Three-dimensional Hydrogels of Alginate/chitosan Semi-interpenetrating Polymer Networks and Nanocelluloses

Abstract The hydrogels are advanced materials used in biomedical applications during wound healing, controlled drug release and to prepare scaffolds. In this work are prepared hydrogels of alginate/chitosan (Alg/Ch) semi-interpenetrating polymer networks (semi-IPN’s) and nanocelluloses. The hydrogels after preparation by freeze drying are namely simply as gels. The cellulose nanocrystals (CNC’s) are obtained from acid hydrolysis of bleached Eucalyptus pulps and oxidized cellulose nanocrystals (CNCT’s) prepared by (2,2,6,6-tetramethylpiperidin-1-yl)oxyl radical catalyzed reaction as known as TEMPO reaction. The cellulose nanofibers (NFC’s) are obtained from mechanical shearing of cellulose pulps and oxidized NFC’s by TEMPO-mediated reaction (NFCT’s). The nanocellulose suspension and gels are characterized by FTIR at ATR mode, TGA, XRD, TEM, SEM, X-ray computed microtomography (micro-CT) and DMTA. The addition of CNC’s, NFC’s, CNCT’s or NFCT’s in the microstructure of gels increases their dimensional stabilities. The best results are obtained when CNCT’s and NFCT’s are added. The mechanical properties and dimensional stability of Alg/Ch semi-IPN’s increase after controlled thermal post-treatment. The heating during thermal post-treatment boosts the physicochemical interactions in the microstructures of semi-IPN’s. The biological assays show biocompatibility of fibroblast cells on the substrates, and differentiation and proliferation up seven days. The optimized mechanical properties, dimensional stability and biocompatibility of the gels studied in this work are important parameters for potential biomedical applications of these biomaterials.