Active Biological Matter

Cytoskletal Active Matter

Microtubules are biopolymers that become active as soon as certain motor proteins bind and move on them. Depending on the density, activity level of the motor proteins, and the properties of the medium, microtubule filaments can exhibit different dynamics and pattern formation. Certain conditions of the medium, such as entropy can be altered by adding depletion agents which exerts local forces on the filaments that lead to their bundling. The activity of motor proteins and the spatial movement of microtubule filaments lead to out-of-equilibrium dynamics. As a result of these dynamics, different patterns of the active microtubule network are formed. We are investigating what parameters can be adjusted to observe different patterns from the same material. Some of the experimental work is listed below:

Formation of active microtubule asters and aggregation of active kinesin clusters inside the asters.
Turbulent beating of active microtubule bundles.
Self-assembly of microtubule bundles in the form of cilia-like beating long bundles in a microfluidic channel.
Tuning the properties of active microtubule networks by depletion forces.
Contraction of microtubule networks by a light-driven ATP module in micrometer-sized droplets.
Active bending of disordered microtubule bundles by kinesin motors.

We use the active filaments of the cytoskeleton as well-characterized biological active matter to understand how such a system can form different patterns by tuning physical or chemical parameters.

Examples of studies related to cytoskeletal active matter (microtubules and kinesin-motor protein mixtures). a) Dynamic microtubule aster and aggregation phase separation of kinesin clusters. b) Tuning of microtubule-aster fusion by modifying the material properties of the active microtubule mixture. c) Self-assembly of microtubule bundles as a cilia-like structure in a microfluidic channel. d) Turbulent beating of active microtubule bundles. e) Tuning the material properties of the passive microtubule network as an isotropic gel-like layer. f) Active bending of disordered microtubule bundles by kinesin motors. j) Investigation of MT network activity excited by a light-driven ATP generation module in micrometer-sized droplets.

1- Nat Rev Mater 2, 17048 (2017). https://doi.org/10.1038/natrevmats.2017.48
2- ACS Synth. Biol. 2021, 10, 6, 1490–1504. https://doi.org/10.1021/acssynbio.1c00071
3- Langmuir 2021, 37, 26, 7919–7927. https://doi.org/10.1021/acs.langmuir.1c00426
4- ACS Omega 2022, 7, 48, 43820–43828. https://doi.org/10.1021/acsomega.2c04958