01945nas a2200193   4500008004100000022001400041245006300055210006200118260000700180300001300187490000700200520139700207653002201604653002001626653001901646653002001665100002301685856004301708       2025                        eng d  a2042-890100aSurface tension-driven boundary growth in tumour spheroids0 aSurface tensiondriven boundary growth in tumour spheroids  c05  a202400350 v153 a<p>Growing experimental evidence highlights the relevant role of mechanics in the physiology of solid tumours, even in their early stages. While most of the mathematical models describe tumour growth as a volumetric increase in mass in the bulk, in vitro experiments on tumour spheroids have demonstrated that cell proliferation occurs in a thin layer at the boundary of the cellular aggregate. In this work, we investigate how elasticity and surface tension interact during the development of tumour spheroids. We model the spheroid as a hyperelastic material undergoing boundary accretion, where the newly created cells are deformed by the action of surface tension. This growth leads to a frustrated reference configuration, resulting in the appearance of residual stress. Our theoretical framework is validated using experimental results from the literature. Like fully developed tumours, spheroids open when subjected to radial cuts. Remarkably, this behaviour is observed even in newly formed spheroids, which lack residual stress. Through both analytical solutions and numerical simulations, we show that this phenomenon is driven by elastocapillary interactions, where the residual stress developed in grown spheroids amplifies the tumour opening. Our model’s outcomes align with experimental observations and allow us to estimate the surface tension acting on tumour spheroids.</p>10aelastocapillarity10aresidual stress10asurface growth10atumour spheroid1 aRiccobelli, Davide  uhttps://doi.org/10.1098/rsfs.2024.0035