Glycosidic Modification and Sulfation of Polymeric Surfaces and their Influence on Blood Compatible Properties

Polymeric surfaces were modified and the impact on the blood compatible properties investigated

Results of an interlaboratory method performance study for the size determination and quantification of silver nanoparticles in chicken meat by single-particle inductively coupled plasma mass spectrometry (sp-ICP-MS)

Single-particle inductively coupled plasma mass spectrometry (sp-ICP-MS) promises fast and selective determination of nanoparticle size and number concentrations. While several studies on practical applications have been published, data on formal, especially interlaboratory validation of sp-ICP-MS, is sparse. An international interlaboratory study was organized to determine repeatability and reproducibility of the determination of the median particle size and particle number concentration of Ag nanoparticles (AgNPs) in chicken meat. Ten laboratories from the European Union, the USA, and Canada determined particle size and particle number concentration of two chicken meat homogenates spiked with polyvinylpyrrolidone (PVP)-stabilized AgNPs. For the determination of the median particle diameter, repeatability standard deviations of 2 and 5% were determined, and reproducibility standard deviations were 15 and 25%, respectively. The equivalent median diameter itself was approximately 60% larger than the diameter of the particles in the spiking solution. Determination of the particle number concentration was significantly less precise, with repeatability standard deviations of 7 and 18% and reproducibility standard deviations of 70 and 90%

First steps towards a generic sample preparation scheme for inorganic engineered nanoparticles in a complex matrix for detection, characterization, and quantification by asymmetric flow-field flow fractionation coupled to multi-angle light scattering and ICP-MS

The applicability of a multi-step generic procedure to systematically develop sample preparation methods for the detection, characterization, and quantification of inorganic engineered nanoparticles (ENPs) in a complex matrix was successfully demonstrated. The research focused on the optimization of the sample preparation, aiming to achieve a complete separation of ENPs from a complex matrix without altering the ENP size distribution and with minimal loss of ENPs. The separated ENPs were detected and further characterized in terms of particle size distribution and quantified in terms of elemental mass content by asymmetric flow-field flow fractionation coupled to a multi-angle light scattering detector and an inductively coupled plasma mass spectrometer. Following the proposed generic procedure SiO2-ENPs were separated from a tomato soup. Two potential sample preparation methods were tested these being acid digestion and colloidal extraction. With the developed method a complete SiO2-ENPs and matrix separation with a Si mass recovery >90% was achieved by acid digestion. The alteration of the particle size distribution was minimized by particle stabilization. The generic procedure which also provides quality criteria for method development is urgently needed for standardized and systematic development of procedures for separation of ENPs from a complex matrix. The chosen analytical technique was shown to be suitable for detecting SiO2-ENPs in a complex food matrix like tomato soup and may therefore be extended to monitor the existence of ENPs during production and safety control of foodstuffs, food labelling, and compliance with legislative limits

Glycosidic Modification and Sulfation of Polymeric Surfaces and their Influence on Blood Compatible Properties

Polymeric surfaces were modified and the impact on the blood compatible properties investigated

Glycosidic Modification and Sulfation of Polymeric Surfaces and their Influence on Blood Compatible Properties

Polymeric surfaces were modified and the impact on the blood compatible properties investigated

Spatial patterns of aeolian sediment deposition in vegetation canopies: observations from wind tunnel experiments using colored sand

In environments affected by wind erosion, plants act as traps for aeolian sediment, which leads to a small-scale mosaic of depositional and erosional sediment transport regimes. This wind tunnel study used colored sand to visualize spatial patterns of sediment redistribution within grass canopies. Wind tunnel experiments were performed with high-, medium- and low-density canopies of Lolium perenne, corresponding to vegetation covers of 47%, 16% and 4%, respectively. In the low and medium-density canopies, the wake areas downstream of the tussocks were the primary locations of sediment deposition. In the medium-density canopy, these wedge-shaped wake deposits overlapped with the adjacent downstream tussocks, while in the low-density canopy they did not, indicating that these vegetation densities respectively represented wake-interference and isolated roughness flow. In the high-density canopy, very few sand grains were entrained by the wind, and were mostly deposited within the disturbed zones surrounding the tussocks. The deposited grains were evenly distributed around the tussocks in the high-density canopy without pronounced accumulations on their upstream, downstream or lateral sides. We interpret the high-density canopy as a skimming flow aerodynamic regime. The fraction of the sand surface which was exposed to erosion was substantially smaller than the area not covered by grasses. It accounted for 67-78% of the non-covered surface in the low-density canopy, and for 44-77% of the surface in the medium-density canopy. This finding indicates that wind erosion models overestimate the sediment source area if they assume the erodible area is the entire exposed surface not covered by roughness elements. © 2012 Elsevier B.V

Feasibility of non-invasive detection of engineered nanoparticles in food mimicking matrices by Optical Coherence Tomography

