Poly(Allylamine Hydrochloride) and ZnO Nanohybrid Coating for the Development of Hydrophobic, Antibacterial, and Biocompatible Textiles

In healthcare facilities, infections caused by Staphylococcus aureus (S. aureus) from textile materials are a cause for concern, and nanomaterials are one of the solutions; however, their impact on safety and biocompatibility with the human body must not be neglected. This study aimed to develop a novel multilayer coating with poly(allylamine hydrochloride) (PAH) and immobilized ZnO nanoparticles (ZnO NPs) to make efficient antibacterial and biocompatible cotton, polyester, and nylon textiles. For this purpose, the coated textiles were characterized with profilometry, contact angles, and electrokinetic analyzer measurements. The ZnO NPs on the textiles were analyzed by scanning electron microscopy and inductively coupled plasma mass spectrometry. The antibacterial tests were conducted with S. aureus and biocompatibility with immortalized human keratinocyte cells. The results demonstrated successful PAH/ZnO coating formation on the textiles, demonstrating weak hydrophobic properties. Furthermore, PAH multilayers caused complete ZnO NP immobilization on the coated textiles. All coated textiles showed strong growth inhibition (2-3-log reduction) in planktonic and adhered S. aureus cells. The bacterial viability was reduced by more than 99%. Cotton, due to its better ZnO NP adherence, demonstrated a slightly higher antibacterial performance than polyester and nylon. The coating procedure enables the binding of ZnO NPs in an amount (<30 µg cm-2) that, after complete dissolution, is significantly below the concentration causing cytotoxicity (10 µg mL-1).

Antibacterial evaluation of different prosthetic liner textiles coated by CuO nanoparticles

Prosthetic liners are mainly used as an interface between residual limbs and prosthetic sockets to minimize physical and biological damage to soft tissue. However, the closed and moist conditions within liners and the amputee's skin provide a suitable environment for bacterial growth to cause infections. This study aimed to coat a comprehensive variant material with copper oxide nanoparticles (CuO NPs) and compare their surface analysis and antibacterial properties. These materials were covered with CuO NPs solution at a concentration of 70 μg mL-1 to achieve this purpose. After drying, their surface characteristics were analyzed by measuring zeta potential, contact angle, surface roughness, and fiber arrangement. Cu-released concentration from the coatings into the acetate buffer solution by inductively coupled plasma mass spectrometry indicated that lycra and nylon quickly released Cu ions to concentrations up to ∼0.2 μg mL-1 after 24 h, causing low metabolic activity of human bone-marrow mesenchymal stem cells (bMSC) in the indirect assay. Antibacterial activity of the coated specimens was evaluated by infecting their surfaces with the Gram-positive bacteria Staphylococcus epidermidis, reporting a significant ∼40 % reduction of metabolic activity for x-dry after 24 h; in addition, the number of viable bacterial colonies adhered to the surface of this material was reduced by ∼23 times in comparison with non-treated x-dry that were visually confirmed by scanning electron microscope. In conclusion, CuO NPs x-dry shows optimistic results to pursue further experiments due to its slow speed of Cu release and prolonged antibacterial activity, as well as its compatibility with human cells.

Environmentally Friendly Approach for Nd2Fe14B Magnetic Phase Extraction by Selective Chemical Leaching: A Proof-of-Concept Study

The green transition initiative has exposed the importance of effective recycling of Nd-Fe-B magnets for achieving sustainability and foreign independence. In this study, we considered strip-cast, hydrogenated, jet-milled Nd-Fe-B powder as a case study to explore the potential for selective chemical leaching of the Nd-rich phase, aiming to extract the Nd₂Fe₁₄B matrix phase. Diluted citric and nitric acids at concentrations of 0.01, 0.1, and 1 M were considered potential leaching mediums, and the leaching time was 15 min. Microstructural investigation, magnetic characterization, and elemental compositional analysis were performed to investigate leaching efficiency and selectivity. Based on SEM analysis, Nd/Fe ratio monitoring via ICP-MS, and the high moment/mass value at 160 emu/g for the sample leached with 1 M citric acid, 1 M citric acid proved highly selective toward the Nd-rich phase. Exposure to nitric acid resulted in a structurally damaged Nd₂Fe₁₄B matrix phase and severely diminished moment/mass value at 96.2 emu/g, thus making the nitric acid unsuitable for selective leaching. The presence of hydrogen introduced into the material via the hydrogen decrepitation process did not notably influence the leaching dynamics. The proposed leaching process based on mild organic acids is environmentally friendly and can be scaled up and adopted for reprocessing industrial scrap or end-of-life Nd-Fe-B magnets to obtain single-phase Nd-Fe-B powders that can be used for novel magnet-making.

Finding the tiny plastic needle in the haystack: how field flow fractionation can help to analyze nanoplastics in food

While the exact health risks associated with nanoplastics are currently the focus of intense research, there is no doubt that humans are exposed to nanoplastics and that food could be a major source of exposure. Nanoplastics are released from plastic materials and articles used during food production, processing, storage, preparation, and serving. They are also likely to enter the food chain via contaminated water, air, and soil. However, very limited exposure data for risk assessment exists so far due to the lack of suitable analytical methods. Nanoplastic detection in food poses a great analytical challenge due to the complexity of plastics and food matrices as well as the small size and expectedly low concentration of the plastic particles. Multidetector field flow fractionation has emerged as a valuable analytical technique for nanoparticle separation over the last decades, and the first studies using the technique for analyzing nanoplastics in complex matrices are emerging. In combination with online detectors and offline analysis, multidetector field flow fractionation is a powerful platform for advanced characterization of nanoplastics in food by reducing sample complexity, which otherwise hampers the full potential of most analytical techniques. The focus of this article is to present the current state of the art of multidetector field flow fractionation for nanoplastic analysis and to discuss future trends and needs aiming at the analysis of nanoplastics in food.

