Sponsor:
Funded by Ministerio de Economía y Competividad (ES); url: http://www.mineco.gob.es/;
RyC2010-06094, Fundación Ramón Areces (ES); url: http://www.fundacionareces.es/fundacionareces/, Ministerío de Economía y Competividad (ES); url: http://www.mineco.gob.es/; SAF2011-24953 (MVM); Ministerio de Economía y Competividad (ES); url: http://www.mineco.gob.es/; DPI2012-38090-C1, European Research Council (BE); url: http://erc.europa.eu/; 306751 (JMGA); European Research Council (BE); url: http://erc.europa.eu/; 308223 (HVO); Ministerio de Economía y Competividad (ES);
url: http://www.mineco.gob.es/; DPI2012-38090-C3 (COS); and Ministerio de Economía y Competividad (ES); url: http://www.mineco.gob.es/; TEC2013- 48552-C2-1-R (AMB). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. European Community's Seventh Framework Program
Project:
Gobierno de España. RyC2010-06094 Gobierno de España. SAF2011-24953 Gobierno de España. DPI2012-38090-C1 Gobierno de España. DPI2012-38090-C3 Gobierno de España. TEC2013-48552-C2-1-R info:eu-repo/grantAgreement/EC/FP7/308223
Traction Force Microscopy (TFM) is a widespread method used to recover cellular tractions from the deformation that they cause in their surrounding substrate. Particle Image Velocimetry (PIV) is commonly used to quantify the substrate's deformations, due to itTraction Force Microscopy (TFM) is a widespread method used to recover cellular tractions from the deformation that they cause in their surrounding substrate. Particle Image Velocimetry (PIV) is commonly used to quantify the substrate's deformations, due to its simplicity and efficiency. However, PIV relies on a block-matching scheme that easily underestimates the deformations. This is especially relevant in the case of large, locally non-uniform deformations as those usually found in the vicinity of a cell's adhesions to the substrate. To overcome these limitations, we formulate the calculation of the deformation of the substrate in TFM as a non-rigid image registration process that warps the image of the unstressed material to match the image of the stressed one. In particular, we propose to use a B-spline -based Free Form Deformation (FFD) algorithm that uses a connected deformable mesh to model a wide range of flexible deformations caused by cellular tractions. Our FFD approach is validated in 3D fields using synthetic (simulated) data as well as with experimental data obtained using isolated endothelial cells lying on a deformable, polyacrylamide substrate. Our results show that FFD outperforms PIV providing a deformation field that allows a better recovery of the magnitude and orientation of tractions. Together, these results demonstrate the added value of the FFD algorithm for improving the accuracy of traction recovery.[+][-]