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The electron microscopy unit EMil

The electron microscopy unit (EMil) is situated at Huddinge University hospital. Our aims are to help researchers to solve biological problems by using electron microscopy techniques.

Our EM lab routinely perform embedding, sectioning, immunolabelling, low temperature embedding and microscopy. Our aim is to help researchers to solve biological questions using various electron microscopy techniques. We have extensive experience in conventional preparation for TEM and SEM, preparation for immunohistochemistry, morphometric analysis, negative staining, low temperature techniques such as low temperature embedding and cryo-sectioning. The unit manages two transmission electron microscopes TEM (FEI Tecnai Spirit BioTwin and Hitachi HT7700) and one scanning electron microscope (Zeiss Ultra 55).

We have a fixed pricelist.

Services

Ultrathin sectioning - TEM

Ultrathin sectioning TEM, a preparation method for ultrastructural analysis of larger biological specimens such as various tissues, cells and bacteria. It involves chemical fixation, dehydration, plastic embedding and ultrathin sectioning. Typical questions are for example general morphology, cellular uptake of nanoparticles, morphological changes of intracellular organelles due to treatment by e.g. a chemical, siRNA etc. The method is routinely used in ultrastructural pathology for the diagnosis of renal, muscle and cilia related diseases.

Immunoelectron - TEM

Immunoelectron microscopy is a powerful tool used to detect and localize single proteins within the cell and different organelles. It allows for the study of various cellular processes and response to various changes in the microenvironment e.g. gene silencing, chemical treatment. Basically primary antibodies directed against the antigen (protein) of interest is used in a first step, the primary antibody can subsequently be detected using a secondary probe conjugated to colloidal gold markers for example species specific secondary antibodies or protein-A or G. The contrast of the colloidal gold markers are so strong that they can easily be detected in the TEM images.

Negative stain TEM

Negative stain TEM, a quick-and-dirty method to assess the morphology, purity, size, aggregation state etc. of suspensions containing various nanoparticles such as protein complexes, virus particles, exosomes, inorganic nanoparticles etc. The method can also be used to analyse suspensions of larger biological specimens such as bacteria and mycoplasma to assess the size and shape but also presence of cellular organelles such as cilia, fimbriae and flagellum. Various membranous materials such as liposomes, LNP’s and virosomes etc can also be analysed using negative stain TEM.

Scanning electron microscopy (SEM)

Scanning electron microscopy of biological specimens typically involves a topographical representation of the specimen which in many scientific questions can give unique and relevant morphological information regarding the overall specimen morphology. Similar to TEM, sample preparation involves chemical fixation and dehydration and prior to imaging the specimen is sputtered using e.g. platinum. The scattered electrons originating from this metal coating will then be detected when irradiated by a scanning beam of incident electrons.

Clinical electron microscopy

The EM facility also performs clinical services of primarily renal biopsies for the diagnostics of kidney related diseases but other diagnostics are performed such as cilia related diseases.

Equipment

TEM

TEM images are acquired using a FEI Tecnai Spirit BioTWIN or a Hitachi HT7700 120kV transmission electron microscope both microscopes equipped with 2kx2k Veleta OSiS CCD cameras.

SEM

SEM images are acquired using a Zeiss Gemini Ultra 55 equipped with on-axis SE detector (InLens SE), Everhart-Thornley SE detector (SE2), energy selective backscatter (ESB), angle selective backscatter (ASB) or STEM detector.

Sample preparation

For the TEM and SEM sample preparation we have access to Leica EM AFS, EM TP and UC6 and UC7 ultramicrotomes and cryo-ultramicrotome for the thin sectioning of tissue and cell specimens. SEM sample preparation is done using a Leica CPD030 critical point dryer and a Qourum Q150T ES sputter coater/carbon evaporation. The sputter coater also have glow discharging functionality for the hydrophilization of grids.

Contact

Forskningssamordnare

Lars Haag

Telefon: 08-524 836 63
Enhet: Institutionen för laboratoriemedicin (LABMED), H5
E-post: lars.haag@ki.se