02372nas a2200205 4500008004100000022001400041245007400055210006900129300001100198490000800209520173200217653001301949653001801962653002201980653002702002653002002029100002302049700002302072856007102095 2020 eng d a0022-509600aSurface tension controls the onset of gyrification in brain organoids0 aSurface tension controls the onset of gyrification in brain orga a1037450 v1343 aUnderstanding the mechanics of brain embryogenesis can provide insights on pathologies related to brain development, such as lissencephaly, a genetic disease which causes a reduction of the number of cerebral sulci. Recent experiments on brain organoids have confirmed that gyrification, i.e. the formation of the folded structures of the brain, is triggered by the inhomogeneous growth of the peripheral region. However, the rheology of these cellular aggregates and the mechanics of lissencephaly are still matter of debate. In this work, we develop a mathematical model of brain organoids based on the theory of morpho-elasticity. We describe them as non-linear elastic bodies, composed of a disk surrounded by a growing layer called cortex. The external boundary is subjected to a tissue surface tension due the intercellular adhesion forces. We show that the resulting surface energy is relevant at the small length scales of brain organoids and affects the mechanics of cellular aggregates. We perform a linear stability analysis of the radially symmetric configuration and we study the post-buckling behaviour through finite element simulations. We find that the process of gyrification is triggered by the cortex growth and modulated by the competition between two length scales: the radius of the organoid and the capillary length generated by surface tension. We show that a solid model can reproduce the results of the in-vitro experiments. Furthermore, we prove that the lack of brain sulci in lissencephaly is caused by a reduction of the cell stiffness: the softening of the organoid strengthens the role of surface tension, delaying or even inhibiting the onset of a mechanical instability at the free boundary.10aBuckling10aEmbryogenesis10aMorpho-elasticity10aPost-buckling analysis10aSurface tension1 aRiccobelli, Davide1 aBevilacqua, Giulia uhttp://www.sciencedirect.com/science/article/pii/S002250961930406500478nas a2200133 4500008004100000245006600041210006600107260001600173300001200189490000700201100002300208700001600231856009700247 2019 eng d00aActivation of a muscle as a mapping of stress–strain curves0 aActivation of a muscle as a mapping of stress–strain curves bElsevier BV a37–420 v281 aRiccobelli, Davide1 aAmbrosi, D. uhttps://www.math.sissa.it/publication/activation-muscle-mapping-stress%E2%80%93strain-curves00512nas a2200133 4500008004100000245007600041210006900117260002200186490000800208100002300216700001500239700002400254856010000278 2019 eng d00aOn the existence of elastic minimizers for initially stressed materials0 aexistence of elastic minimizers for initially stressed materials bThe Royal Society0 v3771 aRiccobelli, Davide1 aAgosti, A.1 aCiarletta, Pasquale uhttps://www.math.sissa.it/publication/existence-elastic-minimizers-initially-stressed-materials00556nas a2200121 4500008004100000245010600041210006900147260002000216100002200236700002400258700002300282856012900305 2018 eng d00aA Comparison Between Active Strain and Active Stress in Transversely Isotropic Hyperelastic Materials0 aComparison Between Active Strain and Active Stress in Transverse bSpringer Nature1 aGiantesio, Giulia1 aMusesti, Alessandro1 aRiccobelli, Davide uhttps://www.math.sissa.it/publication/comparison-between-active-strain-and-active-stress-transversely-isotropic-hyperelastic00454nas a2200133 4500008004100000245005600041210005500097260001600152300001000168490000800178100002300186700002400209856008700233 2018 eng d00aMorpho-elastic model of the tortuous tumour vessels0 aMorphoelastic model of the tortuous tumour vessels bElsevier BV a1–90 v1071 aRiccobelli, Davide1 aCiarletta, Pasquale uhttps://www.math.sissa.it/publication/morpho-elastic-model-tortuous-tumour-vessels00543nas a2200133 4500008004100000245007700041210006900118260004700187300001600234490000700250100002300257700002400280856010500304 2018 eng d00aShape transitions in a soft incompressible sphere with residual stresses0 aShape transitions in a soft incompressible sphere with residual bSAGE Publications Sage UK: London, England a1507–15240 v231 aRiccobelli, Davide1 aCiarletta, Pasquale uhttps://www.math.sissa.it/publication/shape-transitions-soft-incompressible-sphere-residual-stresses00452nas a2200121 4500008004100000245005700041210005700098260002200155490000800177100002300185700002400208856009800232 2017 eng d00aRayleigh–Taylor instability in soft elastic layers0 aRayleigh–Taylor instability in soft elastic layers bThe Royal Society0 v3751 aRiccobelli, Davide1 aCiarletta, Pasquale uhttps://www.math.sissa.it/publication/rayleigh%E2%80%93taylor-instability-soft-elastic-layers00623nas a2200169 4500008004100000245008300041210006900124260002500193300001400218490000800232100001600240700001600256700002300272700002300295700002400318856011100342 2017 eng d00aSolid tumors are poroelastic solids with a chemo-mechanical feedback on growth0 aSolid tumors are poroelastic solids with a chemomechanical feedb bSpringer Netherlands a107–1240 v1291 aAmbrosi, D.1 aPezzuto, S.1 aRiccobelli, Davide1 aStylianopoulos, T.1 aCiarletta, Pasquale uhttps://www.math.sissa.it/publication/solid-tumors-are-poroelastic-solids-chemo-mechanical-feedback-growth