Effects of Initial Domain Packing in Lipid Monolayer Shear Banding Collapse
Session Number
Project ID: BIO 07
Advisor(s)
Anna Gaffney, Dongxu Liu, Luka Pocivavsek, Nhung Nguyen University of Chicago, Program in Biophysics
Discipline
Biology
Start Date
17-4-2024 9:40 AM
End Date
17-4-2024 9:55 AM
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 collapse can take different forms, such as out-of-plane collapse, or in-plane. 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. Previous experimentation has studied shear banding from hexagonal packing, but in this finite element experiment, characteristics of the domains are manually altered to determine the impact of the initial structure on the final configuration. By studying lipid monolayer collapses, we can open gateways into the field of respiratory diseases.
Effects of Initial Domain Packing in 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 collapse can take different forms, such as out-of-plane collapse, or in-plane. 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. Previous experimentation has studied shear banding from hexagonal packing, but in this finite element experiment, characteristics of the domains are manually altered to determine the impact of the initial structure on the final configuration. By studying lipid monolayer collapses, we can open gateways into the field of respiratory diseases.