QUANTIFOIL – Holey Carbon Films


QUANTIFOIL ® is a perforated support foil with pre-defined hole size, shape and arrangement. It has advantages in electron microscopy (EM) or low-energy electron point source (LEEPS) microscopy when compared with conventional holey film.

QUANTIFOIL ® is offered with circular and square, orthogonal arranged holes. Films with different hole sizes and bar widths are available. Carbon is the standard material that makes the foil.

QUANTIFOIL® is a superior quality of holey carbon film, which facilitates the use of automation in TEM. (e.g. The National Resource for Automated Molecular Microscopy, at the Scripps Research Institute, has developed a system, called Leginon, for automatically acquiring images from a transmission electron microscope).

The surface properties of QUANTIFOIL® holey carbon support film, especially the wetting properties, may have to be adapted according to one’s particular requirements. Untreated aging QUANTIFOIL® tends to be hydrophobic. Hydrophillicity of the foil can be achieved by glow discharging in residual air or by metal coating.

QUANTIFOIL® in low-energy electron point source (LEEPS) microscopy. Quantifoil® with a regular pattern is required in order to be able to distinguish an object, which is spanned over a hole. An object cannot be discriminated from the support in the case of conventional holey support film. (H.W. Fink & C. Schonenberger, University of Basel, used QUANTIFOIL® for the measurement of electrical current through DNA molecules.)

The foil is ~12 nm thick and mounted on either copper, nickel or gold grids with either square or round holes of different sizes.

Holey films with 2µ round holes are used at magnifications between 30,000x and 40,000x.

QUANTIFOIL® with Circular Holes

QUANTIFOIL ® with circular holes is used in cryo-electron tomographic reconstruction. The roundness of the holes is advantageous with respect to the formation of an ice layer of constant thickness. The whole size 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.

  • QUANTIFOIL® R 3.5/1 may be preferred over foils with smaller holes if the carbon film should be outside the frame of the image. This option can be desirable in the case of extended objects, such as filamentous objects, for example.

  • QUANTIFOIL® R 1/4 may be preferred over R 1.2/1.3, when an increased tolerance with respect to the position of beam, and a larger beam diameter are desired, such as in the case of automated image acquisition.

  • QUANTIFOIL® R 0.6/1 Hole size is 0.5µ. Space between holes is 1µ. Center to center is 1.6µ (hole size may be as large as 1µ).
  • QUANTIFOIL® R 5/20 Hole size is 5µ. Space between holes is 20µ. Center to center is 25µ.
  • QUANTIFOIL® R 2/4 may be preferred over R 2/2, when an increased tolerance with respect to the position of beam, and a larger beam diameter are desired, such as in the case of automated image acquisition.

  • QUANTIFOIL® R 2/2 Holey films with 2 µm circular holes are used at magnifications between 30,000x and 40,000x.

  • QUANTIFOIL® R 2/1 has more open area than R 2/2. It is used when focusing is carried out on the edge of a hole burnt in the ice in a neighboring hole instead of on the foil adjacent to the hole. 

  • QUANTIFOIL® R 1.2/1.3 A foil with ~1.2µm circular holes and a spacing of ~2.5 µm between the holes. This type is used at magnifications around 50,000x.

QUANTIFOIL® with Square Holes

QUANTIFOIL® with square holes and relatively narrow bars can be used in EM to support a thin carbon film, which by itself is too fragile to span a grid square. Alternatively, this holey film can directly support an object that is larger than the holes.

  • QUANTIFOIL® S 7/2 constitutes an optimum between a maximum of open area on the one hand, and mechanical stability on the other hand.

QUANTIFOIL® with Different Hole Shapes

  • QUANTIFOIL® Multi A is a holey film, which consists of various pattern hole sizes, shapes and arrangements is repeated. In addition to round holes, the pattern includes oval-shaped ones, which appear round at high tilt angles (~70°). The diameters of the round holes are about 1, 1.4 and 2µ, and the bar widths range from 0.5 to 4µ. The oval holes in the foil have a dimension of 8 x 2µ and 4 x 1µ

QUANTIFOIL® with Hexagonal Geometry

This type of QUANTIFOIL® is meant for slot grids. It was especially designed for supporting serial thin sections. It offers an optimum between mechanical stability on the one hand and background-free area on the other hand. The foil is thin enough to allow those parts of the sections that lie on the bars to be interpreted. In this way, the information in the sections can be interpreted to the maximum.

  • QUANTIFOIL® Hex 15 A foil with hole size of 26µm (diameter of inscribed circle) and a repeating distance of 41 µm, the side length of the holes and the bar width are 15 µm.

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