultrasound vibrations, within the frequencies used in medical diagnostic imaging.

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