Antimicrobial Activity of Copper Pyrazolate Coordination Polymers

The need to develop an effective system that allows to fight infections caused by microbial strains resistant to antibiotics has become more and more critical in recent years. An increasing number of scientific studies highlight the great potential, as antibacterial agents, shown by metals in various forms, such as metal surfaces, metal nanoparticles and metal-containing compounds. However, most of them possess the drawback of an excessive release of metal ions that limits their use in food packaging and other food-related applications. Coordination polymers (CPs) can address this disadvantage, based on their very low solubility in water and most solvents. Here we report novel Cu(II) CPs with pyrazole ligands together with a detailed structural characterization and their strong activity against gram-positive (S. aureus) and gram negative (E. coli) bacterial strains. These CPs act through a dual mechanism of action based on surface contact of CPs nanoparticles affording bacterial cell damage by cell membrane disintegration and generation of Reactive Oxygen Species (ROS).