Regensburg 2013 – scientific programme

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BP: Fachverband Biologische Physik

BP 24: Posters: Physics of Cells

BP 24.32: Poster

Wednesday, March 13, 2013, 17:30–19:30, Poster C

Blood platelets - a model system for understanding cellular mechanics — •Aishwarya Paknikar, Sarah Schwarz G. Henriques, Rabea Sandmann, and Sarah Köster — Institute for X-Ray Physics, Georg-August-Universität Göttingen, Germany

Platelets get activated during an injury, change their shape and rearrange their actin-myosin cytoskeleton to generate forces, resulting in contraction. The mechanical principles underlying this dynamic process are poorly understood. The average total traction force of a single platelet on a soft polyacrylamide (PAA) substrate (elasticity ~4 kPa), measured by traction force microscopy (TFM) is ~34 nN. Immunostaining experiments also indicate that the platelet cytoskeletal reorganization is dependent on the substrate stiffness and myosin contributes majorly to the total force generation, leading to some open questions. Firstly, the mechanical response of platelets to different substrate stiffness is elusive. We are analyzing this influence of the substrate stiffness on the spreading of single platelets by varying the substrate elasticity within the physiological range (1-100 kPa). Secondly, the extent of contribution of other, myosin-independent forces to the total measured forces is unclear. Hence, we inhibit platelet myosin by blebbistatin, and simultaneously record the platelet force fields by TFM. We have designed an efficient microflow setup that allows for the defined application of blebbistatin to the platelets adhered to PAA substrates during an ongoing TFM recording. Our experimental findings aim at building a mechanical model for platelet activation.