Abstract: A system of stabilized metallic nanoparticles is described that includes metallic nanoparticles coated with a hydrophilic polymer that has been reacted with a catechol-based ligand. Also described are stable, metallic nanoparticles that can be used alone or in conjunction with biocides, antibiotics, or other treatment systems in a method to disrupt a biofilm and facilitate its removal from a surface. The nanoparticles can be metal, such as platinum, silver, iron (II, III) oxide (Fe3O4), and gold. The nanoparticles can be sterically stabilized, such as with a polymer, or charge stabilized, such as with citrate, resulting in nanoparticles having modified surfaces. This surface modification is thought to enhance the stability of the nanoparticles and decrease their likelihood of aggregation, which, in turn, enhances their ability to disrupt and disperse existing biofilms.