Phenomenological model of motility by spatiotemporal modulation of active interactions

Abstract

Transport at microscopic length scales is essential in biological systems and various technologies, including microfluidics. Recent experiments achieved self-organized transport phenomena in microtubule active matter using light to modulate motor-protein activity in time and space. Here, we introduce a novel phenomenological model to explain such experiments. Our model, based on spatially modulated particle interactions, reveals a possible mechanism for emergent transport phenomena in light-controlled active matter, including motility and contraction. In particular, the model's analytic treatment elucidates the conservation of the center of mass of activated particles as a fundamental mechanism of material transport and demonstrates the necessity of memory for sustained motility. Furthermore, we generalize the model to explain other phenomena, like microtubule aster–aster interactions induced by more complicated activation geometries. Our results demonstrate that the model provides a possible foundation for the phenomenological understanding of light-controlled active matter, and it will enable the design and optimization of transport protocols for active matter devices.

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