Here we're highlighting a textbook example of how to use the absolute concentration measurements delivered by Spectradyne's Microfluidic Resistive Pulse Sensing (MRPS) to tightly control experimental variables and do good science:
Z. Troyer, N. Alhusaini, C. O. Tabler, T. Sweet, K. I. Ladislau de Carvalho, D. M. Schlatzer, L. Carias, C. L. King, K. Matreyek, J. C. Tilton "Extracellular vesicles carry SARS-CoV-2 spike protein and serve as decoys for neutralizing antibodies," J. Extracell. Ves. 10, e12112 (2021)
DOI link to publication
In this publication, researchers from Case Western Reserve University demonstrate that extracellular vesicles (EVs) generated in SARS-CoV-2-infected cells can carry the SARS-CoV-2 spike protein. They also show that these spike-carrying EVs act as decoy targets for antibodies derived from convalescent patient serum, thereby reducing the effectiveness of this type of therapeutic in blocking entry of the SARS-CoV-2 virus into cells. As the authors note in their paper, these findings "...highlight the complex interplay between viruses, extracellular vesicles, and the immune system that occurs during viral infections."
The researchers used Spectradyne's nCS1TM particle analyzer to control for the total quantity of EVs that were used in their experiments. As we've written before, when evaluating the bioactivity of EVs, normalizing their concentration (i.e., dose) is critical for running well controlled science and minimizing variability in experimental outcomes.
Listen to Zach Troyer, the lead author on this paper, present at a webinar we hosted in April 2020 on precisely this topic!
As this paper demonstrates so well, accurate concentration measurements are critical for good extracellular vesicle science!