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Plunge Freezer

Leica EM GP2

Plunge freezing is a cryo-fixation method used to preserve samples in their native state prior to cryo-electron microscopy. The EM GP2 plunge freezes fluid or extremely thin samples spread on an electron microscopy grid into liquid ethane and afterwards excess fluid is removed by automatic blotting. Prior to freezing, the sample is maintained in a temperature and humidity controlled environmental chamber which is adjustable between +4°C and +60°C and room humidity to 99 %.

The main steps of this technique is as follows:
1. The sample is spread onto a glow discharged EM grid
2. The liquid droplet is then blotted with filter paper until only a very thin film of fluid remains
3. The grid is then rapidly plunged into a cryogen (usually liquid ethane)
4. The grid is afterwards stored in a grid box submerged in liquid nitrogen until finally loaded into the cryo-electron microscope for imaging

Operating manual: File:Leica EM GP2 Operating manual.pdf

For further information on the equipment usage or training contact mktracy@dtu.dk [1].

Microtome

RMC MT-7 Microtome

Our RMC MT-7 Microtome is a vintage piece of equipment and can be used for specimen sample preparation for SEM/EDX analysis and/or for cutting relative thin slices (approx. 200nm thick) for TEM analysis. First, the specimen needs to be embedded into a resin or an epoxy, and then can be sectioned using a glass or diamond knife.

For further information about the microtome usage contact mktracy@dtu.dk [2].

Leica EM UC7 Ultramicrotome

The Ultramicrotome Leica EM UC7 provides easy sample preparation of ultrathin sections for TEM, SEM, AFM and LM application. It is suitable for highly skilled or absolute beginners. The Leica ultramicrotome can provide ultra thin sectioning of sample embedded in a resin/epoxy block with a feed range of 1 nm up to 15 µm. Glass or diamond knife can be used for the ultra sectioning of the samples.

The main steps of this technique proceed as follows:
1. Mount sample
2. Mount glass or diamond knife to knife holder
3. Trimming or ultrasectioning of sample
4. Fishing sections
5. Transfer to an EM grid

Operating manual: File:EM UC7 Operating manual.pdf

Requirement for training: Completion of the DTU Epoxy course and purchased of own diamond knife. For further information about the equipment usage or training contact mktracy@dtu.dk [3].

Leica EM FC7 Cryo-Ultramicrotome

Within minutes the Leica EM UC7 ultramicrotome can be change to a cryo-ultramicrotome by mounting the cryo chamber EM FC7. Using the cryo-ultramicrotome, cryo-sections (-15° to -185°C) can be prepared for TEM, SEM, AFM and LM applications.

The main steps of this technique proceed as follows:
1. Set up the cryo chamber EM FC7 to the EM UC7 apparatus
2. Mount both the trim and sectioning diamond knives to the knive holder and set up in the cryo chamber
3. Connect the pump tube between the liquid nitrogen Dewar and the ultramicrotome apparatus
4. Fill up liquid nitrogen Dewar
5. Let equipment to cool down for 1 hour
6. Meanwhile prepare samples (Cut big samples to smaller pieces)
7. Freeze sample in liquid nitrogen and mount sample
8. Trimming and ultrasectioning of sample
9. Collecting sections and transfer to an EM grid

Operating manual: File:EM FC7 Operating manual.pdf

Requirement for training: Purchased of own diamond knife. For further information about the equipment usage or training contact mktracy@dtu.dk [4].

KnifeMaker

LKB Knifemaker 7801A

At DTU Nanolab we offer the possibility to make glass knives for ultramicrotomy applications using the LKB Knifemaker 7801A.

Manual of LKB Knifemaker 7801A: File:LKB Knifemaker 7800B Manual.pdf

LKB Knifemaker Location at DTU Nanolab Building 307 Room 906

For further information about the knifemaker usage and training contact mktracy@dtu.dk [5].

Critical point dryer

Leica EM CPD300

The CPD allows for ideal preservation of specimen's microstructures during drying processes prior to SEM analysis. Since air drying could cause severe deformation and collapse of microstructure due to the effects of high surface tension to air, the water in the biological specimen is replaced with a suitable inert fluid (“transitional fluid”-CO2) which has a lower surface tension to air. This would thus reduce severe structural damages during drying processes.

Because liquid CO2 is not sufficiently miscible with water, a third medium commonly Acetone or Ethanol is used as “intermediate fluid”. The specimen is first dehydrated through various concentrations of the intermediate fluid and thus completely replacing the water in the specimen. Afterwards, the “intermediate fluid” is replaced with the “transitional fluid” (CO2) which can then convert from liquid to gas phase without surface tension effects which distort morphology and ultra-structure.

Operating manual: File:EM CPD300 Operating manual.pdf

For further information on the CPD usage or training contact mktracy@dtu.dk [6].

Drying oven

The TS9026 drying oven is of 26L capacity and is used for epoxy embedding experiments.

Specifications:

Temperature range is from 2°C to 250°C
Fan speed is 0 to 10
Capacity is 26L

For further information on the equipment usage contact mktracy@dtu.dk [7].

Sonic Dismembrator

The Fisherbrand Model 505 sonic dismembrator apparatus applies sound energy to agitate particles in a sample. For biological applications, sonication may be sufficient to disrupt or deactivate a biological material. For example, sonication is often used to disrupt cell membranes and release cellular contents. In nanotechnology sonication is commonly used for evenly dispersing nanoparticles in liquids.

For further information on the equipment usage contact mktracy@dtu.dk [8].

Preparation equipment

Mini tube rotator

The mini tube rotator can be used for rotating various sized laboratory tubes at several mixing angles at speeds ranging from 4 to 18 min–1.

