Biophysical Society Thematic Meeting | Riga 2026

Active and Responsive Soft Matter: From Biological to Engineered Systems

Poster Abstracts

3-POS Board 3 A UNIFYING MECHANISM FOR THE ADHESION-SPEED RELATION, SPEED PERSISTENCE TIME RELATION AND MORPHODYNAMICS OF CELLS ON 1D LANES Martin Falcke 1,3 ; Rainer Marcel Eberhardt 1 ; Santiago Kuhl 2 ; Joachim O Rädler 2 ; 1 Max Delbrück Center for Molecular Medicine, Berlin, Germany 2 Ludwig-Maximilians-Universität München, Fakultät für Physik, Munich, Germany 3 Humboldt University, Dept. of Physics, Berlin, Germany Cell motility on flat substrates exhibits coexisting steady and oscillatory morphodynamics, the biphasic adhesion-speed relation, and the speed-persistence time relation as simultaneous observations with many cell types. A variety of signalling systems or mechanical mechanisms have been suggested to explain each of these observations. However, their universality and concurrency suggest a unifying mechanism causing all three of them to exist. Cells on 1D fibronectin lanes exhibit steady or oscillatory morphodynamics. They either are spread or move. They switch spontaneously between the dynamic regimes of morphodynamics, and spread and moving states. They change their direction spontaneously. At the same time, the moving states obey the adhesion-speed relation and the speed-persistence time relation. In difference to earlier studies, we observe a biphasic speed persistence time relation. All of these observations can be explained by a biophysical model. It is based on the force balance at the protrusion edge, the noisy clutch of retrograde flow and a response function of friction and membrane drag to integrin signaling. Analysis of experiments with the biophysical model establishes a stick-slip oscillation mechanism. It explains multistability of morphodynamic cell states and the statistics of state transitions. It suggests protrusion competition to cause direction reversal events, the statistics of which explain the speed-persistence time relation for a variety of cell types and pharmacological perturbations. The effect of integrin signalling on drag and friction explains the adhesion-speed relation of a variety of cell types and pharmacological perturbations, and cell behavior at Fibronectin density steps. The biophysical model thus harmonizes the explanation of several basic observations in cell motility and morphodynamics. The ideas defining the model see motile cells as non-linear mechanical dynamic system exhibiting multiple dynamic states and with the clutch of retrograde flow as central element. The parameters of this system are controlled by signalling and experimental conditions.

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