In confocal imaging, lasers are scanned across the sample and at each spot, the fluorescence signal is detected by a photomultiplier and recorded on the computer screen as a pixel in your image. Pixel by pixel, this is how your image is built up. The advantage of using confocal over a widefield microscope is that you can get high resolution images of thicker samples. When imaging a thick sample (greater than ~20microns) with a widefield fluorescence microscope, signal from all planes above and below your desired focal plane is collected and this can result in blurry images. In a confocal, there is a pinhole that lies in front of the detector that blocks out-of-focus light, so that you only get signal from the focal plane of interest.

Our facility is equipped with two Zeiss LSM (Confocal, Two-photon) and two Olympus FluoView (FluoView A, FluoView B) confocals. They are all fully loaded confocal microscopes with lasers allowing excitation of most common fluorophores such as DAPI, Alex488, CY3, and Cy5. Some have additional components available such as incubators for live cell imaging, two-photon laser, FRAP module, motorized stage for multi-location acquisition and spectral un-mixing capabilities. These microscopes, along with our Leica fiber-coupled confocal system (Leica FCM), can also be used for intravital imaging of mice.