Momentum transport through bio-polymer networks
Background: Microtubules are hollow, 25nm thin biopolymers and parts of the cytoskeleton of living cells. They self-organize over a large spatial and temporal scale inside of cells as a response to a variety of external stimuli. Most of the highly complex intracellular processes like cell division or mechano-transduction are based on microtubule network. Problem: The mechanical properties of single biopolymers like actin filaments or microtubules have already been studied in a wide context. However, nothing is known about the transfer of mechanical momentum through defined two dimensional microtubule networks. Approach: We use a time-multiplexed array of optically trapped anchor-points to create a small artificial network of fluorescently label microtubules (MT). In addition, we can disturb the network as a whole or just single anchor-points and measure the displacement response at rates of up to 10kHz. | Probing a triangular network of MT filaments with optical traps. (A) Schematic of experiment in pseudo 3D with overlay of fluorescence and brightfield image (bottom). Scatterplots of absolut bead positions during an oscillation in x direction are shown true to scale. The current phase of the actor trap (in red) is color coded.
A single, fluctuating microtubule is attached to two glass beads and its fluctuations are monitored by ROCS microscopy. |
D. Ruh, B. Tränkle, A. Rohrbach
Fast parallel interferometric 3D tracking of numerous optically trapped particles and their hydrodynamic interaction
2011 Optics Express, Band: 19, Nummer: 22, Seiten: 21627 - 21642M. D. Koch
Biomechanics of pro- & eukaryotic cytoskeletal model systems probed by time-multiplexed optical tweezers
2015 PhD thesis, Faculty of Engineering, University of FreiburgKoch M D, Schneider N, Nick P, Rohrbach A
Single microtubules and small networks become significantly stiffer on short time-scales upon mechanical stimulation
2017 Sci Rep-Uk, Band: 7, Nummer: 4229Koch M D, Rohrbach A
Label-free imaging and bending analysis of microtubules by ROCS microscopy and optical trapping
2018 Biophys J, Band: 114, Nummer: 1, Seiten: 168 - 177