Comparison of biodistribution of cerium oxide nanoparticles after repeated oral administration by gavage or snack in Sprague Dawley rats

The rate of translocation of ingested nanoparticles (NPs) and how the uptake is affected by a food matrix are key aspects of health risk assessment. In this study, female Sprague Dawley rats (N = 4/group) received 0, 1.4, or 13 mg of cerium oxide (CeO₂ NM-212) NPs/rat/day by gavage or in a chocolate spread snack 5 days/week for 1 or 2 weeks followed by 2 weeks of recovery. A dose and time-dependent uptake in the liver and spleen of 0.1-0.3 and 0.004-0.005 parts per million (ng/mg) of the total administered dose was found, respectively. There was no statistically significant difference in cerium concentration in the liver or spleen after gavage compared to snack dosing. Microscopy revealed indications of necrotic changes in the liver and decreased cellularity in white pulp in the spleen. The snack provided precise administration and a more human-relevant exposure of NPs and could improve animal welfare as alternative to gavage.

Spatial and temporal variability and sources of dissolved trace elements in the Sava River (Slovenia, Croatia)

The spatial and temporal variability of dissolved trace elements (Al, As, Ba, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Pb, Sb, Sr, Ti, U, V and Zn) in the upper and middle reaches of the Sava River during two campaigns (2007/2008 and 2017/2018) was examined. The study also included important tributaries and wastewater effluents. No crucial change in metal concentrations in the Sava River water between the two sampling periods was detected. Elements Co, Cr, Cu, Fe, Sb and Zn had higher concentrations at several sites in the first period, whereas Ba, Cd and Pb in the second period. The influence of wastewater discharges proved to be negligible. The highest levels of potentially toxic metals (Cd, Cr, Cu, Sb, V and Zn) were found downstream of the industrial town of Sisak. Concentration-discharge relationship of dissolved elements showed a chemostatic behaviour for As, Cr, Cu, Sr and V and chemodynamic behaviour for all other elements. The UNMIX model, used to identify and quantify metal sources, indicated that soil weathering was the main source of most elements (Al, As, Ba, Co, Cu, Fe, Li, Ni, Sb, Sr and V), with an anthropogenic contribution for Cd, Mo, Pb, Ti and Zn, while Mn and U were associated with colloid formation. The Sava River was defined as moderately polluted regarding metals, whose water quality meets environmental quality standards (EQS). These results may help to better understand the behaviour of dissolved metals in rivers under anthropogenic pressure and to control pollution in the Sava River Basin.

Single-Particle ICP-MS as a Screening Technique for the Presence of Potential Inorganic Nanoparticles in Food

In this work, we show the potential of single-particle inductively coupled plasma-mass spectrometry (spICP-MS) as a screening technique for detection of inorganic nanoparticles (NPs) that are expected to be present in food. We demonstrate that the spICP-MS/MS method in combination with collision/reaction cell gases and microsecond dwell times offers sensitive and interference-free detection of NPs. We present the steps that have to be considered to correctly assess the presence of NPs in food, for example, setting a suitable threshold for discriminating particle events from the baseline and analyzing a sufficient number of blank samples to minimize false-positive results. We applied the proposed screening approach to the sequential detection of NPs containing 8 selected elements that could be potentially present in 13 different food products. The highest mass concentrations of NPs (in the mg/g range) were found in the samples with food additives which are known to contain a fraction of NPs. The presence of (nano)particles in some of the investigated food samples was also confirmed by scanning electron microscopy analysis. Moreover, for the example of Al-containing NPs in Chinese noodles, we demonstrate that identification of the source of NPs with an unknown composition can be challenging when using only spICP-MS as particle mass concentration and size distribution can only be estimated by assuming a certain particle composition/shape. Other complementary techniques for particle characterization, such as electron microscopy in combination with elemental analysis, are therefore required.

Particle size analysis of pristine food-grade titanium dioxide and E 171 in confectionery products: Interlaboratory testing of a single-particle inductively coupled plasma mass spectrometry screening method and confirmation with transmission electron microscopy

Titanium dioxide is a white colourant authorised as food additive E 171 in the EU, where it is used in a range of alimentary products. As these materials may contain a fraction of particulates with sizes below 100 nm and current EU regulation requires specific labelling of food ingredient to indicate the presence of engineered nanomaterials there is now a need for standardised and validated methods to appropriately size and quantify (nano)particles in food matrices.

A single-particle inductively coupled plasma mass spectrometry (spICP-MS) screening method for the determination of the size distribution and concentration of titanium dioxide particles in sugar-coated confectionery and pristine food-grade titanium dioxide was developed. Special emphasis was placed on the sample preparation procedure, crucial to reproducibly disperse the particles before analysis. The transferability of this method was tested in an interlaboratory comparison study among seven experienced European food control and food research laboratories equipped with various ICP-MS instruments and using different software packages. The assessed measurands included the particle mean diameter, the most frequent diameter, the percentage of particles (in number) with a diameter below 100 nm, the particles' number concentration and a number of cumulative particle size distribution parameters (D0, D10, D50, D99.5, D99.8 and D100). The evaluated method's performance characteristics were, the within-laboratory precision, expressed as the relative repeatability standard deviation (RSDr), and the between-laboratory precision, expressed as the relative reproducibility standard deviation (RSDR). Transmission electron microscopy (TEM) was used as a confirmatory technique and served as the basis for bias estimation.

