Hindawi Publishing Corporation BioMed Research International Volume 2013, Article ID 285678, 12 pages http://dx.doi.org/10.1155/2013/285678 Research Article 2� and 3� Sel�-Assem�ling �ano�er �ydrogels �or Cardiomyocyte Culture Liisa Ikonen, 1, 2 Erja Kerkelä, 1, 3 Gerald Metselaar, 4, 5 Marc C. A. Stuart, 4, 6 Menno R. de Jong, 4 and Katriina Aalto-Setälä 1, 2, 7 1 Institute of Biomedical Technology (IBT), University of Tampere, Biokatu 12, 33520 Tampere, Finland 2 BioMediTech, Biokatu 10, 33520 Tampere, Finland 3 Finnish Red Cross Blood Service, Kivihaantie 7, 00310 Helsinki, Finland 4 Nano Fiber Matrices B.V., Nijenborgh 4, 9747 AG Groningen, e Netherlands 5 BASF Nederland B.V., Innovatielaan 1, 8466 SN Heerenveen, e Netherlands 6 Department of Biophysical Chemistry, University of Groningen, Nijenborgh 7, 9747 AG Groningen, e Netherlands 7 Heart Center, Tampere University Hospital, Teiskontie 35, 33521 Tampere, Finland Correspondence should be addressed to Liisa Ikonen; liisaikonen@hotmail.com Received 10 August 2012; Revised 9 October 2012; Accepted 12 October 2012 Academic Editor: Daria Nurzynska Copyright © 2013 Liisa Ikonen et al. is 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. Collagen is a widely used biomaterial in cardiac tissue engineering studies. However, as a natural material, it suffers from variability between batches that can complicate the standardization of culture conditions. In contrast, synthetic materials are modi�able, have well-de�ned structures and more homogeneous batches can be produced. In this study, several collagen-like synthetic self-assembling nano�ber hydrogels were examined for their suitability for cardiomyocyte culture in 2D and 3D. Six different nano�ber coatings were used in the 2D format with neonatal rat cardiomyocytes (NRCs) and human embryonic stem-cell-derived cardiomyocytes (hESC-CMs). e viability, growth, and functionality of the 2D-cultured cardiomyocytes were evaluated. e best- performing nano�ber coatings were selected for 3D experiments. Hydrophilic pH-sensitive nano�ber hydrogel coassembled with hyaluronic acid performed best with both NRCs and hESC-CMs. Hydrophilic non-pH-sensitive nano�ber hydrogels supported the growth of NRCs; however, their ability to promote attachment and growth of hESC-CMs was limited. NRCs also grew on hydrophobic nano�ber hydrogels; however, the cell-supporting capacity of these hydrogels was inferior to that of the hydrophilic hydrogel materials. is is the �rst study demonstrating that hydrophilic self-assembling nano�ber hydrogels support the culture of both NRCs and hESC-CMs, which suggests that these biomaterials hold promise for cardiac tissue engineering. 1. Introduction Heart failure arising from myocardial loss is a leading cause of morbidity and mortality worldwide [1] for which stem cell therapy is an emerging treatment option. For treatment of heart failure, cells can potentially be delivered to the site of injury where they can repopulate the injured area, integrate into the host tissue, and restore functionality to the myocardium. However, clinical studies have shown that cells delivered by direct injection into the myocardium or by intracoronary injection are rapidly lost [2–4]. Modest improvements in myocardial function have been suggested to merely arise from paracrine effects [5–7]. To achieve the desired cellular effects in addition to the paracrine effects, biomaterial scaffolds can be used to maintain the cells at the site of injection. An ideal biomaterial scaffold for cardiac repair would allow cardiomyocytes to be grown in vitro in a 3D structure that is optimal for application to the heart, allows cellular differentiation, and integrates well into the host tissue aer implantation. In addition to clinical cell therapy applications, 3D structures can also provide better cardiac tissue models for studying the pathophysiology of cardiac diseases and the function of diseased cardiomyocytes in vitro. Additionally,