细胞&组织形态学

细胞膜是保持细胞内部环境稳定的极其重要的保护层，还与细胞骨架一起作用决定了细胞的形状。

除了维持结构的作用外，细胞膜还在多细胞活动中发挥重大作用，例如细胞分化，信息传递，以及细胞环境的相互作用。细胞外膜的形态改变可以显示出细胞功能的变化，如癌细胞的形成，细胞与病原体的相互作用和干细胞分化。通常通过观察细胞表面凹槽、毛孔、小泡或微绒毛的变化来推测细胞外部环境的变化。利用 TESCAN 扫描电镜的低真空模式及水汽注入系统可观察未经脱水的细胞表面的精细结构。

TESCAN MIRA3 和 MAIA3 场发射扫描电镜是对细胞和组织结构高分辨研究的理想工具。

MAIA3 独特的设计可在低电压下实现超高分辨成像，从而得到样品更多的形貌细节信息。

(贴壁生长的)成纤维细胞

Cryo FIB-SEM-A leap into the ultrastructure of biological specimens

Cryo-electron tomography (Cryo-ET) is an established method with increasing popularity to study molecules, macromolecular complexes and cellular ultrastructure. The principal limitation of the technique is the quality and thickness of the specimen. Introducing artefacts during the cryo sample preparation strongly influences the obtained results. To overcome the disadvantages of cryo-ultramicrotomy, a cryo FIB-SEM is used as a powerful tool for preparation of fine cryo-TEM samples. Using cryo FIB-SEM as a part of the whole cryo-TEM workflow, subcellular structure of the cells can be revealed in a form of a planar lamella (on-grid lamella). The cryo on-grid lamella is prepared without cutting artefacts and is thin enough for transmitted electrons. One of the key advantages of the cryo-FIB is the ability to prepare site-specific lamellas based on correlation with the data from light microscopic methods. By bringing the functional and ultrastructural data together dramatically helps us better understand the complexity of the biological systems.

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LIVE CELL IMAGING

Q-PHASE is a unique instrument dedicated to live cell imaging where advantages such as no need for labeling, low phototoxicity, easy segmentation, cell dry mass interpretation of measured signal, and suitability for long term experiments are used. Q-PHASE is built as a transmitted light microscope in an inverted configuration for easy handling with biological samples. Appropriate conditions for live cells are ensured by the microscope incubator and low exposures of light. Moreover, there is no need for specific sample preparation. The cells are just seeded into a suitable observation chamber and examined.

pdf – 1.7 MB

Serial Block Face Imaging – 3D approach to cell biology

The facility of integrated Gatan 3View2XP ultra-microtome in the TESCAN microscope offers robust solution to the Serial Block Face Imaging (SBFI). We have performed the structural study of the human stem cell colonies and mouse liver tissues, resulting in their 3D reconstruction.

pdf – 668 kB

STEM detector in life science applications

Scanning transmission electron microscopy (STEM) has become a highly effective, easy-to-use technique for imaging biological thin sections (lamellae) in SEM. Multiple sample observation, automated stage navigation, and ultra-high resolution imaging make this technique an attractive solution for high-contrast observation of TEM sections with excellent results, and minimal operator’s time.

pdf – 2.4 MB

CANCER RESEARCH

Q-PHASE allows observation of cell reactions to different treatments without any labeling. This innovative approach opens up new opportunities in cancer research. Through experiments, researchers look at how cancer cells behave and try to understand cancer at its deepest levels. Data from experiments can help researchers figure out what controls cell division and cell death, find out what makes cancer cells spread or metastasize, identify unique characteristics of cancer cells to design new therapeutic strategies, and find out why certain cancer cells become resistant to therapy. Additional fluorescence data provides the possibility to simultaneously verify observed processes using a single instrument.

pdf – 1.3 MB

SEM observation of sperm entering the oocyte

Assisted reproductive technologies are commonly used for treating human infertility, and require handling with gametes. SEM can be used for observing whole oocyte and its surface structures – zona pellucida and plasma membrane – as well for a detailed investigation of gamete interaction during fertilisation (sperm attachment and penetration).

pdf – 2.1 MB

Low temperature scanning electron microscopy for Life Sciences

Low temperature scanning electron microscopy (Cryo-SEM) has become an established technique for capturing and observing biological samples close to their natural state. It is a method of choice, where the traditional sample preparation (e.g. critical point drying) causes unwanted changes in the sample structure. A Cryo-SEM workflow typically involves sample fixation using either flash-freezing in a liquid nitrogen slush or high-pressure freezing. The frozen samples are then transferred under vacuum to a cryo sputter coater, where they are coated with a conductive layer of metals or carbon. Finally, the samples are inserted into a SEM chamber equipped with a cryo-stage and observed in high vacuum environment.

pdf – 4.8 MB

Visualization of the QD- immunostained somatostatin hormone using an ultra-high resolution TESCAN MAIA3 FE-SEM

Somatostatinoma is a type of a neuroendocrine tumor that typically develops in the region of the duodenum or pancreas. This kind of tumor is characterized by an excessive somatostatin hormone secretion. These elevated levels of somatostatin can be used for investigation of the somatostatin tumor cells, typically by the positive immunohistochemical staining. Correlative light-electron microscopy imaging has become a very popular approach due to the usage of quantum-dotbased immunoprobes, which can be inherently detected by both techniques.

pdf – 1.2 MB

NON-INVASIVE AND LABEL-FREE DETECTION OF CELL DEATH

Q-PHASE enables easy and fast detection of specific cell death without any need for labeling nor additional damage to cells. Thanks to the quantitative phase imaging and advanced analysis software, Q-PHASE provides precise information on morphological changes and dynamics of individual cells during cell death processes. Data obtained by Q-PHASE could help researches not only to distinguish between different types of cell death, but also to assess the rate of cell reactions to drug treatment or other stress conditions, and answer the questions of cancer cell behavior.

pdf – 1.6 MB

High resolution analysis of thin foils using the STEM Detector with HADF

Performing scanning transmission electron microscopy (STEM) in a scanning electron microscope (SEM) is a popular technique for laboratories without transmission electron microscopy (TEM) capabilities. The new option for TESCAN STEM detector extends the imaging capabilities by simultaneous acquisition of multiple signals from transmitted and diffracted electrons including bright field, dark field and high angle dark field. The STEM analysis can be further supplemented with transmission EDX or EBSD microanalysis for receiving higher resolution, utilizing the available analytical techniques of the SEM.

pdf – 1.7 MB