subject: Inverted Biological Microscope [print this page] An inverted biological microscope system is designed upside down as compared to a standard upright microscope. The sample is normally placed on the stage but the objectives lenses are under the stage, and the condenser lens is over the specimen. This design is required for samples that are suspended in some type of liquid and housed in a Petri dish, biological bottle, 96 well plate or other similar container.
Contrast is a concern with inverted biological microscopes as the specimen cannot be stained - the specimen is usually suspended in a some type of liquid. Due to this fact, different contrast techniques are introduced into the light path of the microscope. They include phase contrast, Hoffman Modulation Contrast and Differential Interference Contrast (DIC). These different contrast techniques create the ability to see transparent or living cells or microorganisms and sub-cellular particles. With the addition of Hoffman or DIC the specimen takes on a three dimensional view.
There are several options available with most inverted biological microscopes such as camera systems and fluorescence illumination.
Camera options include 35mm, video or digital camera systems. With digital options there is software available that offers a full-featured image capture software suite to easily control all of the cameras advanced settings, and have simple but powerful graphic interfaces. Full-capture solutions are included to provide the user with the ultimate in live image analysis and archival storage capabilities.
Fluorescence inverted biological microscope systems usually provide a 100 watt mercury arc lamp as the illumination source. The light passes through a specially-designed filter system allowing certain excitation wavelengths to reach the specimen. Once the light reaches the specimen it excites certain molecules and causes them to fluoresce. Filter cubes installed in the microscope, along with different dyes, make the determination of what molecules fluoresce in the specimen.
An example of an inverted biological microscope is the VanGuard 1400INi Series, which comes standard with the following filter systems:
