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The Scientific World Journal
Volume 2015, Article ID 859416, 9 pages
http://dx.doi.org/10.1155/2015/859416
Research Article

Mathematical Modeling of Uniaxial Mechanical Properties of Collagen Gel Scaffolds for Vascular Tissue Engineering

1Instituto de Física de Líquidos y Sistemas Biológicos, CONICET-CCT La Plata, B1900BTE La Plata, Buenos Aires, Argentina
2Instituto de Ingeniería y Agronomía, Universidad Nacional Arturo Jauretche, 1888 Florencio Varela, Buenos Aires, Argentina
3Laboratory for Biomaterials and Bioengineering, Canada Research Chair I, Laval University, Quebec City, QC, Canada G1V 0A6
4Laboratorio de Biomecánica, Departamento de Ingeniería Mecánica, Facultad de Ingeniería, Universidad de Buenos Aires, C1063ACV Buenos Aires, Argentina

Received 30 July 2014; Revised 29 January 2015; Accepted 15 February 2015

Academic Editor: Toshio Tsuji

Copyright © 2015 Ramiro M. Irastorza et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Small diameter tissue-engineered arteries improve their mechanical and functional properties when they are mechanically stimulated. Applying a suitable stress and/or strain with or without a cycle to the scaffolds and cells during the culturing process resides in our ability to generate a suitable mechanical model. Collagen gel is one of the most used scaffolds in vascular tissue engineering, mainly because it is the principal constituent of the extracellular matrix for vascular cells in human. The mechanical modeling of such a material is not a trivial task, mainly for its viscoelastic nature. Computational and experimental methods for developing a suitable model for collagen gels are of primary importance for the field. In this research, we focused on mechanical properties of collagen gels under unconfined compression. First, mechanical viscoelastic models are discussed and framed in the control system theory. Second, models are fitted using system identification. Several models are evaluated and two nonlinear models are proposed: Mooney-Rivlin inspired and Hammerstein models. The results suggest that Mooney-Rivlin and Hammerstein models succeed in describing the mechanical behavior of collagen gels for cyclic tests on scaffolds (with best fitting parameters 58.3% and 75.8%, resp.). When Akaike criterion is used, the best is the Mooney-Rivlin inspired model.