MS07 - CDEV-2
Interfaith Prayer and Reflection Room (#3020C) in The Ohio Union

Recent Studies on the Biomechanics and Fluid Dynamics of Living Systems: Cellular Biomechanics and Microfluidics

Thursday, July 20 at 04:00pm

SMB2023 SMB2023 Follow Thursday during the "MS07" time block.
Room assignment: Interfaith Prayer and Reflection Room (#3020C) in The Ohio Union.
Note: this minisymposia has multiple sessions. The other session is MS06-CDEV-2 (click here).

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Wanda Strychalski, Alexander Hoover


From the blebbing of cells to the undulations of fish, biomechanical and biofluidic systems are ubiquitous in nature. Many of these systems involve interplay of multiple physics, such as the structures’ elasticity, the fluid dynamics of differing length scales, and neural activity. Other times, these processes can include chemical signaling, rheological properties of biomaterials, as well as osmotic and the biochemical processes that drive their motion. In this minisymposium, we focus on modeling the biological processes that undergird these biofluidic and biomechanical systems, with methods that range from computational simulation to asymptotic analysis. Talks in this session focus on the modeling and simulation of microscale phenomena, such as cell migration, bone cell signaling, fiber dynamics, and embryogenesis. This minisymposium aims to bring together these communities to discuss recent advances in modeling, analysis, and computational simulation for investigating the interplay of biological processes with fluid mechanics. This is the companion minisymposium of 'Recent Studies on the Biomechanics and Fluid Dynamics of Living Systems: Locomotion and Fluid Transport'.

Hongfei Chen

Tulane University (Department of Mathematics)
"Effects of Choanoflagellate Colony Shape on Hydrodynamic Performance"
Choanoflagellates are believed to be the closest animal relatives and are considered important in the study of animal tissue evolution. In their preferred environment, these microorganisms form a relaxed colony with flagella pointing-inward. However, when conditions become unfavorable, they contract and invert the colony, causing the flagella to point outward. Our proposed coarse model produces the same averaged far field flow as a single cell, and we use it to analyze the feeding and swimming behaviors of the two different colonies.
Additional authors: Ricardo Cortez, Lisa Fauci, Tom Hata, Mimi Koehl, Hoa Nguyen

Nigar Karimli

Indiana University-Purdue University Indianapolis (Mathematics)
"A three-dimensional mathematical model of a viscoelastic osteocyte immersed in flow"
Osteocytes make up 90-95% of all bone cells in an adult skeleton and are responsible for regulating bone remodeling through mechanotransduction (how the cells sense and convert mechanical signals into biochemical signals). In order to better understand the localization of forces on and around an osteocyte, which is essential for understanding mechanotransduction, we have developed a 3D mathematical model of an osteocyte and its interaction with surrounding flow. Our model includes the cell modeled as an interconnected network of viscoelastic elements. We have incorporated forces to model non-negligible bending rigidity, total and local area conservation of the membrane, and total volume conservation. We calculate these solid forces from the corresponding energy functions using the principle of virtual work. Additionally, we use the lattice-Boltzmann method (D3Q19) to model the flow in and around the osteocyte, and the immersed boundary method to handle fluid-structure interactions. After verifying proper model implementation, we have been able to produce simulations of an idealized ellipsoidal osteocyte immersed in flow and advecting along a channel. The model produces estimates for the typical motion and forces experienced by the osteocyte. In preparation for comparing our model with collaborators’ experiments involving stationary cells subjected to shear flow in a channel, we have also investigated and will share typical cellular dynamics that result when the cell is additionally anchored to an underlying surface.
Additional authors: Luoding Zhu, Indiana University-Purdue University Indianapolis; Jared Barber, Indiana University-Purdue University Indianapolis

Sharon R. Lubkin

North Carolina State University (Mathematics)
"Geometry, pattern, and mechanics of notochords"
Chordocytes, in early zebrafish and other teleost notochords, have been shown to pack in a small number of stereotyped patterns. Mutations or treatments which disrupt the typical patterning are associated with developmental defects, including scoliosis. The dominant WT “staircase” pattern is the only regular pattern displaying transverse eccentricity. Morphometry and pattern analysis have established a length ratio governing which patterns will be observed. Physical models of cell packing in the notochord have established relationships between this geometric ratio, a mechanical tension ratio, the transverse aspect ratio, pattern, pressure, and taper. Since a major function of the early notochord is to act as both a column and a beam, we aim to understand the overall resistance to compression and bending in terms of these mesoscale cell/tissue properties. To frame the relationships between these properties, we have developed a model of the notochord as an elastic closed-cell foam, packed in either the “staircase” or “bamboo” pattern. A pressure study reveals a surprising lack of shape change as internal notochord pressure is varied, and determines the tension ratio between different surfaces in the notochord in terms of the relative stiffnesses and internal pressure. A bending study reveals that deformations of the model notochords are well described by classical beam theory, and determines the flexural rigidity of the model notochords in terms of relative stiffnesses and pressure. We find that the staircase pattern is more than twice as stiff as the bamboo pattern. Moreover, the staircase pattern is more than twice as stiff in lateral bending as in dorsoventral bending. This biomechanical difference may provide a specific developmental advantage to regulating the cell packing pattern in early-stage notochords.
Additional authors: Evan J Curcio, North Carolina State University, Biomathematics Graduate Program

Kendall Gibson

Tulane University (Mathematics)
"Modeling the elastohydrodynamics of swimming choanoflagellates"
Choanoflagellates are aquatic single-cell microswimmers that prey on bacteria, and they are of interest in the study of the origins of multicellularity due to their ability to form large colonies. Structurally, they consist of a cell body, a flagellum, and a collar of microvilli. Our model treats the flagellum and the microvilli as elastic Kirchhoff rods whose shapes may be altered due to fluid-structure interactions. In addition to understanding the effect of compliance of these structures on the swimming of a single organism, we aim to study the hydrodynamic interaction of two choanoflagellates and how the collars might affect synchronization of the flagella.

#SMB2023 Follow
Annual Meeting for the Society for Mathematical Biology, 2023.