Zirconium-Coated β-Cyclodextrin Nanomaterials for Biofilm Eradication.

Under alkaline treatment, zirconyl chloride (ZrOCl.8HO) became a zirconia gel and formed a stable complex with beta-cyclodextrin (βCD). This complex was highly active in reactive oxygen species (ROS) formation via HO decomposition. Its surface with numerous hydroxyl groups acts as an ionic sponge to capture the charged reaction intermediates, including superoxide (O) and the hydroxyl radical (OH). ROS, especially OH radicals, are harmful to living microorganisms because of their kinetic instability, high oxidation potential, and chemical nonselectivity. Therefore, OH radicals can engage in fast reactions with virtually any adjacent biomolecule. With HO, the complex with cationic and hydrophobic moieties interacted with the anionic bacterial membrane of two Gram-positive ( and ) and two Gram-negative ( and ) strains. The Zr-βCD-HO also eradicated more than 99% of the biofilm of these four pathogens. Considering the difficult acquisition of resistance to the oxidation of OH, the results suggested that this βCD-based nanomaterial might be a promising agent to target both drug-resistant pathogens with no cytotoxicity and exceptional antimicrobial activity.