title: Molecular expansion of an individual coiled DNA on a graphite surface.
abstract: Direct visualization and manipulation of a single polymer on a solid surface in fluid can greatly contribute to our understanding of polymer dynamics and physics relevant to many practical applications. In this paper, the authors report a novel phenomenon that a randomly coiled DNA molecule can be gradually expanded to form a spiral-like pattern by repeatedly rotating a water droplet on a graphite surface where the DNA molecule was deposited. The process of DNA expansion was traced using atomic force microscopy relocation imaging. A simple theoretical model based on the analysis of centrifugal and resistant forces exerted on the DNA molecule during the manipulation was presented to explain the formation of the spiral-like pattern. This study should provide us insight into the movement of polymers on a solid surface under fluid flow.
authors.affiliation: Laboratory of Physical Biology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800, People's Republic of China.
authors.forename: Huabin
authors.initials: H
authors.lastname: Wang
authors.forename: Xinyan
authors.initials: X
authors.lastname: Wang
authors.forename: Huabing
authors.initials: H
authors.lastname: Li
authors.forename: Xuehua
authors.initials: X
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Jun
authors.initials: J
authors.lastname: Hu
mesh_terms: D000327:Adsorption; D010582:Bacteriophage lambda; D004279:DNA, Viral / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D010316:Particle Size; D013499:Surface Properties
chemical_list: D004279:DNA, Viral; D006108:Graphite