silver surface
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A new, simple photo-deposition method of silver nanoparticles induced by laser inside a fused-silica capillary is described and tested. Silver nanoparticles are immobilized using Ar-ion laser beam of a wavelength of 488 nm and power of 3.6 mW for 60 min. The photodeposited compact spot of a size of ∼10 μm is temporary and spatially stable and resistant to a hydrodynamic flow. The deposit has very good properties for surface-enhanced Raman scattering and serves well for detection in capillary electrophoresis. The advantage of this approach is that neither the silver nanoparticles nor the chemicals for their preparation are components of the background electrolyte during the electrophoretic separation. Thus, the substrate formation and separation of analytes are two independent processes and can be performed under their optimum conditions. The zone broadening due to the sorption of analytes on the immobilized nanoparticles can be significantly reduced by an addition of 20% solution of methanol. The efficiency of capillary electrophoresis and detection selectivity of surface-enhanced Raman scattering induced by He-Ne laser at 632.8 nm is demonstrated by the 3D electropherograms of rhodamines 123 and B as model samples. The limits of detection of about 49 and 150 fmol (1 and 2 μM) have been reached for rhodamine B and 123, respectively.
- MeSH
- chemické modely MeSH
- elektroforéza kapilární metody MeSH
- fotochemické procesy MeSH
- kovové nanočástice chemie MeSH
- limita detekce MeSH
- methanol chemie MeSH
- Ramanova spektroskopie přístrojové vybavení metody MeSH
- rhodaminy analýza izolace a purifikace MeSH
- stříbro chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
In this paper, heavy metal biosensor based on immobilization of metallothionein (MT) to the surface of carbon paste electrode (CPE) via anti-MT-antibodies is reported. First, the evaluation of MT electroactivity was done. The attention was focused on the capturing of MT to the CPE surface. Antibodies incorporated and mixed into carbon paste were stable; even after two weeks the observed changes in signal height were lower than 5%. Further, the interaction of MT with polyclonal chicken antibodies incorporated in carbon paste electrode was determined by square-wave voltammetry. In the voltammogram, two signals--labelled as cys(MT) and W(a)--were observed. The cys(MT) corresponded to -SH moieties of MT and W(a) corresponded to tryptophan residues of chicken antibodies. Time of interaction (300 s) and MT concentration (125 μg/ml) were optimized to suggest a silver(I) ions biosensor. Biosensor (CPE modified with anti-MT antibody) prepared under the optimized conditions was then used for silver(I) ions detection. The detection limit (3 S/N) for silver(I) ions was estimated as 0.5 nM. The proposed biosensor was tested by detection spiking of silver(I) ions in various water samples (from very pure distilled water to rainwater). Recoveries varied from 74 to 104%.
- MeSH
- analýza selhání vybavení MeSH
- biosenzitivní techniky přístrojové vybavení MeSH
- design vybavení MeSH
- elektrody MeSH
- imunoanalýza přístrojové vybavení MeSH
- konduktometrie přístrojové vybavení MeSH
- metalothionein chemie imunologie MeSH
- povrchové vlastnosti MeSH
- protilátky chemie imunologie MeSH
- stříbro analýza imunologie MeSH
- uhlík chemie MeSH
- vazba proteinů MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Biologically active metals, especially silver, are able to form nanostructured coatings of biocompatible polymers with the objective to enhance the functionality of polymeric material. This review refers to three types of strongly antibacterially active silver nanostructures (nanolayers, nanoislands and nanowires) suitable for biological applications, such as coatings which can prevent nosocomial infections. The mechanism of antibacterial effects of nanostructured Ag and its advantages, as compared with conventional antibiotics, are described. Subsequently, selected techniques for the preparation of these antibacterial coatings of biocompatible polymers are discussed. An emphasis is put on the possibility to increase the antibacterial activity and biocompatibility of the material by modifying the surface morphology of original polymer.
- Klíčová slova
- antibakteriální účinek,
- MeSH
- antibakteriální látky MeSH
- biomedicínské a zubní materiály MeSH
- nanostruktury MeSH
- polymery MeSH
- stříbro * MeSH
- Publikační typ
- práce podpořená grantem MeSH
Oxidative stress may cause extended tyrosine posttranslational modifications of peptides and proteins. The 3-nitro-L-tyrosine (Nit), which is typically formed, affects protein behavior during neurodegenerative processes, such as Alzheimer's and Parkinson's diseases. Such metabolic products may be conveniently detected at very low concentrations by surface enhanced Raman spectroscopy (SERS). Previously, we have explored the SERS detection of the Nit NO2 bending vibrational bands in a presence of hydrogen chloride (Niederhafner et al., Amino Acids 53:517-532, 2021, ibid). In this article, we describe performance of a new SERS substrate, "pink silver", synthesized photochemically. It provides SERS even without the HCl induction, and the acid further decreases the detection limit about 9 times. Strong SERS bands were observed in the asymmetric (1550-1475 cm-1) and symmetric (1360-1290 cm-1) NO stretching in the NO2 group. The bending vibration was relatively weak, but appeared stronger when HCl was added. The band assignments were supported by density functional theory modeling.
- MeSH
- oxid dusičitý MeSH
- peptidy MeSH
- proteiny MeSH
- Ramanova spektroskopie * metody MeSH
- stříbro * chemie MeSH
- Publikační typ
- časopisecké články MeSH
The use of untreated medical devices (catheters, endotracheal tubes) can lead to hospital-acquired infections. Antibacterial coatings of biocompatible polymers may reduce the risk of such infections. Silver nanolayers of different thickness were sputtered on polyimide (PI) and investigated both before and after thermal annealing. The electrical continuity of the layers was examined by sheet resistance. After sputtering, the layers become electrically continuous from an effective thickness of 11 nm. However, atomic force microscopy showed that the surface of the annealed samples underwent significant changes; they were transformed into discrete nanoislands and lost continuity completely. This phenomenon was supported by X-ray photoelectron spectroscopy which showed that the amount of Ag was reduced. The antibacterial properties of the as-sputtered and annealed samples were investigated by gram-negative and gram-positive bacterial strains. The inhibition of bacterial strains increased significantly after annealing. In general, our results suggest that Ag nanostructures are promising antibacterial coatings for polymeric medical devices.
