Skip to main content
. 2015 Sep 3;44(1):e7. doi: 10.1093/nar/gkv866

Figure 1.

Figure 1.

DNA pulley system. (A) Schematic of the experiment. The silicon nitride knife is held fixed, while a square capillary carrying a magnetically stretched molecule of DNA on its exterior is brought toward the knife edge (1) until the DNA makes contact with the blade (2). Further movement of the capillary drags the DNA over the blade edge in a pulley fashion (3,4). (B–E) Images of the blade and magnet. Arrows indicate location of the blade. (B and C) Stereomicroscope images of a silicon wafer supporting a silicon nitride blade (not visible) on one face and a permanent magnet glued to the opposite face. (D­ and E) Scanning electron microscope images of the silicon nitride blade. The blade protrudes 10–20 μm from the silicon wafer and has a thickness of 55 nm. (F) Experimental setup. The capillary carrying the DNA is mounted rigidly in a sample chamber, which is held by a piezoelectric positioning stage. Coarse approach of the blade to the DNA is achieved via a micromanipulator; the blade is then held fixed while the capillary and sample chamber are moved by the piezoelectric stage.