Carboxymethylchitosan hydrogel manufactured by radiation-induced crosslinking as potential nerve regeneration guide scaffold

The main objective of the work was to elaborate a methodology of manufacturing tubular guide with an internal scaffold of polysaccharide hydrogel towards potential application for supporting peripheral nerve regeneration. Carboxymethylchitosan (CMSC), a derivative of chitosan and a prospective material in the medical field, was examined with respect to degradation and crosslinking processes and eventually converted into a hydrogel through radiation-induced crosslinking. Physico-chemical properties of the degraded and crosslinked CMCS materials were evaluated by viscometry, UV-Vis, FTIR, TGA, XRD and SEM. Biological characterization of CMCS gels was done with XTT method for potential cytotoxicity and by preliminary in vivo examination using a rat model, to assess local reaction after implantation. Additionally, an antimicrobial potential of the CMCS materials was examined with bacterial suspension and agar diffusion methods using Gram-positive and -negative strains. The positive results of the abovementioned evaluations, after taking under account sorption characteristics of the gels, allowed to consider 12% CMCS aqueous solutions irradiated with an electron-beam dose of 25 kGy as a suitable material for internal filling of biodegradable tubes made of poly(L-lactic acid) and poly(trimethylene carbonate) blend biomaterial. The radiation processing of CMCS resulted in an in situ synthesis of a soft scaffold inside the tube, and simultaneous sterilization of the entire medical implant. Lack of toxicity of the gel and antimicrobial activity of CMCS against E. coli strain combined with hydrophilic properties make the hydrogel a potential material for supporting peripheral nerveregeneration guides.