Identification and Optimization of Carbon Radicals on Hydrated Graphene Oxide for Ubiquitous Antibacterial Coatings

While the antibacterial properties of graphene oxide (GO) have been demonstrated across a spectrum of bacteria, the critical role of functional groups is unclear. To address this important issue, we utilized reduction and hydration methods to establish a GO library with different oxidation, hydroxyl, and carbon radical (•C) levels that can be used to study the impact on antibacterial activity. Using antibiotic-resistant bacteria as a test platform, we found that the •C density is most proximately associated with bacterial killing. Accordingly, hydrated GO (hGO), with the highest •C density, had the strongest antibacterial effects through membrane binding and induction of lipid peroxidation. To explore its potential applications, we demonstrated that coating of catheter and glass surfaces with hGO is capable of killing drug-resistant bacteria. In summary, •C is the principle surface moiety that can be utilized for clinical applications of GO-based antibacterial coatings.