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Please use this identifier to cite or link to this item: https://hdl.handle.net/2445/134787
Condensation Transition in DNA-Polyaminoamide Dendrimer Fibers Studied Using Optical Tweezers
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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.
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RITORT FARRAN, Fèlix, et al. Condensation Transition in DNA-Polyaminoamide Dendrimer Fibers Studied Using Optical Tweezers. Physical Review Letters. 2006. Vol. 96, num. 11, pags. 118301. ISSN 0031-9007. [consulted: 10 of June of 2026]. Available at: https://hdl.handle.net/2445/134787