title: New evidence for hybrid acrylic/TiO2 films inducing bacterial inactivation under low intensity simulated sunlight.
abstract: This study addresses the preparation and characterization of hybrid films prepared from Titanium dioxide (TiO2) Pickering stabilized acrylic polymeric dispersion as well as their bacterial inactivation efficiency under sunlight irradiation. Complete bacterial inactivation under low intensity simulated solar light irradiation (55 mW/cm(2)) was observed within 240 min for the films containing 10 weight based on monomers (wbm) % of TiO2, whereas 360 min were needed for the films containing 20 wbm% of TiO2. The hybrid films showed repetitive Escherichia coli (E. coli) inactivation under light irradiation. TiO2 released from the films surfaces was measured by inductively coupled plasma mass spectrometry (IPC-MS), obtaining values of ∼ 0.5 and 1 ppb/cm(2) for the films containing 10 wbm% and 20 wbm% of TiO2, respectively, far below the allowed cytotoxicity level for TiO2 (200 ppb). Transmission electron microscopy (TEM) of the hybrid films showed that TiO2 nanoparticles (NPs) were located at the polymer particle's surface forming a continuous inorganic network inside the film matrix. Atomic force microscopy (AFM) images showed differences in the TiO2 dispersion between the air-film and film-substrate interfaces. Films containing 10 wbm% of TiO2 had higher roughness (Rg) at both interfaces than the one containing 20 wbm% of TiO2 inducing an increase in the bacterial adhesion as well as the bacterial inactivation kinetics. The highly oxidative OH-radicals participating in the bacterial inactivation were determined by fluorescence.
authors.affiliation: POLYMAT, University of the Basque Country UPV/EHU, Kimika Aplikatua Saila, Kimika Zientzien Fakultate, Joxe Mari Korta Zentro, Tolosa Hiribidea 72, 20018 Donostia-San Sebastián, Spain.
authors.forename: Audrey
authors.initials: A
authors.lastname: Bonnefond
authors.affiliation: POLYMAT, University of the Basque Country UPV/EHU, Kimika Aplikatua Saila, Kimika Zientzien Fakultate, Joxe Mari Korta Zentro, Tolosa Hiribidea 72, 20018 Donostia-San Sebastián, Spain.
authors.forename: Edurne
authors.initials: E
authors.lastname: González
authors.affiliation: POLYMAT, University of the Basque Country UPV/EHU, Kimika Aplikatua Saila, Kimika Zientzien Fakultate, Joxe Mari Korta Zentro, Tolosa Hiribidea 72, 20018 Donostia-San Sebastián, Spain.
authors.forename: Jose María
authors.initials: JM
authors.lastname: Asua
authors.affiliation: POLYMAT, University of the Basque Country UPV/EHU, Kimika Aplikatua Saila, Kimika Zientzien Fakultate, Joxe Mari Korta Zentro, Tolosa Hiribidea 72, 20018 Donostia-San Sebastián, Spain.
authors.forename: Jose Ramon
authors.initials: JR
authors.lastname: Leiza
authors.affiliation: Ecole Polytechnique Federale de Lausanne, EPFL-SB-ISIC-GPAO, Station 6, CH-1015, Switzerland.
authors.forename: John
authors.initials: J
authors.lastname: Kiwi
authors.affiliation: Ecole Polytechnique Federale de Lausanne, EPFL-SB-ISIC-GPAO, Station 6, CH-1015, Switzerland.
authors.forename: Cesar
authors.initials: C
authors.lastname: Pulgarin
authors.affiliation: Ecole Polytechnique Federale de Lausanne, EPFL-SB-ISIC-GPAO, Station 6, CH-1015, Switzerland. Electronic address: sami.rtimi@epfl.ch.
authors.forename: Sami
authors.initials: S
authors.lastname: Rtimi
mesh_terms: D000179:Acrylates / Q000737:chemistry* / Q000528:radiation effects*; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000528:radiation effects*; D001422:Bacterial Adhesion / Q000187:drug effects / Q000528:radiation effects; D004926:Escherichia coli / Q000187:drug effects / Q000528:radiation effects; D017665:Hydroxyl Radical / Q000737:chemistry / Q000528:radiation effects; D053768:Metal Nanoparticles / Q000737:chemistry / Q000528:radiation effects; D018625:Microscopy, Atomic Force; D010795:Phthalic Acids / Q000737:chemistry; D013472:Sunlight; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry* / Q000528:radiation effects*
chemical_list: D000179:Acrylates; D000900:Anti-Bacterial Agents; D010795:Phthalic Acids; C009495:titanium dioxide; D017665:Hydroxyl Radical; C011363:terephthalic acid; D014025:Titanium
keywords: Air-film interface; E. coli; Film stability; Pickering stabilized acrylic polymeric dispersion; TiO(2)