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The elastic properties of single double-stranded DNA chains of different lengths as measured with optical tweezers

Optical tweezers are microscopic tools with extraordinary precision in the determination of the position (±2 nm) of a colloid (diameter: ∼2.0 μm) in 3D-space and in the measurement of small forces in the range between 0.1 and 100 pN (pN=10(−12) N). Experiments are reported in which single double-str...

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Detalles Bibliográficos
Autores principales: Salomo, M., Kegler, K., Gutsche, C., Struhalla, M., Reinmuth, J., Skokow, W., Hahn, U., Kremer, F.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer-Verlag 2006
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3776250/
https://www.ncbi.nlm.nih.gov/pubmed/24058243
http://dx.doi.org/10.1007/s00396-006-1517-4
Descripción
Sumario:Optical tweezers are microscopic tools with extraordinary precision in the determination of the position (±2 nm) of a colloid (diameter: ∼2.0 μm) in 3D-space and in the measurement of small forces in the range between 0.1 and 100 pN (pN=10(−12) N). Experiments are reported in which single double-stranded (ds)-DNA chains of different length [2,000 base pairs (bp), 3,000, 4,000, and 6,000 bp] are spanned between two colloidal particles by use of appropriate molecular linkers. For the forces applied (≤40 pN) a fully reversible and well reproducible force–extension dependence is found. The data can be well described by both the worm-like chain model or by an approach developed by R. G. Winkler. For the resulting persistence length, a pronounced dependence on the ionic concentration in the surrounding medium is found.