Highlighted Technologies

Electron microscopy

  • Immunoelectron microscopy (IEM)
  • 3D electron microscopy
  • Correlative light and electron microscopy (CLEM)

Immunoelectron Microscopy (IEM)

In this variation of electron microscopy (EM), specimens are chemically fixed, cryo-protected, and frozen. After this treatment, the sample is hard enough to be thin-sectioned by cryo-ultramicrotomy. The cryo-sections are then thawed and exposed to probes or antibodies. This technique is very sensitive and adapted to identifying membrane compartments in cells.

Oulu BioImaging Center specializes in imunoelectron microscopy and provides this technology as a service.


3D Electron Microscopy

3D electron microscopy comprises a number of electron microscopy (EM) methods capable of producing 3D image data sets:

  • Electron tomography (ET): transmission electron microscopy (TEM)-based method for high-resolution imaging of relatively small areas.
  • Serial block-face scanning electron microscopy (SB-EM): for lower-resolution imaging of significantly larger areas.

Electron Microscopy Unit at the University of Helsinki specializes in 3D electron microscopy and offers it as a service to Euro-BioImaging users.


Correlative Light and Electron Microscopy (CLEM)

CLEM demonstration. Salo et al. 2019 Dev. Cell.

Correlative light and electron microscopy (CLEM) is the integration of two microscopy techniques, Electron Microscopy (EM) and Light Microscopy (LM), performed on the same sample and the same field of view, utilizing the strengths of each method while simultaneously reducing their individual weaknesses.

Electron Microscopy Unit at the University of Helsinki specializes in CLEM and offers it as a service to Euro-BioImaging users.


Mesoscopic Imaging

  • Optical projection tomography (OPT)
  • Selective Plane Illumination Microscopy (SPIM)
  • Multiphoton Microscopy

Optical Projection Tomography (OPT)

Bioptonics 3001 device and the example of the data acquired using OPT.

Optical Projection Tomography (OPT) is in many ways the optical equivalent of X-ray Computed Tomography (CT) or the medical CT scan. OPT differs in the way that it generally uses ultraviolet, visible, and near-infrared photons as opposed to X-ray photons. However, essential mathematics and reconstruction algorithms used for OPT and CT are similar.

Biocenter Oulu specializes in OPT and offers this technology as a service to Euro-BioImaging users.


Light Sheet Fluorescence Microscopy (LSFM)/Selective Plane Illumination Microscopy (SPIM)

Light sheet fluorescence microscopy (LSFM), often referred to as single plane illumination microscopy (SPIM), combines optical sectioning with multiple-view imaging to observe tissues and living organisms with impressive resolution. SPIM technology offers fast optical sectioning combined with minimally-invasive 3D acquisition of fluorescent specimens over time. This is achieved by focusing a thin laser light-sheet into the specimen, taking 2D images of the illuminated slice with a perpendicularly positioned detector (CCD camera). 3D stacks are obtained by moving the specimen orthogonally to the light sheet between consecutive images.

Biocenter Oulu specializes in SPIM and offers this technology as a service to Euro-BioImaging users.


Super-resolution microscopy

  • 2D and 3D STORM
  • 2D and 3D STED

Stochastic Optical Reconstruction Microscopy (STORM) 

dSTROM image of vimentin.

The fundamental principle behind stochastic optical reconstruction microscopy (STORM) is that the activated state of a photo-switchable molecule must lead to the consecutive emission of sufficient photons to enable precise localization before it enters a dark state or becomes deactivated by photobleaching. Additionally, the sparsely activated fluorescent molecules must be separated by a distance that exceeds the Abbe diffraction limit (in effect, greater than approximately 250 nanometers) to enable the parallel recording of many individual emitters, each having a distinct set of coordinates in the lateral image plane. 

Biomedicum Imaging Unit at the University of Helsinki specializes in STORM and offers this technology as a service to Euro-BioImaging users.


Stimulated Emission Depletion Microscopy (STED)

Stimulated emission depletion microscopy (STED) is one of several super-resolution imaging techniques. It creates super-resolution images by the selective deactivation/depletion of fluorophores in the peripheral area, minimizing the area of illumination at the focal point and thus, enhancing the achievable resolution for a given system.

Cell Imaging and Cytometry imaging core facility in Turku Bioscience specializes in STED microscopy and offers this technology as a service to Euro-BioImaging users.


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