Key microscopy instruments
Several state-of-the-art microscopy instruments are made available to bio-researchers in Turku area by Cell Biology and Anatomy, in co-opeartion with Turku Bioimaging. If you are interested in using these or other microscopy instruments, you can find the contact info for responsible personnel, as well as eventually make your reservation in the BTK reservation system
STimulated Emission Depletion (STED) - super-resolution optical microscope
Stimulated Emission Depletion (STED) microscopy is a confocal-like microscopy technique, in which the traditional diffraction resolution limit of optical microscopy can be effectively surpassed. With an STED instrument, it is possible to acquire purely optical super-resolution images, with details visible at the level of tens of nanometers.
An STED instrument can be used in a manner very similar to that employed when other fluorescence far-field microscopes are used. Compared with, for example, electron microscopy, STED has the obvious benefit of being able to non-invasively image (living) specimens in three dimensions. Also, highly specific fluorescence labeling can be of great assistance, especially in the comparison of different biological samples.
- The use of ATTO647N and Chromeo 494 dyes is recommended for fixed samples.
- We also have Live-cell imaging capabilities. A number of fluorescent proteins have been found to work with STED
- STED-AFM multi-modal imaging
- Time-resolved FCS/FLIM features (PicoQuant), which enable e.g. STED-FCS experiments in live cells.
Atomic Force Microsce (AFM) - mechanical nano-scale imaging
An atomic force microscope (AFM) is a mechanical microscope, as opposed to (for example) an optical microscope. The principle is similar to an old-fashioned record turntable: a sharp tip attached to a flexible spring-like cantilever mechanically senses the force between the tip and the sample. Such forces cause the cantilever to bend, and the deflection is measured using a laser beam reflected from the cantilever.
AFM imaging can be used to obtain high-resolution (even at the level of an atomic lattice) images of fixed samples such as cells or a layer of protein attached to an even surface. The resolution is lower with living samples, but still much better than that afforded by optical microscopy. AFM force spectroscopy can be used to measure the force between the tip and the sample, and if, for example, the tip is coated with a ligand, the position of a receptor molecule on the cell surface can be determined (recognition mapping). In addition, the tip can be replaced by an entire cell attached to the cantilever, and the attachment of this cell to a substrate such as collagen can be measured (cell adhesion measurements). The tip can also be used to physically manipulate a sample, or to pull on a protein to study how the protein unfolds.
Our AFM system: Agilent Technologies 5500ilm has excellent capabilities for imaging biological samples. The AFM tip can be controlled very precisely in Magnetically Actuated (MAC mode), and It is possible to simultaneously acquire force-recognition and topography data. In addition the AFM module can be mounted on our STED microscope, or a fast 2D - array scanning confocal microscope or a normal widefied microscope from Zeiss.
Total Internal Reflection (TIRF) microscope
Total internal reflection fluorescence (TIRF) microscopy is the optimal choice for researchers interested in events that occur on the cell membrane. In TIRF microscopy, an evanescent wave caused by total reflection of the light beam is used for sample excitation. The evanescent wave itself penetrates only approximately 100 nm into the sample.
Turku BioImaging hosts an Olympus CellR fluorescence microscopy system equipped with TIRF. The instrument is suitable for high-resolution detection of events and structures in the immediate vicinity of the object glass-water boundary (i.e., the basal plasma membrane of the cell). The CellR system allows live cell fluorescence imaging at a time resolution of milliseconds.