High-quality mapping of DNA-protein complexes by dynamic scanning force microscopy.

Biomolecular complexes, nanocircles and aggregates of DNA and streptavidin (STV) are studied by dynamic scanning force microscopy. More structural details are observed with an improved dynamic mode assisted with a special feedback circuit (Q-control), as shown in the picture. Under otherwise identical conditions, these improvements indicate that the well cited models relating enlarged lateral size to the finite geometry of the SFM tip have to be modified for soft samples susceptible to tip-sample interactions.