Sample Preparation

WEMC has a range of tools for specimen preparation.

Critical point drying

Leica CPD-030

The critical point dryer CPD-030 is used for drying of samples. It prevents major drying artifacts caused by capillary forces.

High pressure freezing

Balzers HPM-010

Rapidly freezing samples at high pressure drastically reduces the nucleation and growth of ice crystals and therefore results in less structural damage.

Ultra (cryo)microtomy

Leica FCS

Ultramicrotomes are used to prepare ultra-thin sections (<100nm) of resin embedded or frozen material for transmission electron microscopy. This can be done at room temperature or at low temperatures (down to -150°C), using an ultracryotome.

Freeze substitution

Leica AFS and FreezySub

Freeze-substitution is used to dehydrate a sample while preserving the original structure. At -90°C, samples are put in an organic solvent and the ice will be replaced by the organic solvent resulting in a dehydrated sample.

Sputter coating

Leica and Jeol

Sputter coating is used to produce thin (0.5- 20nm) conducting layers on non-conducting samples. Available at WEMC are gold, tungsten, platinum and iridium.

Carbon coating

Carbon coating is used in scanning electron microscopy to make specimens conductive and in transmission electron microscopy it is used as specimen support films on TEM grids.

Vitrification using the Vitrobot

The FEI Vitrobot is an automated, climatecontrolled plunge freezing device. The Vitrobot freezes the sample so quickly that water molecules do not have time to crystallize. Instead the water molecules form an amorphous ice that does no damage to the structure. Cryo-observation of vitrified samples allows the ultrastructural study of macromolecules, molecular assemblies and cells in their natural (= hydrated) environment.