AVS 52nd International Symposium
    DNA Topical Conference Tuesday Sessions
       Session DN+BI-TuM

Paper DN+BI-TuM10
Compression and Free Expansion of Single DNA Molecules in Nanochannels

Tuesday, November 1, 2005, 11:20 am, Room 311

Session: DNA Surface Characterization
Presenter: C.H. Reccius, Cornell University
Authors: C.H. Reccius, Cornell University
J.T. Mannion, Cornell University
J.D. Cross, Cornell University
H.G. Craighead, Cornell University
Correspondent: Click to Email
A variety of micromanipulation techniques have been used in the past to study the mechanical properties of DNA.@footnote 1@ Characterization of these properties is important for an understanding of DNA packing into chromatin or bacteriophage heads and also for the verification of theoretical biopolymer models. Extensive experiments have been conducted on stretching DNA in order to study its elasticity.@footnote 2@ In contrast to stretching by an external force, we are investigating the compression and subsequent free expansion of DNA molecules in artificial nanoscale devices. In this work, single lambda DNA multimers were driven through fluidic channels with a diameter of 100 nm by an electric field. Since the radius of gyration of the biomolecules was bigger than the channel diameter, their equilibrium state was no longer a sphere but instead an elongated cylinder.@footnote 3@ Forcing the stretched DNA into a channel constriction led to a compression of the molecule into a tight conformation. When the electric field was turned off, the DNA molecule slowly expanded back to the energetically favorable stretched out conformation. This expansion can be interpreted with the help of a simple polymer model based on self-avoidance effects. @FootnoteText@ @footnote 1@ Strick T. R., Dessinges M-N., Charvin G., Dekker N. H., Allemand J-F., Bensimon D., and Croquette V., Rep. Prog. Phys., 66, 1-45 (2003).@footnote 2@ Smith S. B., Finzi L., and Bustamente C., Science, 258, 1122-1126 (1992).@footnote 3@ Tegenfeldt J. O., Prinz C., Cao H., Chou S., Reisner W. W., Riehn R., Wang Y. M., Cox E. C., Sturm J. C., Silberzan P., and Austin R. H., PNAS, 101, 10979-10983 (2004).