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  • Preparation and analysis of samples using transmission electron microscopy (complex of services)

    A combined service which includes tissue fixation, dehydration, embedding, sectioning and analysis using a transmission electron microscope.

    • Price: Contract price
  • Preparation of samples for scanning electron microscopy analysis

    Samples are cut to appropriate size, and then dehydrated with a critical point dryer. Afterwards they are placed on conductive platforms and, if necessary, coated with a nano-layer of conductive material (Au, Pt). These sample-baring platforms are then placed into a SEM specimen chamber.

    • Price: Contract price
  • Preparation of semithin and thin sections for transmission electron microscopy analysis

    Ultramicrotomy is a method for cutting specimens into extremely thin slices, called ultra-thin sections, that can be studied and documented at different magnifications in a transmission electron microscope (TEM). It is used mostly for biological specimens, but sections of plastics and soft metals can also be prepared. Sections must be very thin because the 50 to 125 kV electrons of the standard electron microscope cannot pass through biological material much thicker than 150 nm. For best resolutions, sections should be from 30 to 60 nm. This is roughly the equivalent to splitting a 0.1 mm-thick human hair into 2,000 slices along its diameter, or cutting a single red blood cell into 100 slices. There are numerous pieces of equipment involved in the ultramicrotomy process. "Thin" sections, meaning sections from 50 to 100 nm thick, are able to be viewed in the TEM. Semithin or "thick" sections range from 0.5 to 2 µm, and are almost 10 to 20 times thicker than "thin" sections. These thick sections are also known as survey sections and are viewed in a light microscope to determine whether the right area of the specimen is in a position for thin sectioning. It is therefore a very common practice to view thick sections in a light microscope first, before proceeding with ultramicrotomy or thin sectioning. A small sample is taken from the specimen to be investigated. Specimens may be from biological matter, like animal or plant tissue, or from inorganic material such as rock, metal, magnetic tape, plastic, film, etc. The sample block is first trimmed to create a block face 1 mm by 1 mm in size. "Thick" sections (1 μm) are taken to be looked at on an optical microscope. An area is chosen to be sectioned for TEM and the block face is re-trimmed to a size no larger than 0.7 mm on a side. Block faces usually have a square, trapezoidal, rectangular, or triangular shape. Finally, thin sections are cut with a glass or diamond knife using an ultramicrotome and the sections are left floating on water that is held in a boat or trough. The sections are then retrieved from the water surface and mounted on a copper, nickel, gold, or other metal grid. Ideal section thickness for transmission electron microscopy with accelerating voltages between 50kV and 120kV is about 30–100 nm.

    • Price: Contract price
  • Tissue fixation, dehydration and embedding in epoxy resin

    Epoxy embedding serves a dual purpose - it fixates and preserves the structural integrity of biological material of interest without drastically altering the sample and encloses the material in a solid, hard environment that is suitable for cutting semi-thin and thin sections for TEM viewing. Fixation is done using a 2.5% glutaraldehide solution and a 1% osmium tetraoxide solution, the latter also used in tandem with a 2% uranilacetate solution for negative staining. Dehydration is performed by immersing the material in graduated solutions of distilled water and ethanol with a subsequent immersion in pure propylene oxide to fully substitute the materials’ water for a liquid miscible with the epoxy resin of the embedding medium. The tissue is then sent through a mixture of epoxy and acetone, and then through pure epoxy to substitute any liquid for resin components. The prepared tissue is placed into plastic capsules, which are filed with epoxy, and cured for up to 4 days in an incubator (60 oC) until ready for sectioning.

    • Price: Contract price
  • Transmission electron microscopy analysis

    Well established methods are used to assess the ultrastructure appearing under exposure of treatment, experiments, and pathologic conditions, of various tissues or cultured cells grown on substrates or in suspension. We also perform analyses of subcellular fractions isolated from tissues or cells using routine embedding and fine section observation or negative staining.

    • Price: Contract price
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