Since the diameter of grid is a standard length, 3.05mm,  each hole size is less than ~200um in 100 mesh grid,  ~97um in 200 mesh grid, ~63um in 300 mesh grid and ~42um in 400 mesh grid.

Please be noticed that our grids have very smooth hole edge. The smooth edge grids could provide a very flat film coated on them, which is critical for high resolution imaging.

Copper

(Cu-600)

Cu/Rh

(Cu/Rh-600)

Nickel

 (Ni-600)

Copper

(Cu-500)

Nickel

 (Ni-500)

Copper

(Cu-400)

Cu/Rh

(Cu/Rh-400)

Molybdenum

 (Mo-400)

Nickel

 (Ni-400)

Titanium

(Ti-400)

Copper

(Cu-300)

Cu/Rh

(Cu/Rh-300)

Molybdenum

 (Mo-300)

Nickel

 (Ni-300)

Titanium

(Ti-300)

Steel

(Fe-300)

Copper (Cu-200)

Cu/Rh (Cu/Rh-200)

Molybdenum (Mo-200)

Nickel (Ni-200)

Titanium

(Ti-200)

Gold (Au-200)

Tungsten (W-200)

Steel (Fe-200)

Nylon (Ny-200)

Copper (Cu-100)

Cu/Rh (Cu/Rh-100)

Molybdenum (Mo-100)

Nickel (Ni-100)

Titanium

(Ti-100)

Gold (Au-100)

Steel (Fe-100)

Copper (Cu-50)

Molybdenum (Mo-50)

Nickel (Ni-50)

Titanium

(Ti-50)

Gold (Au-50)

Steel (Fe-50)

Copper

(Cu-s)

Molybdenum

(Mo-s)

Copper

(Cu-50/200)

(Cu-75-300)

(Cu-100/400)

Most samples for transmission electron microscopy must be "supported" on some kind of a thin electron transparent film, to hold the specimen in place while in the objective lens of the TEM. Only samples that are "self- supporting" do not need some additional support film. Should an electron microscope user use a support film at all if one is not absolutely needed? Probably not, because even the very best quality of support films do result in more material being placed in the beam's path, resulting even if ever so slightly, the contrast of the final image. But for many users, they don't have the luxury of having to make that decision: More often than not, even what appear to be self-supporting samples, still do need the assistance of a support film to cut down on sample drift.

Mo-300CN, Molybdenum grid coated with thin carbon film.

The selection of the "right" support film has never been an easy exercise, even the most experienced of TEM experts, and the only way to really determine which support film is the best for a particular application it to just "try it!" Therefore, we would like to contribute in a useful way to the needed information base to help make the optimum selections, but the giving of such "guidance" itself is an imprecise science.

We have therefore broken down the different kinds of support films and have tried to present the "trade offs" between one support film system vs. another. We can offer no guarantees, since the range of samples studied is so wide and the environmental range so broad (from cryo temperatures to temperatures exceeding 1000°C) to which the grids and their coatings might be subjected. But the best decisions are usually made by just trying several possibilities and if one works better than the other, the choice for future samples becomes obvious.

Application

1

Thin carbon film

2

Thick carbon film

3

Formvar film

4

Carbon/Formvar film

Protein, single particle, negative stained

good

good

unsuitable

good

Protein, single particle, cryo

good

ok

unsuitable

ok

Protein, 2D crystals, negative stained

good

good

unsuitable

ok

Protein, 2D crystals, cryo

good

good

unsuitable

unsuitable

Polymer, lighter elements

good

ok

unsuitable

unsuitable

Bacterial Suspensions

good

good

unsuitable

ok

Cell fragment suspensions

good

good

unsuitable

good

Diffraction studies

good

good

unsuitable

unsuitable

High resolution microscopy, biology

good

good

unsuitable

ok

High resolution microscopy, materials

good

good

unsuitable

ok

High temperature techniques/ heating stage

good

good

unsuitable

unsuitable

Low magnification microscopy

ok

good

ok

good

Particulate suspension, biological

ok

good

ok

good

Particulate suspension, non-biological

ok

good

ok

ok

ok

good

ok

good

good

good

ok

ok

ok

good

ok

good

good

good

unsuitable

unsuitable

EDS (energy dispersive spectrometry)

good

good

unsuitable

ok

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Carbon/Formvar film coated grids, Carbon ~15nm, Formvar ~20-30nm.

Prod #

Description

Per Grid

Package Price

$1.49

$74.50, pkg/50

Purchase Order Information

$4.99

$174.75, pkg/25

$1.49

$74.50, pkg/50

Purchase Order Information

$6.99

$174.75, pkg/25

$1.49

$74.50, pkg/50

Purchase Order Information

$6.99

$174.75, pkg/25

Although the carbon film could be very thin and usually presents no big problem in obscuring a sample, for high resolution studies of unstained biological macromolecules any interference on the beam can be problematic. For high resolution studies, holey grids are used in conjunction with freeze-sample (cryo) electron microscopy. Similar to normal carbon coated grids, holey grids are covered with a fine layer of carbon. However, as part of the preparation process, the carbon  film is deposited in such a way that there are holes of a desired size in the carbon.

One of the purposes of these holes is to eliminate any absorption and scattering of the electron beam by the carbon film, which will generate noise and obstruct the signal. Because cryo EM does not use staining, any elimination of background noise is desirable. The holes also allow for "pockets" of solvent to form. Within these pockets, the specimen remains fully hydrated, even when the sample has been frozen.

