Light microscopes
At the Centre for Cellular Imaging the focus is on providing access to advanced fluorescence microscopes and technologies, like multiphoton and superresolution. But we also have microscopes for more routine work, such as widefield systems and confocal laser scanning microscopes.
A widefield fluorescence microscope uses a lamp, e.g. a Mercury arc lamp, to illuminate and excite the specimen. This is a fast and economical way to obtain fluorescent images, which can be viewed directly with your eyes through the ocular or captured with a camera.
Thin specimens that do not require confocal imaging might be better analyzed using a conventional widefield microscope as it offers unsurpassed signal to noise.
The advantage of a confocal microscope is that it only collects the light reflected or emitted by a single plane of the specimen. This makes the images from thick specimens much sharper than with a conventional widefield fluorescent microscope, and by collecting images from several focal planes, you can reconstruct a 3D representation of your fluorescent specimen. With a confocal laser scanning microscope (LSM) it is possibile to zoom in on small details, to perform multi-color imaging and to make time series.
The possibility to select certain regions of interest (ROI) in the confocal images makes it possible to measure dynamics and interactions with FRAP and FRET.
Multiphoton (MP) microscopy utilizes a non-linear excitation process, usually two-photon excitation, which occurs only at the focal point of the microscope. This gives inherent optical sectioning capabilities, without cutting off out-of-focus emission, and minimizes the photobleaching and photodamage that are the ultimate limiting factors in imaging live cells. The low energy/ long wavelenght infrared (IR) excitation light is less harmful to living species than the light range used for confocal microscopy. The IR light also undergoes less scattering, which results in less background and longer penetration depths. These advantages allows investigations on thick living tissue specimens that would not otherwise be possible with conventional imaging techniques.
In addition to multiphoton excitation of fluorophores, it is also possible to perform other non-linear microscopy techniques, like second harmonic generation (SHG).
High Content Screening (HCS) microscopy is based on a highly automated imaging system combined with software for processing and analyzing large amounts of data from fixed or living cells.
With a fully automated microscope system, like the Celldiscoverer 7, it is possible to set up very advanced imaging experiment, using scripting and online-image analysis to guide and modify the experiment on the run.
Superresolution microscopy is the common name of the different fluorescence-based microscopy techniques, which has a resolution beyond the diffraction limit of 200 nm in the lateral direction and 500 nm in the axial direction.
CCI offers three such superresolution techniques: the AiryScan, with up to 1.7x resolution enhancement, the structured illumination microscopy (SIM), which doubles the resolution in all directions, and the single molecule localization techniques (PALM/dSTORM), which have a resolution approaching electron microscopy (down to 15 nm).
The Laser Microdissection and Pressure Catapulting (LMPC) technology offers non-contact sample handling without mechanical contact of specific tissue regions for downstream analysis of RNA, DNA and proteins without risk of contamination or infection. In addition, living cells can be catapulted for subsequent recultivation of specific clones of e.g. cells expressing fluorescent proteins.
