Novel Polyhydroxyalkanoate-graphene oxide composites with potential for clinical application against bacterial implant-associated infections in septic surgery

Alexandra Paxinou^1,2,3Rinat Nigmatullin³George Paterakis¹Labrini Sygellou¹Richard Viebahn²Costas Galiotis¹Jochen Salber^2,4*Ipsita Roy^5,6*

• ¹Institute of Chemical Engineering Sciences, Foundation for Research and Technology, Hellas, Patras, Greece
• ²Universitatsklinikum der Ruhr-Universitat Bochum, Bochum, Germany
• ³University of Westminster College of Liberal Arts and Sciences, London, United Kingdom
• ⁴Experimental Surgery, Ruhr University Bochum, Bochum, Germany, Bochum, Germany
• ⁵Insigneo Research Institute, University of Sheffield, Sheffield, United Kingdom
• ⁶University of Sheffield, School of Chemical, Materials & Biological Engineering Faculty of Engineering, Sheffield, United Kingdom

Implant-associated infections are a major clinical challenge, often leading to implant failure, revision surgeries and increased healthcare costs. The development of advanced biomaterials with inherent antimicrobial properties is critical to address this issue. In this study, we present novel two-dimensional (2D) composite films based on polyhydroxyalkanoates (PHAs) combined with graphene oxide (GO) to confer both antimicrobial efficacy and tailored mechanical properties. Composites with varying GO concentrations (0.5, 2 and 5 wt%) were fabricated using a solvent casting method in both short-chain-length (P(3HB)) and medium-chain-length (P(3HO-co-3HD)) PHA matrices. Physicochemical characterization (SEM, XPS, Raman spectroscopy, XRD, DSC, and mechanical testing) confirmed successful GO incorporation, changes in surface morphology, and modifications in thermal and mechanical properties. Notably, the incorporation of 2 wt% GO into P(3HB) increased the Young's modulus from 776 ± 15 MPa to 1055 ± 28 MPa, indicating enhanced stiffness. Antibacterial testing using ISO 22196 against Staphylococcus aureus and Escherichia coli revealed that P(3HB)/2 wt% GO achieved the highest antibacterial efficacy. In contrast, the 5 wt% GO composite showed reduced antibacterial activity, likely due to GO agglomeration. Moreover, in vitro cytocompatibility assays using L929 fibroblasts and NG108-15 neuronal cells demonstrated high cell viability across all composites, indicating minimal cytotoxicity. These findings highlight the potential of PHA/GO composites as sustainable, antimicrobial biomaterials for future use in implantable devices and additive manufacturing in septic surgical applications.