Electron microscopy analysis of soft materials with freeze-fracture techniques

Abstract

Electron microscopy (EM) is a technique that observes the complex microstructure of a sample with a resolution of several angstrom using high-energy electrons with a short wavelength. It is very effective for visualizing nanostructures that would not be observed with an optical microscope. However, there are limitations in that the observation must be carried out with a very thin film in a vacuum, and the electron beam may damage the samples. The sample may be out of the desired state or damaged, and the image may be distorted. As a solution to these problems, a freeze-fracture technique can be proposed. Freeze-fracture method is a process of rapidly freezing a sample and then fracturing it to produce a metal replica of the morphology of the bulk of the surface. This article includes an overview and principles of freeze-fracture techniques and examples of analysis of various soft structures.