Czajkowski, Michael David.
Rheology and Collective Behavior in Living Tissue.
Degree: PhD, Physics, 2018, Syracuse University
Recent experiments and simulations have indicated that confluent epithelial layers,
where there are no gaps or overlaps between the cells, can transition from a soft
fluid-like state to a solid-like state, with dynamics that share many features with
glass transitions. While a coherent picture has begun to form connecting the microscopic
mechanisms that drive this transition with macroscopic observables, much less is known
of its consequences in biological processes. Do tissues tune themselves to a fluid state
in order to promote collective motion? Has evolution made use of the ability of tissues
to tune themselves between fluid and solid states in programming the complex steps
leading from the embryo to the organism? Here we describe our recent e↵orts to answer
such questions using continuum and mesoscopic models. Employing the biophysical vertex
model, active cells in confluent tissue are described as polygons with shape-based
energies. Recent work has shown that this class of models yields a solid-liquid
transition of tissue with evidence of glassy dynamics near the transition line. Here, we
extend one such model to include the influence of cell division and cell death. With
careful numerical studies, we refute a recent claim that the presence of such division
and death will always fluidify the tissue. In the second part of the thesis, we develop
a novel hydrodynamic model of confluent motile tissues that couples a structural order
parameter for tissue rigidity to cell polarization. Using this continuum model we
identify a new mechanism for pattern formation in confluent tissues via rigidity sensing
that we name “morphotaxis”. We find that a single “morphotactic” parameter controls
whether a tissue will remain homogeneous or will develop patterns such as asters and
Advisors/Committee Members: M. Lisa Manning, M. Cristina Marchetti.
Subjects/Keywords: Active; Flocking; Rheology; Tissues; Physical Sciences and Mathematics
to Zotero / EndNote / Reference
APA (6th Edition):
Czajkowski, M. D. (2018). Rheology and Collective Behavior in Living Tissue. (Doctoral Dissertation). Syracuse University. Retrieved from https://surface.syr.edu/etd/914
Chicago Manual of Style (16th Edition):
Czajkowski, Michael David. “Rheology and Collective Behavior in Living Tissue.” 2018. Doctoral Dissertation, Syracuse University. Accessed December 14, 2018.
MLA Handbook (7th Edition):
Czajkowski, Michael David. “Rheology and Collective Behavior in Living Tissue.” 2018. Web. 14 Dec 2018.
Czajkowski MD. Rheology and Collective Behavior in Living Tissue. [Internet] [Doctoral dissertation]. Syracuse University; 2018. [cited 2018 Dec 14].
Available from: https://surface.syr.edu/etd/914.
Council of Science Editors:
Czajkowski MD. Rheology and Collective Behavior in Living Tissue. [Doctoral Dissertation]. Syracuse University; 2018. Available from: https://surface.syr.edu/etd/914