New Evidence for Ag-Sputtered Materials Inactivating Bacteria by Surface Contact without the Release of Ag Ions: End of a Long Controversy?

The study provides new evidence for Ag-coated polyester (PES) mediating inactivation by way of genetically engineered (without porins, from now denoted porinless bacteria). This allows the quantification of the bactericidal kinetics induced by the Ag surface without the intervention of Ag ions. Bacterial inactivation mediated by Ag-PES was seen to be completed within 60 min.

Femtosecond Spectroscopy of Au Hot-Electron Injection into TiO₂: Evidence for Au/TiO₂ Plasmon Photocatalysis by Bactericidal Au Ions and Related Phenomena.

In the present work, we provide evidence for visible light irradiation of the Au/TiO₂ nanoparticles' surface plasmon resonance band (SPR) leading to electron injection from the Au nanoparticles to the conduction band of TiO₂. The Au/TiO₂ SPR band is shown to greatly enhance the light absorption of TiO₂ in the visible region. Evidence is presented for the light absorption by the Au/TiO₂ plasmon bands leading to the dissolution of Au nanoparticles.

Innovative TiNb N-Ag Films Inducing Bacterial Disinfection by Visible Light/Thermal Treatment.

This study presents innovative TiNb N-Ag films obtained by a suitable combination of low-energy and high-energy sputtering leading to bacterial inactivation. The bacterial inactivation kinetics by the TiNbN layers was drastically enhanced by the addition of 6-7% Ag and proceeded to completion within 3 h after the film autoclaving. By X-ray photoelectron spectroscopy (XPS), the samples after autoclaving presented in their upper layers TiO, NbO and AgO with a surface composition of TiNbNAg.

Fungicidal activity of copper-sputtered flexible surfaces under dark and actinic light against azole-resistant Candida albicans and Candida glabrata.

Candida spp. are able to survive on hospital surfaces and causes healthcare-associated infections (HCAIs). Since surface cleaning and disinfecting interventions are not totally effective to eliminate Candida spp.

Evidence for differentiated ionic and surface contact effects driving bacterial inactivation by way of genetically modified bacteria.

New evidence is presented for the bacterial inactivation of E. coli presenting normal porins on sputtered Ag-Cu surfaces compared with similar E. coli porinless bacteria.

VUV/UV light inducing accelerated phenol degradation with a low electric input.

This study presents the first evidence for the accelerated degradation of phenol by Fenton's reagent in a mini-fluidic VUV/UV photoreaction system (MVPS). A low-pressure mercury lamp used in the MVPS led to a complete degradation of phenol within 4-6 min. The HO˙ and HO˙ originating from both Fenton's reagent and VUV photolysis of water were identified with suitable radical scavengers.

Beneficial effect of Cu on Ti-Nb-Ta-Zr sputtered uniform/adhesive gum films accelerating bacterial inactivation under indoor visible light.

This article presents the evidence for the significant effect of copper accelerating the bacterial inactivation on Ti-Nb-Ta-Zr (TNTZ) sputtered films on glass up to a Cu content of 8.3 at.%.

FeOx-TiO2 Film with Different Microstructures Leading to Femtosecond Transients with Different Properties: Biological Implications under Visible Light.

This study presents the first report addressing the effect of FeOx-TiO2 films microstructure on the transients detected by fast spectroscopy related to the long-range bacterial inactivation performance. The different fast kinetic femtosecond transient spectroscopy is reported for each FeOx+TiO2 microstructure. The lifetime of the short transient-species and the oxidative intermediate radicals generated under light were identified.

In Vitro and In Vivo Effectiveness of an Innovative Silver-Copper Nanoparticle Coating of Catheters To Prevent Methicillin-Resistant Staphylococcus aureus Infection.

In this study, silver/copper (Ag/Cu)-coated catheters were investigated for their efficacy in preventing methicillin-resistant Staphylococcus aureus (MRSA) infection in vitro and in vivo Ag and Cu were sputtered (67/33% atomic ratio) on polyurethane catheters by direct-current magnetron sputtering. In vitro, Ag/Cu-coated and uncoated catheters were immersed in phosphate-buffered saline (PBS) or rat plasma and exposed to MRSA ATCC 43300 at 10(4) to 10(8) CFU/ml. In vivo, Ag/Cu-coated and uncoated catheters were placed in the jugular vein of rats.

Bactericidal activity and mechanism of action of copper-sputtered flexible surfaces against multidrug-resistant pathogens.

