Synthesis of Biocompatible Cellulose-Coated Nanoceria with pH-Dependent Antioxidant Property

Recent developments in nanomedicine have validated nanoceria as an antioxidant of therapeutic potential. However, its clinical application is far too limited in view of its poor stability in vivo and the use of hazardous solvents during its synthesis. There is a pertinent need for development of improved strategies for nanoceria to work better, especially by complexation with a matrix to improve upon its antioxidant property without toxicity. In the present study, cellulose has been used as a matrix of nanobiocomposite in which nanoceria are embedded, adopting solution plasma process (SPP). This resulted in cellulose-nanoceria(C/nanoceria) biocomposite by plasma reactions for 15 min using cellulose powder and Ce(NO₃)₂. Three-dimensional scaffold of the C/nanoceria biocomposite was prepared by lyophilization. The biocomposite was characterized adopting UV-vis spectroscopy, FTIR, FESEM equipped with EDS, and HRTEM analysis. The cubical nanoceria, in the size range 3.2-32 nm, were successfully internalized in the cellulose nanomatrix without agglomeration and exhibited excellent antioxidant property in pH-dependent manner. The nanobiocomposite is not cytotoxic to HeLa cell at a concentration as high as >1 mg.mL^-1 as revealed in the cytotoxicity assay. Thus, we describe for the first time synthesis of C/nanoceria, in a manner that is green and sustainable, which has potential in external clinical applications as an effective antioxidative green material for scavenging reactive oxygen species.