| 1. |
- Cappellini, Francesca, et al.
(author)
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Mechanistic insight into reactivity and (geno)toxicity of well-characterized nanoparticles of cobalt metal and oxides
- 2018
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In: Nanotoxicology. - : Taylor & Francis. - 1743-5390 .- 1743-5404. ; 12:6, s. 602-620
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Journal article (peer-reviewed)abstract
- An increasing use of cobalt (Co)-based nanoparticles (NPs) in different applications and exposures at occupational settings triggers the need for toxicity assessment. Improved understanding regarding the physiochemical characteristics of Co metal NPs and different oxides in combination with assessment of toxicity and mechanisms may facilitate decisions for grouping during risk assessment. The aim of this study was to gain mechanistic insights in the correlation between NP reactivity and toxicity of three different Co-based NPs (Co, CoO, and Co3O4) by using various tools for characterization, traditional toxicity assays, as well as six reporter cell lines (ToxTracker) for rapid detection of signaling pathways of relevance for carcinogenicity. The results showed cellular uptake of all NPs in lung cells and induction of DNA strand breaks and oxidative damage (comet assay) by Co and CoO NPs. In-depth studies on the ROS generation showed high reactivity of Co, lower for CoO, and no reactivity of Co3O4 NPs. The reactivity depended on the corrosion and transformation/dissolution properties of the particles and the media highlighting the role of the surface oxide and metal speciation as also confirmed by in silico modeling. By using ToxTracker, Co NPs were shown to be highly cytotoxic and induced reporters related to oxidative stress (Nrf2 signaling) and DNA strand breaks. Similar effects were observed for CoO NPs but at higher concentrations, whereas the Co3O4 NPs were inactive at all concentrations tested. In conclusion, our study suggests that Co and CoO NPs, but not Co3O4, may be grouped together for risk assessment.
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| 2. |
- Nie, Heng-Yong, et al.
(author)
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Detection of gold cysteine thiolate complexes on gold nanoparticles with time-of-flight secondary ion mass spectrometry
- 2021
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In: Biointerphases. - : AMER INST PHYSICS. - 1934-8630 .- 1559-4106. ; 16:2
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Journal article (peer-reviewed)abstract
- Gold (Au) nanoparticles (NPs) are widely used in nanomedical applications as a carrier for molecules designed for different functionalities. Previous findings suggested that biological molecules, including amino acids, could contribute to the dissolution of Au NPs in physiological environments and that this phenomenon was size-dependent. We, therefore, investigated the interactions of L-cysteine with 5-nm Au NPs by means of time-of-flight secondary ion mass spectrometry (ToF-SIMS). This was achieved by loading Au NPs on a clean aluminum (Al) foil and immersing it in an aqueous solution containing L-cysteine. Upon rinsing off the excessive cysteine molecules, ToF-SIMS confirmed the formation of gold cysteine thiolate via the detection of not only the Au-S bond but also the hydrogenated gold cysteine thiolate molecular ion. The presence of NaCl or a 2-(N-morpholino)ethanesulfonic acid buffer disabled the detection of Au NPs on the Al foil. The detection of larger (50-nm) Au NPs was possible but resulted in weaker cysteine and gold signals, and no detected gold cysteine thiolate signals. Nano-gold specific adsorption of L-cysteine was also demonstrated by cyclic voltammetry using paraffine-impregnated graphite electrodes with deposited Au NPs. We demonstrate that the superior chemical selectivity and surface sensitivity of ToF-SIMS, via detection of elemental and molecular species, provide a unique ability to identify the adsorption of cysteine and formation of gold-cysteine bonds on Au NPs.
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| 3. |
- Wang, Xuying, et al.
(author)
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Location of cobalt impurities in the surface oxide of stainless steel 316L and metal release in synthetic biological fluids
- 2022
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In: Materials & design. - : Elsevier BV. - 0264-1275 .- 1873-4197. ; 215, s. 110524-
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Journal article (peer-reviewed)abstract
- Since 2021, cobalt (Co) is in Europe classified as carcinogen in quantities exceeding 0.1 wt-%. This affects nickel-rich stainless steels, which contain about 0.2 wt-% Co impurities. Previous findings show the bioaccessibility of Co in stainless steel to be primarily determined by the corrosion resistance. It has been unclear whether Co is distributed heterogeneously in the alloy and the outermost surface and whether a specific location would pose a risk for Co release under specific exposure conditions. This study aimed at locating Co in stainless steel 316L (0.2 wt-% Co) surfaces prior to and after exposure to different synthetic body fluids for 24 h at 37 °C. Time-of-flight secondary ion mass spectrometry (ToF-SIMS), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma mass spectrometry (ICPMS) investigated the location of Co in the surface oxide and extent of release along with other metals (iron, chromium, nickel, and manganese) into synthetic biological fluids (gastric fluid, pH 1.5; lysosomal fluid, pH 4.5; phosphate buffered saline-PBS, pH 7.4). Co was homogeneously distributed along with metallic nickel beneath the surface oxide and co-released with other metals upon surface reformation and passivation. Exposure in PBS resulted in the incorporation of both Co and phosphate in the oxide.
