title: Preparation of Polyethylene Composites Containing Silver(I) Acylpyrazolonato Additives and SAR Investigation of their Antibacterial Activity.
abstract: Novel composite materials PEn (n = 1-9) have been prepared by an easily up-scalable embedding procedure of three different families of Ag(I) acylpyrazolonato complexes in polyethylene (PE) matrix. In details, PE1-PE3 composites contain polynuclear [Ag(QR)]ncomplexes, PE4-PE6 contain mononuclear [Ag(QR)(L)m] complexes and PE7-PE9 are loaded with mononuclear [Ag(QR) (PPh3)2] complexes, respectively (where L = 1-methylimidazole or 2-ethylimidazole, m = 1 or 2, and HQR= 1-phenyl-3-methyl-4-RC(═O)-5-pyrazolone, where in detail HQfb, R = -CF2CF2CF3; HQcy, R = -cyclo-C6H11; HQbe, R = -C(H)═C(CH3)2). The PEn composites, prepared by using a 1:1000 w/w silver additive/polyethylene ratio, have been characterized in bulk by IR spectroscopy and TGA analyses, which confirmed that the properties of polyethylene matrix are essentially unchanged. AFM, SEM, and EDX surface techniques show that silver additives form agglomerates with dimensions 10-100 μm on the polyethylene surface, with a slight increment of surface roughness of pristine plastic within 50 nm. However, the elastic properties of the composites are essentially the same of PE. The antibacterial activity of all composites has been tested against three bacterial strains (E. coli, P. aeruginosa and S. aureus) and results show that two classes of composites, PE1-PE3 and PE4-PE6, display high and persistent bactericidal and bacteriostatic activity, comparable to PE embedded with AgNO3. By contrast, composites PE7-PE9 exhibit a reduced antibacterial action. Contact and release tests in several conditions for specific migration of Ag+from plastics, indicate a very limited but time persistent release of silver ions from PE1-PE6 composites, thus suggesting that they are potential antibacterial materials for future applications. Instead, PE7-PE9 almost do not release silver, only trace levels of silver ions being detected, in accordance with their reduced antibacterial action. None of the composites is toxic against higher organisms, as confirmed by D. magna test of ecotoxicity.
authors.affiliation: School of Science and Technology, Chemistry Section, University of Camerino , Via S. Agostino 1, 62032 Camerino (MC) Italy.|ICCOM, CNR 62032 Camerino, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Marchetti
authors.affiliation: School of Science and Technology, Chemistry Section, University of Camerino , Via S. Agostino 1, 62032 Camerino (MC) Italy.
authors.forename: Jessica
authors.initials: J
authors.lastname: Palmucci
authors.affiliation: ICCOM, CNR 62032 Camerino, Italy.|School of Pharmacy, Chemistry Section, University of Camerino , Via S. Agostino 1, 62032 Camerino (MC) Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Pettinari
authors.affiliation: ICCOM, CNR 62032 Camerino, Italy.|School of Pharmacy, Chemistry Section, University of Camerino , Via S. Agostino 1, 62032 Camerino (MC) Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Pettinari
authors.affiliation: School of Science and Technology, Chemistry Section, University of Camerino , Via S. Agostino 1, 62032 Camerino (MC) Italy.
authors.forename: Mirko
authors.initials: M
authors.lastname: Marangoni
authors.affiliation: School of Science and Technology, Chemistry Section, University of Camerino , Via S. Agostino 1, 62032 Camerino (MC) Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Ferraro
authors.affiliation: School of Science and Technology, Chemistry Section, University of Camerino , Via S. Agostino 1, 62032 Camerino (MC) Italy.
authors.forename: Rita
authors.initials: R
authors.lastname: Giovannetti
authors.affiliation: Research Centre for Hygienistic, Health and Environmental Sciences, School of Pharmacy, University of Camerino , Via Madonna delle Carceri 9, 62032 Camerino (MC) Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Scuri
authors.affiliation: Research Centre for Hygienistic, Health and Environmental Sciences, School of Pharmacy, University of Camerino , Via Madonna delle Carceri 9, 62032 Camerino (MC) Italy.
authors.forename: Iolanda
authors.initials: I
authors.lastname: Grappasonni
authors.affiliation: Research Centre for Hygienistic, Health and Environmental Sciences, School of Pharmacy, University of Camerino , Via Madonna delle Carceri 9, 62032 Camerino (MC) Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Cocchioni
authors.affiliation: Departamento de Química Inorgánica, Universidad de Granada , Av. Fuentenueva s/n, 18071 Granada, Spain.
authors.forename: Francisco José
authors.initials: FJ
authors.lastname: Maldonado Hodar
authors.affiliation: School of Science and Technology, Physics Section, University of Camerino , Via Madonna delle Carceri 9, 62032 Camerino (MC) Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Gunnella
mesh_terms: D000900:Anti-Bacterial Agents; D004926:Escherichia coli; D020959:Polyethylene / Q000737:chemistry*; D012834:Silver; D013211:Staphylococcus aureus
chemical_list: D000900:Anti-Bacterial Agents; D012834:Silver; D020959:Polyethylene
keywords: AFM analysis; Ag(I) acylpyrazolonato additives; SEM analysis; antibacterial activity; composite materials; contact and release tests; polyethylene