Abstract
In life, processes such as morphogenesis rely on the delicate coordination between chemical signaling and mechanical response. Thus, the study of such coordination is important to understanding active materials and uncovering the rules that govern them. Here, we investigate an active colloidal system propelled by the polymerization of actin filaments. We discover that there is an interplay between the propulsion of these colloids and a remodeling of their biochemical environment that feeds back into modifying the activity of neighboring colloids, leading to a zoo of emergent behavior. We show that consumption of actin generates local depletion which impacts the motility of neighboring colloids by inducing asymmetric polymerization rates along a bead surface. This is supported by experiments demonstrating the preferential aggregation of colloids against a boundary with or without a replenishing protein reservoir on the opposite side. Other behaviors exhibited by the beads, such as mechanical bucking and pair-wise orbiting, prompted investigation and were studied. We show that the beating of an actin comet tail shows similarities to drag-induced filament coiling and flagellar beating. This work demonstrates how an active system can rapidly itself in response to its environment leading to novel emergent behavior key to understanding feedback mechanisms between chemical signaling and mechanical force generation in nature. In the future, the work in this thesis can be used to jump-start investigations into this diverse experimental system as well as provide a basis for working with similar actin-based systems.