Past projects
Cytoskeletal active matter, self-organization of microtubules and motor proteins:
We have studied microtubule filaments in the context of their activity as biopolymers by the activity of motor proteins. However, the question arose as to how physical parameters such as density, activity level of motor proteins and the entropic forces can change the pattern formation in such active filaments. We have studied stabilized microtubule filaments with kinesin motor proteins in microfluidic channels or droplets to understand the role of initial physical parameters in the final self-organization of the filaments, leading to the following conclusions:
- Active microtubule filaments in a bundle show a reversal of motility due to the displacement of motor proteins. This leads to a reversal of gliding, although unidirectional gliding would be expected due to their polarity. The reversal causes the filament to beat, similar to the movement of cilia (https://pubs.acs.org/doi/10.1021/acsomega.2c04958 ).
- The crowding polymer, which pushes the filaments together, leading to a contractive network, can also tune the material properties of the network. By mixing two different crowding agents, the active network's material properties can be tuned (https://pubs.acs.org/doi/full/10.1021/acs.langmuir.1c00426).
- The dimensions of the microfluidic channel, as well as the initial length and concentration of the filaments, can drive the active filaments to a completely different self-organization. Examples include the formation of beating artificial cilia bundles patterned as a cilia carpet and breaking up into local vortices and chaotic mixing (preliminary data).
- In a collaborative project, we showed that studying the activity of microtubule filaments in a droplet with a light-driven ATP module can result in the polar localization of the filaments within the droplet (https://pubs.acs.org/doi/full/10.1021/acssynbio.1c00071).
- In the active mixture of microtubule filaments confined within an evaporating droplet, we observed that coupling of flow forces within the evaporating droplet with the active forces inside the microtubule ntwork resulted in the formation of a symmetric and ring-like organization of the filaments. This suggests that hydrodynamic forces could play an important role in the dynamic organization of the cytoskeletal filaments (https://arxiv.org/abs/2305.07099).
a) Dynamics of the motor protein cluster in a synthetic cilia, the reversal of the sliding filaments. b) Effect of the crowding polymer on the material properties and dynamics of the active microtubule network. c) Activity and dynamics of microtubules induced by a light-driven ATP module in a droplet. d) Effect of filament length and alignment on the final pattern and self-assembly of the filaments. e) Dynamics of the active microtubule network in an evaporating droplet and formation and compact ring-shaped arrangement of microtubule filaments.