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| 4. |
- Alinaghi, Farzad, et al.
(author)
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Metals in used and unused metalworking fluids : X-ray fluorescence spectrometry as a screening test
- 2020
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In: Contact Dermatitis. - : Wiley-Blackwell. - 0105-1873 .- 1600-0536.
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Journal article (peer-reviewed)abstract
- Background: Exposure to metalworking fluids (MWFs) is a well-known cause of occupational contact dermatitis. Objectives: We aimed to (1) determine the amount of nickel, chromium, and cobalt in large samples of used and unused MWFs collected from metalworking plants in Denmark, and (2) evaluate a handheld x-ray fluorescence (XRF) device as a screening instrument for metals in MWFs. Methods: A handheld XRF device was used to screen for metals in MWFs. All samples were also analyzed for concentrations of nickel, chromium, and cobalt using graphite furnace atomic absorption spectroscopy (GFAAS). Results: GFAAS analysis showed that 13 of 80 samples (16.3%) contained >1 mg/kg (ppm) nickel (range: 6.4-17.7 mg/kg), 3 of 80 (3.8%) contained >1 (range: 1.4-3.1) mg/kg chromium, and 1 of 80 (1.3%) contained 1.3 mg/kg cobalt. XRF-screening detected nickel in eight samples (range: 2.5-15.5 mg/kg), but only one sample with 3.0 (±0.5) mg/kg was found subsequently to contain 9.9 (0.02) mg/kg nickel by GFAAS. Although no chromium was found by XRF analysis, cobalt was found in two samples with 6 (±1.5) mg/kg and 5 (±1.5) mg/kg, subsequently found to contain 0.1 (±0.01) mg/kg and 0.08 (±0.01) mg/kg by GFAAS. Similar concentrations of nickel were found in used (N = 6, range: 6.4-17.7 mg/kg) and unused MWFs (N = 7, range: 9.1-17.3 mg/kg). Conclusion: Considerable levels of nickel, chromium, and cobalt were found in some used and unused MWFs indicating that these might represent a source of metal allergy. The XRF device is a poor screening test for these metals in MWFs.
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| 5. |
- Atapour, Masoud, et al.
(author)
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Corrosion and metal release investigations of selective laser melted 316L stainless steel in a synthetic physiological fluid containing proteins and in diluted hydrochloric acid
- 2020
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In: Electrochimica Acta. - : Elsevier BV. - 0013-4686 .- 1873-3859. ; 354
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Journal article (peer-reviewed)abstract
- The corrosion and metal release characteristics of additively manufactured stainless steels are key factors for their applicability in biomedical applications. The effect of building direction on the microstructure, corrosion behavior and metal release of selective laser melted (SLM) AISI 316L stainless steel were therefore investigated in a protein-rich synthetic body fluid (PBS+BSA, pH 7.3) and in diluted hydrochloric acid (HCl, pH 1.5). A multi-analytical approach was applied to characterize SLM 316L surfaces printed in different building directions (denoted XY and XZ) and a post heat treated SLM surface (XZ-HT) compared with wrought surfaces. All SLM specimens revealed an austenitic microstructure without any amounts of delta-ferrite and without large-angled grain boundaries in contrast to the wrought 316L surface. The building direction strongly affected the grain size distribution due to the temperature gradients in the melt pools. The SLM 316L specimens released initially slightly less Fe, Cr and Ni compared with the wrought 316L specimen. Slightly less metal was released from the heat treated SLM specimen (XZ-HT) specimen compared to the other SLM specimens. Relatively high amounts of released Cr were observed in PBS+BSA, most probably attributed to protein-bound Cr, whereas substantially more Ni was released in HCl compared to PBS+BSA due to pitting corrosion and a reduced surface oxide thickness. The surface oxide composition of as-printed SLM specimens was strongly dependent on the building direction and the post heat treatment, whereas no differences were observed after abrasion either among the SLM specimens or compared with the wrought 316L specimen. Cr became in all cases enriched within the outermost surface oxide in PBS+BSA and strongly enriched in the HCl solution, coupled to a strongly reduced amount of released metals with time. The heat treated SLM specimen (XZ-HT) gained a superior charge transfer resistance, the lowest passive current density, and the highest OCP value among all specimens. In HCl, the SLM specimens showed a lower pitting susceptibility compared to the wrought specimens. No pitting was observed in PBS+BSA. No differences in corrosion or metal release characteristics were observed related to the building direction of abraded SLM specimens.
