DOI: 10.1002/adem.201180018 Evaluation of Cell-Material Interactions on Newly Designed, Printable Polymers for Tissue Engineering Applications** By Esther C. Novosel, Wolfdietrich Meyer, Nadine Klechowitz, Hartmut Kru ¨ger, Michael Wegener, Heike Walles, Gu ¨nter E. M. Tovar, Thomas Hirth and Petra J. Kluger* Tissue engineering strategies are based on seeding of human cells on three-dimensional (3D) biomaterial scaffolds in vitro. In the presence of growth-enhancing stimuli, a cell seeded scaffold turns into an artificial tissue, which can be applied as an implant or test system. [1] The principle of this process is elementarily based on the capability of the scaffold to enhance cell viability, attachment, and proliferation. Therefore, biomaterials for tissue engineering applications need to fulfill numerous requirements regarding chemical and physical properties of the material surface, design, function, and biocompatibility. [2,3] Furthermore, the scaffold serves as a template that directs the formation of tissue, hence the architecture plays an important role. [4,5] The inner pore network and its outer geometry need to be well-defined to allow cell migration and successful vascularization, which is a prerequisite for generation of 3D large scale tissue. [6,7] To reach this objective, novel approaches for generating tissue engineering scaffolds are focused on rapid prototyping (RP) techniques. [8] Those methods, primarily developed for non- biomaterial processing, use computer-aided design (CAD) datasets to realize freeform 3D printing. [6] Tissue engineering scaffolds, built via layer-by-layer manufacturing processes, RESEARCH ARTICLE [*] Dr. P. J. Kluger, N. Klechowitz, Dr. G. E. M. Tovar, Prof. T. Hirth Fraunhofer Institute for Interfacial Engineering and Biotechnology Nobelstraße 12, 70569 Stuttgart, (Germany) E-mail: petra.kluger@igb.fraunhofer.de Prof. H. Walles Institute for Tissue Engineering and Regenerative Medicine University of Wu ¨ rzburg Ro ¨ ntgenring 11, 97070 Wu ¨ rzburg, (Germany) E. C. Novosel, Dr. G. E. M. Tovar, Prof. T. Hirth, Dr. P. J. Kluger Institute for Interfacial Engineering IGVT, University of Stuttgart Nobelstraße 12, 70569 Stuttgart, (Germany) Dr. W. Meyer, Dr. H. Kru ¨ ger, Dr. M. Wegener Department of Functional Polymer Systems, Fraunhofer Institute for Applied Polymer Research IAP Geiselbergstraße 68, 14476 Potsdam-Golm, (Germany) [**] We would like to thank Dr. Kirsten Borchers and Dr. Monika Bach for scientific discussion and proof reading, Dr. Michaela Mu ¨ller for performing the contact angle measurements, as well as the Fraunhofer Gesellschaft and the Landesgraduiertenfo ¨r- derung Baden-Wu ¨ rttemberg for funding the project. The generation of advanced scaffolds for tissue engineering is increasingly implemented by rapid prototyping techniques and therefore designed materials. Two novel polymeric networks based on newly synthesized carboxyfunctionalized polyacrylates were created to fit the requirements of 3D printing processes regarding viscosity and their surface tension. The polyacrylates presented carboxylic groups either without any spacer, or, in the case of mono-(2-acryloxyethyl)-succinate, with a substantial spacing from the polymer backbone. The material properties were characterized with rheometry, FTIR, XPS, and contact angle measurements. Polymer surfaces were prepared and seeded with primary human dermal microvascular endothelial cells (HDMEC). Cell–material interaction with the different polymer surfaces were investigated by light microscopy, water soluble tetrazolium-1 (WST-1) viability assay, fluorescein diacetate/propidium iodide (FDA/PI) staining, and acetylated low-density lipoprotein (acLDL) assay. Thus, the cell confluence, viability, and functionality of the HDMEC were evaluated. The non-spaced methacrylic acid derivative was proved in cell culture regarding its biocompatibility. Along with its appropriate physical properties, the novel network- generating polymeric blends constitute promising candidates for future scaffold design in tissue engineering. ADVANCED ENGINEERING MATERIALS 2011, 13, No. 12 ß 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim wileyonlinelibrary.com B467