The number of applications in microscopy can be as manifold as life itself. Different specimens demand different contrast methods to get a decent result. Unstained cells normally do not show a very high contrast. Researchers approach this problem by either staining the specimen with dyes respectively fluorescent molecules; or adding contrast by manipulating the light passing through.
An optical microscope is often one of the central devices in a life-science research lab. It can be used for various applications which shed light on many scientific questions. Thereby the configuration and features of the microscope are crucial for its application coverage, ranging from brightfield through fluorescence microscopy to live-cell imaging. This article provides a brief overview of the relevant microscope features and wraps up the key questions one should consider when selecting a research microscope.
Fluorescence is widely used in microscopy and an important tool for observing the distribution of specific molecules. Most molecules in cells do not fluoresce. They therefore have to be marked with fluorescing molecules called fluorochromes.
The examination of live unstained biological specimens often suffers from poor contrast and therefore bad visibility of the specimen. Thick specimens in particular, such as brain slices, show up as nothing more than light grey structures instead of single cells. This tutorial explains the optical elements in the light path and the operating mode of DIC (differential interference contrast) on the example of an inverted and motorized high-end research light microscope which can be used for transmitted light contrasting methods and fluorescence microscopy.
In this tutorial the principle of phase contrast imaging is described taking the example of an inverted research microscope. Additionally, the alignment of the components needed for phase contrast is shown in the interactive part of the tutorial.