Synthesis and Investigation of Antibacterial Activity of Thin Films Based on TiO2-Ag and SiO2-Ag with Potential Applications in Medical Environment (original) (raw)
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CVD Elaboration of Nanostructured TiO 2 -Ag Thin Films with Efficient Antibacterial Properties
Chemical Vapor Deposition, 2010
Nanostructured TiO 2 -Ag composite coatings are deposited by direct liquid injection metal-organic (DLI-MO) CVD at 683 K in a one-step process. Silver pivalate (AgPiv) and titanium tetra-iso-propoxide (TTIP) are used as Ag and Ti molecular precursors, respectively. Metallic silver nanoparticles are co-deposited with anatase TiO 2 on stainless steel, glass, and silicon wafers. The silver particles are uniformly embedded in the oxide matrix through the entire film thickness. The influence of the growth conditions, including injection parameters, is investigated on the chemical, physical, and structural characteristics of the coatings as well as on their anti-bacterial activities. The bacterium Staphylococcus aureus is employed for anti-bacterial tests. The films are bactericidal, according to the JIS Z 2801 standard test performed in the dark, when they contain less than 1 at.-% of silver. Under UV irradiation they exhibit a photocatalytic activity which decays by increasing the silver content. As a result of this dual functionality, the TiO 2 -Ag nanocomposite coatings show promising potentialities as long-term anti-bacterial surfaces since selfcleaning can be achieved periodically under UV light in order to maintain an efficient anti-bacterial activity in the dark or in visible light.
BioDiscovery
This research aims to study the antibacterial activity of thin films nanostructured TiO doped with Ag and Cu on Gracilicutes and Firmicutes bacteria with clinical significance. The thin films were deposited on glass substrates without heating during the deposition by radio frequency magnetron co-sputtering of TiO target and pieces of Ag and Cu. The total surface area of Ag was 60 mm and this one of Cu was 100 mm. The r.f. power was 50W and sputtering atmosphere was Ar (0,8 Pa). The thickness of the films was about 60 nm. The experiment was conducted under day light regime. The test strains Bacillus cereus, Staphylococcus epidermidis, Salmonella enterica, Escherichia coli and Pseudomonas sp. were used. The bactericidal effect was established at different time point between 30 min-90 min for Pseudomonas sp. and S. enterica. The Firmicutes bacteria B. cereus and S. epidermidis were killed at 4 and 8 h of the treatment respectively. The effect against E.coli was bacteriostatic till 10 hour. The toxic effect was evaluated by classical Koch's method and optical density measurments. The results were confirmed by assessment of dehydrogenase activity inhibition. The film could be used in medical and clinical practice.
Antibacterial Activity of Silver and Gold Particles Formed on Titania Thin Films
Nanomaterials
Metal-based nanoparticles with antimicrobial activity are gaining a lot of attention in recent years due to the increased antibiotics resistance. The development and the pathogenesis of oral diseases are usually associated with the formation of bacteria biofilms on the surfaces; therefore, it is crucial to investigate the materials and their properties that would reduce bacterial attachment and biofilm formation. This work provides a systematic investigation of the physical-chemical properties and the antibacterial activity of TiO2 thin films decorated by Ag and Au nanoparticles (NP) against Veillonella parvula and Neisseria sicca species associated with oral diseases. TiO2 thin films were formed using reactive magnetron sputtering by obtaining as-deposited amorphous and crystalline TiO2 thin films after annealing. Au and Ag NP were formed using a two-step process: magnetron sputtering of thin metal films and solid-state dewetting. The surface properties and crystallographic nature ...
