Abstract

Single Particle Detection of Extracellular Vesicles and Native SARS-CoV-2 Virions by Microfluidic Resistive Pulse Sensing

Zoltan Varga, Biological Nanochemistry Research Group, Research Centre for Natural Sciences (RCNS)

Microfluidic resistive pulse sensing (MRPS) is the nanoscale implementation of the Coulter principle in a microfluidic cartridge. As such, MRPS is a non-optical, single-particle detection method to measure the size distribution and concentration of nanoparticles. MRPS can be used to characterize extracellular vesicles (EVs). Enveloped viruses such as SARS-CoV-2 are spherical biological nanoparticles in the hundred nanometer size range, therefore MRPS is the method of choice for their characterization. In this study, MRPS was used to measure the size distribution of various EVs and SARS-CoV-2. The analysis of the supernatant of infected Vero cells indicated an envelope diameter of approximately 80 nm for the SARS-CoV-2 virions, which is in good agreement with previous cryo-EM studies. The detection of more than ten thousand virions made it possible to determine the size distribution of SARS-CoV-2 and paves the way for the MRPS-based detection of COVID-19 infection.