- Klíčová slova
- Kapton®,
- MeSH
- antibakteriální látky MeSH
- biofilmy MeSH
- cévní protézy MeSH
- imidy MeSH
- katétry MeSH
- lidé MeSH
- nanostruktury * MeSH
- polymery MeSH
- stříbro * terapeutické užití MeSH
- termoregulace MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
Titanium biomaterials are widely used in the medical field due to their biocompatibility and excellent corrosion and mechanical resistance. However, these materials have no antibacterial properties. To obtain an antibacterial active surface, a nanostructure of Ti6Al4V alloy was created. This specific nanostructure contained nanotubes and micro-cavities and was used as a substrate for silver anchoring. The electrochemical approach to silver reduction was studied. It is a common approach for silver deposition and in this work, inhomogeneities in the nanostructure were used as a preferential area for silver localisation. The galvanostatic regimen of deposition allowed for a technically quantitative process and the required silver placement. The experimental conditions used enabled testing and silver dissolution rate evaluation within a reasonable time span. Based on the corrosion and analytical results (EDS, XPS and ICP-MS), a two-phase silver release mechanism was confirmed. The openings of the individual nanotubes were filled with silver nanoparticles, whose release was relatively fast. By contrast, the silver anchored inside the cavities allowed the silver to release gradually. Antibacterial efficiency against Staphylococcus aureus and Escherichia coli was successfully demonstrated. Cytotoxicity testing with murine fibroblasts showed cell metabolic activity far above the normative limit of 70%.
- MeSH
- antibakteriální látky aplikace a dávkování chemie farmakologie MeSH
- biokompatibilní materiály chemie MeSH
- buněčné linie MeSH
- Escherichia coli účinky léků MeSH
- infekce vyvolané Escherichia coli farmakoterapie MeSH
- lékové transportní systémy metody MeSH
- lidé MeSH
- myši MeSH
- nanostruktury chemie MeSH
- protézy a implantáty MeSH
- stafylokokové infekce farmakoterapie MeSH
- Staphylococcus aureus účinky léků MeSH
- stříbro aplikace a dávkování chemie farmakologie MeSH
- titan chemie MeSH
- uvolňování léčiv MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Polymeric biomaterials with antibacterial effects are requisite materials in the fight against hospital-acquired infections. An effective way for constructing a second generation of antibacterials is to exploit the synergic effect of (i) patterning of polymeric materials by a laser, and (ii) deposition of noble metals in their nanostructured forms. With this approach, we prepared highly-ordered periodic structures (ripples) on polyethylene naphthalate (PEN). Subsequent deposition of Ag under the glancing angle of 70° resulted in the formation of self-organized, fully separated Ag nanowire (Ag NW) arrays homogenously distributed on PEN surface. Surface properties of these samples were characterized by AFM and XPS. Vacuum evaporation of Ag at the glancing angle geometry of 70° caused that Ag NWs were formed predominantly from one side of the ripples, near to the top of the ridges. The release of Ag(+) ions into physiological solution was studied by ICP-MS. The results of antibacterial tests predetermine these novel structures as promising materials able to fight against a broad spectrum of microorganisms, however, their observed cytotoxicity warns about their applications in the contact with living tissues.
- MeSH
- antibakteriální látky chemie farmakologie MeSH
- Escherichia coli účinky léků MeSH
- fotoelektronová spektroskopie MeSH
- lasery * MeSH
- mikroskopie atomárních sil MeSH
- nanodráty chemie toxicita MeSH
- polyethylen chemie MeSH
- povrchové vlastnosti MeSH
- Staphylococcus epidermidis účinky léků MeSH
- stříbro chemie MeSH
- Publikační typ
- časopisecké články MeSH
OBJECTIVES: Palladium-silver system alloyed with other metals represents one of possible material choices in prosthetics. Its corrosion properties are influenced by minority components added in order to obtain the properties required for stomatological purposes. The objective of this work was to ascertain the influence of copper on the corrosion mechanism of palladium-silver alloys. METHODS: Corrosion properties of four palladium-silver-copper alloys were compared with the behavior of the palladium-silver binary system. Standard electrochemical measurements in a model saliva solution were complemented with an XPS analysis of the specimens surface. Experimental data were compared with the results of thermodynamic analysis. RESULTS: The foregoing study revealed formation of a saline layer of insoluble silver compounds as the dominant feature of the corrosion mechanism in a binary system. This process is suppressed in ternary alloys where electrochemical reactions of copper take place on the alloy-electrolyte phase boundary leading to the formation of a layer based on copper oxides. SIGNIFICANCE: The alloying of the palladium-silver binary system with copper results in an important change in the corrosion behavior of ternary alloys. A change in the mechanism of interaction with the environment leads to susceptibility to non-uniform corrosion.
- MeSH
- časové faktory MeSH
- elektrochemie MeSH
- koroze MeSH
- lidé MeSH
- měď * chemie MeSH
- mikroanalýza elektronovou sondou MeSH
- náhrada slin * chemie MeSH
- palladium * chemie MeSH
- potenciometrie MeSH
- povrchové vlastnosti MeSH
- stříbro * chemie MeSH
- termodynamika MeSH
- testování materiálů MeSH
- zubní slitiny * chemie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- srovnávací studie MeSH
