A fluorescent microscope uses fluorescence as a detection method. Fluorescent microscopes are able to give detailed images of cell and tissue features that might not be visible using conventional light microscopy. While some cell structures fluoresce naturally, in other cases fluorochromes need to be added to the sample before imaging. In other cases, cells can be genetically modified so a protein of interest fluoresces. This allows scientists to observe where a protein of interest performs its action in a live cell. One drawback to fluorescence microscopy is that viewing the samples will cause the fluorescence to fade over time. Addition of anti-fading reagents can help reduce this effect.
Things to consider when purchasing a fluorescent microscope / fluorescence microscope:
- Light source: An intense light source is needed to excite the molecules; the light source will determine intensity of the excitation wavelength and its spectral breadth and purity. The four types of light sources used in fluorescence microscopy are xenon arc lamps or mercury-vapor lamps with an excitation filter, lasers, supercontinuum sources, and high-power LEDs.
- Wavelength: In fluorescence microcsopy a filter is used to make sure only the excitation wavelengths pass through.
- The optics: The type of lens used will determine the magnification. High aperature and low magnification is ideal for fluorescence microscopy.
- Detector: The imaging camera used is very important as it determines at what level fluorescence can be detected and the ability to resolve certain structures. Cameras used in fluorescence microscopy must offer high signal sensitivity, low noise, and be able to quantify intensity.
- Software: Many companies offer software that can be used for image analysis.