Guiding Self-Organization in Active Matter with Spatiotemporal Boundary Conditions

Citation

Ross, Tyler David (2021) Guiding Self-Organization in Active Matter with Spatiotemporal Boundary Conditions. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/q85h-j730. https://resolver.caltech.edu/CaltechTHESIS:07082020-113341068

Abstract

In this thesis, I demonstrate that self-organized structures and forces can be guided by modulating the interactions between force-generating molecules in space and time. The physics of self-organizing systems is an open frontier. We do not have a complete set of principles that can describe how a dynamic structure forms based on the non-equilibrium dynamics of its constituent components. Yet, living systems appear to depend on some set of rules of self-organization in order to reliably carry out their mechanical functions. Force-generating, active, molecules in the form of motor proteins and filamentous polymers are responsible for performing fundamental tasks in living matter, such as locomotion and division. While it is known that the regulation of motor-filament interactions is necessary to achieve the dynamic structures that drive movement and propagation, the role of spatial and temporal patterning in self-organizing systems has not been explored. I design a artificial system of purified molecules where the interactions between motors and filaments are toggled with light. By patterning molecular interactions in space and time, I show that it is possible to localize the formation of spherically symmetric asters, which can be moved, merged, and used to generate advective fluid flows. The ability to pattern molecular interactions in space and time offers a new perspective in the search for principles of active self-organization. Spatial and temporal control makes it possible to start distilling how the interactions between active molecules determine the mesoscopic behaviors of self-organized structures. These rules ultimately govern the physics of living matter and may eventually be harnessed to build new materials and cell-like machines.

Thesis Files