title: Gels of DNA nanostars never crystallize.
abstract: Using state-of-the-art numerical techniques, we show that, upon lowering the temperature, tetravalent DNA nanostars form a thermodynamically stable, fully bonded equilibrium gel. In contrast to atomic and molecular network formers, in which the disordered liquid is always metastable with respect to some crystalline phase, we find that the DNA nanostar gel has a lower free energy than the diamond crystal structure in a wide range of concentrations. This unconventional behavior, here verified for the first time in a realistic model, arises from the large arm flexibility of the DNA nanostars, a property that can be tuned by design. Our results confirm the thermodynamic stability of the recently experimentally realized DNA hydrogels.
authors.affiliation: Dipartimento di Fisica, Sapienza Università di Roma , Piazzale A. Moro 2, 00185 Roma, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Rovigatti
authors.forename: Frank
authors.initials: F
authors.lastname: Smallenburg
authors.forename: Flavio
authors.initials: F
authors.lastname: Romano
authors.forename: Francesco
authors.initials: F
authors.lastname: Sciortino
mesh_terms: D001483:Base Sequence; D003460:Crystallization; D004247:DNA / Q000737:chemistry* / Q000235:genetics; D020100:Hydrogels / Q000737:chemistry*; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D013696:Temperature
chemical_list: D020100:Hydrogels; D004247:DNA