Observation techniques of nucleic acids and nucleoprotein complexes by AFM

The experimenter who whishes to observe biomolecules can choose between several systems of imagery, including the atomic force microscopy (AFM). Obtaining an image via AFM is achieved by scanning a surface with a microlever ending in a nanometer-sized point. The movements of the microlever are controlled by the deformations of a piezo-electric ceramic under the effects of the applied voltage. Thus the surface of the substrate, the DNA and possibly proteins interact. After having recalled the basic operating principles of the AFM, this article allows for the theoretical and experimental establishment of the conditions for obtaining accurate information concerning the specific interaction between the biomolecules. This technique is essentially improved by increasing the lateral resolution and the scanning speed.