DNA-mediated nanoparticle crystallization into Wulff polyhedra

Abstract

Crystallization is a fundamental and ubiquitous process much studied over the centuries. But although the crystallization of atoms is fairly well understood, it remains challenging to predict reliably the outcome of molecular crystallization processes that are complicated by various molecular interactions and solvent involvement. This difficulty also applies to nanoparticles: high-quality three-dimensional crystals are mostly produced using drying and sedimentation techniques that are often impossible to rationalize and control to give a desired crystal symmetry, lattice spacing and habit (crystal shape). In principle, DNA-mediated assembly of nanoparticles offers an ideal opportunity for studying nanoparticle crystallization: a well-defined set of rules have been developed to target desired lattice symmetries and lattice constants, and the occurrence of features such as grain boundaries and twinning in DNA superlattices and traditional crystals comprised of molecular or atomic building blocks suggests that similar principles govern their crystallization. But the presence of charged biomolecules, interparticle spacings of tens of nanometres, and the realization so far of only polycrystalline DNA-interconnected nanoparticle superlattices, all suggest that DNA-guided crystallization may differ from traditional crystal growth. Here we show that very slow cooling, over several days, of solutions of complementary-DNA-modified nanoparticles through the melting temperature of the system gives the thermodynamic product with a specific and uniform crystal habit. We find that our nanoparticle assemblies have the Wulff equilibrium crystal structure that is predicted from theoretical considerations and molecular dynamics simulations, thus establishing that DNA hybridization can direct nanoparticle assembly along a pathway that mimics atomic crystallization.

DNA-mediated engineering of multicomponent enzyme crystals

“…To test whether DNA-functionalized proteins form similar lattices, aggregates containing an equimolar ratio of two proteins, or a binary system consisting of a protein and a SNA-AuNP conjugate, were heated to a temperature above their melting point, but below the temperature at which protein unfolding begins, and slowly cooled to 20°C at a rate of 0.01°C/min to promote the formation of the thermodynamically stable product. We have recently shown that, compared with an alternative procedure where aggregates are annealed at a temperature slightly below their melting temperature, slowly cooling NP-containing solutions from a dissociated state favors the formation of single crystals over polycrystalline aggregates (11). The rate of 0.01°C/min was determined empirically, after observing that faster cooling rates yielded illdefined single crystals or polycrystalline aggregates (11)…”

“…With such methods, one can make architectures with well-defined lattice parameters (6)(7)(8)(9)(10)(11)(12), symmetries (4,8,10,12), and compositions (10,12,13), but to date they have been confined primarily to the use of hard inorganic nanoparticles (NPs) or highly branched pure nucleic-acid materials (2,14,15). In contrast, Nature's most powerful and versatile nanostructured building blocks are proteins and are used to effect the vast majority of processes in living systems (16).…”

“…S1). When NPs bearing complementary sticky ends are combined, heated to a temperature sufficient to disrupt these multivalent interactions, and then slowly cooled to room temperature, the reversible formation of many individually weak interparticle interactions collectively favor the formation of thermodynamically stable single-crystalline superlattices over kinetically trapped amorphous aggregates (11). Based on this principle, the inclusion of functional proteins into DNA-mediated superlattices should be possible, provided that their surfaces can be sufficiently functionalized with oligonucleotides while leaving their native structures intact, which is crucial to maintaining their functionality.…”

Colloquium : Toward living matter with colloidal particles

“…The interactions between different colors can be made orthogonal to one another by judicious choices of the sequences. Such schemes have been used to assemble colloidal crystals (Auyeung et al, 2014;Kim et al, 2006;Macfarlane et al, 2011;Martinez-Veracoechea et al, 2011;Nykypanchuk et al, 2008;Park et al, 2008), gels (Di Michele et al, 2013), and clusters (McGinley et al, 2013;Schade et al, 2013).…”

Observation of Metal Nanoparticles for Acoustic Manipulation

“…For example, metal nanoparticles can be used as structural building blocks to construct more complex objects in a bottom‐up fashion, holding promise for nanoelectronics and nanorobotics applications 32, 33. In addition, gold or silver nanoparticle aggregate system has been proved to be an excellent substrate for surface‐enhanced Raman scattering applications, which provides the ability to significant amplify the Raman signal of nearby target molecules 34, 35.…”