Electron Beam-Irradiated Crosslinked Hydrogel Scaffold form Natural and Synthetic Polymers: Synthesis and Characterization

Hypothesis: 

Recently, preparation and investigation of hydrogel scaffolds in tissue engineering have gained increasing attentions owing to similarity of their characteristics to extracellular matrix of different tissues. Among different methods for hydrogel preparation, the use of ionizing radiation presents several advantages as it can occur without the need to add chemical agents and the final products can be irradiated to final form in the package, also simultaneously sterilized by irradiation during crosslinking. In this study, chemical modification with glycidylmethacrylate (GMA) as well as physical blending with poly(vinyl alcohol) (PVA) was investigated to prepare hydrogel scaffolds based on polysaccharides, gum tragacanth (GT) and carboxymethyl chitosan (NOCC) using electron beam irradiation.

For preparation of the hydrogels, first, GT and NOCC were functionalized with GMA. Afterwards, the blended solutions of these modified polymers and PVA were exposed to electron beam irradiation. Finally, the morphology, gel content, swelling behavior, compressive strength, rheological properties and biocompatibility of the hydrogels were investigated.

GMA-functionalized GT and NOCC in aqueous solution were crosslinked by electron beam irradiation. Blending of PVA with these modified polymers leads to the formation of an interpenetrating polymeric network (IPN) with enhanced compressive strength, storage modulus and swelling degree in comparison with the hydrogels prepared with unblended polymers. The gel content of the hydrogels varies between 65 to 98% as a function of polymer composition and irradiation dose. The hydrogels show viscoelastic behaviors in both compression and rheology analyses as well as excellent elastic recovery in cyclic compression analysis. The stress fracture of IPN hydrogels is found in the range of 1200-1414 kPa. The viability of MSCs, exposed to hydrogel extracts is above 85% after 24 and 72 h incubation. According to these results, the IPN hydrogels prepared in this study may be suggested as a promising candidate for further investigation, especially in cartilage tissue engineering.