Antibacterial Activity of Cellulose Acetate–Graphene Oxide Composites: A Comprehensive Multimethod Assessment

Bacterial contamination remains a critical concern in the environmental and biomedical fields, driving the demand for multifunctional materials with reliable antibacterial properties. Cellulose acetate–graphene oxide (CA–GO) composites, as a class of polymer nanocomposites, offer an effective solution by combining the biocompatibility of cellulose acetate with the antimicrobial activity of graphene oxide. In this study, the antibacterial performance of CA–GO composites was systematically evaluated by using multiple analytical techniques to better understand their efficacy under diverse conditions. A suite of complementary methods, including the Contact Film Diffusion Assay, Surface Drop Viability Assay, and Dynamic Immersion Exposure Test, was employed to assess how variables such as GO concentration, bacterial strain type, and exposure settings influence antibacterial activity. Results showed that CA–GO composites exhibit strong antibacterial effects, particularly against Gram-positive bacteria, largely attributed to GO’s ability to disrupt bacterial membrane integrity through oxidative stress and physical interactions. This multimethod investigation highlights the importance of testing under varied conditions to capture the full spectrum of antibacterial behavior. The findings not only demonstrate the high potential of CA–GO composites for antimicrobial applications but also underscore the need for standardized evaluation protocols tailored to graphene-based polymer nanocomposites.