Single Molecule Tracking of a Semiflexible Polyelectrolyte Chain in Solvent Under Uniform Electroosmotic Flows
- Authors
- Choung, Sunghun; Chun, Myung-Suk; Kim, Chongyoup
- Issue Date
- 10월-2011
- Publisher
- KOREAN PHYSICAL SOC
- Keywords
- Single molecule tracking; Polyelectrolyte; Chain conformation; Translational diffusion; Uniform flow; Rheology
- Citation
- JOURNAL OF THE KOREAN PHYSICAL SOCIETY, v.59, no.4, pp.2847 - 2854
- Indexed
- SCIE
SCOPUS
KCI
- Journal Title
- JOURNAL OF THE KOREAN PHYSICAL SOCIETY
- Volume
- 59
- Number
- 4
- Start Page
- 2847
- End Page
- 2854
- URI
- https://scholar.korea.ac.kr/handle/2021.sw.korea/111496
- DOI
- 10.3938/jkps.59.2847
- ISSN
- 0374-4884
- Abstract
- Direct single molecule tracking of a polyelectrolyte chain by using fluorescence microscopy has allowed both the assumptions and the predictions of relevant theories to be tested. The center-of-mass displacement is determined as a function of the time that elapses between images, where the radius of gyration can be estimated from a first moment of the image distribution. The translational self-diffusion for the molecule is an ensemble property of the mean square displacement (MSD) with lag time in each trajectory. Experimentally viable two-dimensional imaging of semiflexible polyelectrolyte was performed on a fluorescein-labeled xanthan chain in electroosmosis-driven uniform flow fields. The radius of gyration was almost constant under variations of the electroosmotic flow velocity determined by an externally applied electric field. We try to develop a correction of the MSD in flow field, taking into account the velocity fluctuations. Its advantage allows acquiring the linear fit for the MSD vs lag time, for a good estimate of the translational diffusion. Increasing behavior of the diffusion with increasing fluid velocity ensures a quadratic equation fit, which should connect with the convective effect. Our results exhibit a screening effect such that strong screening caused by a high ionic concentration leads to higher diffusion due to the compact chain conformation. Considering the uniform flow serves as a basis for understanding the behavior of individual polyelectrolyte chains under controlled fluidic flow in confined spaces.
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Collections - College of Engineering > Department of Chemical and Biological Engineering > 1. Journal Articles
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