Magnesium oxide-containing radiopaque polyurethane for infection-resistant catheter applications

The increasing prevalence of antibiotic resistance highlights the urgent need for advanced antimicrobial materials preventing device-associated infections. This growing threat has spurred intensive research into alternative approaches to prevent bacterial colonisation, particularly in medical devices such as catheters highly susceptible to microbial contamination and biofilm formation. The incorporation of magnesium oxide (MgO) nanoparticles on polymeric matrices offers a promising approach to developing antibacterial materials for biomedical applications. In this study, thermoplastic polyurethane filled with barium sulfate (TPU/BaSO₄), was modified with MgO nanoparticles, either as surface coating or as bulk composite. SEM and X-ray analyses confirmed the uniform MgO distribution within the TPU/BaSO₄ matrix and surface. Degradation studies revealed a gradual Mg²⁺ release from composites over time, whereas MgO-coated films exhibited faster ion release and early generation of reactive oxygen species (ROS). Antibacterial testing revealed that MgO coatings achieved complete elimination of planktonic Methicillin-resistant Staphylococcus aureus (MRSA) and strong growth inhibition of Pseudomonas aeruginosa (P. aeruginosa), particularly at higher MgO content. Sessile MRSA and P. aeruginosa biofilms were also significantly reduced after 24 h, while composites showed no significant antibacterial effect due to limited MgO surface exposure and absence of ROS formation. ROS quantification confirmed that MgO coatings induced oxidative stress within 2 h, showing also initial antibacterial effect, supporting a ROS-mediated antibacterial mechanism in addition to Mg²⁺ release and direct particle-bacteria interactions. All coating formulations displayed excellent cytocompatibility with endothelial cells, and in vivo biocompatibility without signs of inflammatory or vascular adverse responses. MgO inclusion also preserved the structural integrity and radiopacity of TPU/BaSO₄ matrix. Overall, MgO-coated TPU/BaSO₄ structures combine antibacterial efficacy while maintaining biocompatibility, and functional performance, offering a scalable pathway toward antibiotic-free, infection-resistant catheter materials applications.