Skip to Content

College of Pharmacy

Microscopy Core

Imaging Services

The Microscopy Core offers a variety of services to expedite research and experimentation.

Phase Contrast Microscopy

  • It is possible to visualize certain cell organelles and structures that are invisible with bright-field
  • Suitable for living cells (long time lapses can be acquired)
  • High-contrast, high-resolution images
  • Good for studying and interpreting thin specimens
  • Can be used in conjunction with fluorescence microscopy
  • Not good for thick specimens (can appear distorted)
  • Shade-off (a steady reduction of contrast moving from the center of the larger objects toward its edges)
  • Halo effect (surrounding by bright areas, which obscure details along the perimeter of the specimen)
  • Modern techniques provide solutions (apodized phase contrast minimizes halo effect) but these limits can never be eliminated completely

Differential Interference Contrast Microscopy (DIC) 

  • It is possible to visualize certain cell organelles and structures that are invisible with bright-field (transparent objects to be seen by using the difference in light’s refraction)
  • The specimen will appear bright in contrast to the dark background
  • Able to use a full width condenser aperture setting resulting in a brighter image
  • No halo effect occurs with differential interference contrast
  • Gives a greater depth of focus - can produce very clear images of thick specimens
  • Can be used in conjunction with fluorescence microscopy
  • Suitable for living cells (long time lapses can be acquired
  • The three-dimensional image of a specimen may not be accurate.
  • The enhanced areas of light and shadow might add distortion to the appearance of the image

Widefield Fluorescence Microscopy 

  • Allows labelling of organelles, molecules and other features of interest
  • Allows tracking the dynamics of processes involving labeled features in real-time and in vivo
  • The technique is highly sensitive: can detect a few molecules per cubic micrometer
  • Location of structures too small to be visible in a light microscope
  • Possibility to use different colors to track distinct molecules
  • Multicolor fluorescence microscopy allows to address possible interactions between molecules by observing colocalization
  • Quantitative imaging
  • Photobleaching - dyes become nonfluorescent due to its molecular structure being altered as a result of exposure to excitation light)
  • Phototoxicity - cells become damaged due to interaction between fluorescent dye and excitation light
  • Inability to show morphology of surrounding structures.
  • Chromatic and spherical aberration
  • The availability of target specific antibodies
  • Limited specificity of the antibody
  • Limited ability of the antibody to diffuse to the target

 Confocal Microscopy

  • Better vertical resolution
  • The ability to serially produce thin optical sections through fluorescent specimens that have a thickness ranging up to 50 micrometers or more
  • Better horizontal resolution
  • Image information is restricted to a well-defined plane, rather than being complicated by signals arising from remote locations in the specimen
  • More efficient use of light (requires less intense light, minimize photodamage)
  • Reduction in background fluorescence
  • Improved signal-to-noise
  • Optical sectioning of both living and fixed specimens
  • The ability to adjust magnification electronically by varying the area scanned by the laser without having to change objectives
  • Improved quantitative imaging
  • The limited number of excitation wavelengths available with common lasers
  • Harmful nature of high-intensity laser irradiation to living cells and tissues
  • High quality images may require significant acquisition times

 Bright-field Microscopy

  • The optics do not change the color of the observed structures.
  • Stains are used to make certain structures visible.
  • Bright-field microscopy requires fewer adjustments before one can observe the specimens.
  • Can be used to view fixed specimens or live cells.
  • Frees fluorescent channels in microscopes
  • Eliminates distortions caused by the overlapping of the color emissions of the stains and the excitation of the fluorescing materials.
  • There are relatively cheap, fast and simple staining protocols to visualize:
  •      The nuclei and cytoplasm (Haematoxylin and Eosin Staining, Methylene Blue       Neutral/Toluylene Red, Nile Blue)
  •      Types of cells (Papanicolaou staining)
  •      Cell walls (Crystal Violet with Mordant)
  •      Bacteria (Giemsa stain, Gimenez stain)
  •      Spores (Malachite Green)
  •      Intracellular lipid globules (Nile Red)
  •      Lipids (Osmium Tetroxide)
  •      Collagen (Fuchsin, Safranin)
  •      Starch (Iodine)
  •      Mitochondria (Fuchsin)
  •      Proteins (Coomassie Blue)
  •      Glycogen (Carmine)
  •      Mucins (Bismarck Brown)
  • low contrast
  • most cells must be stained to be seen
  • staining may introduce extraneous details
  • intense light used for high magnification applications can damage specimens or kill living cells

Time Lapse Imaging

 Time-lapse imaging (serial images taken at regular time points to capture the dynamics process) can be performed using phase contrast, DIC, fluorescence, and confocal microcopy modes.

Image Analysis



A computationally intensive image processing technique which improves the contrast and resolution of digital images captured in the microscope.



Colocalization determines the exact location of cellular structures of interest, and allows for features that they have in common to be examined quantitatively.

Quantification of dynamic processes

Quantification of Dynamic Processes

Application of advanced bioimaging techniques to extract quantitative data from dynamic processes.

Challenge the conventional. Create the exceptional. No Limits.