The optimisation of the sample preparation step showed that when this protocol was applied to the relatively simple sample food matrices used in this study, bath sonication turned out to be sufficient to reach the highest, achievable degree of dispersed constituent particles. For the pristine material, probe sonication was required. Repeatability and reproducibility were below 10% and 25% respectively for most measurands except for the lower (D0) and the upper (D100) bound of the particle size distribution and the particle number concentration. The broader distribution of the lower and the upper bounds could be attributed to instrument-specific settings/setups (e.g. the timing parameters, the transport efficiency, type of mass-spectrometer) and software-specific data treatment algorithms. Differences in the upper bound were identified as being due to the non-harmonised application of the upper counting limit. Reporting D99.5 or D99.8 instead of the effectively largest particle diameter (D100) excluded isolated large particles and considerably improved the reproducibility. The particle number-concentration was found to be influenced by small differences in the sample preparation procedure. The comparison of these results with those obtained using electron microscopy showed that the mean and median particle diameter was, in all cases, higher when using spICP-MS. The main reason for this was the higher size detection limit for spICP-MS plus the fact that some of the analysed particles remained agglomerated/aggregated after sonication.

Single particle ICP-MS is a powerful screening technique, which in many cases provides sufficient evidence to confirm the need to label a food product as containing (engineered) titanium dioxide nanomaterial according to the current EU regulatory requirements. The overall positive outcome of the method performance evaluation and the current lack of alternative standardised procedures, would indicate this method as being a promising candidate for a full validation study.

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Standardised methods for sizing of E171 particles in food matrices are unavailable.

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Screening method based on spICP-MS is proposed.

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Analytical performance parameters and transferability tested in ILC.

Impact of iron oxide nanoparticles on xenobiotic metabolism in HepaRG cells

Iron oxide nanoparticles are used in various industrial fields, as a tool in biomedicine as well as in food colorants, and can therefore reach human metabolism via oral uptake or injection. However, their effects on the human body, especially the liver as one of the first target organs is still under elucidation. Here, we studied the influence of different representative iron oxide materials on xenobiotic metabolism of HepaRG cells. These included four iron oxide nanoparticles, one commercially available yellow food pigment (E172), and non-particulate ionic control FeSO₄. The nanoparticles had different chemical and crystalline structures and differed in size and shape and were used at a concentration of 50 µg Fe/mL. We found that various CYP enzymes were downregulated by some but not all iron oxide nanoparticles, with the Fe₃O₄-particle, both γ-Fe₂O₃-particles, and FeSO₄ exhibiting the strongest effects, the yellow food pigment E172 showing a minor effect and an α-Fe₂O₃ nanoparticle leading to almost no inhibition of phase I machinery. The downregulation was seen at the mRNA, protein expression, and activity levels. Thereby, no dependency on the size or chemical structure was found. This underlines the difficulty of the grouping of nanomaterials regarding their physiological impact, suggesting that every iron oxide nanoparticle species needs to be evaluated in a case-by-case approach.

The presence of iron oxide nanoparticles in the food pigment E172

Iron oxides used as food colorants are listed in the European Union with the number E172. However, there are no specifications concerning the fraction of nanoparticles in these pigments. Here, seven E172 products were thoroughly characterized. Samples of all colors were analyzed with a broad spectrum of methods to assess their physico-chemical properties. Small-Angle X-ray Scattering (SAXS), Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), zeta-potential, Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), X-ray diffraction (XRD), Brunauer-Emmett-Teller analysis (BET), Asymmetric Flow Field-Flow Fractionation (AF4) and in vitro cell viability measurements were used. Nanoparticles were detected in all E172 samples by TEM or SAXS measurements. Quantitative results from both methods were comparable. Five pigments were evaluated by TEM, of which four had a size median below 100 nm, while SAXS showed a size median below 100 nm for six evaluated pigments. Therefore, consumers may be exposed to iron oxide nanoparticles through the consumption of food pigments.

Magneto-Liposomes as MRI Contrast Agents: A Systematic Study of Different Liposomal Formulations

The majority of the clinically approved iron oxide nanoparticles (IO NPs) used as contrast agents for magnetic resonance imaging (MRI) have been withdrawn from the market either due to safety concerns or lack of profits. To address this challenge, liposomes have been used to prepare IO-based T2 contrast agents. We studied the influence of different phospholipids on the relaxivity (r2) values of magneto-liposomes (MLs) containing magnetic NPs in the bilayer, where a strong correlation between the bilayer fluidity and r2 is clearly shown. Embedding 5-nm IO NPs in the lipid bilayer leads to a significant improvement in their relaxivity, where r2 values range from 153 ± 5 s-1 mM-1 for DPPC/cholesterol/DSPE-PEG (96/50/4) up to 673 ± 12 s-1 mM-1 for DOPC/DSPE-PEG (96/4), compared to "free" IO NPs with an r2 value of 16 s-1 mM-1, measured at 9.4 T MRI scanner. In vitro MRI measurements, together with the ICP-MS analysis, revealed MLs as highly selective contrast agents that were preferentially taken up by cancerous T24 cells, which led to an improvement in the contrast and an easier distinction between the healthy and the cancerous cells. A careful selection of the lipid bilayer to prepare MLs could offer efficient MRI contrast agents, even at very low IO NP concentrations.

T2 distribution profiles are a good way to show cartilage regional variabilities and cartilage insufficiency

OBJECTIVE

To use T2 relaxation time distribution profiles to assess inter-group regional differences along articular surfaces and to evaluate the feasibility of this analysis for comparison of cartilage insufficiency.

MATERIALS AND METHODS

Twelve pairs matched according to age and gender (12 healthy volunteers and 12 patients after anterior cruciate ligament reconstruction (ACLR)) underwent 3-T MRI. T2 maps were calculated from six time echo images of the mid-sagittal slice in the lateral and medial compartment. The femoral and tibial cartilage was analyzed by measuring T2 distribution profiles along the articular surfaces.

RESULTS

T2 distribution profiles were generated along the length of the articular surface in the femorotibial compartments. Differences in the T2 distribution profiles between the tibial and femoral cartilage as well as between the cartilage of the femoral condyles were identified in healthy individuals. T2 distribution profiles clearly demonstrated cartilage insufficiency in the weight-bearing areas for subjects in the ACLR group.

