Supplementary Materials

Topology and dynamics of active nematic vesicles

Felix C. Keber, Etienne Loiseau, Tim Sanchez, Stephen J. DeCamp, Luca Giomi, Mark J. Bowick, M. Cristina Marchetti, Zvonimir Dogic, Andreas R. Bausch

Materials/Methods, Supplementary Text, Tables, Figures, and/or References

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  • Materials and Methods
  • Supplementary Text
  • Figs. S1 to S8
  • Captions for movies S1 to S8

Images, Video, and Other Other Media

Movie S1
Dynamics of nematic defects confined on a spherical vesicle. The left panels show the z-projected hemispheres (as explained in Figure 1a of the main text). The microtubule bundles are shown in cyan and the positions of the four +1/2 defects are indicated by the colored markers (magenta, red, yellow, green). The right panel shows the reconstructed 3D-view of the defect dynamics within a unit sphere.
Movie S2
Theoretical model predicts oscillatory dynamics of four +1/2 defects confined on a spherical surface. The left panel shows a 3D-view of the defect movement from numerical simulations. A stereographic projection is given at the upper right. The defect positions ri are marked by the dots and the arrows represent the orientation ui. The corresponding state in the energy landscape is shown on the lower right (violet dot).
Movie S3
Active nematic cortex drives vesicle-shape changes. For membranes with excess membrane area, the active nematic cortex induces significant shape deformation. The vesicle is locally elongated along the direction of the four +1/2 defects oscillatory motion.
Movie S4
Deformations of deflated vesicles with excess membrane. An initially round vesicle undergoes elliptic shape deformation as excess membrane is provided. Protrusions grow out at the positions of the defects. The ring pattern is an artifact of the imaging due to the fact that the z—resolution was reduced to increase the frame rate. A median filter was applied to reduce the noise. At t = 5 min and 25 s the hypertonic stress was applied, which resulted in a drift of the vesicle and the subsequent correction of the sample position.
Movie S5
Ring-mode vesicle. The microtubule nematic forms a rotating ring inside the vesicle. The ring elongates and folds into a structure with four defects that move pairwise towards each other. By the collision of the defects a new ring is formed and the process repeats itself.
Movie S6
Ring-mode schematic. The schematic illustrates the elongation and folding of the ring described in Movie S5.
Movie S7
Spindle-like vesicle. The movie displays the dynamics of a spindle-like vesicle with two +1 defects at its poles. The bundles at the poles extend and create stresses that cause the spindle to flip and fold onto itself as the two poles merge together. Bundles then protrude at the opposite side creating a new pole and thus the process starts to repeat.
Movie S8
Spindle-like vesicle that transforms into a ring. The two poles of an initial spindle configuration (t = 0 s) merge into a spike (t = 75 s). The transport (t = 150 s), breakage (t = 225 s), and subsequent annealing (t = 300 s) of the microtubules results in a ring configuration.