Microscopes for Biological Applications

Microscopes may be optimized for many biomedical applications including live cell specimens, fixed cell specimens and special staining and/or observation methods. Common techniques include brightfield observation, phase contrast observation, polarization and fluorescence staining. As an example, asbestos particles in lung tissue may be observed and identified in a polarized light microscope by a pathologist examining a biopsy as he tries to diagnose a patient with acute respiratory disease. A basic polarized light configuration would include a polarizer, an analyser and perhaps a first order red compensator. A phase contrast microscope for 400x observation would require a phase contrast condenser with a phase ring for a 40x objective and a 40x phase contrast objective with a 40x annulus installed. Other examples include examinations for kidney stone identification, influenza antibodies and intestinal parasites. More advanced microscopes may be equipped so that all of these applications can be achieved on the same stand by selecting the correct installed components. Microscopes for use in hematology will usually include a 100x oil immersion objective for a very detailed examination of a stained differential smear for red blood cell morphology, estimate of platelet sufficiency and white blood cell types and their relative numbers. This analysis will provide valuable information for infections, allergic responses and identification of more serious diseases including acute and chronic leukemias. With a liberal budget, one might be able to create a "universal" microscope.