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oai:recercat.cat:2445/1347872025-12-04T20:44:16Zcom_2072_1057col_2072_478822col_2072_478917

Condensation Transition in DNA-Polyaminoamide Dendrimer Fibers Studied Using Optical Tweezers Ritort Farran, Fèlix Mihardja, S. Smith, S.B. Bustamante, C.J. Condensació Experiments Condensation Experiments 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. 2019-06-07T14:45:46Z 2019-06-07T14:45:46Z 2006-03-22 2019-06-07T14:45:47Z info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 0031-9007 https://hdl.handle.net/2445/134787 602514 eng Reproducció del document publicat a: https://doi.org/10.1103/PhysRevLett.96.118301 Physical Review Letters, 2006, vol. 96, num. 11, p. 118301 https://doi.org/10.1103/PhysRevLett.96.118301 (c) American Physical Society, 2006 info:eu-repo/semantics/openAccess 4 p. application/pdf American Physical Society Articles publicats en revistes (Física de la Matèria Condensada)