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

The behaviour of regenerated cellulose composites produced from rayon (Cordenka (TM)), 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.