As an embryo develops, its cells divide, transfer and work together. In doing so, the mechanical properties of tissues, corresponding to viscosity and elasticity, change over time. David Oriola, a biophysicist with the Trivedi group, research the bodily adjustments that tissues endure throughout early growth. He combines experiments with mathematical modeling to elucidate how cells self-organize to type tissues. His most up-to-date research was printed in Tender Matter.
“Shortly earlier than the beginning of the confinement, I used to be learning the fusion of embryonic stem cell aggregates. To my shock, the 2 aggregates solely partially merged,” Oriola mentioned. “I later found that this course of is called arrested coalescence, and it’s a frequent phenomenon in gentle matter physics.”
Arrested coalescence is essential within the manufacture of petroleum, cosmetics and a few processed meals. For instance, within the meals business, the consistency and texture of whipped cream depends upon the partial coalescence of fats droplets from the cream.
Present bodily fashions describing the fusion of mobile aggregates didn’t think about the potential for partial coalescence and due to this fact couldn’t clarify Oriola’s experimental findings. Nonetheless, earlier than he might repeat the experiments, the pandemic arrived and the lab was locked down.
“I began reviewing the literature on the physics of droplet sintering. The primary mathematical descriptions of sintering date again to 1945, when Frenkel was making an attempt to elucidate the sintering of steel droplets,” Oriola defined. “As we have been all at house, unable to do any new experiments, I reproduced the calculations and re-derived the viscous sintering equations.”
Oriola realized that the mathematical fashions used to check the fusion of mobile aggregates seen tissues as purely viscous supplies. Nonetheless, such fashions couldn’t account for arrested coalescence as a result of they don’t account for the attribute elasticity of viscoelastic supplies like organic tissues.
“I revisited mathematical fashions and determined to mannequin tissues as viscoelastic solids, as an alternative of viscous fluids, which implies elastic results persist even over very long time scales. The subsequent step was to see if this mannequin might match the experimental knowledge,” Oriola mentioned.
And he did. The mannequin efficiently defined the fusion dynamics of mobile aggregates in addition to how fusion dynamics change with mixture dimension. On this method, this mannequin offers a quick and cheap technique to check the mechanical properties of tissues from easy time-lapse melting occasions. Furthermore, with the Ebisuya group, the researchers confirmed that the mannequin efficiently defined the fusion of different varieties of stem cell aggregates. Lastly, in collaboration with the Sharpe group, the fusion experiments have been reproduced utilizing laptop simulations which helped them perceive how microscopic mobile properties relate to macroscopic materials properties.
The work of David Oriola and his colleagues suits completely into the brand new EMBL program, and extra concretely into the analysis theme [email protected]which promotes theory-driven pathways to understanding the underlying rules of organic techniques.
“What’s encouraging about this mannequin is that it might have broader implications past biology. In precept, the identical technique may very well be utilized to characterize the fabric properties of microemulsions just by taking a look at how the fats globules fuse,” Oriola mentioned.