This article aims to explore the antibacterial activity of thin films of TiO doped with Ag and Cu using two types of Gram-negative and Gram-positive test bacteria with clinical significance (Gracilicutes and Firmcutes bacteria). The thin films (thickness of about 60 nm) were deposited on glass substrates by radio frequency magnetron co-sputtering (r.f. power of 50 W) of TiO target with Ag and Cu pieces on its surface in an Ar atmosphere (0.8 Pa) without heating during the deposition. The total surface area of the Ag was 60 mm and that of the Cu was 100 mm . Bacillus cereus, Staphylococcus epidermidis, Salmonella enterica, Escherichia coli and Pseudomonas sp. were used as test strains. The antibacterial actvity of the films was evaluated by the classical Koch's method and optical density measurements. The bactericidal effect was established at different time points between 30 min and 90 min for Pseudomonas sp. and S. enterica. The Firmicutes bacteria B. cereus and S. epidermidis were killed at the 4 and 8 hour of the treatment, respectively. The effect on E. coli was bacteriostatic until the 10 hour. The results were confirmed by assessment of the bacterial dehydrogenase activity. The studied thin films of TiO co-doped with Ag and Cu have a potential for application as antibacterial coatings.
Synthesis of Ag–TiO2composite nano thin film for antimicrobial application
Nanotechnology, 2011
TiO 2 photocatalysts have been found to kill cancer cells, bacteria and viruses under mild UV illumination, which offers numerous potential applications. On the other hand, Ag has long been proved as a good antibacterial material as well. The advantage of Ag-TiO 2 nanocomposite is to expand the nanomaterial's antibacterial function to a broader range of working conditions. In this study neat TiO 2 and Ag-TiO 2 composite nanofilms were successfully prepared on silicon wafer via the sol-gel method by the spin-coating technique. The as-prepared composite Ag-TiO 2 and TiO 2 films with different silver content were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) to determine the topologies, microstructures and chemical compositions, respectively. It was found that the silver nanoparticles were uniformly distributed and strongly attached to the mesoporous TiO 2 matrix. The morphology of the composite film could be controlled by simply tuning the molar ratio of the silver nitrate aqueous solution. XPS results confirmed that the Ag was in the Ag 0 state. The antimicrobial effect of the synthesized nanofilms was carried out against gram-negative bacteria (Escherichia coli ATCC 29425) by using an 8 W UV lamp with a constant relative intensity of 0.6 mW cm −2 and in the dark respectively. The synthesized Ag-TiO 2 thin films showed enhanced bactericidal activities compared to the neat TiO 2 nanofilm both in the dark and under UV illumination.
Structural analysis of TiO2 and TiO2-Ag thin films and their antibacterial behaviors
Journal of Physics: Conference Series, 2012
TiO2 (rutile and anatase) thin films was first prepared using reactive sputtering, in an Ar+O2 plasma. In the 2nd stage of the experiment, various amounts (3, 7, and 10 at. %) of Ag was doped into the rutile film in order to form TiO2-Ag thin films. These films were annealed for one hour in Ar atmosphere, at 300, 400, and 500 °C. The films' structures were then examined using X-ray diffractometry. FESEM (field-emission scaning electron microscopy) was used to investigate the surface emergence of Ag particles. As for the examination of optical band gaps and absorption of these films, UV-Vis-NIR photometer was used. The results show that, in as-deposited condition, the addition of Ag might disrupt the growth of crystalline structure and cause the formation of amorphous films. After annealing, it is found that the structure tends to become anatase phase which is a metastable phase between amorphous titanium oxide and rutile. More importantly, the absorption of the Ag-doped films wo...
2014
In this research, undoped and doped (Fe, Ce, and Ag) antibacterial coatings of nanostructured TiO2 films were prepared by a sol-gel dip coating method. Doped and undoped TiO2 films were excited with ultraviolet (UV) radiation to improve their photo catalytic activity. The antibacterial activity against Staphylococcus Aureus bacteria was studied using an antibacterial–drop test and colony count method. The Fe doped TiO2 films exhibited higher antibacterial activity than other samples. The percent of bacteria killing or killed (PBK) on bare glass substrate, undoped, Ce, Ag, and Fe doped TiO2 thin films (after UV illumination) were 23.8, 50.3, 57.8, and 70.1%, respectively. Uv-Visible Spectrophotometry, Photoluminescence (PL), X-ray Diffraction (XRD), and Atomic Force Microscopy (AFM) were carried out to study the relation between optical, luminescence, structural, and surface morphological characteristics of the samples with their antibacterial activities. Several parameters such as t...
