Biophysics of Blood Platelet Contraction

by Sarah Schwarz G. Henriques
Doctoral thesis
Date of Examination:2012-07-10
Date of issue:2013-05-21
Advisor:Prof. Dr. Sarah Köster
Referee:Prof. Dr. Sarah Köster
Referee:Prof. Dr. Stephan Herminghaus
Persistent Address: http://dx.doi.org/10.53846/goediss-3853

 

 

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Abstract

English

This work is part of a project on blood platelet contraction using an innovative double approach to experiments. First, we adapted the experimental technique, traction force microscopy (TFM), to our cellular system, and measured forces generated by single, activated platelets with hitherto unknown spatial and temporal resolution. In a second set of experiments, we looked at both force generators and force transduction sites (focal adhesions) in platelets that were activated on soft polyacrylamide (PAA) substrates, used in kind already for TFM. Here, we fixed platelets and stained platelet components during different stages of activation. By combining these two experimental approaches, we were able to establish connections between characteristics of measured force fields and the (re-)organization of both the platelet cytoskeleton and focal adhesion sites. Our findings have several implications for experimental concepts applied to future force measurements of platelet contraction. In addition, our experiments on PAA have revealed that platelet activation on materials with physiological elasticities proceeds in a slightly different manner than on glass, the traditional choice of substrate. Lastly, our measurements of local forces illustrate specific characteristics of platelet force fields, which will affect future mechanical models of platelet contraction.
Keywords: focal adhesions;; blood platelets;; cytoskeletal reorganization;; traction forces;; force fields;; cellular contraction;
 
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