It's absolutely crazy how well this bio hybrid material worked. Two years ago I helped modeling the mechanochemical response of the material which embeds single celled algae in a gel matrix developed in the lab of Shengqiang Cai at UCSD and refined by Chris Bellamy.

www.science.org/doi/10.1126/...

Extremely happy that I was awarded with the Emerging Soft Matter Excellence award yesterday!😊

This is a huge honor for me!
But most importantly I met all the amazing other finalists and learned all about their cutting edge research!
engage.aps.org/dsoft/honors...

Thank you @apsdsoft.bsky.social !

On a last note:
Our colleagues Chenghai Li and Prof. Shengqiang Cai at UCSD also managed to make a 3d printable bio-hybrid gel containing our algae. And we provided some modeling to their work.
Such mechano-luminescent materials are just super fun to play with! :D
www.science.org/doi/10.1126/...

To shine a bit more light on the sensing we asked a simple question: "Where does a light-signal go?"

So we shot locally some lasers on our cells to see what happens. In the periphery they contract rapidly on one side only! But on the other side is a fast transient response (contract and extend).

To make more quantitatively sense out of the data, we segmented the cell and measured nodes and edges of the networks, suggesting the motion of the nodes toward the center, while simultaneously buckling.

Also the topology of the structure remains conserved upon folding and unfolding.

The cell contacts its chloroplast area by up to 40%! Where does all the material go?
Smart design! Chlorophyll absorbs a lot - what is crucial is not its volume but is a high 2d-projected area for example a network.
Fast contractions are driven via buckling of the network strands into the voids.

We tried to understand the time scales of the adaptation by using dynamical tests: turning light on and off. This method is similar to what rheologists would do for studying viscoelastic liquids.

We found that the cell essentially works like a low-pass filter. But one question remained unanswered

At day, it also suffers fluctuations of light.
We screened over ecologically relevant light conditions and found transient, weak and strong responses in form of the contraction of the chloroplast towards the cells center.

This all happens in only a few minutes in a ~100µm sized cell!

To study that, we looked at our favorite marine dinoflagellate: Pyrocystis lunula 🌙, a bioluminescent algae that emits light upon mechanical stimulation during night, which we also previously studied with mechanical compression tests using micropipettes :D
journals.aps.org/prl/abstract...

💥Beyond happy 💥 Our work is now published in PNAS!
www.pnas.org/doi/10.1073/...

With Gloria Canales & @mazi1.bsky.social we studied how the single celled alga Pyrocystis lunula 🌙 move their chloroplast in response to strong light.

Get ready for some fun mechanics, signals and organelle motion! 🧵

Hi #SciSky :)
So cool that many are moving here now!

I study how chloroplasts in plants and algae move from a physics-y point of view:
Here's recent work on a dinoflagellate.
doi.org/10.1101/2024...

I'm interested in dynamical systems, complex fluids, bioluminescence, stochastic processes etc. :)