In Vivo Biocompatibility of Non-derivatized Cellulose Regenerated Using Ionic Liquids

The behaviour of regenerated cellulose composites produced from rayon (Cordenka™), dissolved using either ionic liquids or sodium hydroxide (common cellulose solvent) was investigated to determine in vivo biocompatibility. Cellulose-dissolving ionic liquids (1-ethyl-3-methylimidazolium, 1-butyl-3-methylimidazolium, and four triaminocyclopropenium cation salts) and sodium hydroxide were examined in vitro using rat fibroblast-like cells to determine the most cytocompatible ionic liquid. The selected ionic liquid and sodium hydroxide were used to prepare regenerated cellulose constructs. The prepared cellulose constructs and ultra-high-molecular-weight polyethylene controls were implanted subcutaneously into adult male Sprague–Dawley rats. Post-surgery, implants were processed into a resin. Degradation properties were determined, and morphometric analysis was performed on resin sections stained with Haematoxylin & Eosin, Toluidine blue and Verhoeff’s van Giessen. The implants presented excellent biocompatibility. However, the cellulose implants showed a rapid infiltration of several mature fibroblasts and collagen fibres. A steady increase was observed in the granulation tissue ingrowth between the cellulose fibres by 14 days, increasing a further 35% by 28 days. This study indicates that non-derivatized cellulose regenerated using ionic liquids has the potential to be used as a biocompatible alternative to proteinaceous biomaterials like keratin for biomedical applications.