Electrostatic interaction between SARS-CoV-2 virus and charged electret fibre

TL;DR

This study models the electrostatic interactions between SARS-CoV-2 virus particles and charged electret fibers in masks, revealing how environmental factors and spike protein configurations influence filtration efficiency.

Contribution

It provides a detailed electrostatic model of virus-fiber interactions, incorporating charge regulation and environmental effects, advancing understanding of mask filtration mechanisms.

Findings

pH and salt concentration significantly affect electrostatic interactions

Spike protein configuration impacts virus-fiber attraction

Charge regulation influences interaction strength

Abstract

While almost any kind of face mask offers some protection against particles and pathogens of different sizes, the most efficient ones make use of a layered structure where one or more layers are electrically charged. This electret layer is essential to efficient filtration of difficult-to-capture small particles, yet the exact nature of electrostatic capture with respect to both the charge on the particles and the electret fibres as well as the effect of immediate environment remains unclear. Here, we explore in detail the electrostatic interaction between the surface of a single charged electret fibre and a model of SARS-CoV-2 virus. Using Poisson-Boltzmann electrostatics coupled to a detailed spike protein charge regulation model, we show how pH and salt concentration drastically change both the scale and the sign of the interaction. Furthermore, the configuration of the few spike proteins closest to the electret fibre turns out to be as important for the strength of the interaction as their total number on the virus, a direct consequence of spike protein charge regulation. The results of our work elucidate the details of virus electrostatics and contribute to the general understanding of efficient virus filtration mechanisms.