Nanoplastic is an emerging topic of relevance in environmental science. The analytical methods for microplastic have a particle size limit of a few micrometers so that new methods have to be ...developed to cover the nanometer range. This contribution reviews the progress in environmental nanoplastic analysis and critically evaluates which techniques from nanomaterial analysis may potentially be adapted to close the methodological gap. A roadmap is brought forward for the whole analytical process from sample treatment to particle characterization. This includes a critical review of (i) methods for analyte extraction and preconcentration from various environmental matrices; (ii) methods for the separation of the nanoplastic into specific size fractions; (iii) light scattering techniques and various types of microscopy to characterize the particle fractions; (iv) chemical identification of particles to validate the obtained data. For these methods, we will discuss prospects and limitations to develop analytical protocols for specific sampling scenarios.
•Analytical methods for submicrometer- and nanoplastic face a methodological gap.•Methods for nanomaterial characterization that may be applicable for submicrometer- and nanoplastic are presented.•A roadmap for the whole analytical process of submicrometer- and nanoplastic is discussed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Streptococcus pneumoniae bacterial infection can cause serious diseases. Among more than 90 known streptococcus pneumoniae serotypes, more than 30 can cause invasive pneumococcal diseases that could ...lead to morbidity and mortality. Initially, a 23-valent polysaccharide vaccines (PPSV) PNEUMOVAX®23, was developed to generate an antigen-specific immune response and prevent diseases caused by these pneumoniae serotypes. Later, pneumococcal conjugate vaccines (PCV), such as PREVNAR® and VAXNEUVANCE™ have been developed to offer a more robust immune response in the pediatric population.
In our effort to develop novel pneumococcal conjugate vaccines, each serotype of pneumococcal polysaccharide (Ps) is conjugated to a detoxified diphtheria toxin carrier protein CRM197 to form a monovalent conjugate (MVC). MVCs from multiple serotypes are formulated with vaccine adjuvant to form a multi-valent vaccine drug product. During the product development, critical attributes including conjugate molecular weight (Mw), protein and polysaccharide concentration, have been used to monitor process and product quality. To measure these attributes, a size-exclusion chromatography (SEC) method was developed with a series of in-line detectors including UV, multi-angle light scattering (MALS) and refractive index (RI). This SEC-UV-MALS-RI method is employed to characterize and monitor process intermediates and product during process development and for product release and stability testing. With this, we have expanded the multi-attribute SEC method to a 15-valent pneumococcal conjugate vaccine.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•AFM, SEM; TEM and DLS all compared.•Silica, gold, and polymer nanoparticles characterised.•AFM and TEM shown to be most appropriate for small particles.•SEM just as accurate as AFM and TEM for ...larger particles.•DLS shows dynamic behaviour but cannot characterise mixtures.
Nanoparticles have properties that depend critically on their dimensions. There are a large number of methods that are commonly used to characterize these dimensions, but there is no clear consensus on which method is most appropriate for different types of nanoparticles.
In this work four different characterization methods that are commonly applied to characterize the dimensions of nanoparticles either in solution or dried from solution are critically compared. Namely, transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), and dynamic light scattering (DLS) are compared with one another. The accuracy and precision of the four methods applied nanoparticles of different sizes composed of three different core materials, namely gold, silica, and polystyrene are determined. The suitability of the techniques to discriminate different populations of these nanoparticles in mixtures are also studied.
