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| 2. |
- Cronholm, Pontus, et al.
(författare)
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Intracellular Uptake and Toxicity of Ag and CuO Nanoparticles : A Comparison Between Nanoparticles and their Corresponding Metal Ions
- 2013
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 9:7, s. 970-982
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Tidskriftsartikel (refereegranskat)abstract
- An increased understanding of nanoparticle toxicity and its impact on human health is essential to enable a safe use of nanoparticles in our society. The aim of this study is to investigate the role of a Trojan horse type mechanism for the toxicity of Ag-nano and CuO-nano particles and their corresponding metal ionic species (using CuCl2 and AgNO3), i.e., the importance of the solid particle to mediate cellular uptake and subsequent release of toxic species inside the cell. The human lung cell lines A549 and BEAS-2B are used and cell death/membrane integrity and DNA damage are investigated by means of trypan blue staining and the comet assay, respectively. Chemical analysis of the cellular dose of copper and silver is performed using atomic absorption spectroscopy. Furthermore, transmission electron microscopy, laser scanning confocal microscopy, and confocal Raman microscopy are employed to study cellular uptake and particle-cell interactions. The results confirm a high uptake of CuO-nano and Ag-nano compared to no, or low, uptake of the soluble salts. CuO-nano induces both cell death and DNA damage whereas CuCl2 induces no toxicity. The opposite is observed for silver, where Ag-nano does not cause any toxicity, whereas AgNO3 induces a high level of cell death. In conclusion: CuO-nano toxicity is predominantly mediated by intracellular uptake and subsequent release of copper ions, whereas no toxicity is observed for Ag-nano due to low release of silver ions within short time periods.
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| 3. |
- Hedberg, Jonas, et al.
(författare)
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Interactions between surfactants and silver nanoparticles of varying charge
- 2012
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Ingår i: Journal of Colloid and Interface Science. - Amsterdam : Elsevier. - 0021-9797 .- 1095-7103. ; 369:1, s. 193-201
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Tidskriftsartikel (refereegranskat)abstract
- The interaction between silvernanoparticles (Ag NPs) of different surface charge and surfactants relevant to the laundry cycle has been investigated to understand changes in speciation, both in and during transport from the washing machine. Ag NPs were synthesized to exhibit either a positive or a negative surface charge in solution conditions relevant for the laundry cycle (pH 10 and pH 7). These particles were characterized in terms of size and surface charge and compared to commercially laser ablated Ag NPs. The surfactants included anionic sodium dodecylbenzenesulfonate (LAS), cationic dodecyltrimethylammoniumchloride (DTAC) and nonionic Berol 266 (Berol). Surfactant–Ag NP interactions were studied by means of dynamic light scattering, Raman spectroscopy, zeta potential, and Quartz Crystal Microbalance. Mixed bilayers of CTAB and LAS were formed through a co-operative adsorption process on positively charged Ag NPs with pre-adsorbed CTAB, resulting in charge reversal from positive to negative zeta potentials. Adsorption of DTAC on negatively charged synthesized Ag NPs and negatively charged commercial Ag NPs resulted in bilayer formation and charge reversal. Weak interactions were observed for nonionic Berol with all Ag NPs via hydrophobic interactions, which resulted in decreased zeta potentials for Berol concentrations above its critical micelle concentration. Differences in particle size were essentially not affected by surfactant adsorption, as the surfactant layer thicknesses did not exceed more than a few nanometers. The surfactant interaction with the Ag NP surface was shown to be reversible, an observation of particular importance for hazard and environmental risk assessments.
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| 4. |
- Hedberg, Jonas, et al.
(författare)
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Ion selective electrodes are not suitable for measurements of silver ion concentrations in alkaline carbonate media
- 2013
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Ingår i: Analytical Methods. - : RSC Publishing. - 1759-9660 .- 1759-9679. ; 5:4, s. 1068-1070
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Tidskriftsartikel (refereegranskat)abstract
- An ion selective electrode (ISE) for determination of the labile silver ion concentration in carbonate containing solutions of pH 10 was seen to give incorrect results due to shifts in the Ag vertical bar Ag+ equilibrium. This drawback was not the case for the differential pulse anodic stripping voltammetry (DPASV) method.
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| 5. |
- Lowe, Troy A., et al.
(författare)
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Chemical Speciation Measurements of Silver Ions in Alkaline Carbonate Electrolytes Using Differential Pulse Stripping Voltammetry on Glassy Carbon Compared With Ion Selective Electrode Measurements
- 2013
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Ingår i: International Journal of Electrochemical Science. - 1452-3981. ; 8:3, s. 3851-3865
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Tidskriftsartikel (refereegranskat)abstract
- Given the increasing incorporation of silver nanoparticles as an antibacterial additive in washing machines and textiles, sensitive methods for accurate determination of Ag+ ions in laundry relevant electrolytes (alkaline carbonate) are required. The most widely reported method, the silver ion selective electrode (ISE), lacked sensitivity and accuracy and was affected by the concentration of Na2CO3 in solution. Differential pulse stripping voltammetry (DPSV) on glassy carbon electrodes (GCE) was therefore investigated as an alternative technique. Surface preparation of the GCE surface was essential and a suitable procedure was developed. A linear response was observed from 0 to 180 mg L-1 with a lower detection limit of 500 ng L-1 (5 nM). DPSV was shown to be significantly more sensitive and accurate in determining the Ag+ activity than the silver ISE technique, particularly below 200 nM.
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| 6. |
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| 7. |
- Skoglund, Sara, et al.
(författare)
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Effect of Laundry Surfactants on Surface Charge and Colloidal Stability of Silver Nanoparticles
- 2013
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 29:28, s. 8882-8891
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Tidskriftsartikel (refereegranskat)abstract
- The stability of silver nanoparticles (Ag NPs) potentially released from clothing during a laundry cycle and their interactions with laundry-relevant surfactants [anionic (LAS), cationic (DTAC), and nonionic (Berol)] have been investigated. Surface interactions between Ag NPs and surfactants influence their speciation and stability. In the absence of surfactants as well as in the presence of LAS, the negatively charged Ag NPs were stable in solution for more than 1 day. At low DTAC concentrations (<= 1 mM), DTAC-Ag NP interactions resulted in charge neutralization and formation of agglomerates. The surface charge of the particles became positive at higher concentrations due to a bilayer type formation of DTAC that prevents from agglomeration due to repulsive electrostatic forces between the positively charged colloids. The adsorption of Berol was enhanced when above its critical micelle concentration (cmc). This resulted in a surface charge dose to zero and subsequent agglomeration. Extended DLVO theory calculations were in compliance with observed findings. The stability of the Ag NPs was shown to depend on the charge and concentration of the adsorbed surfactants. Such knowledge is important as it may influence the subsequent transport of Ag NPs through different chemical transients and thus their potential bioavailability and toxicity.
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