Surface tension-driven boundary growth in tumour spheroids

Area of Science:

• Biophysics
• Mathematical Biology
• Cancer Research

Background:

• Tumor growth mechanics are crucial, even in early stages.
• Traditional models focus on bulk volumetric increase, but experiments show boundary-layer proliferation.
• Tumor spheroids offer a model to study these mechanics in vitro.

Purpose of the Study:

• To investigate the interplay between elasticity and surface tension in tumor spheroid development.
• To model spheroid growth considering boundary accretion and resulting residual stress.
• To validate the theoretical framework with experimental data and estimate surface tension.

Main Methods:

• Modeling tumor spheroids as hyperelastic materials undergoing boundary accretion.
• Analyzing the deformation of newly formed cells due to surface tension.
• Employing analytical solutions and numerical simulations to study elastocapillary interactions.
• Comparing model outcomes with experimental results from the literature.

Main Results:

• Tumor spheroids exhibit opening behavior when subjected to radial cuts, similar to fully developed tumors.
• This opening is observed even in nascent spheroids lacking residual stress.
• Elastocapillary interactions, amplified by residual stress in grown spheroids, drive the opening phenomenon.
• The model successfully aligns with experimental observations and allows for surface tension estimation.

Conclusions:

• The interaction of elasticity and surface tension is fundamental to tumor spheroid mechanics.
• Elastocapillary forces, not just residual stress, explain spheroid opening.
• The developed theoretical framework provides a valuable tool for understanding and quantifying forces within tumor spheroids.