Abstract

Authors: Jan Rozman and Julia M. Yeomans We study a mixture of extensile and contractile cells using a vertex model extended to include active nematic stresses [1]. The two cell populations phase separate over time. While an increase in contractile activity always aids phase separation, sufficiently high extensile activity reduces the extent of sorting. This can be understood by analysing a small contractile droplet in an extensile bulk: Increasing extensile activity results in the droplet being torn apart by the activity of the bulk, whereas greater contractile activity leads to cells “sticking” together, maintaining a connected droplet for longer. We compare these results with a “wet” vertex model in which substrate-vertex friction is replaced by vertex-vertex friction [2] as a proxy for internal dissipation. This significantly changes the dynamics of the vertex model, allowing, e.g., long range velocity correlations and unidirectional flows in a channel due to nematic activity [3]. References

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