04/18/2025
By Zhiyong Gu
Date: Thursday, April 24
Time: 3:30 to 4:45 p.m.
Location: Shah Hall, Room 303
Abstract: In one important chemical engineering unit operation of messenger ribonucleic acid (mRNA) vaccine manufacture, the precious mRNA payload is encapsulated in lipid nanoparticles. Recent elegant cryogenic-transmission electron microscopy [Biophys J 120, 2766 (2021)] reveals that these lipid nanoparticles take the form of dumbbell suspensions. When encapsulating their mRNA payloads, these dumbbells can be both lopsided and interpenetrating, with the smaller of the two beads carrying the payload. In this work, we arrive at analytical expressions for these suspensions of lopsided lipid nanoparticle dumbbells encapsulating mRNA payloads. For this, we first exploit rigid dumbbell theory [Appl Sci Res, 30, 268 (1975)], which relies on the orientation distributions of the lopsided dumbbells to predict the suspension rheology, and specifically to predict how this departs from Newtonian behavior. We next exploit elastic dumbbell theory [Phys Fluids, 36, 071707 (2024)], which also relies on the orientation distributions of the lopsided dumbbells to which we add dumbbell stretching. Our results include analytical expressions for the relaxation time, rotational diffusivity, zero-shear viscosity, shear stress relaxation function, steady-shear viscosity and both the viscous part and minus the elastic part of the complex viscosity. We determine the rotational diffusivity of the mRNA-loaded lipid nanoparticle nanodumbbells from small-amplitude oscillatory shear measurements.
Biography: Dr. Mona Kanso is a Postdoctoral Associate in the Chemical Engineering Department at Massachusetts Institute of Technology in Boston. She earned her Ph.D. in Chemical Engineering at Queen’s University, Canada where she held a Vanier Canada Research Scholarship. Born in Beirut, Lebanon, Kanso earned her bachelor’s in Chemical Engineering from the American University of Beirut. She then earned her master’s degree in Chemical Engineering from Queen’s, under Professor Jeffrey Giacomin’s supervision, her thesis titled “Polymeric Liquid Behavior in Oscillatory Shear Flow”. She has developed a way to design polymer molecules and calculate their complex viscosities from first principles.
Dr. Kanso defended her PhD thesis in May 2023 on “Coronavirus Hydrodynamics” at Queen’s University. She has already published over 30 articles and 1 book chapter on polymer flow (on order, branching, block copolymers, DNA and SARS-CoV-2). At the moment, she works on foundational research to create, construct, and run a pilot continuous production facility for mRNA vaccines at MIT. She enjoys long distance running and cycling.