Unveiling the antimicrobial potential of oxidized graphene derivatives: Promising materials for advanced wound dressings and antibacterial surfaces

This study investigates the influence of oxygen-containing functional groups resulting from varying degrees of oxidation on the antimicrobial, antifungal and cytotoxic properties of graphene oxide (GO). Four GO derivatives with different oxidation degrees (GO1.5, GO2, GO3, and GO6) were prepared and analyzed using Transmission Electron Microscopy (TEM), Energy Dispersive Spectroscopy (EDS), and UV–visible spectroscopy. EDS results showed a progressive decrease in the C/O ratio from GO1.5 to GO6, indicating that GO6 had the highest concentration of oxygen-containing chemical groups. The cytotoxic effects of these compounds were evaluated using the MTT colorimetric assay on the 3T3 cell line. After 72 h, GO6 exhibited significantly superior biocompatibility across various concentrations. Furthermore, antimicrobial activities were assessed through Minimum Inhibitory Concentration (MIC), Minimum Bactericidal/Fungicidal Concentration (MBC/MFC), Antibiofilm, and Time-Kill tests against Gram-positive Staphylococcus aureus (StaA) and Gram-negative Pseudomonas aeruginosa (PseA) bacteria, as well as Candida albicans (CanA) fungus. Notably, all tested compounds demonstrated significant efficacy against StaA, PseA and CanA. GO6, with higher levels of hydrophilic functional groups and oxidation, exhibited highly enhanced antibacterial effects compared to GO1.5, GO2, and GO3. While previous research has explored generic GO's antimicrobial characteristics, our study uniquely delves into the relationship between GO's degree of oxidation and its antibacterial, antifungal, and cytotoxic effects. This study confirms that, compared to generic GO materials, highly oxidized GO (GO6) holds the potential to be a highly efficient antibacterial agent, reinforcing its relevance for medical applications in combating pathogenic microbes.