Introduction to Turku BioImaging key technologies (see the Turku BioImaging Black Book for more information).

Advanced Light Microscopy

Confocal microscopy

Confocal microscopy is a light microscopy technique that can produce true three-dimensional images of biological samples without harming the cells, tissue or organism being imaged. Combined with advanced software, confocal microscopy is one of the most popular and versatile biomedical imaging methods available. The technique is based on a laser beam scanning a fluorescent sample, and a pinhole excluding light not coming from the focal plane. Confocal microscopy can be used for numerous purposes, ranging from localization of particular proteins inside cells, to studies of protein dynamics and interaction. Several variations on the basic imaging technique exist. Turku BioImaging offers several confocal microscopes, such as several Zeiss LSMs, each tailored to slightly different applications.

High content analysis

High-throughput light microscopy allows simultaneous imaging and analysis of large numbers of fixed or live microscopy samples. A typical experiment consists of three steps: sample preparation, automated imaging of samples, and image analysis. This method ideally produces data reflecting the physiological parameters of cells in a given population. Typical assays explore the effects of siRNA or feature small molecule (drug) screens. The method is also suitable for more common multi-well plate applications. Many properties can be analyzed, including distribution and expression of a fluorescent label within cells over time, cell shape and movement, cell count and extent of apoptosis, and organelle/cytoskeleton characteristics. For high content analysis Turku BioImaging offers for instance a Leica SP5 confocal microscope with a Matrix scanner, and a ScanR automated widefield fluorescence microscopy and analysis platform. The BioImageXD software, developed in part by Turku BioImaging, can be applied for high content analysis.

Two-photon microscopy

Two-photon microscopy is a laser-scanning microscopic technique typically used for the acquisition of three-dimensional time-lapse images of living samples. As a major advantage, it allows a greater penetration depth into tissues (several hundred microns) than what is possible with conventional confocal microscopy (approx. 80 µm), with even lower phototoxicity. Two-photon excitation occurs after the near-simultaneous absorption of two photons (emitted by an infrared, femtosecond-pulsed laser), each of which carries only half of the energy needed. The result is fluorescent excitation occurring exclusively in the focal plane, not above or beneath it. Thus, optical sectioning is an inherent property of the technique, and no pinholes are needed. The utilization of high excitation wavelengths results in great tissue penetration. The technique is ideally suited for intravital microscopy in living, anaesthetized animals or living, explanted tissues. Turku BioImaging offers a Leica SP5 multiphoton system.

Other techniques

Turku BioImaging offers also many other advanced light microscopic techniques, such as spinning disk confocal  microscopy (for very fast acquisition of 3D images from living samples), total internal reflection fluorescence microscopy (TIRF, for imaging a 100 nm thick plane above the sample glass surface), stereo microscopy with microinjection and laser-capture microdissection. Also for instance fluorescence correlation spectroscopy (FCS, for analyzing fluorescence fluctuations of molecules diffusing through a small volume) and fluorescence lifetime imaging (FLIM) are supported by Turku BioImaging.