The rise of antimicrobial resistance (AMR) has become a critical health challenge. This, plus the antimicrobial discovery void, had led scientists to search for an effective alternative to antimicrobials. In this context, nanomaterials, such as graphene oxide (GO), a two-dimensional (2D) carbon molecule with oxidized functional groups, have been shown to interact physically and chemically with bacteria. Moreover, the addition of polyethylene glycol (PEG) to its surface enhances GO’s biocompatibility and water solubility, making it a promising candidate for biomedical applications. This study evaluates the antimicrobial efficacy of GO and its polyethylene glycol-modified form (GO-PEG) against Staphylococcus aureus, a bacterium responsible for numerous hospital-acquired and multidrug-resistant infections. After their production, both nanomaterials were characterized using various techniques to provide insight into their morphology, stability, and functional group composition. Then, the antimicrobial activity of GO and GO-PEG was assessed using the Müeller–Hinton broth microdilution method, determining the minimum inhibitory concentration (MIC) for S. aureus among ten different concentrations of both nanomaterials (from 0.0625 to 32 mg/mL). The results demonstrate the potential of GO as an effective antimicrobial agent at 16 and 32 mg/mL, offering new strategies in the fight against AMR. Further research could establish its role in future therapeutic applications.

This study investigates the interaction between copper (Cu) and silver (Ag) clusters and graphene-based materials using molecular dynamics simulations. It focuses on how graphene oxidation and aminated polyethylene glycol (PEG-NH₂) functionalization influence interaction strength and cluster dynamics. The analysis includes pristine graphene (PG), low-oxidized graphene oxide (GOL), and PEGylated graphene oxide (GO-PEG-NH₂). The results reveal that clusters on PG exhibit high mobility, while GO-PEG-NH₂ significantly restricts mobility due to strong interactions, as evidenced by highly negative interaction energies. GO-PEG-NH₂ systems also display pronounced subdiffusive behavior (α < 1), indicating strong binding and constrained motion. These findings underscore the critical role of PEG-NH₂ functionalization in controlling cluster diffusion, paving the way for innovative designs in biomedical and catalytic nanocarrier applications.

Bimetallic nanomaterials that couple catalytic reactivity with light-responsive behaviour provide a promising route for multifunctional antimicrobial materials. Here, we report Cu–Au core–nanocluster nanostructures that integrate a cost-effective Cu core with ultrafine Au clusters to form an interface-engineered antimicrobial platform. Density functional theory shows that Cu–Au interfacial sites lower O–O bond dissociation barriers and enhance charge transfer, enabling efficient catalytic generation of reactive oxygen species (ROS). Experimentally, the nanostructures exhibit enhanced Cu2+ release relative to Cu alone, consistent with galvanic coupling, and demonstrate strong antimicrobial activity under dark conditions, confirming a ROS- and ion-mediated mechanism. Under visible-light irradiation, photothermal simulations and measurements show localised heating to ~60 °C at particle densities an order of magnitude lower than conventional Au nanoparticles, enabling material-efficient thermal inactivation. These results establish a structure–property–function relationship in which catalytic oxygen reduction and galvanic Cu dissolution provide continuous dark activity, while plasmonic photothermal effects introduce a controllable light-driven amplification pathway. This multi-mechanistic framework supports the design of scalable antimicrobial coatings and interfaces capable of operating across both illuminated and non-illuminated environments.

Although graphene oxide (GO)-supported plasmonic nanostructures are promising platforms for surface-enhanced Raman spectroscopy (SERS), the mechanistic relationship between oxidation-controlled interface chemistry, nanoparticle organisation and plasmonic behaviour remains poorly understood. Here, GO with two controlled oxidation levels (GO10 and GO30) was functionalised with polyethylene glycol (PEG-NH2) and decorated with Ag and Cu nanoparticles to establish multiscale structure-property relationships linking surface chemistry, interfacial organisation and optical performance. Complementary experimental characterisation combined with molecular dynamics (MD) and finite-difference time-domain (FDTD) simulations demonstrated that increasing oxidation from GO10 (O/C = 0.048) to GO30 (O/C = 0.522) promotes more extensive PEG-related surface modification, strengthens nanocluster adsorption, suppresses mobility and produces more uniform nanoparticle organisation. FDTD simulations further revealed that PEG-controlled sub-10 nm interparticle spacing enhances plasmonic coupling, generating localised electromagnetic hotspots with simulated SERS enhancement factors approaching 105. Together, the experimental and computational results establish a continuous mechanistic pathway linking oxidation-controlled surface chemistry to nanoparticle organisation, plasmonic coupling and optical performance. These findings demonstrate that oxidation-controlled interface engineering provides a predictive design strategy for the rational development of reproducible graphene-supported plasmonic nanostructures for SERS and related optical sensing applications.