Microtubule + kinesin active nematic. Glyphs label ± ½ defects (magenta and cyan, respectively) identified using QCon.
Experimental data from Linnea Lemma (Dogic Lab).

Controlling Active Fluids

Active fluids are systems comprised of energy-consuming constituents swimming in an otherwise passive medium. Examples include flocks of birds, swarms of insects and bacteria, and the motor-protein-driven contents of cells. They are known for their ability to spontaneously exhibit complex spatiotemporal patterns on length and timescales much larger than the underlying active agents (PRL 2021). In the case of active nematic liquid crystals built from reconstituted biopolymeric components (above), these dynamics take the form of low Reynolds number chaotic flows laden with motile topological disclinations (magenta and cyan symbols in the above movie).

Corralling these defects into desired configurations is an ongoing challenge. In order to leverage the impressive chemomechanical abilities of these materials, I use computational methods to understand how boundary conditions (PRE 2018, PNAS 2019, PRL 2022) and spatiotemporal patterns of active stress strength (PRL 2020, Nat. Comm. 2022) can be used to steer their dynamics.

Engineering Bioinspired Chemical Oscillator Networks

The rich spatiotemporal diversity of living systems is underpinned by intertwined reaction-diffusion and chemomechanical systems. By manipulating topology and coupling-type in discrete networks of Belousov-Zhabotinsky reactors, my collaborators and I showed how to build synthetic oscillator networks that spontaneously manifest desired, synchronous patterns such as those created by small groups of neurons called central-pattern-generators.