Innovation and Partnerships Office

High-Affinity Specimen Support Film for Electron Microscopy 2015-002


  • Sample preparation for electron microscopy of biological macromolecules


  • Protective, soluble coating ensures long shelf life, enabling commercial distribution
  • Employs streptavidin monolayer-crystals for a combination of high affinity and specificity when binding macromolecules
  • Affinity binding to the substrate prevents unwanted interaction with the air-water interface of very thin specimens
  • Thin carbon backing enhances stability and reduces risk of charging in the electron beam
  • Crystalline structure of the streptavidin layer eases removal of background during image processing


Researchers at Berkeley Lab have invented an enhanced support film designed to improve the efficiency of cryogenic electron microscopy (cryo-EM) experiments. These specimen-support films can be manufactured and stored for long periods, enabling their commercial production and distribution. This allows researchers to carry out cryo-EM experiments without the need to prepare the support films immediately before use.

The films utilize streptavidin monolayer crystals, which selectively bind appropriately tagged macromolecules. This type of affinity binding is well established in biochemical work as a superior way to immobilize macromolecules of interest. In addition, the image of the streptavidin crystal serves as a fiducial that improves the ability of researchers to correct the unavoidable specimen motion that occurs in the electron beam. Finally, the Berkeley Lab film has a thin carbon layer evaporated onto the back of the film that provides stability not present in earlier films of this type.

Cryogenic electron microscopy, which ideally allows the observation of biological specimens in their native state, is carried out in many hundreds of laboratories across the globe. The superior specimen-binding properties and long shelf life of the Berkeley Lab specimen support films enables commercial availability, making them a better and ultimately more economical choice for the user.

STATUS: Patent pending. Available for licensing or collaborative research.

DEVELOPMENT STAGE: Prototype tested in lab.