Breaking News in Biophysics: What I Learned at the German Physics Society Meeting

List of talks that I found interesting.

Posted on: 04 Apr 2023

  1. Hydraulic and osmotic control of lumen coarsening by Mathieu Le Verge Serandour and Hervé Turlier: Hydraulic fracture in the blastocyst. Instead of modelling them as bubbles, they can extend it model to tubes which connect different pressure cavities. https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1009333
  2. Mechanical Properties of the Premature Lung by Jonas Naumann, Nicklas Koppe, Ulrich Thome, Mandy Laube, and Mareike Zink: They measured viscoelastic properties of lungs, if you want to know the material parameters you can get them from this paper. https://www.frontiersin.org/articles/10.3389/fbioe.2022.964318/full
  3. Tracking and comprehending single cell dynamics in Drosophila dorsal closure using machine learning by Daniel Härtter, Yuxi Long, Janice Crawford, Daniel P. Kiehart, and Christoph F. Schmidt: Very nice work of segmenting cells in drosophila embryos with local projection. This work highlights the curly cell-cell junctions. https://journals.biologists.com/dev/article-abstract/149/21/dev200621/281059/DeepProjection-specific-and-robust-projection-of
  4. Chiral flows can drive pattern formation in viscoelastic surfaces by Eloy de Kinkelder, Elisabeth Fischer-Friedrich, and Sebastian Aland: Interesting model with curved viscoelastic surfaces simulating cell division and forces involved. https://arxiv.org/abs/2211.07183
  5. Neutrophil mechanotransduction during durotaxis by Fatemeh Abbasi, Matthias Brandt, and Timo Betz: Most interesting talk, showing a micro-confiner, where you can squeeze cells, organoids, embryos between two hydrogels. This device enables traction measurements at the same time. One cool thing we saw was that the cells could move from bottom gel to top if top gel was stiffer. The paper is yet to be published.
  6. Mechanical fingerprint of the intra-cellular space by Till M. Muenker, Bart E. Vos, and Timo Betz: Another Betz lab talk, where they show that the microrheology experiments can be useful in characterizing different cell types with power law rheology parameters.
  7. Nuclear mechanics probed by optical tweezers-based active microrheology by Bart Vos, Till Müncker, Ivan Avilov, Peter Lenart, and Timo Betz: Another one, where they show that the nucleus is softer than the cytoplasm. Unbelievable. But the presenter says its like a balloon where stiffness measured from the outside will appear stiffer, but inside its air. I don’t buy it.
  8. Hydrostatic pressure and lateral actomyosin tension control stretch and tension of the basement membrane in epithelia by Karla Yanin Guerra Santillan, Elisabeth Fischer-Friedrich, and Christian Dahmann: Cell pressure and actomyosin affects the basement membrane tension. They show this using AFM measurements on wing disc explants. https://www.biorxiv.org/content/10.1101/2022.09.02.506324v2
  9. Noisy growth and buckling in soft tissues by Rahul G. Ramachandran, Ricard Alert, and Pierre A. Haas: For a simplistic geometry, where they show that the noisy growth could lead to local buckling. Unpublished.
  10. Viscoelastic measurements in glioblastoma-infiltrated cerebral organoids by Michael Frischmann, Elijah Shelton, Sofia Kalpazidou, Jovica Ninkovic, and Friedhelm Serwane: They are using Otger Campas system of magnetic droplets to measure the properties of the cerebral organoids. Interesting system but they are in too early stage of the project. Unpublished.
  11. Quantitative 3D live-imaging of self-organisation in embryonic organoids by Valentin Dunsing, Sham Tlili, Claire Chardès, Léo Guignard, and Pierre-François Lenne: This talk was about a cool microscopy setup they have developed. This has a mirror arrangement in a well, where you can create a light sheet and perform high throughput light sheet microscopy. They are also developing segmentation tools. Unpublished.
  12. Dynamics of confined cell migration in 3D micro-dumbbells by Stefan Stöberl, Johannes Flommersfeld, Maximilian M. Kreft, Chase P. Broedersz, and Joachim O. Rädler: They made a dumbbell shaped hole in a hydrogel and watched cells go from one side to other in this confinement. Most interesting thing about this talk was that they were making this 3D hydrogel with PDMS mold and UV polymerization. As polyacrylamide gel can’t do this, they use PEG-Norbornene hydrogels. This work is an extension from the theory work by David Bruckner. https://www.nature.com/articles/s41567-019-0445-4
  13. T-cell migration: Improving searching efficiency by targeting Microtubules by Galia Montalvo, Bin Qu, and Franziska Lautenschläger: Microtubules disruption improves T cell migration through small channels
  14. Viscoelastic characterization of biological cells in hyperbolic microfluidic channels by Felix Reichel and Jochen Guck: Its about the deformable cytometry setup of Guck lab, modified to hyperbolic shape to create an extensional flow field where the acting stresses can be measured using calibration particles and yield a simple relationship between acting stress and resulting cell strain. Unpublished.
  15. Chromatin and Nucleocytoplasmic Transport Control the Nuclear Biophysical Properties during Assembly in Egg Extracts by Omar Muñoz, Abin Biswas, Kyoohyun Kim, Simone Reber, Jochen Guck, and Vasily Zaburdaev: Interesting work to embed beads in the nucleus of the cells and measure properties. However, the beads were too large for the nucleus, so they chose a system where the nucleus in very large. Xenopus egg extracts is like a giant cell with giant nucleus and they can measure properties of nucleus and cytoplasm. They said that cytoplasm is stiffer than nucleus. Suprising. Second talk saying this. Unpublished.
  16. The physical regulation of brain development by Kristian Franze: Gave a nice talk about material transport in neurons with microtubules. He talked about the microtubule orientation as prerequisite to the long range transport. https://elifesciences.org/articles/77608
  17. Capturing the mechanosensitivity of cell proliferation in models of epithelium by Maxime Hubert, Kevin Höllring, Lovro Nuić, Luka Rogić, Sara Kaliman, Simone Gehrer, Florian Rehfeldt, and Ana-Sunčana Smith: They do a simple experiment of cell proliferation and they use computational model simulating growing and dividing cells to explain the behavior. https://www.biorxiv.org/content/10.1101/2023.01.31.526438v1
  18. Mechanosensitive binding of filamins in the actin cytoskeleton of live cells by Valentin Ruffine and Elisabeth Fischer-Friedrich: They use combination of AFM and confocal imaging to show that under tension filamin-actin bond lifetime increases. Unpublished.
  19. Global membrane tension is independent of polyacrylamide substrate stiffness by Eva Kreysing, Jeffrey McHugh, Sarah Foster, Kurt Andresen, Ryan Greenhalgh, Eva Pillai, Andrea Dimitrcopoulus, Ulrich Keyser, and Kristian Franze: They show this by optical tweezer experiments, with pulling a tether from the membrane. This work discussed the effect of the piezo1 channel and its tension dependent activation. They use a simple actin-membrane model to explain the results. https://academic.oup.com/pnasnexus/article/2/1/pgac299/6973213
  20. Odd dynamics of living chiral crystals by Tzer Han Tan, Alexander Mietke, Junang Li, Yuchao Chen, Hugh Higinbotham, Peter Foster, Shreyas Gokhale, Jorn Dunkel, and Nikta Fakhri: They show that swimming starfish embryos can form chiral crystals that exhibit unconventional deformation response behaviors and self-sustained chiral oscillations, which is controlled by the hydrodynamic properties and natural development of embryos. They also provide experimental evidence for non-equilibrium phases of chiral active matter. https://www.nature.com/articles/s41586-022-04889-6