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| 6. |
- Atapour, Masoud, et al.
(author)
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Corrosion of Binder Jetting Additively Manufactured 316L Stainless Steel of Different Surface Finish
- 2020
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In: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 167:13
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Journal article (peer-reviewed)abstract
- One technique of additive manufacturing is the binder-jetting technique that has the advantages of low costs, printing at room temperature and in air, and no need of a support structure. The aim of this study was to investigate the corrosion behavior of printed 316L surfaces with and without different post surface treatments of blasting and superfinishing. Comparative studies were performed on abraded wrought 316L. Surface topography, porosity, surface oxide composition, and electrochemical characteristics, including pitting corrosion, were investigated at room temperature as a function of post surface treatments in diluted hydrochloric acid at pH 1.5. The blasting and superfinishing treatment significantly reduced the surface roughness and level of surface porosity. Blasting detrimentally affected on the pitting corrosion resistance. The superfinishing process induced an enrichment of chromium in the surface oxide and improved the pitting corrosion resistance. All surfaces revealed slightly reduced susceptibility to pit initiation and metastable pitting as compared to wrought 316L, possibly explained by the absence of inclusions. Once pitting propagation was induced, repassivation was hindered for all surfaces compared with the wrought surface. The pitting corrosion resistance of the as-superfinished 316L was improved compared with wrought 316L.
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| 7. |
- Atapour, Masoud, et al.
(author)
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Metal release from stainless steel 316L in whey protein - And simulated milk solutions under static and stirring conditions
- 2019
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In: Food Control. - : ELSEVIER SCI LTD. - 0956-7135 .- 1873-7129. ; 101, s. 163-172
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Journal article (peer-reviewed)abstract
- Stainless steel is an important transport and processing contact material for bovine milk and dairy products. Release (migration) of metals, ions, complexes or wear debris/particles, and metal-induced protein aggregation in such environments are hence important to consider both from a corrosion and food safety perspective. This study aims on investigating the release of iron (Fe), chromium (Cr), and nickel (Ni) from AISI 316L stainless steel in contact with whey protein solutions relevant for protein drinks, and on how the whey proteins are influenced by stirring with a magnetic stir bar and metal release. Mechanistic insight is gained by parallel investigations of metal release from two reference non-protein containing solutions, a metal-complexing (citrate-containing) simulated milk solution (SMS) and a low complexing phosphate buffered saline solution (PBS). All immersion exposures were conducted at pH 6.8 for 0.5, 4, 24 and 48 hat room temperature at static and stirring conditions. All solutions and samples were investigated using different chemical, spectroscopic, microscopic, and electrochemical methods. Significantly higher amounts of Fe, Cr, and Ni were released into the whey protein solution (80 g/L) as compared to SMS and PBS. Strong enrichment of Cr in the surface oxide and reduction of the surface oxide thickness were associated with a higher amount of Ni release in the metal-complexing solutions (SMS and whey protein) compared with PBS. Stirring conditions resulted in higher amounts of metal release, enrichment of Cr in the surface oxide, and clear signs of wear of the 316L surface in all solutions compared to static conditions. The wear mechanism in the whey protein solution was different as compared to corresponding processes in SMS and PBS, involving an etching-like process and larger-sized wear debris. Electrochemical measurements at static conditions confirmed observed differences between the solutions, with the lowest corrosion resistance observed for coupons exposed in the whey protein solution, followed by SMS and PBS. Released metals in solution from the 316L coupons in contact with the whey protein solution resulted in enhanced rates of protein aggregation and precipitation of protein aggregates from solution. Further studies should be made to investigate other relevant test conditions and assess toxicological risks.
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| 8. |
- Atapour, Masoud, et al.