CONCLUSIONS

T2 distribution profiles can identify regional differences in femoral and tibial cartilage. The T2 distribution profile pattern is preserved with cartilage insufficiency, however, with important differences in T2 values for the ACLR group in weight-bearing areas.

Monolithic chromatography on conjoint liquid chromatography columns for speciation of platinum-based chemotherapeutics in serum of cancer patients

BACKGROUND

Monolithic chromatography using convective interaction media (CIM) disks or columns can be used in the separation step of speciation analysis. When different monolithic disks are placed in one housing, forming conjoint liquid chromatography (CLC) monolithic column, two-dimensional separation is achieved in a single chromatographic run.

METHODS

Here, we assembled low-pressure (maximum 50 bar) CLC monolithic column, which consists of two 0.34 mL shallow CIM monolithic disks and high-pressure CLC column (maximum 150 bar) from 0.1 mL analytical high performance short bed CIMac monolithic disks. Both the CLC columns constructed from affinity Protein G and weak anion exchange diethylamine (DEAE) disks, were applied for the speciation of cisplatin, oxaliplatin and carboplatin in spiked standard serum proteins, spiked human serum and serum of cancer patients. The analytical performances of the CLC columns used were evaluated by comparing their robustness, selectivity, repeatability and reproducibility. The separated serum proteins were detected on-line by ultraviolet (UV) and eluted Pt species by inductively coupled plasma mass spectrometry (ICP-MS). For accurate quantification of the separated Pt species (unbound Pt-based chemotherapeutic from species associated to transferrin (Tf), human serum albumin (HSA) and Immunoglobulin G (IgG)), post column isotope dilution (ID)-ICP-MS was used.

RESULTS

The data from analyses showed that both tested CLC monolithic columns gave statistically comparable results, with the low-pressure CLC column exhibiting better resolving power and robustness. It also enables more effective cleaning of monolithic disks and to analyse larger series of serum samples than the high-pressure CLC column. Analyses of serum samples of cancer patients treated with cisplatin or carboplatin showed that Pt-chemotherapeutics were bound preferentially to HSA (around 80%). The portion of unbound Pt in general did not exceed 2%, up to 5% of Pt was associated with Tf and approximately 20% with IgG. Column recoveries, calculated as a ratio between the sum of concentrations of Pt species eluted and concentration of total Pt in serum samples, were close to 100%.

CONCLUSIONS

Low-pressure CLC column exhibited greater potential than high-pressure CLC column, and can be thus recommended for its intended use in speciation analysis of metal-based biomolecules.

A Multiparametric Approach to Cerium Oxide Nanoparticle Toxicity Assessment in Non-Biting Midges

Cerium oxide nanoparticles (CeO₂ NPs) are included in the Organisation for Economic Co-operation and Development (OECD) priority list of engineered nanomaterials for assessment of their environmental impact. The present study was carried out to assess the CeO₂ NP toxicity to the freshwater midge Chironomus riparius larvae at concentrations of 2.5, 25, 250, and 2500 mg of CeO₂ NP/kg of sediment. Experiments were designed to assess the prolonged exposure of midges to CeO₂ NPs while adhering to OECD test guideline 218. The following parameters were investigated: CeO₂ NP uptake by larvae, oxidative stress parameters, in vivo genotoxic effects, and life trait parameters. Inductively coupled plasma-mass spectrometry analysis showed a significant positive correlation between the concentration of CeO₂ NPs in the sediment and its uptake by the larvae. No significant mortality was observed in C. riparius, and oxidative stress was not detected. The only significantly induced sublethal effect was genotoxicity, which began to manifest at a lowest-observed-effect concentration of 25 mg kg^-1 of sediment and progressively increased at higher concentrations. Our results indicate that exposure to CeO₂ NP-contaminated freshwater sediments does not pose a risk to chironomids at environmentally realistic concentrations. However, the significant accumulation of CeO₂ NPs by chironomid larvae may pose a risk through trophic transfer to organisms further up the food chain. Environ Toxicol Chem 2019;39:131-140. © 2019 SETAC.

Direct Recycling of Nd-Fe-B Magnets Based on the Recovery of Nd2 Fe14 B Grains by Acid-free Electrochemical Etching

Recycling of end-of-life Nd-Fe-B magnets is an important strategy for reducing the environmental dangers associated with rare-earth mining and overcoming the supply risks associated with the rare-earth elements. In this study, a novel concept for recycling of sintered Nd-Fe-B magnets by directly recovering the matrix Nd₂ Fe₁₄ B grains is presented. The procedure is based on the anodic etching of sintered Nd-Fe-B magnets in a nonaqueous dimethylformamide (DMF)/0.3 mol L^-1 FeCl₂ bath. Selective recovery of Nd₂ Fe₁₄ B grains was realized within the applied current density <5 mA cm^-2 based on the etching priority of phases: metallic Nd > intergranular NdFe₄ B₄ > matrix Nd₂ Fe₁₄ B. The total energy consumption of the proposed recycling route is estimated to be 2.99 kWh kg^-1 , which is comparable to the state-of-the-art methods. However, the proposed recycling route is currently the only procedure that enables repeated recycling of sintered Nd-Fe-B magnets in a closed-loop system.

Potentially toxic elements in muscle tissue of different fish species from the Sava River and risk assessment for consumers

Fish from the Sava River are consumed daily by the local people: therefore, concern has been raised about the health implications of eating contaminated fish. In the present study, potentially toxic elements (PTE), such as Zn, Cu, Cr, Ni, Cd, Pb, As, Hg, and methylmercury (MeHg), were determined in ichthyofauna that are commonly consumed. PTE were determined in the fish muscle tissue. Fish were sampled at 12 locations from the source of the Sava River to its confluence with the Danube River during two sampling campaigns, namely; in 2014 under high water conditions and in 2015 under normal water conditions. Due to the different water regimes, different fish species were collected for chemical analysis. We observed that the concentrations of elements analysed in the fish muscle tissue were generally very low, except for those of Hg. Moreover, more than 90% of Hg present in the fish was in its most toxic form, namely MeHg. Especially in fish from the 2015 sampling campaign, Hg and MeHg concentrations increased with fish size, trophic level, and in the downstream direction. In addition, for Pb and As, and to some extent for Cd and Cr, spatial differences were detected in both years. The highest concentrations of PTE were detected in fish from sites with intensive industrial and agricultural activities. The consumption of fish in general does not pose a health risk for the PTE studied, except for Hg/MeHg at selected contaminated sites.

