Like silicon for electronics, DNA is the revolution-enabling material for biotechnology. It is chemically stable, readily produced with high purity, and, when spiked with well-chosen defects, its predictable structure supports a range of devices. Also like silicon, the DNA-based devices of today are being engineered on the nanoscale, where technologically relevant material properties are often dominated by aspects that are negligible in bulk. As a prime example, short (<100 bp) dsDNA cyclize much more readily than the well-studied stiffness of long (>1 kbp) dsDNA would seem to allow. Years of debate and study suggest kinking of the double helix is the explanation. We have built a DNA device that allows bent states of short dsDNA to reconfigure a micron-scale structure, so that fluorescence videomicroscopy can reveal its bend angles and their stiffness. Using this device, affectionately termed a “DNA nunchuck”, we are able to characterize the angle and stiffness of a predominant, metastable bent state in B-form dsDNA and in dsDNA with bulge and bubble defects. I will explain our approach, elaborate on these results and discuss their implications.
Deborah Fygenson, Professor, University of California - Santa Barbara
Host: John Marko