Specifications:

Variable speed with LCD display
Digital microprocessor control
An adjustable 0 – 90° mixing angle
Interchangeable carousels for all common laboratory tubes
Cold room and incubator compatible

For further information on the equipment usage contact mktracy@dtu.dk [9].

Centrifuge

The Eppendorf Mini Spin plus centrifuge is a desktop centrifuge with maximum speed/force at 13,400rpm/12,100xG. It has a 30-minute timer, which is settable in 15-sec increments and has a short-spin mode fixed at maximum speed.

Instruction manual: File:Eppendorf Mini Spin plus centrifuge_Original Instructions.pdf

For further information on the equipment usage contact mktracy@dtu.dk [10].

Magnetic stirrer

The myPlate magnetic stirrer is ideal for homogeneous mixing chemicals. The speed range (min-1) is 100 - 2500.

Specifications:

High chemical resistance
Can be used at 5 to 40 °C (80% relative humidity), in an incubator or cold room
Speed range (min-1) 100 to 2500

For further information on the equipment usage contact mktracy@dtu.dk [11].

Pulsing Vortex Mixer

The VWR pulsing vortex mixer can suit different applications. It provides optimum comfort and minimal stress when used for the several applications.

Specifications according to the instruction manual:

Can be used at 4 to 40 °C (maximum 85% relative humidity, non condensing), in an incubator, CO₂ incubator or cold room
Pulsing model can reduce heat generation and ensures efficient mixing and disruption
Have timer from 1 s to 160 h

Instruction manual: File:VWR pulsing vortex mixer_Instruction Manual.pdf

For further information on the equipment usage contact mktracy@dtu.dk [12].

Magnetic hotplate stirrer

VWR Professional hotplate stirrers are designed for applications that require exceptional accuracy, stability and repeatability. Enhanced microprocessor control offers an external resistance thermometer (RTD) probe option that delivers superior temperature control of the sample. Stirring function, with continuous duty motor and powerful magnet, maintains set speed even under changing load or viscosity. Touch pad controls with easy to read, independent LED displays for temperature, speed and time, allow operator to view all settings at once. Rear housing features a built-in support rod holder with locking knob that accepts the supplied probe kit.

Specifications:

Temperature range (°C) +5 to 400
Speed range (min-1) 60 to 1600
Excellent temperature uniformity with consistent stirring at all speeds
Separate digital displays for temperature, speed and time; show set and actual values. Display will show last used settings, even after power has been turned off
Cool touch, chemically resistant housing
Includes external RTD temperature probe kit

Low profile design takes up less space and fits into fume hoods. Spill resistant housing channels fluids away from internal components. A 'hot' symbol warning light is illuminated when heat is turned on and remains on until top plate cools down. Stir protection; if stirrer motor stops or fails, unit will automatically shut down heater. Plate over-temperature limit ensures plate temperature will never exceed users programmed set temperature limit, allowing for control of sensitive flash points. An audible alarm will sound when time reaches zero or when unit reaches set point temperature in timed mode, and if the probe disengages from sample, unit will automatically shut off heater. Microprocessor control with enhanced electronics regulates both heating and stirring and brings samples to temperature quickly and efficiently. Ramping feature slowly increases speed for improved safety and enhanced coupling. Avoids splashing, improves spin bar control and provides excellent low end speed control. Durable aluminium tops will not crack or chip, and provide a more even heating surface.

For further information on the equipment usage contact mktracy@dtu.dk [13].

Hotplate

VWR Hotplate W10 is suitable for drying paraffin sections on slides or for de-icing tools when doing cryo experiments. The W10 heating plate, with its sleek compact design, accommodates two rows of up to 40 slides in total. The heating plate is very useful as a stretch bench for mounting, stretching and drying paraffin sections on slides, fixing bacterial smears, and heating fluid samples in Petri dishes. The black anodised surface provides an excellent visual contrast. The working plate is made of solid 8 mm aluminium with black anodised surface and ensures a constant, homogenous temperature over the entire heating surface. The touch display and switch are protected from water and paraffin. The unit has over-temperature protection for extra safety. Temperature adjustment and power On/Off switch, with control light for 'On' mode, are conveniently located at the front of the unit.

Electronic touch display
Sleek and compact
Ideal size for drying up to 40 slides
Temperature range between ambient and +89 °C
Digital thermostat

Instruction manual: File:VWR Hotplate W10_Instruction Manual.pdf

For further information on the equipment usage contact mktracy@dtu.dk [14].

Analytical balance PX224

The Ohaus Pioneer PX224 combines essential weighing functionality with performance, offering high accuracy and repeatability for applications in laboratory, industrial and education settings. PX models are economically priced, and intuitively designed for intelligent operation. Their durable design has a cast metal lower housing, metal sub-pan and stainless steel weighing pan for long-term use.

Weighing capacity is 220 g
Readability is 0.1 mg
Stabilisation time is 4 s
A static removal bar (permanent static electric dissipative ABS) provides a convenient grounding location
Applications include basic weighing, part counting, percent weighing, dynamic weighing and density determination

For further information on the equipment usage contact mktracy@dtu.dk [15].

pH meter

If you are planning on doing chemical fixation on biological samples you will probably need to make buffers and use a pH-meter. The VWR pH-meter (model pH 1000L) is located in building 314, in the Soft Mater (toxic) Lab and it is dedicated to “Soft Matter” related work.

For further information on the equipment usage contact mktracy@dtu.dk [16].

EM sample preparation workflow

For TEM imaging of biological and softmaterial sample at room temperature or cryo conditions:

For SEM imaging of biological and softmaterial sample at room temperature or cryo conditions:

For further information on EM sample preparation of biological and softmaterial samples contact mktracy@dtu.dk [17].