Bacterial cellulose-titanium dioxide nanocomposites: nanostructural characteristics, antibacterial mechanism, and biocompatibility

Regenerated bacterial cellulose (RBC) nanocomposites with titanium dioxide nanoparticles (TiO2 NPs) were prepared with the aim to enhance the bactericidal activity and tissue regeneration properties of BC. Powdered BC was dissolved in an N-methyl-morpholine-N-oxide/water (NMMO/H2O) system, TiO2 NPs were mixed into the BC solution, and RBC-TiO2 nanocomposite films were prepared by casting the composite solutions on a glass plate using an applicator. The structural features of composites were confirmed through TEM, X-ray diffraction and EDS assisted FE-SEM analysis. Antibacterial studies against E. coli revealed a significant reduction in bacterial growth with incorporation of RBC-TiO2 in growth media. The bactericidal mechanism was investigated through a DCFH-DA staining assay, glutathione reduction assay, and morphological study of treated bacterial cells. The results suggested that the bactericidal activities were due to reactive oxygen species and membrane stress generated by the TiO2 NPs present in the composite membranes. In addition to antibacterial properties, the RBC-TiO2 nanocomposites showed impressive cell adhesion and proliferation capabilities with animal fibroblast cells without showing any toxic effects. The composite surface was completely covered by a cell layer within 7 days of incubation. These RBC-TiO2 nanocomposites demonstrate potential bactericidal and biocompatible properties and could be effectively applied in the medical field, specifically for wound healing and tissue regeneration applications.