Hook Formation of Electrically Driven DNA Collisions with Finite-Sized Obstacles

ABSTRACTWe present a comprehensive study of the hooking mechanism of a single DNA molecule in electrophoretic motion colliding with a single microfabricated obstacle. During a collision, DNA impacts an obstacle and deforms. The impact conditions dictate whether this collision results in a “roll-off” event or “hooking” event. Our objective is to better understand the physics of a collision. Specifically, we note that a finite-sized insulating obstacle induces local electric field gradients that can enhance the size-dependent hooking probability. We validate that the hooking mechanism is analogous to a polymer in a transient, non-homogeneous elongational field with a strength characterized by the Deborah number, De. We then show that hook formation increases with De for finite-sized obstacles in the regime De<40.