Buckling without Bending: A New Paradigm in Morphogenesis.

Area of Science:

• Developmental biology
• Biophysics
• Morphogenesis

Background:

• Organ and organoid morphogenesis exhibits variable spatial oscillations in film thickness relative to substrate deformation.
• Existing models like elastic bilayer instability fail to explain out-of-phase oscillations, challenging universal mechanisms for organ folding.
• This variability suggests a need for novel models to understand diverse developmental processes.

Purpose of the Study:

• To develop a new 2D model of morphogenesis that explains observed phenomena in organ development.
• To incorporate microstructural features, specifically elastic fibers, to explain preferred radius and resistance to thickness gradients.
• To account for out-of-phase oscillations and scale invariance observed in various developing organs.

Main Methods:

• Development of a novel 2D analytical model inspired by embryonic cerebellum microstructure.
• Inclusion of system-spanning elastic fibers to define a preferred organ radius.
• Modeling of a separate fiber network in the outer film to resist thickness gradients, incorporating a "growth potential" for uniform thickening/thinning.

Main Results:

• The model successfully explains out-of-phase oscillations between film thickness and substrate deformation in morphogenesis.
• It accounts for observed features in cerebellum, organoid, and retinal fovea development, including amplitude relationships.
• The model may also explain scale invariance in cerebellar fold numbers.

Conclusions:

• A new model incorporating elastic fibers and growth potentials provides a unified explanation for diverse organ morphogenesis patterns.
• This framework moves beyond elastic bilayer instability to explain complex folding dynamics.
• The model offers insights into developmental biology and has potential for bioinspired applications.