Examining the Interplay Between Advective and Crowding Effects During Intercellular Cargo Transport

The cytoskeleton is a prime example of active matter. Its composition, consisting of a network of proteins, molecular motors, and biopolymers, facilitates many different transport methods. Crowding causes anomalous, subdiffusive passive transport; additionally, the restructuring of the cytoskeleton facilitates active transport of particles through advective diffusion. However, understanding the interplay between the transport types and how both the network’s and the cargo’s properties impact transport has been difficult. We previously showed that DNA and microspheres tracked in these complex environments exhibit heterogeneous and lagtime-dependent transport dynamics. The lagtime-dependent transport was interpreted to mean that two competing effects whose dominance changed. This talk describes followup experiments designed to decouple these competing effects. To uncover this relationship, we form a composite network of actin, myosin, and tubulin that allows us to control the actomyosin content. We use a variety of particle sizes and actomyosin density to change activation while holding mesh size to particle size ratio constant. Our results shed light on the interplay between crowding and advection in addition to other non-equilibrium processes. Our findings are also applicable to other active matter systems to understand transport and dynamics.