Resolution cryogenic microscopy

Within the last one and a half decades, it became possible to perform experiments directly on the atomic and molecular level. This came with the improvement of existing experimental techniques such as electron microscopy, where the resolution was increased to make single atoms visible [1] high-resolution spectroscopy of single ions or atoms trapped in a radio frequency field or in focused laser beams [2-4] and the spectroscopic isolation of single molecules in solids at cryogenic temperatures [5-7], which evolved from spectral hole-burning spectroscopy. 

Cryogenic transmission electron microscopy (Cryo-TEM) or cryogenic high resolution transmission electron microscopy (Cryo-HRTEM) involves the observation of samples of vitrified macromolecules. 

With the advent of cryogenic scanning tunneling microscopy (STM) it became possible to achieve vacuum tunneling gap conditions between sample and counter electrode, and to achieve atomic resolution on the surfaces of these materials. Vacuum tunneling is considered to be the best experimental situation, because it can avoid chemical reactions on the interface between the specimen and the insulating layer. In parallel to the above advancement, various physical properties of these materials have been intensively investigated, and many unique features of HTSC have been revealed. 

Different modes of operation of AFM may be applied to the characterisation of biopolymers. As biopolymers differ in their rigidity (Young s modulus), their responses to the normal and sheer forces apphed by the AFM tip will also differ. As different modes of AFM are available, the user can forego resolution in order to minimise sample distortion (as in the case of tapping mode atomic force microscopy), or improve the resolution using noncontact or cryogenic AFM. 

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