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Received Jun 5, 2017; Revised Aug 22, 2017; Accepted Sep 18, 2017
This 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.
1. Introduction
The current care of SCI patients is mostly palliative. Thus, it is extremely important to develop new strategies that support both structural and functional restoration of the damaged or lost tissue. For this purpose, tissue engineering approaches, using biomaterials, stem cells, and often neurotrophic factors, are being extensively explored [1]. Biomaterials, particularly hydrogels, are interesting for SCI approaches mainly due to their physical properties that resemble central nervous system (CNS) soft tissues. Moreover, their porous structure allows molecule diffusion and the possibility to establish a three-dimensional (3D) environment that mimics the living tissues. These biomaterials are widely used to support cell transplantation [2]. For this purpose, natural hydrogels are an interesting tool, as they are mostly constituted by extracellular matrix (ECM) molecules or can be easily functionalized with them [3]. Among the variety of available natural hydrogels, this study will focus on the use of gellan gum, NVR-gel, and collagen as matrices for cell encapsulation. Gellan gum (GG), a linear anionic polysaccharide with a free carboxylic group per repeating units, was already reported to be biocompatible and nontoxic after injection in a hemisection SCI rat model [4]. Moreover, it was also shown to be suitable for functionalization, as its modification with a fibronectin-derived peptide (GRGDS) promoted higher cell adhesion and viability in comparison to unmodified GG [5]. Regarding NVR-gel, this is a biocompatible and biodegradable scaffold composed of hyaluronic acid (HA) and laminin [6]. While HA has a vital role in cell morphogenesis and proliferation [7], laminin provides...