EM Processing Equipment

 

PELCO 344l Laboratory Microwave System

Capabilities:
- Microwave technology facilitates the rapid sample processing from the fixation to resin infiltration.

Comparison of processing time of tissue for TEM
Conventional: up to 3 days
Microwave: less than half a day

Cost:
BIF members: $7.92/hour, Academic users: $13.20/hour

Specifications:
- True variable wattage to control power level and keep a constant microwave environment
- Temperature probe with adjustable temperature water recirculation system to control heat generation during irradiation
- Vacuum chamber facilitates fixation and resin infiltration processes


LEICA HPM100 High Pressure Freezer

Capabilities:
- Cryo-fixation/immobilization of biological samples (must fit into 3mm or 6mm diameter carrier)
- 2100 bar of high pressure applied to the sample to suppress ice crystal formation and growth
- Capable of vitrification up to a thickness of 200 µm

Cost:
BIF members: $18.48/shot, Academic users: $30.80/shot

Specifications:
High pressure freezing is the ultimate fixation method to preserve cells and tissues as close to their natural condition as possible. Samples are kept in liquid nitrogen and then processed using the Leica AFS2 (automatic freeze substitution) to substitute the intracellular water for acetone in preparation for resin infiltration and embedding.

Advantages:
- Complete arrest of all cellular processes (non-selective, within msec)
- Problems caused by osmotic shock or inappropriate pH, often associated with chemical fixation, are not present
Disadvantages
- Formation of ice crystals can damage the ultrastructure

Comparison of High pressure freezing vs Chemical fixation:

LEICA AFS2 (automatic freeze substitution)

Capabilities:
- Automated freeze substitution machine for cryo-fixed/chemically-fixed samples

Cost:
BIF members: $31.68/h, Academic users: $52.80/day

Specifications:
Leica AFS2 is an automatic freeze substitution system for substituting the intracellular water for acetone in preparation of resin embedding.
- Automatic handling and dilution of reagents
- Adjustable transfer function of gaseous liquid nitrogen
- Low temperature embedding and UV polymerization
- Stereomicroscope for viewing and positioning of samples

Samples and reagents can be added and left until the end of the run.
- No contamination of the specimen
- Specimens and chamber remain dry
- Dramatic reduction in time used to handle reagents and set-up


FEI Vitrobot Mark IV

Capabilities:
- Plunge-freezing of aqueous (colloidal) suspensions for Cryo-TEM imaging (link)

Cost:
BIF members: $72.60, Academic users: $121, Industry users: $242

Specifications:
FEI VitrobotMark IV is an automated vitrification device for plunge-freezing to quickly and easily prepare reproducible samples.
Biological structures are physically immobilized within ultra-thin vitrified (amorphous) ice layers so that samples can withstand the high voltages used in Cryo-TEM.

Special care should be taken to control the temperature and humidity.