CIPF‑ISABIAL Joint Electron Microscopy Unit

The CIPF‑ISABIAL Joint Electron Microscopy Unit is available to its researchers as well as to other public and private institutions, offering access to cutting‑edge technologies for the analysis and preparation of biological samples. Among the services provided by the platform are high‑pressure freezing (HPF), cryosubstitution (ASF), and automated serial ultrathin sectioning (ARTOS 3D). These techniques enable detailed ultrastructural studies of biological material—such as cells, biopsies, or animal and plant tissues—as well as the acquisition of three‑dimensional images through tomography (Array Tomography).

The unit also enables the correlation between electron microscopy and fluorescence microscopy images, providing a comprehensive view of the samples by combining functional and structural information. In addition, the electron microscope allows direct analysis of material morphology, complementing the study with spectroscopic techniques for compositional characterization.

• Methodological consulting for the processing of biological samples for Electron Microscopy.
• High‑pressure freezing (HPF) of samples.
• Cryosubstitution and embedding in Epoxy or Acrylic (ASF2) resin.
• Fixation and room‑temperature embedding of samples in Epoxy or Durcupan resin.
• Semithin sectioning with the ultramicrotome of resin‑embedded material for evaluation by optical microscopy (Zeiss Axio Observer 7). Toluidine blue staining and sample mounting.
• Ultrathin sectioning on grids for STEM electron microscopy.
• Serial ultrathin sectioning on silicon wafers or ITO‑coated coverslips for Array Tomography (Volume EM).
• Operation of the Zeiss Axio Observer 7 inverted fluorescence microscope with Apotome 3.
• Operation of the FE‑SEM GeminiSEM 460 (Zeiss) microscope in scanning or STEM mode.
• Image analysis consulting.

The Electron Microscopy Platform specializes in scanning electron microscopy for biological samples (Array Tomography and STEM), but we are open to all scientific disciplines. Our goal is to provide high‑quality EM services, training, and access to specialized equipment for all ISABIAL users, as well as for other public or private institutions.

We adapt, optimize, and develop methods tailored to your scientific questions. Please consult the equipment and techniques listed on the website. If you have any questions and/or wish to initiate a project, please contact the EM Platform.

The CIPF‑ISABIAL Joint Electron Microscopy Unit is fully equipped for the advanced preparation of biological samples. The processes include fixation, post‑fixation, dehydration, and embedding in epoxy or acrylic resins using silicone molds. These resins provide the biological material with the hardness and support required for cutting by ultramicrotomy, yielding semithin sections (0.5–2 µm) or ultrathin sections (60–100 nm) for subsequent microscopic analysis.

One of the major added values of the platform is the incorporation of the high‑pressure freezing technique (HPF), which allows exceptional preservation of the ultrastructure of biological samples. This technique—still not widely implemented in conventional electron microscopy—freezes tissue under high pressure, preventing the formation of ice crystals thanks to the transition of water into an amorphous solid state. When combined with cryosubstitution and resin embedding, HPF enables the acquisition of highly faithful images of tissue structure.

Additionally, the laboratory enables the acquisition of section mosaics using optical microscopy, whether from vibratome‑cut sections or from semithin sections stained with toluidine blue. The electron microscope, in turn, allows detailed observation of the ultrastructure of the samples. To improve the interaction of the electron beam with the sample, contrast is applied using heavy metals such as osmium, uranyl acetate, or lead citrate, a fundamental step for the visualization of biological specimens.

This unit also has a state‑of‑the‑art ultramicrotome (Leica ARTOS 3D), capable of producing ultrathin serial sections (60–90 nm) in the hundreds or thousands for array tomography techniques. These sections can then be scanned with the Zeiss GeminiSEM 460 scanning electron microscope, enabling three‑dimensional reconstruction of the samples.

Additionally, the laboratory is equipped to perform correlative light–electron microscopy (CLEM). Thanks to the available adapters, it is possible to scan the same region of interest first with a Zeiss Axio Observer 7 inverted fluorescence microscope with Apotome 3, and then with the electron microscope. This technique allows precise localization of fluorescent signals within tissues or cells, depending on the specific labeling. The Apotome 3 system enhances resolution through optical sectioning, eliminating out‑of‑focus light and optimizing image quality in both live and fixed samples.

Three‑dimensional electron microscopy combined with HPF represents a key tool in advanced biomedical research, especially in fields such as neuroscience and the diagnosis of neurodegenerative diseases, including hereditary peripheral neuropathies. Currently, this technology is not available in other healthcare areas or universities in the province of Alicante.

The platform accepts samples at any stage of preparation for electron microscopy, completing the process according to the researcher’s needs. In cases where only the use of the electron microscope is required, the user must contact the laboratory and indicate the nature of the sample to be analyzed.

The Microscopy Unit has extensive equipment for carrying out the required functions:

• High‑pressure freezing device or HPF (Leica EM ICE).
• Cryosubstitution device (Leica ASF2).
• Ultramicrotome (Leica ARTOS 3D).
• Fabrication of glass knives for the ultramicrotome (Leica KMR3) and vibratome for cutting biological material (Leica VT1200).
• FESEM GeminiSEM 460 Zeiss Scanning Electron Microscope.
• Zeiss Axio Observer 7 inverted fluorescence microscope with Apotome3.
• Software and workstations for the handling and analysis of the images obtained with the microscope (Atlas5 Array Tomography, ZEN Connect, Dragonfly, Fiji, MIB, and Ilastik software).

Fees of the CIPF–ISABIAL Joint Electron Microscopy Unit