3D porous structure imaging of membranes for medical devices using scanning probe microscopy and electron microscopy: from membrane science points of view.

The evolution of hemodialysis membranes (dialyzer, artificial kidney) was remarkable, since Dow Chemical began manufacturing hollow fiber hemodialyzers in 1968, especially because it involved industrial chemistry, including polymer synthesis and membrane manufacturing process. The development of hemodialysis membranes has brought about the field of medical devices as a major industry. In addition to conventional electron microscopy, scanning probe microscopy (SPM), represented by atomic force microscopy (AFM), has been used in membrane science research on porous membranes for hemodialysis, and membrane science contributes greatly to the hemodialyzer industry. Practical studies of membrane porous structure-function relationship have evolved, and methods for analyzing membrane cross-sectional morphology were developed, such as the ion milling method, which was capable of cutting membrane cross sections on the order of molecular size to obtain smooth surface structures. Recently, following the global pandemic of SARS-CoV-2 infection, many studies on new membranes for extracorporeal membrane oxygenator have been promptly reported, which also utilize membrane science researches. Membrane science is playing a prominent role in membrane-based technologies such as separation and fabrication, for hemodialysis, membrane oxygenator, lithium ion battery separators, lithium recycling, and seawater desalination. These practical studies contribute to the global medical devices industry.

Scanning Probe Microscopy Techniques for Studying the Cell Glycocalyx.

The glycocalyx is a brush-like layer that covers the surfaces of the membranes of most cell types. It consists of a mixture of carbohydrates, mainly glycoproteins and proteoglycans. Due to its structure and sensitivity to environmental conditions, it represents a complicated object to investigate. Here, we review studies of the glycocalyx conducted using scanning probe microscopy approaches. This includes imaging techniques as well as the measurement of nanomechanical properties. The nanomechanics of the glycocalyx is particularly important since it is widely present on the surfaces of mechanosensitive cells such as endothelial cells. An overview of problems with the interpretation of indirect data via the use of analytical models is presented. Special insight is given into changes in glycocalyx properties during pathological processes. The biological background and alternative research methods are briefly covered.

Histological, histochemical and ultrastructural characterization of the pancreas of the grass carp (Ctenopharyngodon idella)

The purpose of this study is to describe the histological, histochemical and ultrastructural features of pancreas of the grass carp (Ctenopharyngodon idella), one of the common herbivorous freshwater fish of Egypt. The pancreas is divided into exocrine and endocrine portions. Exocrine pancreatic tissues consists of scattered serous acini, and is observed in two forms: 1) disseminated in the spleen tissue, in mesentery around intestine and intestinal bulb, and 2) intrahepatically, around the branches of the portal vein. Two alveolar cell types are present in pancreatic acini; centroacinar cells and typical pyramidal acinar cells. Pancreatic stellate cells (PSC) are demonstrated in the perivascular and the periacinar space of the pancreas. The pancreatic acini gave positive reaction to PAS, Best's carmine, and osmium tetraoxide, and negative to alcian blue. The acini also show high lipase and alkaline phosphatase activity, and moderate activity for acid phosphatase. Scanning electron microscopy show apical microvilli of the acinar cells, and branched PSC extend their processes between the pancreatic cells. Ultrastructure of pancreatic acini reveals well-developed rER, membrane-bound zymogen granules, and abundant lipid droplets. The duct system is composed of intralobular duct, interlobular pancreatic duct and main duct opened in the intestinal bulb. The endocrine parts of the pancreas are organized as lightly staining Langerhan’s islets between exocrine acinar cells found in the liver, in mesenteries around the intestinal bulb and the intestine, and consisted of three cell types. Alpha cells were the most dominant cells, and were ovoid in shape. Beta cells were polyhedral in shape, and they grouped in small clusters. Delta cells were small fusiform, argyrophilic cells. In conclusion, the present study revealed that the exocrine portion of the pancreas of the grass carp had two forms, disseminated and intrahepatic, with characteristic cellular and histochemical components, and an endocrine portion that consisted of Alpha, Beta and Delta cells

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Estudian las características histopatológicas y moleculares de las células de Langerhans en la mucosa bucal / Langerhans cells in oral mucosa: hystopatological and molecular characterization

Actualmente, las células dendríticas en tejidos periféricos, piel y mucosas son centro de numerosas publicaciones. De acuerdo con su localización se clasifican en subtipos de diferente denominación. Su posición apropiada les permite ejercer un papel crucial en la detección y la captación de antígenos y su presentación a los linfocitos T en centros linfoides, iniciando la inmunidad innata y la inmunidad adaptativa. Debe destacarse además su actuación en la tolerancia inmunitaria y su participación en diversas enfermedades autoinmunitarias como la enfermedad periodontal e incluso el cáncer de células escamosas. Presentamos una actualización resumida de los últimos estudios realizados y destacamos el conocimiento de los marcadores inmunológicos y las características fundamentales de los subtipos, células de Langerhans y células plasmocitoides, especialmente en la mucosa oral. La disminución de los distintos fenotipos de células dendríticas en lesiones cancerizables y en la vejez, como su ausencia en neoplasias malignas son aspectos destacables. Comunicamos a la vez nuestro primer acercamiento a la microscopia electrónica de barrido para observarlas en tejido mucoso sano y de tres lesiones: mucosa hiperplásica, gingivitis descamativa y úlceras aftosas recidivantes con vasculitis.

Microscopia de força atômica: uma breve revisäo e o uso de sua sonda na construçäo de biossensores / Atomic force microscopy: a brief review and the use of its tip in the construction of biosensors

Esta revisäo relata um breve histórico sobre o advento do microscópio de força atômica. A introduçäo de novas tecnologias a esse potente aparelho tornou possível vencer alguns problemas na geraçäo de imagens de amostras biológicas. A principal vantagem dessa técnica é gerar imagens de amostras näo cobertas e näo fixadas de uma forma näo destrutiva. O mais recente desenvolvimento nessa área é a construçäo de biossensores usando a ponta do microscópio de força atômica. Esses biossensores säo muito sensíveis e têm possíveis aplicaçöes em vários campos: química orgânica, bioquímica, química farmacêutica e farmacologia.