A problem can arise when holey grids are used in conjunction with proteins that are positively charged, such as DNA binding proteins. Because carbon film has a slight negative charge, especially after glow discharging, it readily attracts positively charged proteins. Therefore, such a protein will preferentially land on the carbon as opposed to the holes. A workaround has been developed using a secondary carbon layer. A holey grid is made as described above. Before depositing the sample, however, a very thin layer of carbon is deposited above the original film. Because this carbon is continuous, there is no preference to where the protein will lay down. Furthermore, the layer is thin enough to not have a great impact on the signal to noise ratio of the sample.

1

2

3

4

5

thin holey

carbon film

thick holey

carbon film

holey carbon

/carbon film

holey formvar

film

holey carbon

/formvar film

Protein, single particle, negative stained

unsuitable

unsuitable

unsuitable

unsuitable

unsuitable

Protein, single particle, cryo

good

good

good

ok

good

Protein, 2D crystals, negative stained

unsuitable

unsuitable

unsuitable

unsuitable

unsuitable

Protein, 2D crystals, cryo

good

good

good

unsuitable

good

Polymer, lighter elements

good

good

good

unsuitable

good

Bacterial Suspensions

good

good

good

unsuitable

ok

Cell fragment suspensions

good

good

good

unsuitable

good

Diffraction studies

good

good

good

ok

ok

High resolution microscopy, biology

good

good

good

unsuitable

good

High resolution microscopy, materials

good

good

good

unsuitable

good

High temperature techniques/ heating stage

good

good

good

unsuitable

unsuitable

Low magnification microscopy

good

good

good

ok

good

Particulate suspension, biological

good

good

good

ok

good

Particulate suspension, non-biological

good

good

good

ok

ok

good

good

good

ok

good

good

good

good

ok

good

good

good

good

ok

good

good

good

good

unsuitable

good

EDS (energy dispersive spectrometry)

good

good

good

unsuitable

good

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$62.25, pkg/25

Purchase Order Information

$199.75, pkg/25

$62.25, pkg/25

Purchase Order Information

$199.75, pkg/25

$62.25, pkg/25

Purchase Order Information

$199.75, pkg/25

A lacey network support film. The holes in the lacey support film vary in size from less than a quarter micron to more than 10 microns making them ideal for any type of specimen. Lacey support films are extremely strong and withstand vigorous specimen preparation treatment. The specimen material is supported by the film network but lies across or protrudes into the holes of the mesh. This allows high definition imaging without the effects of underlying support material.
 

Lacey films can be used for specimens ranging from large crystals and other particulate material to virus particles. Smaller particles, such as viruses or bacteria, tend to adhere around the inner edges of the holes, an ideal situation for high resolution microscopy. Lacey films are also ideal for selected area electron diffraction imaging. We offer two types of lacey film:

A problem can arise when holey grids are used in conjunction with proteins that are positively charged, such as DNA binding proteins. Because carbon film has a slight negative charge, especially after glow discharging, it readily attracts positively charged proteins. Therefore, such a protein will preferentially land on the carbon as opposed to the holes. A workaround has been developed using a secondary carbon layer. A holey grid is made as described above. Before depositing the sample, however, a very thin layer of carbon is deposited above the original film. Because this carbon is continuous, there is no preference to where the protein will lay down. Furthermore, the layer is thin enough to not have a great impact on the signal to noise ratio of the sample

1

2

Protein, single particle, negative stained

unsuitable

good

Protein, single particle, cryo

good

good

Protein, 2D crystals, negative stained

unsuitable

good

Protein, 2D crystals, cryo

good

good

Polymer, lighter elements

good

good

Bacterial Suspensions

good

good

Cell fragment suspensions

ok

good

Diffraction studies

ok

good

High resolution microscopy, biology

good

good

High resolution microscopy, materials

ok

good

High temperature techniques/ heating stage

good

good

Low magnification microscopy

ok

good

Particulate suspension, biological

ok

good

Particulate suspension, non-biological

ok

good

ok

good

good

good

ok

good

good

good

EDS (energy dispersive spectrometry)

good

good

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Four reasons to use Quantifoil:
1. With the known size of the pore of the Quantifoil, one can estimate the size of a particle observed directly.

2. With the defined size and pitch of the holes in the Quantifoil one can use automated electron microscopy for the first time.

3. The Quantifoil 7/2 gives a good portion of "free" area.
 

4. Hole size and hole distribution uniform over a wide range

These grids have been cleaned and trested very carefully, therefore, no any plastics film and less charging under electron beam

1

2

Application

Protein, single particle, negative stained

unsuitable

good

Protein, single particle, cryo

good

good

Protein, 2D crystals, negative stained

unsuitable

good

Protein, 2D crystals, cryo

good

good

Polymer, lighter elements

good

good

Bacterial Suspensions

good

good

Cell fragment suspensions

ok

good

Diffraction studies

ok

good

High resolution microscopy, biology

good

good

High resolution microscopy, materials

ok

good

High temperature techniques/ heating stage

good

good

Low magnification microscopy

ok

good

Particulate suspension, biological

ok

good

Particulate suspension, non-biological

ok

good

ok

good

good

good

ok

good

good

good

EDS (energy dispersive spectrometry)

good

good

QUANTIFOIL^?/sup> with circular holes is mainly used in cryo-EM. The roundness of the holes is advantageous with respect to the formation of an ice layer of constant thickness. Some information about the preparation of vitrified specimens as well as some other application examples can be found on our applications page. The hole size that is chosen depends on the magnification used, and on whether or not one wishes to include support film in the image. Assessment of the image quality is easier when foil is included in the picture, because the power spectrum of a foil is stronger than that of unsupported ice.