sami RTIMI
Ecole Polytechnique Federale de Lausanne, SB-ISIC-GGRC, Department Member
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Castles fall from inside: Evidence for dominant internal photo-catalytic mechanisms during treatment of Saccharomyces cerevisiae by photo-Fenton at near-neutral pHmore
by sami RTIMI
Publication Date: 2016
Publication Name: Applied Catalysis B: Environmental
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Antibacterial surfaces based on functionally graded photocatalytic Fe 3 O 4 @TiO 2 core–shell nanoparticle/epoxy compositesmore
by sami RTIMI
Publication Date: 2015
Publication Name: RSC Adv.
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Light wavelength-dependent E. coli survival changes after simulated solar disinfection of secondary effluentmore
by sami RTIMI and Cesar Pulgarin
In this study, the photoreactivation and the modification of dark repair of E. coli in a simulated secondary effluent were investigated after initial irradiation under different conditions. The simulated solar exposure of the secondary... more
In this study, the photoreactivation and the modification of dark repair of E. coli in a simulated secondary effluent were investigated after initial irradiation under different conditions. The simulated solar exposure of the secondary wastewater was followed by exposure to six different low-intensity fluorescent lamps (blacklight blue, actinic blacklight, blue, green, yellow and indoor light) for up to 8 h. When photoreactivation was monitored, blue and green colored fluorescent light led to increased bacterial regrowth. Blacklight lamps further inactivated the remaining bacteria, while yellow and indoor light led to accelerated growth of healthy cells. Exposure to fluorescent lamps was followed by long term storage in darkness, to monitor the bacterial repair in the dark. The response was correlated with the pre-exposure dose of applied solar irradiation, and to a lesser extent with the fluorescent light dose. Bacteria which had undergone extensive exposure showed no response under fluorescent light or during storage in the dark. Finally, the statistical treatment of the data allowed us to suggest a linear model, which is non-selective in terms of the fluorescent light applied. The estimation of the final bacterial population was predicted well (R-sq ∼ 75%) and the photoreactivation risk was found to be more important for cultivable cells.
Publication Date: 2015
Publication Name: Photochem. Photobiol. Sci.
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Kinetics and mechanism for transparent polyethylene-TiO2 films mediated self-cleaning leading to MB dye discoloration under sunlight irradiationmore
by sami RTIMI and Cesar Pulgarin
Publication Date: 2015
Publication Name: Applied Catalysis B: Environmental
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Preparation and Mechanism of Cu-Decorated TiO 2 –ZrO 2 Films Showing Accelerated Bacterial Inactivationmore
by sami RTIMI and Cesar Pulgarin
Publication Date: 2015
Publication Name: ACS Applied Materials & Interfaces
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New evidence for hybrid acrylic/TiO2 films inducing bacterial inactivation under low intensity simulated sunlightmore
by sami RTIMI and Cesar Pulgarin
Publication Date: 2015
Publication Name: Colloids and Surfaces B: Biointerfaces
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Duality in the Escherichia coli and methicillin resistant Staphylococcus aureus reduction mechanism under actinic light on innovative co-sputtered surfacesmore
by sami RTIMI and Cesar Pulgarin
Publication Date: 2015
Publication Name: Applied Catalysis A: General
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Effect of surface pretreatment of TiO2 films on interfacial processes leading to bacterial inactivation in the dark and under light irradiationmore
by sami RTIMI and Cesar Pulgarin
Evidence is presented for radio-frequency plasma pretreatment enhancing the amount and adhesion of TiO2 sputtered on polyester (PES) and on polyethylene (PE) films. Pretreatment is necessary to attain a suitable TiO2 loading leading to an... more
Evidence is presented for radio-frequency plasma pretreatment enhancing the amount and adhesion of TiO2 sputtered on polyester (PES) and on polyethylene (PE) films. Pretreatment is necessary to attain a suitable TiO2 loading leading to an acceptable Escherichia coli reduction kinetics in the dark or under light irradiation for PES-TiO2 and PE-TiO2 samples. The amount of TiO2 on the films was monitored by diffuse reflectance spectroscopy and X-ray fluorescence. X-ray electron spectroscopy shows the lack of accumulation of bacterial residues such as C, N and S during bacterial inactivation since they seem to be rapidly destroyed by TiO2 photocatalysis. Evidence was found for Ti(4+)/Ti(3+) redox catalysis occurring on PES-TiO2 and PE-TiO2 during the bacterial inactivation process. On PE-TiO2 surfaces, Fourier transform infrared spectroscopy (ATR-FTIR) provides evidence for a systematic shift of the na(CH2) stretching vibrations preceding bacterial inactivation within 60 min. The discon...
