The battle between internal and external forces in microtubule–kinesin active fluid

Описание: In this video, we present experimental and numerical studies of how microtubule–kinesin active fluids respond to externally imposed shear under different confinement geometries. By comparing slab-like cavities, toroidal confinement, and connected toroids, we identify a common stress threshold for response and show that the nature of the response depends on confinement topology. Our results reveal two distinct mechanisms governing active fluid responses to external forcing: stress competition and stress cooperation.

Chapters:
0:00 Introduction
0:53 Microtubule–kinesin active fluids
3:49 Cavity flow experiments
8:25 Flow analysis of cavity flow experiments
13:36 Estimation of the stress threshold
16:58 Microtubule network under driving
18:43 Numerical simulations
24:40 Toroidal confinement
27:10 Flow analysis of the toroidal confinement experiments
30:18 Flow reversal dynamics
33:07 Mini-cavity flow in toroidal confinement
34:02 Connected toroids experiment
35:52 Take-home messages

Full publication:
Dickie et al. Geometry-dependent transmission of externally imposed shear stress in confined microtubule–kinesin active fluids. Soft Matter (2026)
https://doi.org/10.1039/d5sm00871a

Funding:
This work was supported by the National Science Foundation (NSF-CBET-2045621, NSF-CBET-2227361, NSF-MRSEC-DMR-2011846, NSF-PHY-2309135).