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Title: Smectic phase in suspensions of gapped DNA duplexes

Smectic ordering in aqueous solutions of monodisperse stiff double-stranded DNA fragments is known not to occur, in spite of the fact that these systems exhibit both chiral nematic and columnar mesophases. Here, we show, unambiguously, that a smectic-A type of phase is formed by increasing the DNA's flexibility through the introduction of an unpaired single-stranded DNA spacer in the middle of each duplex. This is unusual for a lyotropic system, where flexibility typically destabilizes the smectic phase. We also report on simulations suggesting that the gapped duplexes (resembling chain-sticks) attain a folded conformation in the smectic layers, and argue that this layer structure, which we designate as smectic-fA phase, is thermodynamically stabilized by both entropic and energetic contributions to the system's free energy. These results demonstrate that DNA as a building block offers an exquisitely tunable means to engineer a potentially rich assortment of lyotropic liquid crystals.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [1] ;  [1] ;  [6] ;  [5] ;  [1] ;  [5]
  1. Kent State Univ., Kent, OH (United States)
  2. Forschungszentrum Julich (Germany); Chinese Academy of Sciences (CAS), Beijing (China)
  3. University of Groningen, Groningen, (Netherlands)
  4. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS)
  5. Forschungszentrum Julich (Germany)
  6. Sapienza Univ. of Rome (Italy)
Publication Date:
Grant/Contract Number:
AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 7; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES
OSTI Identifier:
1377590