International Journal of Biological Macromolecules 64 (2014) 11–16 Contents lists available at ScienceDirect International Journal of Biological Macromolecules jo ur nal homep age: www.elsevier.com/locate/ijbiomac Bioactivity and biocompatibility of a chitosan-tobermorite composite membrane for guided tissue regeneration A.P. Hurt, G. Getti, N.J. Coleman ∗ School of Science, University of Greenwich, Chatham Maritime, Kent ME4 4TB, UK a r t i c l e i n f o Article history: Received 22 September 2013 Received in revised form 7 November 2013 Accepted 22 November 2013 Available online 1 December 2013 Keywords: Chitosan Tobermorite Bioactive a b s t r a c t A polymer-mineral composite membrane of the mucopolysaccharide derivative, chitosan, and calcium silicate hydrate phase, tobermorite, was prepared by solvent casting and characterised by scanning electron microscopy (SEM) and Fourier Transform infrared spectroscopy (FTIR). The bioactivity and bio- compatibility of the chitosan-tobermorite composite were evaluated in vitro with respect to its potential for use as a biodegradable guided tissue regeneration (GTR) membrane. The in vitro bioactivity of the composite was confirmed by the formation of crystalline substituted hydroxyapatite on the surface of the embedded tobermorite particles in simulated body fluid. The presence of the composite membrane was found to enhance the growth of MG63 human osteosarcoma cells by up to 30%. The findings of this initial study have indicated that this novel chitosan-tobermorite composite may be a suitable material for GTR applications. © 2013 Published by Elsevier B.V. 1. Introduction Chitosan is the partially N-deacetylated derivative of chitin, a structural mucopolysaccharide obtained on an industrial scale from the shells of crustaceans [1,2]. The structure of chitosan, a basic linear copolymer of N-acetylglucosamine and glucosamine, is shown in Fig. 1a. Chitosan affords many advantages over synthetic petroleum-based polymers as it is a readily renewable resource which is edible, non-toxic, non-antigenic, biodegradable, biocom- patible, haemostatic and antimicrobial [1,2]. It is readily processed into membranes, gels, beads, mats, fibres and foams by a range of techniques including: solvent casting; freeze-drying; electro- spinning and supercritical fluid processing [3–9]. Current and prospective applications of chitosan include: tissue engineering scaffolds; wound dressings; resorbable sutures; medical textiles; artificial skin; drug delivery systems; pharmaceuticals; contact lenses; cosmetics; food packaging materials; and water filtration media [1–10]. Chitosan is one among the numerous biocompatible biodegrad- able polymeric materials (such as poly(glycolic acid), poly(lactic acid), poly(caprolactone) and poly(urethane)) which have been evaluated as scaffold materials for in vitro and in situ bone and peri- odontal tissue engineering [1–11]. A major advantage of chitosan as a substrate for bone tissue regeneration is that its structure resem- bles those of glycosaminoglycans which are principal components of bone extracellular matrix (ECM) [5–7]. Disadvantages of chitosan ∗ Corresponding author. Tel.: +44 07980 017088. E-mail address: nj coleman@yahoo.co.uk (N.J. Coleman). in these applications are that it is mechanically weak and lacks suffi- cient bioactivity to induce initial rapid bone regeneration; however, both of these problems can be addressed by reinforcing the chi- tosan with finely divided osteogenic mineral phases to improve mechanical strength and stimulate bone tissue formation [3–7]. To date, candidate tissue scaffold composites of chitosan blended with hydroxyapatite [3,7], -tricalcium phosphate [5], silica [6,12] and bioactive glass [4] have been reported in the literature to possess superior mechanical and osteogenic properties relative to those of pure chitosan. The development of bioactive membranes for guided tissue regeneration (GTR) of periodontal structures is an area of increas- ing interest in the treatment of periodontitis, an infectious disease that destroys the tooth-attachment apparatus [8,11]. During the progression of periodontitis, the epithelial tissue detaches from the tooth, the periodontal ligament (PDL) disconnects and the alveolar bone tissue is resorbed (as shown in Fig. 2a). Traditional treatment of this condition involves the debridement and cleaning of the root surfaces without the restoration of the compromised periodontal attachment apparatus (i.e. PDL and alveolar bone). Epithelial cells, which migrate approximately ten times faster than other peri- odontal tissues, then grow alongside the tooth root and prevent the re-establishment of the PDL and alveolar bone at the defect site. GTR involves the use of a biocompatible membrane to exclude the fast-growing epithelial and gingival tissues from the exposed root and allow the more slow-growing bone and PDL tissues to regenerate (as shown in Fig. 2b). Canine models have indicated that chitosan GTR membranes enhance the re-establishment of the PDL and alveolar bone compared with conventional treatment of periodontal defects [13–15]. Improvements in the performance of 0141-8130/$ – see front matter © 2013 Published by Elsevier B.V. http://dx.doi.org/10.1016/j.ijbiomac.2013.11.020