Effects of Compressive Velocity on Lipid Monolayer Shear Banding Collapse
Session Number
BIO 13
Advisor(s)
Anna Gaffney, Univeristy of Chicago, Program in Biophysics;Dongxu Liu; Luka Pocivavsek; Nhung Nguyen
Discipline
Biology
Start Date
17-4-2025 2:15 PM
End Date
17-4-2025 2:30 PM
Abstract
Found in alveoli in the form of lung surfactants, the structure of a lipid monolayer is composed of hydrophobic tails surrounded by air and hydrophilic heads that assimilate with water. As we breathe in and out, lung surfactants expand and contract to optimize air intake volume and pressure, causing collapse under high compressive stresses and strains during exhalation. We can experimentally observe the compression and collapse of lipid monolayers using fluorescence microscopy images on a Langmuir trough. The lipid dyes visualize coexisting phases during compression and collapse, including condensed domains and the matrix surrounding them. Depending on the starting conditions (ie. composition, temperature, etc), collapse can take different forms, such as out-of-plane collapse (folding, crumpling, vesiculation), or in-plane collapse (shear banding).
Shear banding is a type of collapse where the lipid domains shift from a hexagonal organization into horizontal condensed rows under high compression. In this study, elastic continuum mechanics is used to model the collapse of lipid monolayer systems computationally, through MATLAB and ABAQUS. Fluorescence microscopy images of lipid monolayers on Langmuir troughs provide data for shear banding collapse and allow us to compare our computational results to experimental results.
Previous computational experimentation has studied shear banding while compressing at one speed. In this study, we test whether different compressive velocities affect strain localization. We look at homogenous cases as well as heterogeneous cases that involve large models and small models of domain geometry pulled from experimental data. By further studying the lipid monolayer collapse, we can open gateways of research into the field of respiratory diseases.
Effects of Compressive Velocity on Lipid Monolayer Shear Banding Collapse
Found in alveoli in the form of lung surfactants, the structure of a lipid monolayer is composed of hydrophobic tails surrounded by air and hydrophilic heads that assimilate with water. As we breathe in and out, lung surfactants expand and contract to optimize air intake volume and pressure, causing collapse under high compressive stresses and strains during exhalation. We can experimentally observe the compression and collapse of lipid monolayers using fluorescence microscopy images on a Langmuir trough. The lipid dyes visualize coexisting phases during compression and collapse, including condensed domains and the matrix surrounding them. Depending on the starting conditions (ie. composition, temperature, etc), collapse can take different forms, such as out-of-plane collapse (folding, crumpling, vesiculation), or in-plane collapse (shear banding).
Shear banding is a type of collapse where the lipid domains shift from a hexagonal organization into horizontal condensed rows under high compression. In this study, elastic continuum mechanics is used to model the collapse of lipid monolayer systems computationally, through MATLAB and ABAQUS. Fluorescence microscopy images of lipid monolayers on Langmuir troughs provide data for shear banding collapse and allow us to compare our computational results to experimental results.
Previous computational experimentation has studied shear banding while compressing at one speed. In this study, we test whether different compressive velocities affect strain localization. We look at homogenous cases as well as heterogeneous cases that involve large models and small models of domain geometry pulled from experimental data. By further studying the lipid monolayer collapse, we can open gateways of research into the field of respiratory diseases.