Understanding the self-organization of living systems is one of the biggest conceptual challenges of the present century. A generic mechanism that drives such organization is interaction among the individual elements — which may represent cells, bacteria, or even enzymes — via chemical signals. The ability of an individual cell to follow a gradient of chemicals is called chemotaxis1.
The interplay between cellular growth and cell-cell signaling is essential for the aggregation and proliferation of bacterial colonies, as well as for the self-organization of cell tissues. During this internship, we will consider microscopic and coarse-grained models for assemblies of chemotactic cells that produce their own chemical field, leading to effective long-range interactions between them. To characterize the nonlinear pattern formation stemming from the interplay between cell proliferation and cell-cell chemotactic signaling, several approaches could be considered:
a numerical approach, based on simulations of the microscopic equations of motions or on solving the coarse-grained partial differential equations2, a field-theoretical approach, that will allow characterizing the critical points and scaling properties of such colonies345.
- Keller and Segel, “Model for chemotaxis”, J. Theor. Biol. 30, 225 (1971) ↩︎
- Hillen and Painter, “A user’s guide to PDE models for chemotaxis”, J. Math. Biol. 58, 183 (2009) ↩︎
- R. Ben Alì Zinati, C. Duclut, S. Mahdisoltani, A. Gambassi, and R. Golestanian, “Stochastic dynamics of chemotactic colonies with logistic growth”, EPL 136, 50003 (2022) ↩︎
- S. Mahdisoltani, R. Ben Alì Zinati, C. Duclut, A. Gambassi, and R. Golestanian, “Nonequilibrium polarity-induced chemotaxis: Emergent Galilean symmetry and exact scaling exponents”, Phys. Rev. Research 3, 13100 (2021) ↩︎
- Jasper van der Kolk, Florian Raßhofer, Richard Swiderski, Astik Haldar, Abhik Basu, and Erwin Frey, “Anomalous Collective Dynamics of Autochemotactic Populations”, Phys. Rev. Lett. 131, 088201 (2023) ↩︎