Microscopy

Confocal microscopy is a pillar of modern cellular research, allowing a great variety of cellular imaging assays. The presence of adjustable pinholes in the optical pathway of confocal microscope allows the acquisition of fluorescent signals from a very restricted sample volume limited to a thin layer around the focal plane of the objective.  Thus, it is possible to perform fine optical cross-sectioning of the biological samples using confocal microscope.

Then 3-D reconstruction of the sample can be obtained from these optical slices (z-stack). The spatial resolution in the XY plane of our confocal microscopes is down to 200 nm while it is about 500 nm in the axial direction (along the Z-axis). The microscopes are equipped with sensitive galvano-scanners allowing fast signal acquisition from one point, line or frame with different pixel resolutions, ranging from 128 x 128 to 2048 x 2048. Crop, zoom, rotation and offset functions are available for the scanner. Each microscope has set of lasers as light sources and 4 photodetectors (photomultipliers, PMT) – one for transmitted light and three for reflected (fluorescence).

This makes possible multi-dye labeling (up to 8) of the samples. Laser beams are transmitted into the system via an acousto-optic tunable filter (AOTF) allowing for fast laser line switching and intensity adjustment. For the perfect dye separation multitracking algorithm, sequential scanning is available in fast (after each line) or in slow (after each frame) modes.

Specialized imaging techniques including colocalization, live cell microscopy, kinetic measurements, fluorescence recovery after photobleaching (FRAP), fluorescence resonance energy transfer (FRET), measurements of intracellular ion concentrations (e.g. pCa2+) etc. can be implemented.

The confocal microscopy unit provides access to the following confocal laser scanning microscopes :, Zeiss LSM 510, Zeiss LSM 510-META and Leica SP8. This specialized and sensitive machinery requires high levels of maintenance and proficiency of usage. Confocal microscopy users must pass a two-part course which includes theoretical and practical sections in order to be authorized for independent use of the LSM systems.

Services include acquiring images for non-authorized users and assistance with set-up and shut down of the systems for authorized users. Image acquisition by operators for non-authorized users is available for a hourly fee and must be coordinated in advance.

 
For further information including training for authorized usage, please contact - Dr. Alex Barbul (abarbul@tauex.tau.ac.il), tel. 03-6406006