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April, 2018: Mechanobiology in developing tissues and organoids using ferrofluid droplets

24.04.2018 11:00 Uhr

Vortrag: Herr Serwane, Max Planck Institut für medizinische Forschung in Heidelberg (Abteilung J. Spatz)
Veranstaltungsort: Seminar room ICS-7/PGI-3, Building 02.4w, Room 309b
Abstract: Development in biology is driven by cells dynamically assembling into tissues which in turn form organs and ultimately organisms. While cell motility and differentiation play a key role in tissue formation, their guidance by local mechanical signals has been revealed by in vitro studies. However, the mechanical cues cells experience within living tissues have not been quantified, due to a lack of techniques to probe and sense tissue-scale mechanics inside living organisms.
I will present a technique that allows quantitative spatiotemporal measurements of mechanical properties in vivo and in situ. We realize this by employing biocompatible ferrofluid microdroplets as local mechanical actuators. We inject those ‘phantom cells’ into living tissues and deform using magnetic fields. Recording the dynamic droplet deformation allows us to quantify the mechanical properties within the region surrounding the droplet.
Using this technique, we show that vertebrate body elongation involves a variation in tissue mechanics along the anteroposterior axis. Specifically, we find that the zebrafish tailbud is viscoelastic, elastic below a few seconds and fluid after just 1 minute. Further studies reveal the existence of a yield stress regulating tissue mechanical integrity, which is established via N-Cadherin adhesion molecules and decreases towards the growing tip. This hints to a possible mechanism how shape is controlled via molecular factors in developing tissues.
Finally, ongoing research towards retina mechanobiology will be presented. Combining stem cell-derived retina organoids with biophysical tools will allow us to explore, how light-induced signals are processed and how this processing depends on local mechanical cues.
Beyond basic research, this biomechanical platform could open the door to diagnose and tackle diseases related to mechanical abnormalities including glaucoma.