Nanofluidic channel fabrication and manipulation of DNA molecules

Confining DNA molecules in a nanofluidic channel, particularly in channels with cross sections comparable to the persistence length of the DNA molecule (about 50 nm), allows the discovery of new biophysical phenomena. This sub-100 nm nanofluidic channel can be used as a novel platform to study and analyze the static as well as the dynamic properties of single DNA molecules, and can be integrated into a biochip to investigate the interactions between protein and DNA molecules. For instance, nanofluidic channel arrays that have widths of approximately 40 nm, depths of 60 nm, and lengths of 50 mum are created rapidly and exactly by a focused-ion beam milling instrument on a silicon nitride film; and the open channels are sealed with anodic bonding technology. Subsequently, lambda phage DNA (lambda-DNA; stained with the fluorescent dye, YOYO-1) molecules are introduced into these nanoconduits by capillary force. The movements of the DNA molecules, e.g. stretching, recoiling, and transporting along channels, are studied with fluorescence microscopy.