Títol:
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Condensation Transition in DNA-Polyaminoamide Dendrimer Fibers Studied Using Optical Tweezers
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Autor/a:
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Ritort Farran, Fèlix; Mihardja, S.; Smith, S.B.; Bustamante, C.J.
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Altres autors:
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Universitat de Barcelona |
Abstract:
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When mixed together, DNA and polyaminoamide dendrimers form fibers that condense into a compact structure. We use optical tweezers to pull condensed fibers and investigate the decondensation transition by measuring force-extension curves (FECs). A characteristic force plateau (around 10 pN) and hysteresis between the pulling and relaxation cycles are observed for different dendrimer sizes, indicating the existence of a first-order transition between two phases (condensed and extended) of the fiber. Upon salt variation FECs change noticeably confirming that electrostatic forces drive the condensation transition. We propose a simple model for the decondensing transition that qualitatively reproduces the FECs and which is confirmed by atomic force microscopy images. |
Matèries:
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-Condensació -Experiments -Condensation -Experiments |
Drets:
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(c) American Physical Society, 2006
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Tipus de document:
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Article Article - Versió publicada |
Publicat per:
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American Physical Society
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