Publication Date: Jan 6, 2015
Publication Name: Interface focus
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Publication Date: 2012
Publication Name: RSC Advances
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Corrigendum to “RF-plasma pretreatment of surfaces leading to TiO2 coatings with improved optical absorption and OH-radical production” [Appl. Catal. B: Environ. 130–131 (2013) 65–72]more
by O. Baghriche and sami RTIMI
ABSTRACT Fig. 1. (a) Spectral distribution of the Osram Lumilux 827/18 W lamp reported in the Osram catalogue (2001) and (b) spectral distribution of the Osram Lumilux 827/18 W lamp as provided May 2013 by Osram Winterthur, Switzerland.
Publication Date: 2013
Publication Name: Applied Catalysis B: Environmental
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Photocatalysis/catalysis by innovative TiN and TiN-Ag surfaces inactivate bacteria under visible lightmore
by O. Baghriche and sami RTIMI
Publication Date: 2012
Publication Name: Applied Catalysis B: Environmental
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Publication Date: 2015
Publication Name: Applied Catalysis B: Environmental
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RF-plasma pretreatment of surfaces leading to TiO2 coatings with improved optical absorption and OH-radical productionmore
by O. Baghriche and sami RTIMI
Publication Date: 2013
Publication Name: Applied Catalysis B: Environmental
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The bacterial inactivation of E. coli by cotton TiO(2)/Cu DC-magnetron sputtered thin films was investigated in the dark and under low-intensity actinic light. The TiO(2)/Cu sputtered layers revealed to be sensitive to actinic light... more
The bacterial inactivation of E. coli by cotton TiO(2)/Cu DC-magnetron sputtered thin films was investigated in the dark and under low-intensity actinic light. The TiO(2)/Cu sputtered layers revealed to be sensitive to actinic light showing the spectral characteristics of Cu/CuO. This indicates that Cu does not substitute Ti(4+) in the crystal lattice. Under diffuse actinic light (4 mW/cm(2)), the hybrid composite TiO(2)/Cu sample lead to fast bacterial inactivation times <5 min. This study presents evidence for a direct relation between the film optical absorption obtained by diffuse reflectance spectroscopy (DRS) and the bacterial inactivation kinetics by the TiO(2)/Cu samples. The Cu-ions inactivating the bacteria were followed in solution by inductively plasma coupled spectroscopy (ICPS). The amounts of Cu-ions detected by ICPS provide the evidence for an oligodynamic antibacterial effect. The changes in the oxidation state of Cu during bacterial inactivation were followed by XPS. The E. coli cell viability was detected by standard coliform counting CFU methods. The TiO(2)/Cu thickness layer was determined by profilometry and the film microstructure by XPS, TEM, AFM, XRD, XRF and contact angle (CA). A mechanism of bacterial inactivation by TiO(2)/Cu samples is suggested in terms of interfacial charge transfer (IFCT) involving charge transfer between TiO(2) and Cu.
