The influence of the chain length and the functional group steric accessibility of thiols on the phase transfer efficiency of gold nanoparticles from water to toluene

The papers were published with the financial support from the budget of the West Pomeranian Voivodeship.This paper describes the influence of the chain length and the functional group steric accessibility of thiols modifiers on the phase transfer process efficiency of water synthesized gold nanoparticles (AuNPs) to toluene. The following thiols were tested: 1-decanethiol, 1,1-dimethyldecanethiol, 1-dodecanethiol, 1-tetradecanethiol and 1-oktadecanethiol. Nanoparticles (NPs) synthesized in water were precisely characterized before the phase transfer process using Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM). The optical properties of AuNPs before and after the phase transfer were studied by the UV-Vis spectroscopy. Additionally, the particle size and size distribution before and after the phase transfer of nanoparticles were investigated using Dynamic Light Scattering (DLS). It turned out that the modification of NPs surface was not effective in the case of 1,1-dimethyldecanethiol, probably because of the difficult steric accessibility of the thiol functional group to NPs surface. Consequently, the effective phase transfer of AuNPs from water to toluene did not occur. In toluene the most stable were nanoparticles modified with 1-decanethiol, 1-dodecanethiol and 1-tetradecanethiol.This work was supported by FP7-NMP-2010-SMALL-4 program (HYMEC), project number 263073. Scientific work supported by the Polish Ministry of Science and Higher Education, funds for science in 2011–2014 allocated for the cofounded international project

Elektroosadzanie i właściwości nanokrystalicznych stopów na osnowie niklu z trudnotopliwym metalem z kąpieli cytrynianowych

Głównym celem pracy było ustalenie optymalnych warunków procesu elektroosadzania metalicznych powłok Ni-Mo o podwyższonych właściwościach mikromechanicznych. Charakteryzowane stopy zostały osadzone na podłożu ze stali ferrytycznej, w warunkach galwanostatycznych, w modelowym układzie z wirujaca elektroda dyskowa (WED), z wodnych kompleksowych roztworów cytrynianowych zawierających sole niklu i molibdenu. Określono wpływ pH elektrolitu (regulowanego przez dodatek kwasu siarkowego lub amoniaku) na zawartość molibdenu w stopie, jakość osadów, jak również wydajnosc pradowa procesu elektroosadzania. Stwierdzono, że wzrost pH jest związany ze stopniowym zwiększaniem zawartości molibdenu w powłokach. Maksymalna zawartość molibdenu uzyskano w stopach wydzielonych z kąpieli galwanicznej o pH 7, gdzie jednocześnie zaobserwowano najwyższe stężenie cytrynianowych, elektroaktywnych kompleksów molibdenu typu [MoO4(Cit)H]4?-(Cit=C6H5O3-7 ). Dla wybranej kąpieli galwanicznej o optymalnym pH badano wpływ gęstości prądu katodowego (kluczowego parametru operacyjnego, kontrolującego między innymi skład chemiczny oraz mikrostrukturę, w tym skład fazowy i rozmiar krystalitów) na właściwości mechaniczne i tribologiczne wytworzonych powłok. Wykazano, że w całym analizowanym zakresie gęstości prądu, otrzymano powłoki Ni-Mo bez siatki mikropęknięć, o dobrej adhezji do stalowego podłoża, charakteryzujące się podwyższoną twardością w zakresie 6.5 do 7.8 GPa. Ponadto, powłoki osadzane przy wyższych gęstościach prądu (powyżej 3.5 A/dm2) odznaczają się zwartą i jednorodną mikrostrukturą, a tym samym najwyższą odpornością na zużycie przez tarcie.The main aim of the present work was to determine the optimal conditions for electrodeposition of metallic Ni-Mo coatings of enhanced micromechanical properties. These alloys were electrodeposited on the ferritic steel substrate, under galvanostatic regime in a system with a rotating disk electrode (RDE), from an aqueous citrate complex solution containing nickel and molybdenum salts. The effect of the electrolyte solution pH (adjusted by sulphuric acid or ammonia) on the molybdenum content and on deposit quality as well as on the current efficiency of the electrodeposition process, has been studied. It was established that increase of bath pH is correlated with gradual increase of molybdenum content in deposits up to pH 7, where the maximum concentration of Mo(VI) electroactive citrate complex ions [MoO4(Cit)H]4- (Cit= C6H5O7-3 ) in plating bath was observed. In the selected bath of the optimum pH value, the effect of cathodic current density, as a crucial operating parameter which strongly controls the chemical composition and microstructure parameters (e.g. phase compositions, crystallite size), on the mechanical and tribological properties of the resulting coatings has been determined. It has been shown that - under all investigated current density range - crack-free, well adherent Ni-Mo coatings, characterized by microhardness of 6.5-7.8 GPa, were obtained. Alloys deposited at higher tested current densities (above 3.5 A/dm2) were characterized by compact and uniform microstructure, and thus had the highest wear and friction resistance

