Title: Theory of mechano-chemical patterning in biphasic biological tissues,
Abstract: The formation of self-organized patterns is key to the morphogenesis of
multicellular organisms, although a comprehensive theory of biological pattern
formation is still lacking. Here, we propose a minimal model combining tissue
mechanics to morphogen turnover and transport in order to explore new routes to
patterning. Our active description couples morphogen reaction-diffusion, which
impact on cell differentiation and tissue mechanics, to a two-phase poroelastic
rheology, where one tissue phase consists of a poroelastic cell network and the
other of a permeating extracellular fluid, which provides a feedback by
actively transporting morphogens. While this model encompasses previous
theories approximating tissues to inert monophasic media, such as Turing's
reaction-diffusion model, it overcomes some of their key limitations permitting
pattern formation via any two-species biochemical kinetics thanks to
mechanically induced cross-diffusion flows. Moreover, we describe a
qualitatively different advection-driven Keller-Segel instability which allows
for the formation of patterns with a single morphogen, and whose fundamental
mode pattern robustly scales with tissue size. We discuss the potential
relevance of these findings for tissue morphogenesis.