Comparative Study of Antibacterial Efficiency of M-TiO2 (M = Ag, Cu) Thin Films Grown by CVD
Key Engineering Materials, 2014
M-TiO2 (M = Ag, Cu) nanocomposite layers were grown by pulsed direct liquid injection chemical vapor deposition (DLICVD) on various substrates to produce bactericidal surfaces with long term activity. Monodisperse Ag nanoparticles (NPs) with an average size of 5-10 nm are embedded in an anatase matrix. A bactericidal behavior determined by the JIS Z 2801 standard test was found for Ag-TiO2 films for Ag ≤ 1 at. % and above. Higher Ag content is not necessary since efficiency is already at its maximum (relative activity 100%). By contrast, using Cu as antibacterial agent, a larger size distribution of metal particles was found (20 to 400 nm). Cu-TiO2 films exhibit a bactericidal behavior if their thickness is higher than 100 nm and Cu content ≥ 3.5 at. %. These coatings are still antibacterial after 5 months of aging and their efficiency has decreased by only 35%.
Journal of Materials Science, 2007
In the present study, Ag/SiO 2 -TiO 2 thin films on ceramic tiles with glazed surface were successfully prepared by a liquid phase deposition method (LPD) at a low temperature. The Ag/SiO 2 -TiO 2 thin films obtained were homogenous, well adhered and colored by interference of reflected light. The films were characterized by scanning electron microscopy and X-ray diffraction. From these analysis data, it was found that silver (Ag) nanoparticles were trapped in SiO 2 -TiO 2 matrix. The antibacterial effects of Ag/SiO 2 -TiO 2 thin films against S. aureus and E. coli were examined by the so-called antibacterial-drop test. The bactericidal activity for the above bacteria cells was estimated by relative number of bacteria survived calculated from the number of viable cells which form colonies on the nutrient agar plates. The Ag/SiO 2 -TiO 2 thin films had an excellent antibacterial performance. Atomic absorption spectroscopy (AAS) was used for the quantitative determination of the Ag ion concentration releasing from the Ag/SiO 2 -TiO 2 thin film. The releasing rate of Ag ions from the Ag/SiO 2 -TiO 2 film is 0.123 lg/mL during 192 h. The antibacterial effect of Ag/SiO 2 -TiO 2 thin film before and after aging in a weathering chamber for 48 h was compared and the results show that the antibacterial activity is not compromised after weathering.
Polymer/silver hybrid thin films for anti-pathogenic bacterial applications
Surface Innovations, 2014
Gold-and indium-tin-oxide (ITO)-coated glass plates grafted with polymer/Ag nanoparticle hybrid coatings were prepared and served as biocidal surfaces directed against two biofilm positive bacteria, namely L. monocytogenes ATCC 19115 and S.aureus ATCC25923. The polymer films were prepared by surface-initiated radical photopolymerization of methacrylic acid (MAA) and 2-hydroxyethyl methacrylate (HEMA) in the presence of gold or ITO surfaces grafted with photoinitiator groups from diazotized benzophenone or N,Ndimethylaminobenzenediazonium tetrafluoroborate (N 2 C 6 H 4 N(CH 3 ) 2 BF 4 ). The silver nanoparticles were generated in-situ on the polymer surfaces by reduction of silver nitrate. The degree of biofilm formation by L. monocytogenes ATCC 19115 and S.aureus ATCC25923 strains on these surfaces was evaluated. Viable attached cells were quantified using a colorimetric method based on the ability of viable attached cells to metabolically reduce 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) to a formazan dye. This study shows that diazonium salts permit to anchor robust hydrophilic coatings with immobilized silver nanoparticles of remarkable antifouling properties against pathogenic S. aureus and L. monocytogenes bacteria: antifouling due to both hydrophilic MAA and/or HEMA repeat units, and bactericidal due to the Ag NPs complexed by the COOH groups from MAA repeat units.