Title: Determination of the viscoelastic properties of hydrogels based on polyethylene glycol diacrylate (PEG-DA) and human articular cartilage

Authors: Stefan Gabler, Jurgen Stampfl, Thomas Koch, Sabine Seidler, Georg Schuller, H. Redl, Vladimir Juras, Siegfried Trattnig, Roland Weidisch

Addresses: Institute of Materials Science and Engineering, Technical University of Vienna, Vienna, Austria; Fresnel Optics GmbH, Flurstedter Marktweg 13, D-99510, Apolda, Germany. ' Institute of Materials Science and Engineering, Technical University of Vienna, Favoritenstrabe 9-11, A-1040, Vienna, Austria. ' Institute of Materials Science and Engineering, Technical University of Vienna, Favoritenstrabe 9-11, A-1040, Vienna, Austria. ' Institute of Materials Science and Engineering, Technical University of Vienna, Karlsplatz 13, A-1040, Vienna, Austria. ' Ludwig Boltzmann Institute for Experimental and Clinical Traumatology; Austrian Cluster for Tissue Regeneration, Donaueschingenstrabe 13, A-1200, Vienna, Austria. ' Austrian Cluster for Tissue Regeneration; Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Donaueschingenstrabe 13, A-1200, Vienna, Austria. ' Austrian Cluster for Tissue Regeneration; University Hospital of Vienna, Department of Radiology, MR-Center, Lazarettgasse 40, A-1090, Vienna, Austria; Department of Imaging Methods, Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia. ' Austrian Cluster for Tissue Regeneration; University Hospital of Vienna, Department of Radiology, MR-Center, Lazarettgasse 40, A-1090, Vienna, Austria. ' Friedrich-Schiller University, Institute of Materials Science and Technology, Lobdergraben 32, D-07743, Jena, Germany

Abstract: In this work, a systematic study of the viscoelastic properties of hydrogels based on polyethylene glycol diacrylate (PEG-DA) is presented. In addition to artificial PEG-DA-based hydrogels, natural hydrogels in the form of human articular cartilage were examined. Specimens were (unconfined) compression tested under static and dynamic load. Besides this, instrumented indentation tests with different indenter geometries (cylindrical, spherical) and load ranges (macro- and nano-indentation) were carried out and relaxation tests for the determination of moduli and relaxation time were performed. Tensile tests completed the list of measurement techniques. The measured initial moduli of the evaluated hydrogels range from 104–107 Pa. Spherical indentation was used in testing human articular cartilage in phosphate buffered saline (PBS). Cartilage samples were measured shortly after explantation, being stored at room temperature. The influence of freezing and shock-freezing was evaluated. It turned out that freezing has a massive impact on sample properties, especially on the stress relaxation time and the ratio of initial to equilibrium modulus.

Keywords: PEG-DA based hydrogels; polyethylene glycol diacrylate; PEG; mechanical properties; viscoelasticity; articular cartilage; degradation; human cartilage; natural hydrogels; compression testing; tensile tests; freezing; shock-freezing; stress relaxation; initial to equilibrium modulus.

DOI: 10.1504/IJMATEI.2009.024024

International Journal of Materials Engineering Innovation, 2009 Vol.1 No.1, pp.3 - 20

Published online: 24 Mar 2009 *

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