The Boulder Lab for 3D Electron Microscopy
The Boulder laboratory for 3-D electron microscopy of cells has functioned as a nationally funded research resource since 1970. The lab has been successful in developing methods for imaging diverse cells and tissues in three dimensions (3-D) at a resolution of ~ 5 nm. The numerous features of cell structure that become visible at this level are highly informative about the mechanisms that underlie cellular processes.
The lab has accomplished this by advancing the following techniques:
1) Accurate preservation of cellular structure by rapid freezing (vitrification) and freeze substitution fixation (RF-FSF)
2) Tomographic reconstruction of 3-D data, based on images acquired as tilted projections, using high or intermediate voltage electrons
3) Effective programs for 3-D reconstruction and image modeling
More recently the facility has emphasized data collection from vitrified samples maintained in the frozen-hydrated state. This method gives better preservation than RF-FSF and is now the standard for many electron microscopy studies.
The overall strategy of the current research in the lab can be described as "Placing Molecules into Cells" with a clear focus on advancing cell biology by developing imaging technologies that will allow us to study a functional cell in 3-D at the best possible resolution. While fully exploiting the achievements of tomography on samples prepared by RF-FSF, as carried out in several collaborations and numerous service projects, we turn our focus to cryo-electron microscopy (cryo-EM) and molecular structures.
To this end we are working on pushing the resolution of cryo-electron tomography data beyond 2nm. The 3-D data we generate here are from large, irregular cellular structures and macromolecular assemblies. Our focus is not on generating atomic data, but on applying a comprehensive structural and functional approach to large complex structures such as cellular organelles and macromolecular assemblies.