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論文種別	原著
言語種別	英語
査読の有無	査読あり
表題	Rod-to-Globule Transition of pDNA/PEG–Poly(l-Lysine) Polyplex Micelles Induced by a Collapsed Balance Between DNA Rigidity and PEG Crowdedness
掲載誌名	正式名：Small (Weinheim an der Bergstrasse, Germany) 略　 称：Small ISSNコード：16136810/16136829
掲載区分	国外
巻・号・頁	12(9),pp.1193-1200
総ページ数	8
著者・共著者	Theofilus A. Tockary, Kensuke Osada, Yusuke Motoda, Shigehiro Hiki, Qixian Chen, Kaori M. Takeda, Anjaneyulu Dirisala, Shigehito Osawa, Kazunori Kataoka
発行年月	2015/10/01
概要	The role of poly(ethylene-glycol) (PEG) in rod-shaped polyplex micelle structures, having a characteristic core of folded plasmid DNA (pDNA) and a shell of tethered PEG chains, is investigated using PEG-detachable polyplex micelles. Rod shapes undergo change to compacted globule shapes by removal of PEG from polyplex micelles prepared from block copolymer with acid-labile linkage between PEG and poly(l-lysine) (PLys) through exposure to acidic milieu. This structural change supports the previous investigation on the rod shapes that PEG shell prevents the DNA structure from being globule shaped as the most favored structure in minimizing surface area. Noteworthy, despite the PEG is continuously depleted, the structural change does not occur in gradual shortening manner but the rod shapes keep their length unchanged and abruptly transform into globule shapes. Analysis of PEG density reveals the transition occurred when tethered PEG of rod shapes has decreased to a critical crowdedness, i.e., discontacted with neighboring PEG, which eventually illuminates another contribution, rigidity of DNA packaged as bundle in the rod shapes, in addition to the steric repulsion of PEG, in sustaining rod shapes. This investigation affirms significant role of PEG and also DNA rigidity as bundle in the formation of rod-shaped structures enduring the quest of compaction of charge-neutralized DNA in the polyplex micelles.
DOI	10.1002/smll.201501815