Graphene based antimicrobial biomaterials

Antibiotic-resistant bacterial infections are a growing concern in bone replacement surgeries. Therefore, new implant biomaterials should both prevent bacterial adhesion and colonization and support osseointegration. Titanium is widely used for bone implants, but its antimicrobial performance still needs improvement. In this work, titanium is functionalized with 2D materials, such as molybdenum disulfide (MoS₂), tungsten disulfide (WS₂) and graphene nanowalls, to combine intrinsic antimicrobial activity with biocompatibility.

To investigate the antimicrobial properties of transition metal dichalcogenide (TMD) materials, homogeneous, large-scale TMD-based nanowalls were grown on titanium substrates using a metalorganic chemical vapor deposition (MOCVD) system. By tuning the growth parameters different morphologies of MoS₂ and WS₂ morphologies are achieved. The prepared samples are characterized by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and Raman spectroscopy and contact angle measurements (CAM).

To further investigate the biological performance of the engineered implant surfaces, clinically relevant pathogens associated with orthopedic implant infections are evaluated on the surface coatings. Bacterial adhesion and colonization are assessed using fluorescence microscopy (FM), confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), and quantitative microbiological analyses. The interaction of the materials with different bone cell types is investigated to evaluate cell attachment and osseointegration potential, while their antimicrobial functionality is further assessed using the Galleria mellonella larval infection model. In parallel, the role of the bacterial adhesive proteins Eap, Emp, FnBPA, and FnBPB in mediating adhesion to host tissues and biomaterial surfaces is investigated to improve our understanding of implant-associated infections.