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There are numerous issues associated with bacteria, particularly biofilms, which exhibit a strong resistance to antibiotics. This is currently considered an urgent global issue owing to the lack of effective treatments. Graphene oxide (GO) nanosheets are twodimensional carbon materials that are available as a substrate for metal nanoparticles and have a lower release rate of metal ions than free metal nanoparticles by regulating the oxidation of metal nanoparticles, which is known to reduce the cytotoxicity caused by the free metal nanoparticles. Over centuries, metal particles, including Ag and Cu, have been considered as antibacterial agents. In this study, Ag and Cu bimetallic nanoparticles on a GO surface (Ag/Cu/GO) were synthesized using a chemical reduction method, and their antimicrobial effects against several bacterial species were demonstrated. Ag/Cu/GO nanocomposites were characterized by transmission electron microscopy and energy-dispersive X-ray spectroscopy. The in vitro cytotoxicity of an Ag/Cu/GO nanocomposite was evaluated in human dermal fibroblasts, and its antibacterial activity against Methylobacterium spp., Sphingomonas spp., and Pseudomonas aeruginosa (P. aeruginosa) was also tested. The synthesized Ag/Cu/GO nanocomposite was able to eradicate all three bacterial species at a concentration that was harmless to human cells. In addition, Ag/Cu/GO successfully removed a biofilm originated from the culturing of P. aeruginosa in a microchannel with a dynamic flow. In a small-animal model, a biofilm-infected skin wound was healed quickly and efficiently by the topical application of Ag/Cu/GO. The Ag/Cu/GO nanocomposites reported in this study could be used to effectively remove antibiotic-resistant bacteria and treat diseases in the skin or wound due to bacterial infections and biofilm formation.

Mesoporous carbon derived from pyrolysis of metal–organic frameworks (MOFs) is advantageous owing to its high specific surface area, large pore volume, and versatility in both structure and composition. Heteroatom doping on mesoporous carbon by synthesizing with heteroatom containing ligands (pre-synthetic process) or incorporating heteroatom-containing compounds during pyrolysis (post-doping) can further enhance its electrochemical properties. Although both methods have been applied to increase the doping content, the effects of the pre-synthetic process and post-doping have not yet been systematically studied. Herein, we have synthesized mesoporous carbon derived from sulfur-containing MOFs for the first time using 2,5-disulfanylterephthalic acid as a ligand and added dopants (melamine for N-doping and thiourea for N,S-codoping). We systematically compared the performance of mesoporous carbon as cathodes for the oxygen reduction reaction (ORR) and lithium–sulfur (Li–S) batteries with previous studies, which used terephthalic acid and its analogues as pre-synthetic ligands and various dopants as post-doping sources. Our work showed the synergetic effect of heteroatoms from dual-doping processespecially sulfur (S from pre-synthetic process and N,S from post-doping), which not only enhanced catalytic activity (limiting current density (J L) of −5.19 mA·cm–2), stability, and methanol tolerance as an ORR catalyst but also rendered superior stability of 85.2% over 100 cycles as a cathode of Li–S batteries.

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