Single-molecule force spectroscopy is a powerful technique for studying the detailed behaviour of biopolymers such as DNA and proteins: by applying pN-scale forces to individual molecules, properties such as conformations, folding pathways, and intermolecular interaction strengths can be determined. Traditionally these studies have been carried out under static tension. The dynamic response of polymers to a sudden change in force is exper- imentally more challenging as the polymer is often coupled to an external molecular handle, which suppresses
important physics at short (∼ms) timescales. Here we use a nanopore to electrically control the application of
force to the end of a double-stranded DNA molecule; the other end of the molecule is attached to a bead held in
an optical trap. By shutting off the voltage, the fast relaxation dynamics of the free polymer end can be studied. We observe for the first time an enhanced viscous friction which arises from the rapid internal contraction of the DNA, which is fully explained by theory. These studies pave the way for new dynamic force spectroscopy experiments, such as investigations of tension propagation along biomolecules, which has applications for both polymer theory as well as biological systems such as the cytoskeleton where dynamic tension can affect cellular response.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.