Potentially toxic elements in water, sediments and fish of the Evrotas River under variable water discharges

Among different stressors like drought, hydro-morphological alterations, and pollution from agricultural activities, nutrients, organic compounds and discharges from wastewater treatment plants (WWTPs), potentially toxic elements (PTE) may also contribute to the overall pollution of the Evrotas River, Greece. Nevertheless, information on pollution of elements in water and sediments in this river is scarcely documented. There is also no information available on the impact of elemental pollution from the aquatic environmental compartments on biota. To fill these gaps, in this study, water, sediment and fish samples were collected from four sampling sites along the Evrotas River under variable flow regimes (July 2015, higher discharge; June 2016, low discharge and September 2016, minimum discharge). Total and dissolved element concentrations in water samples, total and acetic acid extractable contents in sediments, and element concentrations in fish samples were determined by inductively coupled plasma mass spectrometry and significant relationships between samples were established using correlation analysis. The concentrations of PTE (Ni, Cr, Cd, As, Pb, Zn and Cu) in water were generally low, while elevated Ni and Cr contents were found in sediments (up to 150 and 300 mg/kg, respectively), with total Cr concentration in water and sediment being positively correlated. The ecological risk posed by the simultaneous presence of PTE in sediments evaluated by calculating the Probable Effect Concentration Coefficient (PEC-Q), demonstrated that PEC-Qs, which were above the critical value of 0.34, derived mostly from Cr and Ni inputs. Since their mobile sediment fraction was extremely low, Cr and Ni origin is most probably geogenic. The analysis of elements in the target fish species, the Evrotas chub, showed low to moderate PTE concentrations, with Pb being positively correlated with total Pb concentration in water. Moderate Zn concentrations found in fish samples from the Evrotas are possibly derived from pesticides and fertilizers.

Particle bound pollutants in rivers: Results from suspended sediment sampling in Globaqua River Basins

Transport of hydrophobic pollutants in rivers such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and heavy metals is often facilitated by suspended sediment particles, which are typically mobilized during high discharge events. Suspended sediments thus represent a means of transport for particle related pollutants within river reaches and may represent a suitable proxy for average pollutant concentrations estimation in a river reach or catchment. In this study, multiple high discharge/turbidity events were sampled at high temporal resolution in the Globaqua River Basins Sava (Slovenia, Serbia), Adige (Italy), and Evrotas (Greece) and analysed for persistent organic pollutants such as PAHs (polycyclic aromatic hydrocarbons) or PCBs (polychlorinated biphenyls) and heavy metals. For comparison, river bed sediment samples were analysed as well. Further, results are compared to previous studies in contrasting catchments in Germany, Iran, Spain, and beyond. Overall results show that loadings of suspended sediments with pollutants are catchment-specific and relatively stable over time at a given location. For PAHs, loadings on suspended particles mainly correlate to urban pressures (potentially diluted by sediment mass fluxes) in the rivers, whereas metal concentrations mainly display a geogenic origin. By cross-comparison with known urban pressure/sediment yield relationships (e.g. for PAHs) or soil background values (for metals) anthropogenic impact - e.g. caused by industrial activities - may be identified. Sampling of suspended sediments gives much more reliable results compared to sediment grab samples which typically show a more heterogeneous contaminant distribution. Based on mean annual suspended sediment concentrations and distribution coefficients of pollutants the fraction of particle facilitated transport versus dissolved fluxes can be calculated.

Occurrence of C60 and related fullerenes in the Sava River under different hydrologic conditions

The presence of nanomaterials in the environment has caught the attention of the scientific because of the uncertainties in their fate, mobility and potential toxic effects. However, few studies have determined experimentally their concentration levels in aquatic systems up to date, which complicates the development of an adequate risk assessment. In the present study, the occurrence of ten fullerenes has been assessed in the Sava River (Southeastern Europe): 27 freshwater samples and 12 sediment samples from 12 sampling points have been analysed during two sampling campaigns. C₆₀ was the most ubiquitous fullerene, with concentrations of 8 pg/l-59 ng/l and 108-895 pg/g_dw in water and sediments, respectively. Statistically significant differences existed between the levels in 2014 and 2015, which has been attributed to the extreme hydrologic conditions (severe floods and drought, respectively). C₇₀ fullerene has been detected in most of the samples and the fullerene derivatives [6,6]-phenyl C₆₁ butyric acid methyl ester and N‑methyl fulleropyrrolidine have been detected eventually, which highlights that nanotechnology research and development activities are responsible for emitting these emerging contaminants to the environment. The role of diverse potential anthropogenic sources (including oil refinery, general industrial activity, river navigation, urban emissions and nanotechnology) is discussed.

An environmentally relevant concentration of titanium dioxide (TiO2) nanoparticles induces morphological changes in the mouthparts of Chironomus tentans

The present study was carried out in order to assess the influence of environmentally relevant concentrations of TiO₂ nanoparticles (E171 human food grade) toxicity on the freshwater midge Chironomus tentans. Tested concentrations were 125, 250, 500, 1000, 2000 and 4000 mg of E171 TiO₂ per 1 kg of sediment, for the experiment aiming at life trait toxicity observation; and 2.5, 25 and 250 mg of E171 TiO₂ per 1 kg of sediment for the experiment aiming at mouthpart deformity observation. The experimental design was constructed for the sediment dwelling chironomid larvae according to OECD guidelines. For the first time, a geometric morphometric approach was used to assess the deformities in chironomid larvae as sublethal implications of nanoparticle exposure. The present study showed a concentration-response relationship between the TiO₂ concentration in the substrate and the TiO₂ intake. The mortality and emergence ratio was affected at concentrations >1000 mg/kg. Geometric Morphometrics revealed the tendency of the mentum teeth to narrow and elongate and the mandibles to widen, as well as the loss of the first inner tooth, with a TiO₂ concentration rise. The variability of morphological changes observed in the mouthparts indicates that C. tentans could be used as a bioindicator in nano-TiO₂ monitoring.

