Research Article 3D Bioprinting of Carboxymethylated-Periodate Oxidized Nanocellulose Constructs for Wound Dressing Applications Adam Rees, 1 Lydia C. Powell, 2,3 Gary Chinga-Carrasco, 4 David T. Gethin, 1 Kristin Syverud, 4 Katja E. Hill, 3 and David W. Thomas 3 1 Welsh Centre for Printing and Coating (WCPC), Swansea University, Swansea SA2 8PP, UK 2 Centre for NanoHealth, Swansea University, Swansea, UK 3 Tissue Engineering and Reparative Dentistry, Cardif University School of Dentistry, Cardif CF14 4XY, UK 4 Paper and Fibre Research Institute (PFI), Høgskoleringen 6b, 7491 Trondheim, Norway Correspondence should be addressed to Gary Chinga-Carrasco; gary.chinga.carrasco@pf.no Received 24 July 2014; Accepted 30 September 2014 Academic Editor: Sylvia Colliec-Jouault Copyright © 2015 Adam Rees et al. Tis 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. Nanocellulose has a variety of advantages, which make the material most suitable for use in biomedical devices such as wound dressings. Te material is strong, allows for production of transparent flms, provides a moist wound healing environment, and can form elastic gels with bioresponsive characteristics. In this study, we explore the application of nanocellulose as a bioink for modifying flm surfaces by a bioprinting process. Two diferent nanocelluloses were used, prepared with TEMPO mediated oxidation and a combination of carboxymethylation and periodate oxidation. Te combination of carboxymethylation and periodate oxidation produced a homogeneous material with short nanofbrils, having widths <20 nm and lengths <200 nm. Te small dimensions of the nanofbrils reduced the viscosity of the nanocellulose, thus yielding a material with good rheological properties for use as a bioink. Te nanocellulose bioink was thus used for printing 3D porous structures, which is exemplifed in this study. We also demonstrated that both nanocelluloses did not support bacterial growth, which is an interesting property of these novel materials. 1. Introduction Nanocellulose is a novel material that can be produced from a variety of biodegradable and renewable resources and holds the potential to transform various areas of research and development [1–7]. As a novel biomaterial, nanocellulose may be deposited as a gel to form three-dimensional structures that have potentially diverse applications. Te material has various characteristics that make it suitable as a substrate for printing functionality and also as a component in bioinks. Firstly, well-fbrillated nanocellulose materials are composed of a large fraction of nanofbrils with widths in the nanometer scale and lengths in the micrometer scale. Tese high aspect ratio nanofbrils are capable of self-assembling and form dense, smooth, transparent, and strong structures [8, 9]. Based on these characteristics, recent studies have proposed using nanocellulose as the main component in the pro- duction of smooth flms, which are suitable for subsequent functionalization by printing [10, 11]. Secondly, depending on the pretreatment, diferent types of nanocellulose can be produced with a defned morphology and surface chemistry. In this respect, it has been demon- strated that oxidized nanocellulose gels could act as pH responsive structures, based on cellulose nanocrystals [12] or cellulose nanofbrils [13], which may have applications in dressings for chronic wounds. Te development of novel bio- material solutions with added functionality is of great interest in wound healing research, as current medical treatments present major societal, economic, and clinical challenges. Recently, the cytotoxicity of various nanocellulose qualities has been verifed, confrming that the assessed materials were not cytotoxic against a series of cell lines [14–16]. Hindawi Publishing Corporation BioMed Research International Volume 2015, Article ID 925757, 7 pages http://dx.doi.org/10.1155/2015/925757