The results indicate that in general, scanning electron microscopy is suitable for large nanoparticles (above 50 nm in diameter), while AFM and TEM can also give accurate results with smaller nanoparticles. DLS reveals details about the particles’ solution dynamics, but is inappropriate for polydisperse samples, or mixtures of differently sized samples. SEM was also found to be more suitable to metallic particles, compared to oxide-based and polymeric nanoparticles. The conclusions drawn from the data in this paper can help nanoparticle researchers choose the most appropriate technique to characterize the dimensions of nanoparticle samples.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
We consider light scattering off a two-dimensional (2D) dipolar array and show how it can be tailored by properly choosing the lattice constant of the order of the incident wavelength. In particular, ...we demonstrate that such arrays can operate as a nearly perfect mirror for a wide range of incident angles and frequencies, and shape the emission pattern from an individual quantum emitter into a well-defined, collimated beam. These results can be understood in terms of the cooperative resonances of the surface modes supported by the 2D array. Experimental realizations are discussed, using ultracold arrays of trapped atoms and excitons in 2D semiconductor materials, as well as potential applications ranging from atomically thin metasurfaces to single photon nonlinear optics and nanomechanics.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Ion-exchange chromatography coupled to light scattering detectors represents a fast and simple analytical method for the assessment of multiple critical quality attributes (CQA) in one single ...measurement. The determination of CQAs play a crucial role in Adeno-Associated Virus (AAV)-based gene therapies and their applications in humans. Today, several different analytical techniques, including size-exclusion chromatography (SEC), analytical ultracentrifugation (AUC), qPCR or ELISA, are commonly used to characterize the gene therapy product regarding capsid titer, packaging efficiency, vector genome integrity, aggregation content and other process-related impurities. However, no universal method for the simultaneous determination of multiple CQAs is currently available. Here, we present a novel robust ion-exchange chromatography method coupled to multi-angle light scattering detectors (IEC-MALS) for the comprehensive characterization of empty and filled AAVs concerning capsid titer, full-to-total ratio, absolute molar mass of the protein and nucleic acid, and the size and polydispersity without baseline-separation of both species prior to data analysis. We demonstrate that the developed IEC-MALS assay is applicable to different serotypes and can be used as an orthogonal method to other established analytical techniques.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Abstract The paper describes simulating light scattering of an electromagnetic field on a deformed gas bubble suspended in a liquid. The field intensity distributions around the deformed bubble were ...obtained. It turned out that field scattering increases with bubble deformation up to a certain limit of the deformation coefficient A (relative deformation amplitude). At A = 0.7 and higher, the scattering remains independent of the magnitude of the deformation.
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► Exosomes from three different cell lines had a diameter of 110
nm. ► Ultracentrifugation does not change size or shape of exosomes. ► Multiple shock-freezing and thawing does not ...affect the exosomes. ► Storage at 4
°C and 37
°C in dispersion leads to slow degradation of exosomes. ► Nanoparticle tracking analysis is well suited to study exosomes.
Exosomes from three different cell types (HEK 293T, ECFC, MSC) were characterised by scanning electron microscopy (SEM), dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA). The diameter was around 110
nm for the three cell types. The stability of exosomes was examined during storage at −20
°C, 4
°C, and 37
°C. The size of the exosomes decreased at 4
°C and 37
°C, indicating a structural change or degradation. Multiple freezing to −20
°C and thawing did not affect the exosome size. Multiple ultracentrifugation also did not change the exosome size.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Particulate contamination, the unintentional presence of particles in parenteral fluids, is associated with potential risks such as phlebitis and thrombophlebitis. Recent guidelines recommend the use ...of filter needles when withdrawing parenteral fluid from vials with a rubber stopper. However, the literature is limited and lacks clarity regarding the advantages of filter needles over conventional needles. The aim of this study was to assess the compliance of parenteral fluids regarding particulate contamination after withdrawing fluid using both conventional needles and filter needles, following the guidelines of European Pharmacopoeia (Ph. Eur.) and United States Pharmacopoeia (USP). Visible particles were counted through visual inspection and sub-visible particles were quantified utilizing the light obscuration particle count test. Particle counts for both types of needles were compared to Ph. Eur. and USP standards and differences in particle contamination were assessed using a Mann-Whitney U test. Both types of needles demonstrated compliance with Ph. Eur. and USP standards regarding particulate contamination of visible and sub-visible particles. However, filter needles exhibited a significantly higher particle count for particles with a size of ≥25 µm compared to conventional needles (p = 0.0029). In conclusion, both types of needles demonstrate suitability for aspirating fluid from vials featuring rubber stoppers regarding particulate contamination. Nevertheless, non-filter needles are preferred for withdrawing fluid from vials with a rubber stopper over filter needles due to their lower cost.
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FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ
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