Ion-Crosslinked Nanocellulose Hydrogels for Advanced Wound Care Applications

Abstract: A current trend in the field of wound care is the development of wound healing materials that are designed to address specific types of wounds or underlying pathologies to achieve improved healing. At the same time, there is a societal drive to replace synthetic materials with renewable alternatives. The work presented in this thesis was therefore carried out to investigate the use of wood nanocellulose, produced from the world’s most abundant biopolymer, cellulose, in advanced wound care applications.Wood-based nanofibrillated cellulose (NFC) was chemically functionalized and crosslinked using calcium to obtain a self-standing hydrogel. The NFC hydrogel was evaluated in terms of its physicochemical properties, biocompatibility, blood interactions, bacterial interactions, in vivo wound healing ability and, finally, as a protein carrier. Parallel with the assessment of the NFC hydrogel, modified versions of the material were tested to investigate the tunability of the above-mentioned characteristics.The ability of the hydrogel to maintain a moist wound bed was demonstrated. Evaluation of the biocompatibility showed that the material was cytocompatible and did not trigger inflammatory mechanisms. Furthermore, the NFC hydrogel supported cell proliferation, and was shown to possess hemostatic properties. It was also discovered that the material had a slight bacteriostatic effect and the ability to act as a barrier against bacteria. When tested in vivo, the hydrogel was found to significantly improve wound healing.Modifications through the incorporation of additives to the hydrogel matrix, as well as exchange of the crosslinking ion, were shown to influence the biological response to the material. Moreover, the results presented here demonstrate the possibility of using the NFC hydrogel as a protein carrier; the easily adjustable charge property being identified as a central parameter for manipulation to regulate the release profile.In conclusion, this work has demonstrated the extensive wound healing ability of the calcium-crosslinked NFC hydrogel, and represents an important milestone in the research on NFC towards advanced wound care applications. It is expected that the easily modifiable nature of the material can be exploited to further develop the NFC hydrogel to suit the treatment needs for a broad range of wound types.