Publication Date: 2012
Publication Name: ACS Applied Materials & Interfaces
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Microstructure of Cu-Ag Uniform Nanoparticulate Films on Polyurethane 3D Catheters: Surface Propertiesmore
by Cesar Pulgarin and sami RTIMI
The preparation, characterization, and antibacterial testing of Cu-Ag sputtered polyurethane (PU) catheters are addressed in this study. PU catheters with different atomic ratios Cu:Ag have been sputtered and led to different optical... more
The preparation, characterization, and antibacterial testing of Cu-Ag sputtered polyurethane (PU) catheters are addressed in this study. PU catheters with different atomic ratios Cu:Ag have been sputtered and led to different optical properties as followed by diffuse reflectance spectroscopy (DRS) and the surface redox properties were also different for different Cu-Ag ratios as observed by X-ray photoelectron spectroscopy (XPS). The surface atomic percentage concentration of the oxidized/reduced C-species originating from bacterial cultures before and after bacterial inactivation were determined on the Cu-Ag PU catheters. The crystallographic properties were determined by X-ray diffraction (XRD). The XRD-diffractogram showed the presence of Cu2O (111), Cu (200), CuO (020), and Ag (111) indicating that Cu nanoparticles present a more crystalline character compared to Ag nanoparticles. Increasing the percentage of Ag in the Cu-Ag films, bigger Ag-particle agglomerates were detected b...
Publication Date: Jan 23, 2015
Publication Name: ACS applied materials & interfaces
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Quasi-Instantaneous Bacterial Inactivation on Cu-Ag Nanoparticulate 3D Catheters in the Dark and Under Light: Mechanism and Dynamicsmore
by Cesar Pulgarin and sami RTIMI
The first evidence for Cu-Ag (50%/50%) nanoparticulate hybrid coatings is presented leading to a complete and almost instantaneous bacterial inactivation in the dark (≤5 min). Dark bacterial inactivation times on Cu-Ag (50%/50%) were... more
The first evidence for Cu-Ag (50%/50%) nanoparticulate hybrid coatings is presented leading to a complete and almost instantaneous bacterial inactivation in the dark (≤5 min). Dark bacterial inactivation times on Cu-Ag (50%/50%) were observed to coincide with the times required by actinic light irradiation. This provides the evidence that the bimetal Cu-Ag driven inactivation predominates over a CuO/Cu2O and Ag2O oxides inducing a semiconductor driven behavior. Cu- or Ag-coated polyurethane (PU) catheters led to bacterial inactivation needing about ∼30 min. The accelerated bacterial inactivation by Cu-Ag coated on 3D catheters sputtered was investigated in a detailed way. The release of Cu/Ag ions during bacterial inactivation was followed by inductively coupled plasma mass-spectrometry (ICP-MS) and the amount of Cu and Ag-ions released were below the cytotoxicity levels permitted by the sanitary regulations. By stereomicroscopy the amount of live/dead cells were followed during the...
Publication Date: Jan 23, 2015
Publication Name: ACS applied materials & interfaces
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Publication Date: 2014
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Publication Date: 2014
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TiO2 and TiO2-doped films able to kill bacteria by contact: New evidence for the dynamics of bacterial inactivation in the dark and under light irradiationmore
by sami RTIMI and Cesar Pulgarin
Publication Date: 2014
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Corrigendum to "RF-plasma pretreatment of surfaces leading to TiO2 coatings with improved optical absorption and OH-radical production" [Appl. Catal. B: Environ. 130-131 (2013) 65-72]more
by sami RTIMI and Cesar Pulgarin
ABSTRACT Fig. 1. (a) Spectral distribution of the Osram Lumilux 827/18 W lamp reported in the Osram catalogue (2001) and (b) spectral distribution of the Osram Lumilux 827/18 W lamp as provided May 2013 by Osram Winterthur, Switzerland.
