title: Entropy-Driven Crystallization Behavior in DNA-Mediated Nanoparticle Assembly.
abstract: Herein, we report an example of entropy-driven crystallization behavior in DNA-nanoparticle superlattice assembly, marking a divergence from the well-established enthalpic driving force of maximizing nearest-neighbor hybridization connections. Such behavior is manifested in the observation of a non-close-packed, body-centered cubic (bcc) superlattice when using a system with self-complementary DNA linkers that would be predicted to form a close-packed, face-centered cubic (fcc) structure based solely on enthalpic considerations and previous design rules for DNA-linked particle assembly. Notably, this unexpected phase behavior is only observed when employing long DNA linkers with unpaired "flexor" bases positioned along the length of the DNA linker that increase the number of microstates available to the DNA ligands. A range of design conditions are tested showing sudden onsets of this behavior, and these experiments are coupled with coarse-grained molecular dynamics simulations to show that this entropy-driven crystallization behavior is due to the accessibility of additional microstates afforded by using long and flexible linkers.
authors.affiliation: †Department of Chemistry, ‡Department of Materials Science and Engineering, and §The International Institute of Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: Ryan V
authors.initials: RV
authors.lastname: Thaner
authors.affiliation: †Department of Chemistry, ‡Department of Materials Science and Engineering, and §The International Institute of Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: Youngeun
authors.initials: Y
authors.lastname: Kim
authors.affiliation: †Department of Chemistry, ‡Department of Materials Science and Engineering, and §The International Institute of Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: Ting I N G
authors.initials: TI
authors.lastname: Li
authors.affiliation: †Department of Chemistry, ‡Department of Materials Science and Engineering, and §The International Institute of Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Macfarlane
authors.affiliation: †Department of Chemistry, ‡Department of Materials Science and Engineering, and §The International Institute of Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: SonBinh T
authors.initials: ST
authors.lastname: Nguyen
authors.affiliation: †Department of Chemistry, ‡Department of Materials Science and Engineering, and §The International Institute of Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: Monica
authors.initials: M
authors.lastname: Olvera de la Cruz
authors.affiliation: †Department of Chemistry, ‡Department of Materials Science and Engineering, and §The International Institute of Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, United States.
authors.forename: Chad A
authors.initials: CA
authors.lastname: Mirkin
mesh_terms: D003102:Colloids / Q000737:chemistry; D003460:Crystallization; D004247:DNA / Q000737:chemistry*; D019277:Entropy; D006046:Gold / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D053758:Nanoparticles / Q000737:chemistry*; D009693:Nucleic Acid Hybridization
chemical_list: D003102:Colloids; D006046:Gold; D004247:DNA
keywords: DNA; colloidal crystals; nanomaterials; nanoparticle superlattice; self-assembly