Cytotoxic and genotoxic effects of bacterial cellulose-collagen membranes

Bacterial cellulose formed by fermentation from Acetobacter xylinum promotes bone neoformation being a promising material for guided tissue regeneration, particularly when incorporate bioactive materials. Type I collagen matrix offers a suitable environment for induction of osteogenesis. Collagen membranes have been used to regenerate periodontal tissues. For a safe use in humans, all materials should not present cytotoxic and genotoxic effects. Objectives: to evaluate the potencial cytotoxic and genotoxic effects of bacterial cellulose (BC) and type I collagen-BC (COL-BC) membranes. Methods: BC was modified by glicine esterification through solid phase methodology (Fmoc strategy), followed by cross-linking of type I collagen employing 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide. CHO-K1 cells were seeded in a 24-well platform containing discs of BC or COL-BC membranes and positive (doxorubicin) and negative controls (NC), for 24h. Cytotoxicity was assessed by XTT (CHO-K1, 2x10⁴) and clonogenic survival (CS) (CHO-K1, 5x10⁴) assays. Genotoxic effect of BC and COL-BC membranes was evaluated by comet assay and cytokinesis block micronucleus (CBMN) test (CHO-K1, 5x10⁴). Results: XTT and CS assays showed no cytotoxicity of BC and COL-BC membranes when compared to the negative control (Tukey, p>0.05). Slight higher rate of cell proliferation (101.9%) was observed in COL-BC membranes compared to BC and NC. No significant DNA damage (comet assay) was observed in BC and COL-BC membranes (p>0.05). Interestingly, the COL-BC presented a slight lower DNA Damage Index in comparison with NC. The nuclear division index (NDI) measured by CBMN assay did not demonstrate significant differences between the membranes and NC (ANOVA, p=0.96). For BC and COL-BC, the NDI were, respectively, 12.0±1.2 and 14.3±0.7. In contrast, positive control presented a statistically higher NDI score (350.3, p<0.01). Conclusion: BC and COL-BC membranes did not present cytotoxic and genotoxic effects in vitro , indicating that these materials are safe for application in guided tissue regeneration.