Antimicrobial Polymeric Composites to Prevent Hospital-Acquired Infections ^†

More than half of all hospital-acquired infections are associated with medical devices, with infections related to central venous catheters being some of the most serious ones, thus contributing to increased patient morbidity, hospitalization periods, health care costs, and mortality [1,2].

Most of the actual solutions available in the market that are used to avoid catheter-associated infections are combined with antibiotics and/or antiseptics, but the global rise in antibiotic resistance often makes these products ineffective. In addition, considering the socioeconomic impact of such infections, the development of new materials that avoid bacterial colonization is crucial to minimize this problem. Inorganic antimicrobial agents such as metal and metal oxide nanoparticles have been studied to control microbial infections, as they possess low toxicity, high stability, and strong antibacterial effects [3,4,5]. Magnesium oxide (MgO) has been studied due to its excellent antibacterial activity towards different microorganisms, low cost, and environmental friendly material, and is considered a harmless materials by the US Food and Drug Administration [6]. MgO is more attractive than other metal oxides such as silver or titanium oxide because it presents biodegradable and nontoxic products such as Mg²⁺, which is naturally present in the human body and plays vital roles in human biology [7]. The precise mechanism of antibacterial action behind MgO and other metal oxides’ nanoparticles is still under debate, and there are several hypotheses described in the literature. However, the most commonly reported mechanism is the formation of reactive oxygen species that induce oxidative stress [8]. These species chemically attack essential biological components such as DNA, proteins, lipids, and the bacteria cell membrane, causing its disruption and, consequently, cell death.

In the present work, polyurethane thermoplastic and magnesium oxide mixtures were prepared with different amounts of magnesium oxide particles in order to determine the ideal concentration range to achieve a correct balance between the best combination of antimicrobial and biocompatibility performances. The produced mixtures were optimized and characterized in terms of morphological and chemical properties. The results revealed that MgO particles induced antibacterial activity against the most frequently associated bacteria found in catheter-associated infections.