Electrospun scaffolds can imitate the hierarchical structures present in the extracellular matrix, representing one of the main concerns of modern tissue engineering. They are characterized in order to evaluate their capability to support cells or to provide guidelines for reproducibility. The issues with widely used methods for morphological characterization are discussed in order to provide insight into a desirable methodology for electrospun scaffold characterization. Reported methods include imaging and physical measurements. Characterization methods harbor inherent limitations and benefits, and these are discussed and presented in a comprehensive selection matrix to provide researchers with the adequate tools and insights required to characterize their electrospun scaffolds. It is shown that imaging methods present the most benefits, with drawbacks being limited to required costs and expertise. By making use of more appropriate characterization, researchers will avoid measurements that do not represent their scaffolds and perhaps might discover that they can extract more characteristics from their scaffold at no further cost.

The laser-induced damage threshold of optics is an issue of essential importance in high-power laser applications. However, the complex and partially interacting mechanisms as well as the underlying reasons for laser damage of glass surfaces are not yet fully understood. The aim of the present work is to contribute to a better understanding of such damage mechanisms by providing original results on the impact of classical glass surface machining on the laser-induced damage threshold. For this purpose, glass samples were prepared with well-defined process conditions in terms of the used lapping and polishing agents and suspensions. Further, the samples were post-processed by atmospheric pressure plasma for precision cleaning. The laser-induced damage threshold and surface contamination by residues from the manufacturing process were determined before and after plasma post-processing. It is shown that the polishing suspension concentration has a certain impact on the laser-induced damage threshold and surface contamination by residues from used working materials. The highest damage threshold of 15.2 J/cm² is found for the lowest surface contamination by carbon which occurs in the case of the highest polishing suspension concentration. After plasma treatment for merely 60 s, this value was increased to 20.3 J/cm² due to the removal of surface-adherent carbon. The results thus imply that the laser-induced damage threshold can notably be increased by first choosing appropriate process parameters during classical manufacturing and second plasma post-processing for surface finishing.

We report on investigations of the spatial variations of contamination, roughness, and index of refraction of classically manufactured polished fused silica surfaces. Therefore, laser-induced breakdown spectroscopy was used to probe surface and subsurface impurities via the detection of aluminum. Measurements at different positions on the surface of the cylindrical fused silica windows evidenced an almost contamination-free center region, whereas a relatively large contamination area was found close to the edge. In-depth measurements verify the presence of aluminum atoms in the bulk until a depth of several tens of microns for the edge region. In addition, atomic force microscopic measurements show that the surface roughness is larger in the center region compared to the edge. Further, the index of refraction increases from the center region towards the edge as measured via ellipsometry. The results indicate a nonuniform impact of the grinding, lapping, and polishing tools on the surface. The findings turn out to be of specific interest for different applications, particularly for the realization of large-scale high-performance coatings.

Electrospun scaffolds have a 3D fibrous structure that attempts to imitate the extracellular matrix in order to be able to host cells. It has been reported in the literature that controlling fiber surface topography produces varying results regarding cell–scaffold interactions. This review analyzes the relevant literature concerning in vitro studies to provide a better understanding of the effect that controlling fiber surface topography has on cell–scaffold interactions. A systematic approach following PRISMA, GRADE, PICO, and other standard methodological frameworks for systematic reviews was used. Different topographic interventions and their effects on cell–scaffold interactions were analyzed. Results indicate that nanopores and roughness on fiber surfaces seem to improve proliferation and adhesion of cells. The quality of the evidence is different for each studied cell–scaffold interaction, and for each studied morphological attribute. The evidence points to improvements in cell–scaffold interactions on most morphologically complex fiber surfaces. The discussion includes an in-depth evaluation of the indirectness of the evidence, as well as the potentially involved publication bias. Insights and suggestions about dose-dependency relationship, as well as the effect on particular cell and polymer types, are presented. It is concluded that topographical alterations to the fiber surface should be further studied, since results so far are promising.

When exposing food and feedstuff to cold atmospheric pressure plasmas (CAPP), e.g., for decontamination purposes, possible unwanted effects on the contained nutrients might occur. In the present study, we thus concentrated on CAPP-induced degrading effects on different sugars, namely glucose and sucrose. The treatments were performed using admixtures of argon and synthetic air over durations of up to $12\min$. Continuous degradation of sucrose and glucose was determined using ATR-FTIR and XPS analyses. OH stretching bands showed notable broadening in the ATR-FTIR spectra, which possibly indicates reduced crystallinity of the sugars caused by the CAPP treatment. In the fingerprint regions, most bands, especially the more intense C-O bands, showed decreases in peak heights. In addition, two new bands occurred after CAPP treatment. The bands were detectable in the range between 1800 and $1600{\mathrm{cm}}^{-1}$ and potentially can be assigned to C=C and, after comparison with the results of the XPS measurements, O-C=O bindings. The XPS measurements also showed that the O-C=O bonds probably originated from earlier C-O bonds.