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

Paper DN+BI-TuM2
Entropic Recoil of Single DNA Molecules from Nanochannels

Tuesday, November 1, 2005, 8:40 am, Room 311

Session: DNA Surface Characterization
Presenter: J.T. Mannion, Cornell University
Authors: J.T. Mannion, Cornell University
C.H. Reccius, Cornell University
J.D. Cross, Cornell University
H.G. Craighead, Cornell University
Correspondent: Click to Email
Entropic recoil of DNA molecules from pillar arrays has previously been reported.@footnote 1@ It has been shown that this effect has the potential to separate molecules according to length.@footnote 2@ A molecule straddling the interface between two microfabricated regions with vastly different volumes of configuration space experiences a force causing it to retract from the region which has less accessible volume. We have tested a device in which DNA molecules recoil from an array of channels as opposed to pillars. Nanochannels (100nm by 100nm) connected to the end of a microchannel (40 microns by 100nm) have been fabricated in a fused silica wafer. This change in geometry eliminates the possibility of herniation, which had previously been observed for molecules recoiling from pillar arrays. Using channels instead of pillars also makes it possible to track a molecule undergoing the recoil process more precisely and to carefully observe the dynamics of this process. As a consequence, we have been able to study the recoil and drag forces in greater detail. In addition we have clearly identified molecules that enter channels in a folded manner, and can observe unfolding events during recoil. @FootnoteText@ @footnote 1@ Turner, S. W. P.; Cabodi, M.; Craighead, H. G. Phys. Rev. Lett. 2002, 88, 128103-1-128103-4.@footnote 2@ Cabodi, M.; Turner, S. W. P.; Craighead, H. G. Anal. Chem. 2002, 74, 5169-5174. .