Investigation of the behaviour of zero-valent iron nanoparticles and their interactions with Cd2+ in wastewater by single particle ICP-MS

Zero-valent iron nanoparticles (nZVI) exhibit great potential for the removal of metal contaminants from wastewater. After their use, there is a risk that nZVI will remain dispersed in remediated water and represent potential nano-threats to the environment. Therefore, the behaviour of nZVI after remediation must be explored. To accomplish this, we optimised a novel method using single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) for the sizing and quantification of nZVI in wastewater matrices. H₂ reaction gas was used in MS/MS mode for the sensitive and interference-free determination of low concentrations of nZVI with a low size limit of detection (36nm). This method was applied to study the influence of different iron (Fe) loads (0.1, 0.25, 0.5 and 1.0gL^-1) and water matrices (Milli-Q water, synthetic and effluent wastewater) on the behaviour of nZVI, their interactions with Cd²⁺ and the efficiency of Cd²⁺ removal. The aggregation and sedimentation of nZVI increased with settling time. Sedimentation was slower in effluent wastewater than in Milli-Q water or synthetic wastewater. Consequently, Cd²⁺ was more efficiently (86%) removed from effluent wastewater than from synthetic wastewater (73%), while its removal from Milli-Q water was inefficient (19%). The trace amounts of Cd²⁺ that remained in the remediated water were either dissolved or sorbed to residual nZVI. The results of the nanoremediation of effluent wastewater with varying Fe loads showed that sedimentation was faster at higher initial concentrations of nZVI. After seven days of settling, low concentrations of Fe remained in the effluent wastewater at Fe loads of 0.5gL^-1 or higher, which could indicate that the use of nZVI in nanoremediation under the described conditions may not represent an environmental nano-threat. However, further studies are needed to assess the ecotoxicological impact of Fe-related NPs used for the nanoremediation of wastewaters.

Connecting the in vitro and in vivo experiments in electrochemotherapy - a feasibility study modeling cisplatin transport in mouse melanoma using the dual-porosity model

In electrochemotherapy two conditions have to be met to be successful - the electric field of sufficient amplitude and sufficient uptake of chemotherapeutics in the tumor. Current treatment plans only take into account critical electric field to achieve cell membrane permeabilization. However, permeabilization alone does not guarantee uptake of chemotherapeutics and consequently successful treatment. We performed a feasibility study to determine whether the transport of cisplatin in vivo could be calculated based on experiments performed in vitro. In vitro, a spectrum of parameters can be explored without ethical issues. Mouse melanoma B16-F1 cell suspension and inoculated B16-F10 tumors were exposed to electric pulses in the presence of chemotherapeutic cisplatin. The uptake of cisplatin was measured by inductively coupled plasma mass spectrometry. We modeled the transport of cisplatin with the dual-porosity model, which is based on the diffusion equation, connects pore formation with membrane permeability, and includes transport between several compartments. In our case, there were three compartments - tumor cells, interstitial fraction and peritumoral region. Our hypothesis was that in vitro permeability coefficient could be introduced in vivo, as long as tumor physiology was taken into account. Our hypothesis was confirmed as the connection of in vitro and in vivo experiments was possible by introducing a transformation coefficient which took into account the in vivo characteristics, i.e., smaller available area of the plasma membrane for transport due to cell density, presence of cell-matrix in vivo, and reduced drug mobility. We thus show that it is possible to connect in vitro and in vivo experiments of electrochemotherapy. However, more experimental work is required for model validation.

Translocation of silver nanoparticles in the ex vivo human placenta perfusion model characterized by single particle ICP-MS

With the extensive use of silver nanoparticles (AgNPs) in various consumer products their potential toxicity is of great concern especially for highly sensitive population groups such as pregnant women and even the developing fetus. To understand if AgNPs are taken up and cross the human placenta, we studied their translocation and accumulation in the human ex vivo placenta perfusion model by single particle ICP-MS (spICP-MS). The impact of different surface modifications on placental transfer was assessed by AgNPs with two different modifications: polyethylene glycol (AgPEG NPs) and sodium carboxylate (AgCOONa NPs). AgNPs and ionic Ag were detected in the fetal circulation in low but not negligible amounts. Slightly higher Ag translocation across the placental barrier for perfusion with AgPEG NPs and higher AgNP accumulation in placental tissue for perfusion with AgCOONa NPs were observed. Since these AgNPs are soluble in water, we tried to distinguish between the translocation of dissolved and particulate Ag. Perfusion with AgNO3 revealed the formation of Ag containing NPs in both circulations over time, of which the amount and their size in the fetal circulation were comparable to those from perfusion experiments with both AgNP types. Although we were not able to clarify whether intact AgNPs and/or Ag precipitates from dissolved Ag cross the placental barrier, our study highlights that uptake of Ag ions and/or dissolution of AgNPs in the tissue followed by re-precipitation in the fetal circulation needs to be considered as an important pathway in studies of AgNP translocation across biological barriers.

