LMP Seminar: Constructing a Three-Sphere Swimmer from a Model of Coupled Enzymes

Self-propulsion without the use of inertial effects is a topic far beyond our everyday experience, and one that is of continuing interest due to recent advances in chemical engineering, such as the successful design of molecular machines. In this talk I will present the results of our work in which we introduce --- inspired by the three-sphere swimmer model --- a low Reynolds number swimmer consisting of two individual but coupled enzymes that undergo noise-driven conformational changes. We will see how hydrodynamic interactions between different parts of the enzyme complex lead to directed motion when the two enzymes are non-identical, breaking the reciprocity of the swimmer's deformation. I will discuss the conditions under which the two units exhibit a form of cooperation that results in more efficient swimming and enhanced diffusion. These observations will be justified by exploiting the minimal number of degrees of freedom in our model and the purely geometric nature of locomotion in the low Reynolds number regime. Finally, we will discuss our proposal for a way to construct stochastic microswimmers.