Reduced graphene oxide-histidine-silver nanocomposite coating with antibacterial activity for abdominal biomedical textiles

Abstract

The synthesis and characterization of a novel antibacterial hybrid nanocomposite composed of reduced graphene oxide (RGO) functionalized with histidine and decorated with Ag nanoparticles (NPs) is reported. The material was developed via an in situ colloidal approach, performed in water at ice bath temperature. Histidine was selected as molecular linker due to its unique physicochemical properties: (i) ability to exfoliate RGO and enhance its dispersion in aqueous media, (ii) π–π aromatic stacking interactions with the graphene basal plane, and (iii) presence of imidazole and amine groups that provide coordination sites for Ag⁺ ions, enabling controlled nucleation and anchoring of monodispersed Ag NPs. The nanocomposite structure was finely tuned by systematically optimizing synthetic parameters, and each parameter was evaluated through morphological and spectroscopic characterization to assess NP size distribution and anchoring density. The nanocomposite was applied as coating on cotton fabrics and tested for the antibacterial activity against Escherichia coli (E. coli), following the ISO 20743:2021 quantitative standard protocol. The nanocomposite demonstrated superior and more stable antibacterial performance compared to Ag NP coatings synthesized with comparable size and surface properties. MTS assays confirmed that the modified textiles did not significantly impair cell viability. Given its colloidal stability, sustained antibacterial efficacy, and safety profile, the nanocomposite represents a robust platform for functional coatings in biomedical textiles, wound dressings and surgical fabrics, particularly suited to abdominal and intestinal procedures where E. coli contamination is a major concern.