Single stranded DNA: A new model system for single molecule polymer dynamics

single molecule;polymer dynamics;rolling circle replication;fluorescence microscopy

Brockman, Christopher A. ; Schroeder ; Charles M.

关键词: single molecule;    polymer dynamics;    rolling circle replication;    fluorescence microscopy;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/24412/Brockman_Christopher.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

The study of polymer dynamics has been an active area of research for many years. For nearly two decades, fluorescently-labeled double stranded DNA (dsDNA) has been the model system for studying single molecule polymer dynamics in non-equilibrium conditions. However, dsDNA is a semiflexible polymer with markedly different local molecular properties compared to flexible polymer chains, such as synthetic organic polymers. In this work, we developed a new model system for single molecule studies of flexible polymers based on single stranded DNA (ssDNA). Using a biochemical synthesis scheme called rolling circle replication, long strands (>25 µm) of ssDNA containing “designer sequences” have been generated to prevent intramolecular base pairing. Polymer chains are synthesized with amine modified bases incorporated along the backbone to facilitate labeling with fluorescent dyes. As proof-of-principle demonstration of this new chemical platform, we use epifluorescence microscopy to image individual ssDNA molecules stretching in an extensional flow generated inside a microfluidic device. It is anticipated that the model polymer system presented here will serve to promote further investigations of flexible polymer dynamics at the molecular level.