Shape transitions in a network model of active elastic shells

Ajoy Maji, Kinjal Dasbiswas, Yitzhak Rabin

Research output: Contribution to journalArticlepeer-review


Morphogenesis involves the transformation of initially simple shapes, such as multicellular spheroids, into more complex 3D shapes. These shape changes are governed by mechanical forces including molecular motor-generated forces as well as hydrostatic fluid pressure, both of which are actively regulated in living matter through mechano-chemical feedback. Inspired by autonomous, biophysical shape change, such as occurring in the model organism hydra, we introduce a minimal, active, elastic model featuring a network of springs in a globe-like spherical shell geometry. In this model there is coupling between activity and the shape of the shell: if the local curvature of a filament represented by a spring falls below a critical value, its elastic constant is actively changed. This results in deformation of the springs that changes the shape of the shell. By combining excitation of springs and pressure regulation, we show that the shell undergoes a transition from spheroidal to either elongated ellipsoidal or a different spheroidal shape, depending on pressure. There exists a critical pressure at which there is an abrupt change from ellipsoids to spheroids, showing that pressure is potentially a sensitive switch for material shape. We thus offer biologically inspired design principles for autonomous shape transitions in active elastic shells.

Original languageEnglish
Pages (from-to)7216-7226
Number of pages11
JournalSoft Matter
Issue number37
StatePublished - 27 Sep 2023

Bibliographical note

Publisher Copyright:
© 2023 The Royal Society of Chemistry.


YR would like to thank David Kessler for the helpful discussions and suggestions, and Eli Sloutskin for his critical comments on the manuscript. AM would like to acknowledge the hospitality of the Physics department of Bar-Ilan University where part of the work was done. AM would like to thank Yuval Garini and Biophysics, Nano-dynamics lab (Technion-IIT) where the rest of the work was performed.

FundersFunder number
Yuval Garini and Biophysics


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