Actin is a vital cytoskeletal protein that functions as a molecular polymerization motor. Within living cells, actin filaments generate mechanical forces (without any molecular motors) through a dynamic balance of polymerization and depolymerization in a process known as treadmilling.
This machinery allows cells to crawl and reshape themselves. Pathogens like the bacteria Listeria monocytogenes also exploit this mechanism, hijacking the host cell’s actin to build propulsion tail networks that drive them forward. Our works reconstruct this treadmilling mechanism within synthetic biological materials. By transitioning from complex cellular environments to controlled synthetic systems, we explore how biomimetic force generation leads to emergent non-equilibrium phenomena.
 
In this talk, I will present two complementary approaches that exploit actin treadmilling within synthetic biological materials. First, I will discuss how local actin filament growth alters the phase-separation dynamics of DNA-nanostar condensates, driving emergent structural behaviors from droplet reorganization to fragmentation. Second, I will show how leveraging this same motor mechanism allows us to engineer microscopic "beating tails" driven purely by polymerization. These findings collectively demonstrate how simple, localized molecular mechanisms can be leveraged to drive complex macroscopic behaviors, offering a new playground for exploring emergent active matter physics.