A new optical method for characterizing single molecule interactions based on dark field microscopy

Single-molecule techniques continue to gain in popularity in research disciplines such as the study of intermolecular interactions. These techniques provide information that otherwise would be lost by using bulk measurements that deal with a large number of molecules. We describe in this report the motion of tethered DNA molecules that have been tagged with gold nanobeads and observed under dark field microscopy to study single molecular interactions (SMI). We further report on the derivation and use of several physical parameters and how these parameters change under differing experimental conditions.