Publication Date: 2013
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Coupling of narrow and wide band-gap semiconductors on uniform films active in bacterial disinfection under low intensity visible light: Implications of the interfacial charge transfer (IFCT)more
by sami RTIMI and Cesar Pulgarin
Publication Date: 2013
Research Interests: Engineering, Thermodynamics, Electrochemistry, Kinetics, Semiconductors, and 16 morePHOTOELECTRON SPECTROSCOPY, Transmission Electron Microscopy, Atomic Force Microscopy, X Rays, Silver, Escherichia coli, Light, Temperature, Hazardous Materials, Absorption, Disinfection, Time Factors, Surface Properties, Optics and Photonics, Polyesters, and Microbial Viability
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Publication Date: 2013
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Innovative semi-transparent nanocomposite films presenting photo-switchable behavior and leading to a reduction of the risk of infection under sunlightmore
by sami RTIMI and Cesar Pulgarin
Publication Date: 2013
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RF-plasma pretreatment of surfaces leading to TiO2 coatings with improved optical absorption and OH-radical productionmore
by sami RTIMI and Cesar Pulgarin
Publication Date: 2013
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Publication Date: 2012
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by sami RTIMI and Cesar Pulgarin
The bacterial inactivation of Escherichia coli on Cu/CuO-polyester surfaces prepared by direct current magnetron sputtering was investigated in the dark and under actinic light (360 nm≤ λ ≤ 720 nm; 4.1 mW/cm(2)) as used commonly in... more
The bacterial inactivation of Escherichia coli on Cu/CuO-polyester surfaces prepared by direct current magnetron sputtering was investigated in the dark and under actinic light (360 nm≤ λ ≤ 720 nm; 4.1 mW/cm(2)) as used commonly in hospital facilities. In the dark, complete bacterial inactivation (6log10 reduction) was observed within 150 min and under actinic light within 45 min. Sputtered samples led to nanoparticulate uniform Cu/CuO films ~70 nm thick. The deposition rate used was 2.2×10(15) atoms/cm(2) s as determined by profilometry. X-ray fluorescence was used to determine the sample Cu-content and transmission electron microscopy determined Cu-particles ~20 ± 5 nm in size. The film optical absorption was observed to increase with Cu-content of the sample by diffuse reflection spectroscopy. The bacterial inactivation involved redox processes between Cu/CuO-polyester and the bacteria as observed by x-ray photoelectron spectroscopy. During sample recycling, the amount of Cu-release was determined by inductively coupled plasma-mass spectroscopy. The values required for E. coli inactivation were below the cytotoxicity level threshold allowed for mammalian cells. The E. coli inactivation by Cu/CuO-polyester seems to involve an oligodynamic effect since bacterial inactivation was achieved at very low Cu-concentrations.
Publication Date: 2014
Publication Name: Biointerphases
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Evidence for TiON sputtered surfaces showing accelerated antibacterial activity under simulated solar irradiationmore
by sami RTIMI and Cesar Pulgarin
Publication Date: 2013
Publication Name: Solar Energy
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Innovative transparent non-scattering TiO2 bactericide thin films inducing increased E. coli cell wall fluiditymore
by sami RTIMI and Cesar Pulgarin
Publication Date: 2014
Publication Name: Surface and Coatings Technology
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Publication Date: 2013
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Publication Date: 2013
Publication Name: Surface and Coatings Technology
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New evidence for TiO2 uniform surfaces leading to complete bacterial reduction in the dark: Critical issuesmore
by sami RTIMI and Cesar Pulgarin
Publication Name: Colloids and surfaces B: Biointerfaces
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Publication Date: 2013
Publication Name: Journal of Photochemistry and Photobiology A: Chemistry
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Innovative TiO 2 /Cu Nanosurfaces Inactivating Bacteria in the Minute Range under Low-Intensity Actinic Lightmore
by sami RTIMI and Cesar Pulgarin
Publication Date: 2012
Publication Name: ACS Applied Materials & Interfaces
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Publication Date: 2014
Publication Name: Journal of Photochemistry and Photobiology A: Chemistry
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ZrNO–Ag co-sputtered surfaces leading to E. coli inactivation under actinic light: Evidence for the oligodynamic effectmore
by sami RTIMI and Cesar Pulgarin