Porous, polymer-based materials are increasingly used as stationary phases in separation science and catalysis, yet their morphology remains largely unknown. The main difficulty lies in reconciling their soft matter nature with the demands of microscopic imaging techniques. We analyze the morphology of a hyper-cross-linked poly(styrene-divinylbenzene) monolith in capillary column format from a sample volume of 60.5 × 60.5 × 19.9 μm(3) reconstructed by serial block-face scanning electron microscopy. To obtain a suitable specimen, the polymer skeleton was stained with tetraphenyllead and the void space filled with resin before the whole monolith was resin-embedded after removing the fused-silica capillary. Chord length distribution analysis revealed characteristic lengths of 7.32 and 0.73 μm, corresponding to two distinct macropore types. The macroporosity (77% on average) was found to increase systematically from the wall to the center. Our results provide valuable insights into the formation process of the monolith and its stationary-phase properties.
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J Comp Neurol
January 2025
Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai, Tamil Nadu, India.
Direction selectivity is a fundamental feature in the visual system. In the retina, direction selectivity is independently computed by ON and OFF circuits. However, the advantages of extracting directional information from these two independent circuits are unclear.
View Article and Find Full Text PDFPulm Circ
January 2025
Department of Imaging and Pathology, Biomedical MRI KU Leuven Leuven Belgium.
The pulmonary vasculature plays a pivotal role in the development and progress of chronic lung diseases. Due to limitations of conventional two-dimensional histological methods, the complexity and the detailed anatomy of the lung blood circulation might be overlooked. In this study, we demonstrate the practical use of optical serial block face imaging (SBFI), ex vivo microcomputed tomography (micro-CT), and nondestructive optical tomography for visualization and quantification of the pulmonary circulation's 3D architecture from macro- to micro-structural levels in murine lung samples.
View Article and Find Full Text PDFbioRxiv
October 2024
National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA.
Volume electron microscopy (vEM) enables biologists to visualize nanoscale 3D ultrastructure of entire eukaryotic cells and tissues prepared by heavy atom staining and plastic embedding. The highest resolution vEM technique is focused ion-beam scanning electron microscopy (FIB-SEM), which provides nearly isotropic (~5-10 nm) spatial resolution at fluences of > 10,000 e/nm. However, it is not clear how such high resolution is achievable because serial block-face (SBF) SEM, which incorporates an in-situ ultramicrotome instead of a Ga FIB beam, results in radiation-induced collapse of similar specimen blocks at fluences of only ~20 e/nm.
View Article and Find Full Text PDFCommun Biol
January 2025
Wellcome Centre for Mitochondrial Research, Translational and Clinical Research, Faculty of Medical Sciences, Newcastle University, Newcastle, UK.
Mitochondria play a crucial role in maintaining cellular health. It is interesting that the shape of mitochondria can vary depending on the type of cell, mitochondrial function, and other cellular conditions. However, there are limited studies that link functional assessment with mitochondrial morphology evaluation at high magnification, even fewer that do so in situ and none in human muscle biopsies.
View Article and Find Full Text PDFSci Rep
December 2024
Structural Biophysics Research Group, School of Optometry & Vision Sciences, Cardiff University, Cardiff, Wales, UK.
Fuchs' endothelial corneal dystrophy (FECD) is a common sight-threatening condition characterised by pathological changes in the posterior cornea. Here we report observations by light, transmission and volume scanning electron microscopy on changes in the endothelium and matrix associated with the characteristic deformations of Descemet's membrane, termed guttae. Specimens were archived full-thickness human corneal tissue, removed during graft surgery, that had been fixed, stained and embedded by conventional processing methods for examination by transmission electron microscopy more than 40-years previously.
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