title: Phase behavior and critical activated dynamics of limited-valence DNA nanostars.
abstract: Colloidal particles with directional interactions are key in the realization of new colloidal materials with possibly unconventional phase behaviors. Here we exploit DNA self-assembly to produce bulk quantities of "DNA stars" with three or four sticky terminals, mimicking molecules with controlled limited valence. Solutions of such molecules exhibit a consolution curve with an upper critical point, whose temperature and concentration decrease with the valence. Upon approaching the critical point from high temperature, the intensity of the scattered light diverges with a power law, whereas the intensity time autocorrelation functions show a surprising two-step relaxation, somehow reminiscent of glassy materials. The slow relaxation time exhibits an Arrhenius behavior with no signs of criticality, demonstrating a unique scenario where the critical slowing down of the concentration fluctuations is subordinate to the large lifetime of the DNA bonds, with relevant analogies to critical dynamics in polymer solutions. The combination of equilibrium and dynamic behavior of DNA nanostars demonstrates the potential of DNA molecules in diversifying the pathways toward collective properties and self-assembled materials, beyond the range of phenomena accessible with ordinary molecular fluids.
authors.affiliation: Department of Medical Biotechnology and Translational Medicine, Universitá degli Studi di Milano, I-20133 Milan, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Biffi
authors.forename: Roberto
authors.initials: R
authors.lastname: Cerbino
authors.forename: Francesca
authors.initials: F
authors.lastname: Bomboi
authors.forename: Elvezia Maria
authors.initials: EM
authors.lastname: Paraboschi
authors.forename: Rosanna
authors.initials: R
authors.lastname: Asselta
authors.forename: Francesco
authors.initials: F
authors.lastname: Sciortino
authors.forename: Tommaso
authors.initials: T
authors.lastname: Bellini
mesh_terms: D004247:DNA / Q000737:chemistry*; D032085:Isochores; D053758:Nanoparticles / Q000737:chemistry*; D044367:Phase Transition
chemical_list: D032085:Isochores; D004247:DNA
keywords: DNA nanotechnology; critical behavior; limited valence colloids
references.citation: Nat Mater. 2009 May;8(5):388-91
references.pmid: 19329992
references.citation: Nature. 2009 Sep 3;461(7260):74-7
references.pmid: 19727196
references.citation: Nat Mater. 2004 May;3(5):330-6
references.pmid: 15098025
references.citation: Nat Struct Mol Biol. 2012 May 13;19(6):623-7
references.pmid: 22580558
references.citation: Proc Natl Acad Sci U S A. 2008 Sep 16;105(37):13711-5
references.pmid: 18779565
references.citation: Phys Rev Lett. 2006 Oct 20;97(16):168301
references.pmid: 17155440
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2002 Aug;66(2 Pt 1):020803
references.pmid: 12241142
references.citation: Proc Natl Acad Sci U S A. 2006 Apr 18;103(16):6190-5
references.pmid: 16606839
references.citation: Phys Rev Lett. 2011 Feb 25;106(8):085703
references.pmid: 21405587
references.citation: J Chem Phys. 2008 Apr 14;128(14):144504
references.pmid: 18412456
references.citation: Nat Mater. 2012 Apr 29;11(6):518-22
references.pmid: 22543302
references.citation: Proc Natl Acad Sci U S A. 2004 Jan 20;101(3):717-22
references.pmid: 14709674
references.citation: Top Curr Chem. 2012;318:225-79
references.pmid: 21826603
references.citation: Proc Natl Acad Sci U S A. 2008 Jan 29;105(4):1111-7
references.pmid: 18212117
references.citation: Proc Natl Acad Sci U S A. 2012 Jan 24;109(4):1110-5
references.pmid: 22233803
references.citation: Nature. 2012 Nov 1;491(7422):51-5
references.pmid: 23128225
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2002 Feb;65(2 Pt 1):021802
references.pmid: 11863550
references.citation: Science. 2007 Nov 23;318(5854):1276-9
references.pmid: 18033877
references.citation: Nature. 2003 Jan 23;421(6921):427-31
references.pmid: 12540916
references.citation: Nature. 2011 Jan 20;469(7330):381-4
references.pmid: 21248847
references.citation: Nat Mater. 2004 Jan;3(1):38-42
references.pmid: 14704783
references.citation: Proc Natl Acad Sci U S A. 2001 Nov 6;98(23):12996-3001
references.pmid: 11606775
references.citation: Nature. 2012 May 30;485(7400):623-6
references.pmid: 22660323
references.citation: Nat Mater. 2007 Aug;6(8):557-62
references.pmid: 17667968
references.citation: Chem Soc Rev. 2011 Dec;40(12):5730-44
references.pmid: 21858293
references.citation: Biomacromolecules. 2005 Nov-Dec;6(6):2943-5
references.pmid: 16283712
references.citation: Nat Rev Genet. 2006 Jul;7(7):565-75
references.pmid: 16770339
references.citation: Nat Mater. 2011 Jan;10(1):56-60
references.pmid: 21151164