Electron dense, heavy metal compounds of uranium, tungsten and molybdenum have long been utilized for "negative staining" in electron microscopy. As demand for ultra-fine structure in biomolecules has increased, new fine grain structure materials are required.

Polysciences, Inc. is pleased to offer uranyl formate, UO₂(CHO₂)₂- H₂O, as an advancement in negative EM staining. The fine grain structure, fast biomedical tissue fixation properties and stability of this material make it unique for many imaging protocols.

Density: 3.7g/cc
Appearance: solid yellow crystals

Photo Caption: Negative stain electron microscopy of the integrin α5β1 headpiece with and without a bound fibronectin (Fn) fragment containing Fn domains 7 to 10 (Fn9-10). a: Negative stain electron microscopy reveals that the α5β1 headpiece adopts two conformations, namely a closed (black circles) and an open conformation (white circles). b and c: Class averages representing the closed (b) and the open conformation (c). Binding of Fn9-10 fragment (arrow in c) induces the open conformation of the headpiece, while the unliganded is in the closed conformation (b). d and e: 3D reconstructions of an unliganded (d) and an Fn9-10-liganded α5β1 headpiece (e) with the fit atomc structures of the αV and β3 subunit (33) in red and blue, respectively, and of the Fn9-10 fragment (34) in white. The scale bar corresponds to 50 nm and panels b to e have a side length of 22 nm.

Electron Micrographs courtesy of Tom Walz, Harvard Medical School.