Spatio-Temporal Regulation of Active Fluids via Light

Living systems regulate dynamical structures through internal biochemical networks, enabling processes like cell division, movement, and development. In this study, we replicate this behavior in synthetic materials using a compressible microtubule-kinesin active fluid with optically responsive kinesin motors, where the dynamics are controlled by external light patterns.

By investigating how this active fluid responds to varying spatial wavelengths of light patterns, we examine their effect on microtubule density and velocity buildup. A critical length scale is identified, below which microtubule density remains uniform without variation. Additionally, two distinct timescales are found to govern the formation of density and velocity fields—one on the order of hours, and the other around a minute. These findings highlight the spatial and temporal constraints in controlling active fluid dynamics.