Exploiting the Versatility of Polydopamine‐Coated Nanoparticles to Deliver Nitric Oxide and Combat Bacterial Biofilm

In this study, an antimicrobial platform in the form of nitric oxide (NO) gas‐releasing polydopamine (PDA)‐coated iron oxide nanoparticles (IONPs) is developed for combating bacterial biofilms. NO is bound to the PDA‐coated IONPs via the reaction between NO and the secondary amine moieties on PDA to form N‐diazeniumdiolate (NONOate) functionality. To impart colloidal stability to the nanoparticles in aqueous solutions (e.g., phosphate buffered saline (PBS) and bacteria cell culture media M9), a polymer bearing hydrophilic and amine pendant groups, P(OEGMA)‐b‐P(ABA), is synthesized via reversible addition‐fragmentation chain transfer (RAFT) polymerization and is subsequently grafted onto the PDA‐coated IONPs by employing the Schiff base/Michael addition reaction between o‐quinone and a primary amine. These nanoparticles are able to effectively disperse Pseudomonas aeruginosa biofilms (up to 79% dispersal) at submicromolar NO concentrations. In addition, the nanoparticles demonstrate excellent bactericidal activity toward P. aeruginosa planktonic and biofilm cells (up to 5‐log10 reduction). An antimicrobial platform in the form of nitric oxide (NO) gas‐releasing polydopamine (PDA)‐coated iron oxide nanoparticles (IONPs) is developed for combating bacterial biofilms. NO is conjugated to the PDA‐coated IONPs via the reaction between NO and the secondary amine moieties on PDA to form N‐diazeniumdiolate (NONOate) functionality.