Four-Arm Oligonucleotide Ni(II)−Cyclam-Centered Complexes as Precursors for the Generation of Supramolecular Periodic Assemblies

Stewart, Kristen M.; McLaughlin, Larry W.

doi:10.1021/ja037424o

Cited by 103 publications

(88 citation statements)

References 46 publications

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“…Although the one-bond-per-patch limitations renders this model inadequate for colloidal particles with large attractive surface regions, we stress here that the model mimics systems with a limited-valence bonding mechanism that retains a large degree of bonding flexibility for all experimentally relevant temperature scales. For example, one might consider colloidal particles functionalized with a limited number (f ) of long strands of DNA (refs 12,16), DNA constructs that can form a fixed number of bonds 14,17 , or even polymer networks 18 where the particles are polymerizable monomers with a fixed functionality.…”

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Liquids more stable than crystals in particles with limited valence and flexible bonds

2013

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All liquids (except helium owing to quantum effects) crystallize at low temperatures, forming ordered structures. The competition between disorder, which stabilizes the liquid phase, and energy, which leads to a preference for the crystalline structure, inevitably favours the crystal when the temperature is lowered and entropy becomes progressively less relevant. The liquid state survives at low temperatures only as a glass, an out-of-equilibrium arrested state of matter. This textbook description holds inevitably for atomic and molecular systems, where particle interactions are set by quantum-mechanical laws. The question remains whether it holds for colloidal particles, where interparticle interactions are usually short-ranged and tunable. Here we show that for patchy colloids with limited valence 1 , conditions can be found for which the liquid phase is stable even in the zero-temperature limit. Our results offer fresh cues for understanding the stability of gels 2 and the glass-forming ability of molecular network glasses 3,4 .The ability to control the selectivity and angular flexibility of interparticle interactions 5 makes it possible to provide valence to colloids. This can be done by means of chemical [6][7][8] or physical 9 patterning of the colloid surface, that is, locally changing either its chemical properties (for example, hydrophobicity), or the physical properties (for example, roughness). Exploiting valence offers enormous possibilities, some of which have been addressed in recent years, theoretically 10 , numerically 4,11,12 and experimentally 2,7,13,14 . As colloidal interactions are typically shortranged, valence provides an implicit quantization of the particle energy, which becomes essentially proportional to the (limited) number of formed bonds. In an optimal arrangement, all particles bind with their maximum number of neighbours and the system is in its lowest possible (ground) energy state. Typically, such an optimal arrangement is spatially ordered, defining the most stable crystal phase(s).In principle, when the density is not too high, it is possible to imagine disordered arrangements in which all particles are fully bonded, with exactly the same energy as the crystal. Such a state, which was recently shown to be stable in a model system for DNA-functionalized colloids 12 , is a liquid: a fluid, disordered phase at temperatures below the critical temperature. Under this unconventional condition, the stability of the system becomes controlled by its entropy, a case reminiscent of (purely entropydriven) hard-sphere particles. In this study we demonstrate that the flexibility of the bonds (encoded in the angular patch width)-a tunable quantity in the design of patchy colloidal particles-is the key element in controlling the entropy of the liquid as compared with that of the crystal. Large binding angles combined with limited valence give rise to a thermodynamically stable, fully bonded liquid phase.Department of Physics, Sapienza, Universitá di Roma, Piazzale Aldo Moro 2, I-00185, Roma,...

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Liquids more stable than crystals in particles with limited valence and flexible bonds

2013

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“…Such tetramers have also been experimentally synthesized (11). The model retains two important basic features: (i) base pair selectivity and (ii) the limitation that each ssDNA can bind to only one other ssDNA to form a dsDNA.…”

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Hierarchies of networked phases induced by multiple liquid–liquid critical points

Hsu

Largo

Sciortino

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

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Nanoparticles and colloids functionalized by four single strands of DNA can be thought of as designed analogs to tetrahedral network-forming atoms and molecules, with a difference that the attached DNA strands allow for control of the length scale of bonding relative to the core size. We explore the behavior of an experimentally realized model for nanoparticles functionalized by four single strands of DNA (a tetramer), and show that this single-component model exhibits a rich phase diagram with at least three critical points and four thermodynamically distinct amorphous phases. We demonstrate that the additional critical points are part of the Ising universality class, like the ordinary liquid-gas critical point. The dense phases consist of a hierarchy of interpenetrating networks, reminiscent of a woven cloth. Thus, bonding specificity of DNA provides an effective route to generate new nano-networked materials with polyamorphic behavior. The concept of network interpenetration helps to explain the generation of multiple liquid phases in single-component systems, suggested to occur in some atomic and molecular network-forming fluids, including water and silica. DNA functionalization ͉ nanoparticles ͉ self-assembly ͉ polyamorphism ͉ nanotechnology T echnological developments are creating a wide variety of building blocks that play the role of ''functionalized atoms'' for designed materials (1, 2). Borrowing ideas from biological specificity (3-6), it is now possible to control bonding between engineered building blocks in a selective way, moving in the direction of an effective synthetic bottom-up strategy for selfassembly. The complementary binding of base pairs, combined with the ability to directly control the base sequence, makes DNA an ideal candidate for the development of network-based, nanostructured materials (5-8). A variety of experiments (7)(8)(9)(10)(11)(12)(13)(14)(15) have demonstrated the possibility to realize nanostructured, DNAbased materials, including ordered crystal structures (9, 10).By grafting short single strands of DNA to core particles, the core can act as a ''node'' of a complex network formed when single strands combine into dsDNA. Longer linking ''arms'' may be achieved by using a double-stranded spacer near the core nanoparticle (9, 10). With an intelligent choice of the core, it is possible to control the number of attached strands and thus the nearest-neighbor coordination of the functionalized nanoparticle, providing a direct route to study materials where the bonding coordination is much less than that of spherically symmetric molecules (16). In such limited coordination systems, the general features of network formation are expected to be observed.By functionalizing the central core with four DNA strands, we expect to generate an engineered analog of tetrahedral networkforming atoms or molecules, in which the bonding contribution to the interparticle interaction energy can be tuned by modulating the length L of the DNA strand, as well as the chemical properties of the solvent....

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“…As a working example, we discuss the development of an effective potential for a macromolecule composed by a core particle decorated by a small number of short single strands (ss) DNA [11] to show (i) the importance of properly accounting for valence and bond selectivity; (ii) the need for a non-pair-wise additive effective potential. The full model is graphically explained in Fig.…”

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Effective nonadditive pair potential for lock-and-key interacting particles: The role of the limited valence

2007

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Theoretical studies of self-assembly processes and condensed phases in colloidal systems are often based on effective inter-particle potentials. Here we show that developing an effective potential for particles interacting with a limited number of "lock-and-key" selective bonds (due to the specificity of bio-molecular interactions) requires -beside the non-sphericity of the potential -a (many body) constraint that prevent multiple bonding on the same site. We show the importance of retaining both valence and bond-selectivity by developing, as a case study, a simple effective potential describing the interaction between colloidal particles coated by four single-strand DNA chains.

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Four-Arm Oligonucleotide Ni(II)−Cyclam-Centered Complexes as Precursors for the Generation of Supramolecular Periodic Assemblies

Cited by 103 publications

References 46 publications

Liquids more stable than crystals in particles with limited valence and flexible bonds

Liquids more stable than crystals in particles with limited valence and flexible bonds

Hierarchies of networked phases induced by multiple liquid–liquid critical points

Effective nonadditive pair potential for lock-and-key interacting particles: The role of the limited valence

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