Great thread, thank you for all the references! We recently posted a preprint on force inference for organoids with an accompanying Python tool, ForceIn3D, which we will hopefully publish soon together with the paper (www.biorxiv.org/content/10.1...).

This work was my main PhD project @uniheidelberg.bsky.social and @mattertolife.bsky.social. I am proud that we can present it now! If you are interested, please check out our preprint on bioRxiv: biorxiv.org/content/10.1...

So can we find a signature of this effect in our inference? Yes. We introduce line tension inference and find that apical and basal line tensions seem to be increased. Especially the basal line tensions can only be explained through additional intracellular physics.

No! Tensions decrease afterwards and, in fact, apical tension and the apico-basal tension difference in buds decrease. We even find anti-correlation of tissue-scale
mean curvature H and cell-scale tension difference. Thus a ratchet-like mechanism has to maintain bud shape.

We next looked at budding intestinal organoids and found that at the time point where budding occurs (48h) apico-basal tension differences are increased, leading to spontaneous curvature. Buds form through apical contraction. Are they stabilized through this mechanism though?

Our method has been extensively tested on in-silico organoids, which we have simulated with our recently introduced bubbly vertex model. Organoids are modeled through cell interfaces subject to surface and line tensions and inference results are tested against ground truth data.

We developed a 3D reconstruction method, where we perform segmentation of organoid image stacks with subsequent geometrical reconstruction in order to use force balance to infer underlying surface and line tensions.

If this image was intriguing, I invite you to check out the publication: doi.org/10.1103/Phys....
There is actually some nice follow-up work on the arXiv, which I will discuss soon in a Bsky thread.