The physics of organoids: a biophysical approach to understanding organogenesis

Organoids representing a diversity of tissues have recently been created, bridging the gap between cell culture and experiments performed in vivo. Being small and amenable to continuous monitoring, they offer the opportunity to scrutinize the dynamics of organ development, including the exciting prospect of observing aspects of human embryo development live. From a physicist's perspective, their ability to self- organize - to differentiate and organize cells in space - calls for the identification of the simple rules that underlie this capacity. Organoids provide tractable conditions to investigate the effects of the growth environment, including its molecular composition and mechanical properties, along with the initial conditions such as cell number and type(s). From a theoretical standpoint, different types of in silico modeling can complement the measurements performed in organoids to understand the role of chemical diffusion, contact signaling, differential cell adhesion and mechanical controls. Here, we discuss what it means to take a biophysical approach to understanding organogenesis in vitro and how we might expect such approaches to develop in the future.