(author)
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Stainless steel in simulated milk and whey protein solutions - Influence of grade on corrosion and metal release
- 2020
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In: Electrochimica Acta. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0013-4686 .- 1873-3859. ; 331
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Journal article (peer-reviewed)abstract
- Reactions at the biointerfaces between stainless steel and protein-rich dairy products, which contain whey proteins, are important to consider in terms of food safety and material grade selection. Changes in corrosion behavior, metal release, and surface composition of austenitic (AISI 316 L), ferritic (AISI 430), and lean duplex (LDX 2101) stainless steels in simulated milk (SMS) and whey protein solution were investigated. The amount of released metals and the corrosion susceptibility increased according to 2101 < 316 L < 430. All grades revealed low corrosion rates in the whey protein solution without any sign of active/metastable corrosion. Pitting corrosion was evident for 430 in SMS. The total amount of released metals (iron, chromium, and nickel) was significantly higher in whey protein solution compared with SMS. This suggests the metal release process to be mainly governed by complexation reactions. Nickel was preferentially released compared to its bulk composition fraction for both 316 L and 2101 in the highly complexing SMS. Reduced metal release rates with time correlated with the enrichment of chromium in the surface oxide. The extent of metal release was for all metals substantially lower than release limits of metals stipulated in health regulations related to the use of alloys and metals in food-related environments.
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| 9. |
- Carlander, U., et al.
(author)
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Macrophage-Assisted Dissolution of Gold Nanoparticles
- 2019
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In: ACS Applied Bio Materials. - : American Chemical Society. - 2576-6422. ; 2:3, s. 1006-1016
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Journal article (peer-reviewed)abstract
- Gold nanoparticles (AuNPs) are readily functionalized and considered biocompatible making them useful in a wide range of applications. Upon human exposure, AuNPs will to a high extent reside in macrophages, cells that are designed to digest foreign materials. To better understand the fate of AuNPs in the human body, their possible dissolution needs to be explored. In this study, we tested the hypothesis that macrophages, and especially stimulated macrophages, can impact the dissolution of AuNPs in a size-dependent manner. We developed an in vitro method to compare the dissolution of citrate coated 5 and 50 nm-sized AuNPs, in terms of released gold ions as measured by inductive coupled mass spectrometry (ICP-MS), in (i) cell medium (alone) (ii) in medium with macrophages present and (iii) in medium with lipopolysaccharide (LPS) triggered macrophages (simulating inflammatory conditions). We found an evident, time-dependent dissolution of AuNPs in cell medium, corresponding to 3% and 0.6% of the added amounts of 5 and 50 nm AuNPs, respectively, after 1 week (168 h) of incubation. The dissolution of 5 nm AuNPs was further increased to 4% in the presence of macrophages and, most strikingly, 14% was dissolved in case of LPS-triggering. In contrast, only a minor increase was observed for 50 nm AuNPs after 1 week in the presence of LPS-triggered macrophages compared to medium alone. Dissolution experiments in the absence of cells highlighted the importance of biomolecules. Our findings thus show dissolution of citrate coated AuNPs that is dependent on size, presence of macrophages, and their inflammatory state. These findings have implications for understanding the transformation/dissolution and fate of AuNPs.
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| 10. |
- Ferraris, Sara, et al.
(author)
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Interactions Between the Physiological Environment and Titanium-Based Implant Materials: From Understanding to Control
- 2022
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In: Nanoscale Engineering of Biomaterials. - Singapore : Springer Nature. ; , s. 3-26
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Book chapter (other academic/artistic)abstract
- Titanium and titanium alloys are widely used in different biomedical applications owing to their high biocompatibility, high corrosion resistance, good mechanical properties, and good osseointegration ability. Titanium and its alloys rapidly form a surface oxide layer in air and aqueous environments. This passive and thin (a few nanometers) surface oxide hinders active corrosion and ensures a low metal ion release, enhancing biocompatibility. Compared to that of other biomedical alloys, this surface oxide is exceptionally resistant to chemical attack by halides, primarily chlorides; the presence of fluorides can, in some cases, result in localized corrosion of titanium and its alloys. However, the combination of proteins, inflammatory conditions and bacteria, which for instance generate hydrogen peroxide, can result in a reduction of the corrosion resistance of titanium-based materials. Titanium and its alloying elements, such as aluminum and vanadium, can then be released as ions, which might trigger an immune system response and reduce biocompatibility. Several surface modifications have been proposed in order to improve the bone-bonding ability of titanium and its alloys, facilitate the healing process, and enhance the success of the implant with a decreased risk of micromotions. Moreover, antimicrobial ions/nanoparticles can be added to the surface to reduce the infection risk. Surface modification of titanium (e.g., with artificially grown, micrometer-thick, titanium oxide layers) can significantly increase the corrosion resistance under critical conditions (e.g., inflammatory response and infection); however, the surfaces are not completely inert and the effect of metal ion/nanoparticle release should be carefully taken into account. This chapter reviews and discusses the current strategies for modifying and controlling the surface of titanium-based implant materials, with particular focus on corrosion resistance, bone integration, inflammatory and infection control, and interactions with the physiological environment.
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