Instabilities in hexanematic models of epithelia

Epithelial tissues, whose study remain fundamental to understand processes such as cancer progression, have revealed to exhibit multiscale orientational order. While the large scale dynamics is ruled by the nematic symmetry, hexatic order instead controls the behavior of small clusters of cells. By considering a hydrodynamic approach, we investigate the stability of hexanematic liquid crystals identifying the role of activity and flow alignment in the generation of spontaneous flows, which also reflect the interplay between different length scales. We finally address possible consequences when confining such a fluid in a channel, connecting this phenomenology with recent observations of metastatic cell invasion.