Hybrid FePt/SiO2/Au nanoparticles as a theranostic tool: in vitro photo-thermal treatment and MRI imaging

We have produced an innovative, theranostic material based on FePt/SiO₂/Au hybrid nanoparticles (NPs) for both, photo-thermal therapy and magnetic resonance imaging (MRI). Furthermore, a new synthesis approach, i.e., Au double seeding, for the preparation of Au nanoshells around the FePt/SiO₂ cores, is proposed. The photo-thermal and the MRI response were first demonstrated on an aqueous suspension of hybrid FePt/SiO₂/Au NPs. The cytotoxicity together with the internalization mechanism and the intracellular fate of the hybrid NPs were evaluated in vitro on a normal (NPU) and a half-differentiated cancerous cell line (RT4). The control samples as well as the normal cell line incubated with the NPs showed no significant temperature increase during the in vitro photo-thermal treatment (ΔT < 0.8 °C) and thus the cell viability remained high (∼90%). In contrast, due to the high NP uptake by the cancerous RT4 cell line, significant heating of the sample was observed (ΔT = 4 °C) and, consequently, after laser irradiation the cell viability dropped significantly to ∼60%. These results further confirm that the hybrid FePt/SiO₂/Au NPs developed in the scope of this work were not only efficient but also highly selective photo-thermal agents. Furthermore, the improvement in the contrast and the easier distinction between the healthy and the cancerous tissues were clearly demonstrated with in vitro MRI experiments, proving that hybrid NPs have an excellent potential to be used as contrast agents.

Magnetic interactions and in vitro study of biocompatible hydrocaffeic acid-stabilized Fe–Pt clusters as MRI contrast agents

A detailed magnetic study of separated Fe–Pt NPs and Fe–Pt clusters was performed to predict their optimal size and morphology for the maximum saturation magnetization, a factor that is known to influence the performance of a magnetic-resonance-imaging (MRI) contrast agent. Excellent stability and biocompatibility of the nanoparticle suspension was achieved using a novel coating based on hydrocaffeic acid (HCA), which was confirmed with a detailed Fourier-transform infrared spectroscopy (FTIR) study. An in vitro study on a human-bladder papillary urothelial neoplasm RT4 cell line confirmed that HCA-Fe–Pt nanoparticles showed no cytotoxicity, even at a very high concentration (550 μg Fe–Pt per mL), with no delayed cytotoxic effect being detected. This indicates that the HCA coating provides excellent biocompatibility of the nanoparticles, which is a prerequisite for the material to be used as a safe contrast agent for MRI. The cellular uptake and internalization mechanism were studied using ICP-MS and TEM analyses. Furthermore, it was shown that even a very low concentration of Fe–Pt nanoparticles (<10 μg mL⁻¹) in the cells is enough to decrease the T₂ relaxation times by 70%. In terms of the MRI imaging, this means a large improvement in the contrast, even at a low nanoparticle concentration and an easier visualization of the tissues containing nanoparticles, proving that HCA-coated Fe–Pt nanoparticles have the potential to be used as an efficient and safe MRI contrast agent.

Study of magnetic interactions revealed optimal size and morphology of Fe–Pt nanoparticles. Novel biocompatible hydrocaffeic acid coating was used to prepare highly efficient and safe MRI contrast agent, which was proven by in vitro study.

Potentially toxic elements in water and sediments of the Sava River under extreme flow events

River ecosystems are exposed to various stressors. Among them, elements may contribute to overall pollution of riverine environments, in particular during the extreme flow events. To evaluate the influence of variable river flow conditions on the mobilization of potentially toxic elements (PTE) (Cr, Ni, Cd, Zn, Pb, As and Cu) from sediments into the overlaying waters of the Sava River, samples were collected in September 2014, during extremely high water discharges and in September 2015, under low water discharge conditions. In water samples the total element concentrations and the dissolved element contents (<0.45μm) were determined. Sediment pollution was estimated by determination of the total element concentrations and mobile element fraction (0.11molL^-1 acetic acid). Anthropogenic inputs of elements to sediments were evaluated by normalizing elemental against Al concentration. The results showed that concentrations of PTE in water were in general higher during high water discharges, while the soluble concentrations were higher during low water level conditions. Concentrations of PTE in the Sava sediments collected in 2015 were lower than those collected in 2014, mainly because during the extreme floods a mixture of bank sediment material and contaminated soil was sampled. Partitioning coefficients between suspended particulate matter (SPM) and soluble content of elements in the water under high and low flow conditions, indicated on different affinity of elements to SPM in relation to different flow regimes. The potential ecological risk posed by the simultaneous presence of PET in sediments was evaluated by Probable Effect Concentration Coefficient (PEC-Q) approach. Under high water level conditions, PEC-Qs were all above critical value 0.34 and derived mostly from anthropogenic inputs of Cr and Ni. Overall sediment toxicity was much lower under low water discharges. The data from this study importantly contribute to the knowledge regarding the behaviour of PTE under extreme flow events.

pH and metal concentration of synovial fluid of osteoarthritic joints and joints with metal replacements

BACKGROUND

Due to degradation and metal dissolution during articulation of metal joint replacements the chemical periprosthetic environment may change. The aim was to establish whether metal replacements cause the local changes in pH and elevated metal concentrations.

METHODS

pH was measured on samples from 167 patients: native hip and knee osteoarthritic joints, joints with hip and knee replacements revised for aseptic or septic reasons. pH of synovial fluid and periprosthetic tissue was measured perioperatively using a microelectrode and pH indicator papers for removed metal components. Metal concentrations were measured in 21 samples using inductively coupled plasma mass spectrometry.

RESULTS

The mean pH value of synovial fluid at native osteoarthritic joints (n = 101) was 7.78 ± 0.38. The mean pH value of synovial fluid at revision aseptic operation (n = 58) was 7.60 ± 0.31, with statistically significant difference (p = 0.002) compared to native osteoarthritic joints. The mean pH value of synovial fluid at revision septic operation (n = 8) was 7.55 ± 0.25, with statistically significant difference (p = 0.038) compared to native osteoarthritic joints. Measurements in tissue and at stems were not reliable. In the majority of samples taken at revision increased levels of cobalt and chromium were measured.

