Regensburg 2004 – scientific programme

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AKB: Biologische Physik

AKB 50: Poster Session "Biological Physics"

AKB 50.125: Poster

Friday, March 12, 2004, 10:30–13:00, B

Optical Microheology on Biological Cells — •Falk Wottawah, Stefan Schinkinger, Bryan Lincoln, Maren Romeyke, Revathi Ananthakrishnan, Josef Käs, and Jochen Guck — Fakultät für Physik und Geowissenschaften, Universität Leipzig

Biological cells, such as fibroblasts, can be described as a polymeric compound material. Their passive rheological response to optically applied step stresses on the time scale of seconds suggests a hybrid between a crosslinked and an entangled actin network, a transiently crosslinked actin cortex, as the main contributor. Their frequency dependent shear modulus reveals elastic to viscous transitions, requiring stress relaxation beyond reptation-based mechanisms. This viscoelastic response is defining for cells within the same cell line, and distinguishes between different cell lines. Strain on the time scale of a minute additionally triggers an active response, exceeding the mere relaxation of applied stresses.