Tricomponent polymer aerogels containing cellulose nanocrystals and chitin nanofibers and their use in aerogel/hydrogel hybrids as fibrocartilage replacements

Abstract

AbstractConsidering the design of structures and materials for use as replacements for biological structures, polymer nanocomposites are desirable materials of construction since they have a large design space, allowing property customization. Biobased nanofibers are particularly suited for these applications since they have high specific mechanical properties and cytocompatibility. Motivated by these attributes, this work examines nanocomposite aerogels and an aerogel/hydrogel hybrid structure designed to mimic an intervertebral disc (IVD), with the aerogel and hydrogel serving as analogs for the annulus fibrosus and the nucleus pulposus, respectively. The aerogels and aerogel/hydrogel hybrid structure contain a mixture of biobased nanofibers, cellulose nanocrystals (CNCs) and chitin nanofibers (ChNFs), and a polyvinyl alcohol (PVA) matrix. Characterization of the structure and properties shows that the nanocomposite aerogels containing CNC/ChNF mixtures have larger pores and decreased mechanical properties as compared to aerogels containing only CNCs or only ChNFs. Building on these results, a hybrid comprised of a CNC/PVA aerogel and a CNC/ChNF/PVA hydrogel is constructed with mechanical properties similar to natural IVDs, providing initial validation of the hybrid concept for IVD replacements and pathways to customization through changing material composition in the aerogel and hydrogel and changing the aerogel and hydrogel fractions in the hybrid structure.