Using direct current magnetron sputtering (DCMS), we generated flexible copper polyester surfaces (Cu-PES) and investigated their antimicrobial activity against a range of multidrug-resistant (MDR) pathogens including eight Gram-positive isolates (three methicillin-resistant Staphylococcus aureus [MRSA], four vancomycin-resistant enterococci, one methicillin-resistant Staphylococcus epidermidis) and four Gram-negative strains (one extended-spectrum β-lactamase-producing [ESBL] Escherichia coli, one ESBL Klebsiella pneumoniae, one imipenem-resistant Pseudomonas aeruginosa, and one ciprofloxacin-resistant Acinetobacter baumannii). Bactericidal activity (≥3 log10 CFU reduction of the starting inoculum) was reached within 15-30 min exposure to Cu-PES. Antimicrobial activity of Cu-PES persisted in the absence of oxygen and against both Gram-positive and Gram-negative bacteria containing elevated levels of catalases, indicating that reactive oxygen species (ROS) do not play a primary role in the killing process.

Microstructure of Cu-Ag Uniform Nanoparticulate Films on Polyurethane 3D Catheters: Surface Properties.

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.

Quasi-Instantaneous Bacterial Inactivation on Cu-Ag Nanoparticulate 3D Catheters in the Dark and Under Light: Mechanism and Dynamics.

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.

New evidence for hybrid acrylic/TiO2 films inducing bacterial inactivation under low intensity simulated sunlight.

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.

Preparation and Mechanism of Cu-Decorated TiO2-ZrO2 Films Showing Accelerated Bacterial Inactivation.

Antibacterial robust, uniform TiO2-ZrO2 films on polyester (PES) under low intensity sunlight irradiation made up by equal amounts of TiO2 and ZrO2 exhibited a much higher bacterial inactivation kinetics compared to pure TiO2 or ZrO2. The TiO2-ZrO2 matrix was found to introduce a drastic increase in the Cu-dopant promoter enhancing bacterial inactivation compared to Cu sputtered in the same amount on PES. Furthermore, the bacterial inactivation was accelerated by a factor close to three, by Cu- on TiO2-ZrO2 at extremely low levels ∼0.

Effect of surface pretreatment of TiO2 films on interfacial processes leading to bacterial inactivation in the dark and under light irradiation.

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.

New evidence for TiO2 uniform surfaces leading to complete bacterial reduction in the dark: critical issues.

This study presents new evidence for the events leading to Escherichia coli reduction in the absence of light irradiation on TiO2-polyester (from now on TiO2-PES. By transmission electron microscopy (TEM) the diffusion of TiO2 NP's aggregates with the E. coli outer lipo-polyssacharide (LPS) layer is shown to be a prerequisite for the loss of bacterial cultivability.

Accelerated Escherichia coli inactivation in the dark on uniform copper flexible surfaces.

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.

Inactivation of bacteria under visible light and in the dark by Cu films. Advantages of Cu-HIPIMS-sputtered films.

Introduction: The Cu polyester thin-sputtered layers on textile fabrics show an acceptable bacterial inactivation kinetics using sputtering methods.

Materials And Methods: Direct current magnetron sputtering (DCMS) for 40 s of Cu on cotton inactivated Escherichia coli within 30 min under visible light and within 120 min in the dark. For a longer DCMS time of 180 s, the Cu content was 0.

Comparison of methods for evaluation of the bactericidal activity of copper-sputtered surfaces against methicillin-resistant Staphylococcus aureus.

Bacteria can survive on hospital textiles and surfaces, from which they can be disseminated, representing a source of health care-associated infections (HCAIs). Surfaces containing copper (Cu), which is known for its bactericidal properties, could be an efficient way to lower the burden of potential pathogens. The antimicrobial activity of Cu-sputtered polyester surfaces, obtained by direct-current magnetron sputtering (DCMS), against methicillin-resistant Staphylococcus aureus (MRSA) was tested.

TiO2 nanoparticles suppress Escherichia coli cell division in the absence of UV irradiation in acidic conditions.

TiO(2) nanoparticles (NPs) activated by UV irradiation are known to have a bactericidal effect. In this study we report the details of TiO(2) NPs influence on the colony-forming capacity of E. coli in the dark at pH 4.

Preparation, testing and characterization of doped TiO2 active in the peroxidation of biomolecules under visible light.

Doped TiO2 samples using different preparative procedures were synthesized using either urea or thiourea leading to N- or S-doped TiO2. Photocatalytic peroxidation and oxidation (mineralization) of phosphatidylethanolamine (PE) lipid with doped TiO2 were carried out under light irradiation lambda > 410 nm. The formation of conjugated double bonds in PE molecules was followed to detect the formation of peroxy radicals (peroxidation index) under light excitation (lambda > 410 nm) when doped TiO2 was used.

Photobleaching of Orange II within seconds using the oxone/Co2+ reagent through Fenton-like chemistry.

The bleaching and photobleaching of Orange II due to oxone was observed to proceed within seconds due to the catalytic effect of the Co2+ ions added in solution.