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

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

Quantifoil® is generally delivered as a carbon foil; it can be reinforced with plastic film. The standard thickness for the carbon foil is 12nm; other thicknesses between 10 and 25nm can be made upon request. The grids are packed with their coated side toward the center of the grid box.