Confinement spectroscopy: A novel approach to force spectroscopy*

In physics DNA is readily described by its mechanical properties, neglecting its chemical composition. By studying variations in these properties conclusions can be drawn about the interaction between DNA and both its environment and also ligand binding to DNA. These investigations are normally performed by force spectroscopy using optical or magnetic tweezers associated with an elaborate experimental setup. We introduce confinement spectroscopy, as a complementary technique, where a continuously variable degree of spatial restriction is applied to the molecule in a fluidic funnel-like geometry. By driving the molecule along the funnel, an extension versus confinement curve is obtained. This curve contains not only information regarding the molecule elasticity, but also new details concerning the self- and surface-interactions of the molecule. It is also easily integrated into lab-on-a-chip devices.