Versatile Phase Transfer Method for the Efficient Surface Functionalization of Gold Nanoparticles: Towards Controlled Nanoparticle Dispersion in a Polymer Matrix

In electronic devices based on hybrid materials such as nonvolatile memory elements (NVMEs), it is essential to control precisely the dispersion of metallic nanoparticles (NPs) in an insulating polymer matrix such as polystyrene in order to control the functionality of the device. In this work the incorporation of AuNPs in polystyrene films is controlled by tuning the surface functionalization of the metallic nanoparticles via ligand exchange. Two ligands with different structures were used for functionalization: 1-decanethiol and thiol-terminated polystyrene. This paper presents a versatile method for the modification of gold nanoparticles (AuNPs) with thiol-terminated polystyrene ligands via phase transfer process. An organic colloid of AuNPs (5±1 nm diameter) is obtained by the phase transfer process (from water to toluene) that allows exchanging the ligand adsorbed on AuNPs surface (hydrophilic citrate/tannic acid to hydrophobic thiols). The stability, size distribution, and precise location of modified AuNPs in the polymer matrix are obtained from UV-Vis spectroscopy, dynamic light scattering (DLS), and electron tomography. TEM tomographic 3D imaging demonstrates that the modification of AuNPs with thiol-terminated polystyrene results in homogeneous particle distribution in the polystyrene matrix compared to 1-decanethiol modified AuNPs for which a vertical phase separation with a homogeneous layer of AuNPs located at the bottom of the polymer matrix was observed.This work was supported by FP7-NMP-2010-SMALL-4 Program (“Hybrid Organic/Inorganic Memory Elements for Integration of Electronic and Photonic Circuitry,” HYMEC), Project no. 263073. Eric Gonthier is acknowledged for technical support in the preparation of hybrid thin films. Scientific work was supported by the Polish Ministry of Science and Higher Education Funds for Science in 2011–2014 allocated for the cofunded international project

Laboratory tests of how selective factors impact the durability and functionality of road safety steel devices

Road safety devices, such as guides and wire rope barriers have a direct impact on road safety. These devices are mounted close to the road therefore they are exposed to mechanical damage and corrosive factors, which causes them to degrade subsequently leading to adverse changes of the useful properties. The objective of research was to determine the influence of exploitation factors (corrosion, mechanical damage) on the functionality changes of these selected steel road safety elements. Samples for testing mechanical properties were taken from guides and wire rope material in delivery condition and after exposure to a corrosive environment. In order to simulate mechanical damage, samples were cut or holes were made or they were gravelled. In the case of wires taken from ropes, tensile tests of wires subjected to pre-cycles of fatigue load corresponding to cycles of changes in rope stress in operating conditions were also performed

Tannic Acid-Modified Silver Nanoparticles in Conjunction with Contact Lens Solutions Are Useful for Progress against the Adhesion of Acanthamoeba spp. to Contact Lenses