The study was dedicated towards the detection of Engineered Nanoparticles (ENPs) by means of Optical Coherence Tomography (OCT). Polymeric films were produced to mimic complex food matrices whereas gold nanorods (AuNRs) were embedded to act as ENPs. The straightforward coating application resulted in a sufficient film wetting, adhesion and homogenous AuNR distribution. Compared to food samples, these films are simpler and better defined. Such artefacts are therefore promising candidate materials for quality assurance and regulatory matters. The OCT investigations revealed a dependency of the measured signal intensity on the AuNR concentration in the film. The limit of detection for the setup and material was estimated to be 8 dB. This value corresponds to a ppm nanoparticle concentration being well below the concentration used in food additive applications. Thus, the findings indicate the potential of OCT to screen food/feed products for a number of ENPs.JRC.D.2-Standards for Innovation and sustainable Developmen

Results of an interlaboratory method performance study for the size determination and quantification of silver nanoparticles in chicken meat by single-particle-inductively coupled plasma-mass spectrometry (sp-ICP-MS)

Single-particle inductively coupled plasma mass spectrometry (sp-ICP-MS) promises fast and selective determination of nanoparticle size and number concentrations. While several studies on practical applications have been published, data on formal, especially interlaboratory validation of sp-ICP-MS is sparse. An international interlaboratory study was organized to determine repeatability and reproducibility of the determination of the median particle size and particle number concentration of Ag nanoparticles (AgNPs) in chicken meat, Ten laboratories from the European Union, USA and Canada, determined particle size and particle number concentration of two chicken meat homogenates spiked with polyvinylpyrrolidone (PVP) stabilized AgNPs. For the determination of the median particle diameter, repeatability standard deviations of 2 % and 5 % were determined, and reproducibility standard deviations were 15 % and 25 %, respectively. Determination of the particle number concentration was significantly less precise, with repeatability standard deviations of 7 % and 18 % and reproducibility standard deviations of 70 and 80 %.JRC.F.6-Reference Material

Chip electrophoresis of gelatin-based nanoparticles

Recently, biodegradable nanoparticles received increasing attention for pharmaceutical applications as well as applications in the food industry. With the current investigation we demonstrate chip electrophoresis of fluorescently (FL) labeled gelatin nanoparticles (gelatin NPs) on a commercially available instrument. FL labeling included a step for the removal of low molecular mass material (especially excess dye molecules). Nevertheless, for the investigated gelatin NP preparation two analyte peaks, one very homogeneous with an electrophoretic net mobility of mu = −24.6 ± 0.3 × 10−9 m2/Vs at the peak apex (n = 17) and another more heterogeneous peak with mu between approximately −27.2 ± 0.2 × 10−9 m2/Vs and −36.6 ± 0.2 × 10−9 m2/Vs at the peak beginning and end point (n = 11, respectively) were recorded. Filtration allowed enrichment of particles in the size range of approximately 35 nm (pore size employed for concentration of gelatin NPs) to 200 nm (pore size employed during FL labeling). This corresponded to the very homogeneous peak linking it to gelatin NPs, whereas the more heterogeneous peak probably corresponds to gelatin not cross-linked to such a high degree (NP building blocks). Several further gelatin NP preparations were analyzed according to the same protocol yielding peaks with electrophoretic netmobilities between −23.3 ± 0.3 × 10−9 m2/Vs and −28.9 ± 0.2 × 10−9 m2/Vs at peak apexes (n = 15 and 6). Chip electrophoresis allows analyte separation in less than two minutes (including electrophoretic sample injection). Together with the high sensitivity of the FL detection – the LOD as derived for the first main peak of the applied dye from the threefold standard deviation of the background noise values 80 pM for determined separation conditions – this leads to a very promising high throughput separation technique especially for the analysis of bionanoparticles. For gelatin NP preparations, chip electrophoresis allows for example the comparison of preparation batches concerning the amount of NPs and gelatin building blocks as well as the indirect assessment of the degree of gelatin cross-linking (from obtained FL signals).JRC.D.2-Standards for Innovation and sustainable Developmen

Production and characterization of antibodies against crosslinked gelatin nanoparticles and first steps toward developing an ELISA screening kit

Nanotechnologies are finding a growing range of applications in the food sector. Nanoparticles are used notably to add vitamins and other nutrients to foods and beverages without affecting taste and color. They are also used to develop new tastes, preserve food texture, control the release of flavors, improve the bioavailability of compounds such as antioxidants and vitamins, and monitor freshness with nanosensors. Crosslinked gelatin nanoparticles are a component of nano-sized carriers for nutrient and supplement delivery in foods and related products. This paper describes the production and characterization of polyclonal antibodies against gelatin nanoparticles. Two immunization schemes were investigated: subcutaneous injection with and without a first intravenous injection. Two enzyme-linked immunosorbent assay formats were used to characterize the antibodies: an inhibition format with an antigen-coated plate for detection of the immune response and a sandwich format for development of the method. The antibodies showed good sensitivity with an IC50 equal to 0.11 ng mL-1 using indirect ELISA format and a good specificity for the nanomaterials, without significant cross-reactivity against native gelatin. The limit of detection was determined—0.42, 0.27, 0.26, and 0.24 µg mL-1 for apple, orange juice, milk, and soft drink matrices, respectively. ELISA technology offers rapid, low-cost assays for screening foods, feeds, and beverages. We have studied a prototype ELISA for detection of gelatin-based nanocarrier systems. Fruit juices, milk, and a soft drink were the matrices selected for assay development