title: Aggregation of cationic p-phenylene ethynylenes on Laponite clay in aqueous dispersions and solid films.
abstract: Previous studies of cationic p-phenylene ethynylenes oligomers (OPEs) have revealed strong antimicrobial activity and strong photophysical changes upon their aggregation that can be utilized for sensing various chemicals and biomolecules. In this article, the adsorption of two types of OPEs with different placement of charged groups onto the synthetic clay Laponite is studied, and the changes to photophysical properties, photochemical degradation efficiency, and biocidal effectiveness are determined. In addition to solution-phase studies, the material and biocidal properties of solid films formed from the OPE-Laponite complex were assessed. The results of this study suggest that OPEs aggregate on Laponite and induce aggregation between Laponite discs, leading to drastic changes to their photophysical and material properties. Solid OPE-Laponite films were shown to have fair resistance to dissolution in aqueous solution compared with Laponite alone, and adhesion and minor killing of both Gram-negative and Gram-positive bacteria on the surface was observed. The results of this study give insight into controlling the colloidal phases of Laponite via molecular aggregation, may be useful for development of sensors and biocides involving Laponite as a scaffold, and lead to further control over slow-release and surface interactions of biocidal materials.
authors.affiliation: Center for Biomedical Engineering, Department of Chemical and Biological Engineering and the Nanoscience and Microsystems Engineering Program University of New Mexico, Albuquerque, New Mexico 87131-1341, United States.
authors.forename: Eric H
authors.initials: EH
authors.lastname: Hill
authors.affiliation: Center for Biomedical Engineering, Department of Chemical and Biological Engineering and the Nanoscience and Microsystems Engineering Program University of New Mexico, Albuquerque, New Mexico 87131-1341, United States.
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Center for Biomedical Engineering, Department of Chemical and Biological Engineering and the Nanoscience and Microsystems Engineering Program University of New Mexico, Albuquerque, New Mexico 87131-1341, United States. Electronic address: whitten@unm.edu.
authors.forename: David G
authors.initials: DG
authors.lastname: Whitten
mesh_terms: D000327:Adsorption; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology*; D002412:Cations / Q000737:chemistry / Q000494:pharmacology; D006090:Gram-Negative Bacteria / Q000187:drug effects; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy; D006094:Gram-Positive Bacteria / Q000187:drug effects; D016908:Gram-Positive Bacterial Infections / Q000188:drug therapy; D006801:Humans; D010782:Photolysis; D011108:Polymers / Q000737:chemistry* / Q000494:pharmacology*; D017640:Silicates / Q000737:chemistry*; D012996:Solutions; D014867:Water / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D002412:Cations; D011108:Polymers; D017640:Silicates; D012996:Solutions; C473966:poly(phenylene ethynylene); D014867:Water; C524813:laponite
keywords: Cell adhesion; Dye aggregation; Layered silicates; Loading; Photoprotection; Self-assembly