Acanthamoeba spp. are amphizoic amoebae that are widely distributed in the environment and capable of entering the human body. They can cause pathogenic effects in different tissues and organs, including Acanthamoeba keratitis (AK), which may result in a loss of visual acuity and blindness. The diagnostics, treatment, and prevention of AK are still challenging. More than 90% of AK cases are related to the irresponsible wearing of contact lenses. However, even proper lens care does not sufficiently protect against this eye disease, as amoebae have been also found in contact lens solutions and contact lens storage containers. The adhesion of the amoebae to the contact lens surface is the first step in developing this eye infection. To limit the incidence of AK, it is important to enhance the anti-adhesive activity of the most popular contact lens solutions. Currently, silver nanoparticles (AgNPs) are used as modern antimicrobial agents. Their effectiveness against Acanthamoeba spp., especially with the addition of plant metabolites, such as tannic acid, has been confirmed. Here, we present the results of our further studies on the anti-adhesion potential of tannic acid-modified silver nanoparticles (AgTANPs) in combination with selected contact lens solutions against Acanthamoeba spp. on four groups of contact lenses. The obtained results showed an increased anti-adhesion activity of contact lens solutions in conjunction with AgTANPs with a limited cytotoxicity effect compared to contact lens solutions acting alone. This may provide a benefit in improving the prevention of amoebae eye infections. However, there is still a need for further studies on different pathogenic strains of Acanthamoeba in order to assess the adhesion of the cysts to the contact lens surface and to reveal a more comprehensive picture of the activity of AgTANPs and contact lens solutions

Investigation of the Microstructure, Optical, Electrical and Nanomechanical Properties of ZnOx Thin Films Deposited by Magnetron Sputtering

The paper presents the results of an investigation of the influence of technological parameters on the microstructure, optical, electrical and nanomechanical properties of zinc oxide coatings prepared using the pulsed reactive magnetron sputtering method. Three sets of ZnOx thin films were deposited in metallic, shallow dielectric and deep dielectric sputtering modes. Structural investigations showed that thin films deposited in the metallic mode were nanocrystalline with mixed hexagonal phases of metallic zinc and zinc oxide with crystallite size of 9.1 and 6.0 nm, respectively. On the contrary, the coatings deposited in both dielectric modes had a nanocrystalline ZnO structure with an average crystallite size smaller than 10 nm. Moreover, coatings deposited in the dielectric modes had an average transmission of 84% in the visible wavelength range, while thin films deposited in the metallic mode were opaque. Measurements of electrical properties revealed that the resistivity of as-deposited thin films was in the range of 10−4 Ωcm to 108 Ωcm. Coatings deposited in the metallic mode had the lowest hardness of 2.2 GPa and the worst scratch resistance among all sputtered coatings, whereas the best mechanical properties were obtained for the film sputtered in the deep dielectric mode. The obtained hardness of 11.5 GPa is one of the highest reported to date in the literature for undoped ZnO

Lactoferrin-Functionalized Noble Metal Nanoparticles as New Antivirals for HSV-2 Infection

(1) Background: Lactoferrin has been recognized as a potent inhibitor of human herpetic viruses, such as herpes simplex type 1 (HSV-1) and 2 (HSV-2). In this work, we tested if silver and gold nanoparticles modified with lactoferrin (LF-Ag/AuNPs) can become novel microbicides with additional adjuvant properties to treat genital herpes infection. (2) Methods: The antiviral and cytotoxic activities of LF-Ag/AuNPs were tested in human skin HaCaT and vaginal VK-2-E6/E7 keratinocytes. Viral titers and immune responses after treatment with LF-Ag/AuNPs were tested in murine vaginal HSV-2 infection. (3) Results: LF-Ag/AuNPs inhibited attachment and entry of HSV-2 in human keratinocytes much better than lactoferrin. Furthermore, pretreatment with LF-AgNPs led to protection from infection. Infected mice treated intravaginally with LF-Ag/AuNPs showed lower virus titers in the vaginal tissues and spinal cords in comparison to treatment with lactoferrin. Following treatment, vaginal tissues showed a significant increase in CD8+/granzyme B + T cells, NK cells and dendritic cells in comparison to NaCl-treated group. LF-Ag/AuNPs-treated animals also showed significantly better expression of IFN-γ, CXCL9, CXCL10, and IL-1β in the vaginal tissues. (4) Conclusions: Our findings show that LF-Ag/AuNPs could become effective novel antiviral microbicides with immune-stimulant properties to be applied upon the mucosal tissues