Polymer Thin Films Designed to Decrease Microbial Pathogenicity by Altering Metabolic Activity

Advancements in biointerfacial materials focused on antifouling outcomes have extended the range of time of antifouling performance, yet bacteria will eventually persevere in attaching and forming persistent biofilms with enough time. Incorporating antibacterial features, which have a destructive impact on the vital functions of bacteria, into those same materials can support the antifouling action in fighting the formation of viable biofilms, but microbes are known to develop resistance to antibacterial elements. This creates an opportunity for the next generation of safe biointerfacial materials to implement surface chemistries that are capable of directing the metabolic behavior of bacteria that will inevitably attach. Such materials could pacify or eliminate the pathways that create pathogenic biomolecules, thus decreasing the potential for harm towards human health through an action that is less susceptible to bacterial resistance. The present work exhibits a polymer thin film coating of poly(4-vinylpyridine-<i>co-</i>divinylbenzene) synthesized using initiated chemical vapor deposition (iCVD) that was designed to alter the metabolic behavior of biofilm-forming <i>Pseudomonas aeruginosa </i>(PAO1 strain). The pyridine-rich material that was selected due to it capability of coordinating iron, a critical nutrient, from the surroundings. By enriching iron to the surface where biofilms grow, the coating facilitated the iron scavenging behavior of PAO1, leading to decreased production of siderophores and phenazines that validated the material design strategy. Without repelling and eliminating biofilms, the material reduced iron scavenging behavior that is tied to the production of PAO1’s primary virulence factors and reduced the virulence of the biofilms grown on the polymer coating to 32% of biofilms grown on a standard bacteria culture material (e.g., polyvinyl chloride). The solvent-free nature of the iCVD technique ensured an impurity-free coating was applied and due to its substrate-independent nature, iCVD could be used to apply this polymer coating to bacteria-contacting surfaces of virtually any type. This materials-based approach to influencing the metabolic behavior of bacteria and reducing pathogenicity sets the stage for future work on insoluble, tunable biointerfaces that beneficially manipulate the bacteria that penetrate antifouling defenses.