Contents lists available at ScienceDirect Radiation Physics and Chemistry journal homepage: www.elsevier.com/locate/radphyschem Radiation synthesis of biocompatible hydrogels of dextran methacrylate Kamila Szafulera, Radosław A. Wach ⁎ , Alicja K. Olejnik, Janusz M. Rosiak, Piotr Ulański Institute of Applied Radiation Chemistry, Faculty of Chemistry, Lodz University of Technology, Poland ARTICLE INFO Keywords: Dextran Dextran methacrylate Hydrogels Ionizing radiation Cytotoxicity Crosslinking ABSTRACT The aim of this work was to synthesize biocompatible dextran-based hydrogels through crosslinking initiated by ionizing radiation. A series of derivatives of dextran has been synthesized by coupling of methacrylated glycidyl to the structure of this polysaccharide, yielding dextran methacrylate (Dex-MA) of the degree of methacrylate substitution (DS) up to 1.13 as characterised by FTIR and NMR spectroscopy. Chemically crosslinked hydrogels were formed by electron-beam irradiation of Dex-MA in aqueous solution in the absence of low-molecular- weight additives such as catalysts, monomers or crosslinking agents. Crosslinking of Dex-MA in aqueous solutions of 20 g/l and above was an efficient process, the gels were formed at doses as low as 0.5 kGy (experiments conducted up to 100 kGy) and were characterised by high content of insoluble fraction (70– 100%). Due to high crosslinking density the equilibrium degree of swelling of fabricated gels was controlled principally by the initial concentration of Dex-MA solution subjected to irradiation, and it was in the range of 20 to over 100 g of water absorbed by gram of gel. Cytocompatibility of hydrogels was examined using XTT assay through evaluation of the cell viability being in indirect contact with hydrogels. The results indicated that hydrogels of Dex-MA of the average DS below 1 were not cytotoxic. Altogether, our data demonstrate that irradiation of methacrylated dextran in aqueous solution is an efficient method of fabrication of biocompatible hydrogels, which applications in regeneration medicine are anticipated. 1. Introduction Dextran is a non-toxic, hydrophilic, bacterially derived polysacchar- ide, mainly composed of linear α–1,6 linked D-glucopyranose residuals with a low percentage of α–1,2, α–1,3 or α–1,4 linked side chain (Dumitriu, 2005). Biomaterials based on this natural polymer are widely used for biomedical applications due to dextran biological activity, and well-documented biocompatibility and biodegradability in physiological environment (De Groot, 2001; Maia et al., 2014; Sun et al., 2011a; Sun and Mao, 2012). Its biomedical applications include plasma expander (de Jonge and Levi, 2001), drug delivery systems (Pacelli et al., 2015), hydrogels and wound dressings (Sun et al., 2011a). Soft tissue reconstruction solutions and novel wound dressings that apply techniques of tissue engineering require biodegradable and biocompatible materials capable to form three-dimensional structures supporting cell proliferation and regenerative processes of tissues. A possible approach may involve controlled chemical modification of natural polymers such as polysaccharides and their further transforma- tion into chemically-stable hydrogel. Hydroxyl groups present in the structure of dextran provide opportunity for its modifications. Hydrogen in these groups can be replaced by functional substituents yielding derivatives with specific, tailored characteristics, which can be further engineered to obtain various microstructured scaffolds includ- ing spheres, fibers or hydrogels for biomedical applications (Sun and Mao, 2012). In recent years, wide range of different functionalization of dextran has been accomplished, yielding materials of specific proper- ties although with preserved biocompatible character of their parent polysaccharide (Pitarresi et al., 2003; Wang et al., 2012; Yuba et al., 2014). Hydrogels are three-dimensional crosslinked polymeric networks able to absorb significant amount of water and/or biological fluids (Peppas and Mikos, 1986). Hydrogels can be formulated from synthetic materials, from natural polymers such as dextran, alginate or chitosan, and from combination of both synthetic and natural materials (Hoffman, 2012; Malafaya et al., 2007). Hydrogels of natural origin or with polysaccharides incorporated in the synthetic hydrogels, i.e. semi interpenetrating network, have been often used in biomedical field, mainly due to their specific biofunctionality. Chemically cross- linked dextran-based hydrogels have been manufactured and their potential applications in soft tissue engineering or as wound dressings were proposed (Sun et al., 2011b; Sun and Mao, 2012). Hydrogels can be manufactured by various techniques. One approach involves cross-linking agents in hydrogel fabrication process, http://dx.doi.org/10.1016/j.radphyschem.2017.01.004 Received 26 October 2016; Received in revised form 12 December 2016; Accepted 9 January 2017 ⁎ Corresponding author. E-mail address: wach@mitr.p.lodz.pl (R.A. Wach). Radiation Physics and Chemistry (xxxx) xxxx–xxxx 0969-806X/ © 2017 Elsevier Ltd. All rights reserved. Please cite this article as: Szafulera, K., Radiation Physics and Chemistry (2017), http://dx.doi.org/10.1016/j.radphyschem.2017.01.004