2. Surfaces and AFM imaging of nucleic acids

The observation of nucleic acids or protein complexes by AFM requires these molecules to be adsorbed and spread on the surface of a substrate. Interactions between the biomolecule and the substrate must have as little influence as possible on biomolecule properties such as structure and reactivity, despite the change in dimensionality (from 3D to 2D during adsorption). This implies an adsorption compromise between surface and biomolecules, where the latter must be able to equilibrate on the surface and interact freely with their partners, while being sufficiently attached to the surface to be imaged with the best possible resolution.

Numerous types of surface have been used to date to image biomolecules and their complexes by AFM, but the user can easily select 3 whose fields of application are complementary:

• Mica...