CONCLUSION

A small but statistically significant difference was observed in the pH of synovial fluid between natural joints with degenerative diseases and joints treated with metal replacements. Based on the increased metal levels we expected the value of pH to be lower, but the influence of metal ions is counteracted by the buffering capacity of human body. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2507-2515, 2017.

Evaluation of Genotoxic Pressure along the Sava River

In this study we have performed a comprehensive genotoxicological survey along the 900 rkm of the Sava River. In total, 12 sites were chosen in compliance with the goals of GLOBAQUA project dealing with the effects of multiple stressors on biodiversity and functioning of aquatic ecosystems. The genotoxic potential was assessed using a complex battery of bioassays performed in prokaryotes and aquatic eukaryotes (freshwater fish). Battery comprised evaluation of mutagenicity by SOS/umuC test in Salmonella typhimurium TA1535/pSK1002. The level of DNA damage as a biomarker of exposure (comet assay) and biomarker of effect (micronucleus assay) and the level of oxidative stress as well (Fpg—modified comet assay) was studied in blood cells of bleak and spirlin (Alburnus alburnus/Alburnoides bipunctatus respectively). Result indicated differential sensitivity of applied bioassays in detection of genotoxic pressure. The standard and Fpg—modified comet assay showed higher potential in differentiation of the sites based on genotoxic potential in comparison with micronucleus assay and SOS/umuC test. Our data represent snapshot of the current status of the river which indicates the presence of genotoxic potential along the river which can be traced to the deterioration of quality of the Sava River by communal and industrial wastewaters. The major highlight of the study is that we have provided complex set of data obtained from a single source (homogeneity of analyses for all samples).

Dissolution Mechanism of Upconverting AYF4:Yb,Tm (A = Na or K) Nanoparticles in Aqueous Media

The dissolution of upconverting AYF4:Yb,Tm (A = Na or K) nanoparticles (UCNPs) in aqueous media was systematically studied. UCNPs with a cubic structure and sizes of between 10 and 33 nm were synthesized solvothermally in ethylene glycol at 200 °C. The UCNPs of both compositions showed an upconversion fluorescence emission characteristic of Tm(3+). The effects of the A cation, the particle size, the temperature, the pH, and the composition of the aqueous medium on the dissolution of the UCNPs were evaluated. The degree of dissolution was determined from the fraction of dissolved fluoride (F(-)) using potentiometry. Unexpectedly, the composition of aqueous media had the most significant effect on the dissolution of the UCNPs. The highest degree of dissolution and rate were measured for the phosphate-buffered saline (PBS), which can be explained by the formation of stable lanthanide compounds with phosphates. The degree of dissolution was much lower in water and in the phthalate buffer, which was attributed to the release of F(-) as a result of the hydrolysis of the UCNPs' surfaces.

Modelling the effect of laminar axially directed blood flow on the dissolution of non-occlusive blood clots

Axially directed blood plasma flow can significantly accelerate thrombolysis of non-occlusive blood clots. Viscous forces caused by shearing of blood play an essential role in this process, in addition to biochemical fibrinolytic reactions. An analytical mathematical model based on the hypothesis that clot dissolution dynamics is proportional to the power of the flowing blood plasma dissipated along the clot is presented. The model assumes cylindrical non-occlusive blood clots with the flow channel in the centre, in which the flow is assumed to be laminar and flow rate constant at all times during dissolution. Effects of sudden constriction on the flow and its impact on the dissolution rate are also considered. The model was verified experimentally by dynamic magnetic resonance (MR) microscopy of artificial blood clots dissolving in an in vitro circulation system, containing plasma with a magnetic resonance imaging contrast agent and recombinant tissue-type plasminogen activator (rt-PA). Sequences of dynamically acquired 3D low resolution MR images of entire clots and 2D high resolution MR images of clots in the axial cross-section were used to evaluate the dissolution model by fitting it to the experimental data. The experimental data fitted well to the model and confirmed our hypothesis.

[Aortic valve insufficiency due to rupture of the cusp in a patient with multiple trauma]

Lesions of the heart valve caused by blunt chest trauma is rare, but when it does occur it can significantly injure the patient. On the basis of autopsy studies, research shows that heart valves are injured in less than 5% of patients who have died due to impact thoracic trauma. Among the heart valves, the aortic valve is the most often lacerated, which has been proved by relevant autopsy and clinical studies. Aortic valve lesions can be the only injury, but it is possible that additional heart or large vessel injuries are also present (myocardial contusion, rupture of the atrial septum, aortic rupture, rupture of the left common carotid artery). The force that causes such an injury is often great and often causes injuries to other organs and organ systems. In a multiple trauma patient, it is very important to specifically look for heart-related injuries because it is possible that they may be overlooked or missed by the surgeon, because of other obvious injuries. We describe the case of a 41-year-old man with multiple trauma who was diagnosed with aortic valve insufficiency due to rupture of the left coronary cusp 6 weeks after a road accident. Valvuloplasty was performed. Seven years later the patient is free of symptoms and is in good physical condition. Echocardiography showed normal dimensions of the heart chambers, a normal thickness of the heart walls, and normal systolic and diastolic function of the left ventricle. Heart valves are morphologically normal, and only an unimportant aortic insufficiency was noticed by echocardiography.

[Traumatic jejunal entrapment in a patient with Bechterew disease]

We report an unusual case of incarceration of small bowel between the 4th and 5th lumbar vertebrae in a patient with rheumatoid spondylitis. Incarceration of the loop of jejunum within the fracture or between dislocated lumbar vertebrae is an uncommon entity. The cases of traumatic jejunal entrapment have been previously reported in the literature [1, 2, 3, 4, 5, 6, 7, 8, 9, 11]: 2 cases occurred in adults and 8 in children. There has been no report on this injury in patients with rheumatoid spondylitis (Bechterew arthritis).