Cryo-focused-ion-beam applications in structural biology.

Area of Science:

• Structural Biology
• Biophysics
• Materials Science

Background:

• Electron cryo-microscopy requires precise biological sample preparation for high-resolution ultrastructural imaging.
• Focused ion beam (FIB) microscopes, originally from materials science, are increasingly used in life sciences due to their versatility.
• Cryo-preparation techniques enable the use of FIB/SEM instruments on frozen-hydrated biological specimens.

Purpose of the Study:

• To review the applications of cryo-focused ion beam (cryo-FIB) in structural biology.
• To highlight the use of cryo-FIB for preparing specimens for transmission electron microscopy (TEM) and tomography.
• To discuss the utility of FIB/SEM tomography for 3D volumetric imaging of biological samples.

Main Methods:

• Site-specific thinning of vitrified specimens using cryo-FIB for TEM.
• Sequential material removal with ion beam and imaging with electron beam (FIB/SEM tomography).
• Application of cryo-preparation equipment with FIB/SEM instruments.

Main Results:

• Cryo-FIB enables precise control over specimen thickness, crucial for achieving high resolution in TEM.
• FIB/SEM tomography allows for the acquisition of three-dimensional volumetric data from biological specimens.
• The combined approach of cryo-FIB/SEM facilitates advanced ultrastructural analysis.

Conclusions:

• Cryo-FIB is a powerful tool for both preparing samples for TEM cryo-tomography and for direct 3D imaging via cryo-FIB/SEM tomography.
• Precise sample preparation using cryo-FIB is essential for advancing high-resolution biological imaging.
• FIB/SEM technology offers versatile solutions for complex biological structure investigations.