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Microscopy and Imaging

Cryofixation and Chemical Fixation for Electron Microscopy

Specimen preparation is the most important aspect of biological electron microscopy (EM), as it influences everything from the preservation of the sample itself to the kind of information that can be obtained. It is vital to define the questions you are asking of the sample before embarking on an electron microscopy project. This enables you…

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Ultramicrotomy for Electron Microscopy

Ultramicrotomy is the process by which a sample is cut into very thin slices or “sections”, usually for imaging by transmission electron microscopy (TEM) or relatively new techniques using scanning electron microscopy (See Array tomography in three dimensional scanning electron microscopy for biology). This technique requires a bit of finesse, and this article will help…

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Laser in a droplet

When you hear about a laser, you likely imagine a medium-size apparatus with a light beam coming out of it, not a bacterium in a drop of liquid. Well, Turkish and British scientists went beyond ordinary imagination – they expressed a fluorescent protein in E.coli and suspended live bacteria in droplets. Illuminated droplets served as…

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Optimal Conditions for Live-Cell Imaging

Live-cell imaging is the investigation of dynamic physiological processes in living cells using time-lapse imaging from milliseconds to hours. Live-cell imaging turns multiple snapshots to movies, which is in contrast to fixed-cell imaging that examines cellular activity at a time point. Typical applications of live-cell imaging that are used to study kinetic events include enzyme…

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Thinking Outside the Box: Microscopy for Immunologists

When you think of an immunologist, you will likely imagine someone who studies the immune system… or maybe a person who speaks in a completely different language (CD? IL? The list goes on.). You may also think of a slew of assays that almost exclusively “belong” to immunologists, including ELISA, ELISpot, Flow Cytometry, chromium release…

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An Introduction to Live Cell Imaging

The term live cell imaging collectively refers to the technologies used to capture images of cells in a living, active state, either as individual static pictures or as time-lapse series. Correspondingly, the applications of live cell imaging can be divided in two broad categories: image recording of cells in their natural, living state observing and…

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An Introduction to Cardiac Optical Mapping

What Is Optical Mapping and How Is It Used? Synchronisation of the contraction of heart muscle is essential for the efficient pumping of blood through the circulatory system. Cardiac contraction is controlled by the regulated spread of electrical impulses from cell-to-cell within the heart.  In pathological conditions, these electrical impulses can become disordered and lead…

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New-ISH on the Block: Introduction to RNAscope®

When sensitive detection of RNA is required, many scientists turn to qPCR as it is a versatile technique that can detect many different types of RNAs from mRNA, non-coding RNA, to microRNA. However, if you also require spatial information, like which cells are producing your RNA, the technology of choice has historically been in situ…

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Automated Image Analysis – the Future of Data Acquisition?

Automated image analysis uses finely tuned software to extract data from digital images. Algorithms recognize specific shapes and patterns in the images and gather quantitative information that is then used for further data analysis. The pharmaceutical and biological research industries have benefitted greatly from this technology, which allows researchers to analyze hundreds—if not thousands—of samples…

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Safranin: Cheap Stain to Visualize Chromosomes

As an undergraduate student, one of the first experiments I did was staining chromosomes in mitotically active onion root tip cells. The stains that are conventionally used for this purpose are acetocarmine or aceto-orcein (which smell like vinegar). However, the cost of these stains is quite high. Personally, I find safranin, which is another stain, more…

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Color Transmission Electron Microscopy

There are two types of electron microscopy—transmission electron microscopy (TEM) and scanning electron microscopy (SEM). SEM creates fascinating 2D images by bouncing electrons off the surface of the sample. I highly recommend searching for SEM samples on Google images. While SEM images are aesthetically amazing, the TEM images bring us inside the world of the…

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From Cells to Scope: Chamber Slide Immunochemistry

Immunolabeling is the tried-and-true immunochemistry method of getting the stain you want onto the molecular target you want. Whether that target is contained within a large region of tissue (immunohistochemistry) or inside a single cell (immunocytochemistry), the ability to accurately label large numbers of samples will simplify your workflow and help you to achieve excellent…

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Lasers for Confocal Microscopy: Part II

Continuing from our first article on lasers for confocal microscopy, we will now discuss two specialized types of lasers: lasers for two-photon excitation and tunable, white light lasers. We will also discuss the applications of the two lasers. Lasers for Two-Photon Excitation The two-photon absorption phenomenon was first described for microscopy in 1931. Here, the…

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The A to Z of Histological Stains

With the use of stains and dyes, histology allows researchers to visualize particular tissue structures, chemical elements within cells, tissues and even microorganisms. The advent and evolution of histology follows that of microscopy as outlined in ‘A (very) Short History of Histology’. Histology, which means ‘tissue science’ became an academic discipline in its own right…

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