A general strategy for the DNA-mediated self-assembly of functional nanoparticles into heterogeneous systems
TL;DR: This work reports a general strategy for the creation of heterogeneous nanoparticle superlattices using DNA and carboxylic-based conjugation, and shows that nanoparticles with all major types of functionality--plasmonic, magnetic, catalytic, and luminescent--can be incorporated into binary systems in a rational manner.
Abstract: Nanoparticles coated with DNA molecules can be programmed to self-assemble into three-dimensional superlattices. Such superlattices can be made from nanoparticles with different functionalities and could potentially exploit the synergetic properties of the nanoscale components. However, the approach has so far been used primarily with single-component systems. Here, we report a general strategy for the creation of heterogeneous nanoparticle superlattices using DNA and carboxylic-based conjugation. We show that nanoparticles with all major types of functionality--plasmonic (gold), magnetic (Fe2O3), catalytic (palladium) and luminescent (CdSe/Te@ZnS and CdSe@ZnS)--can be incorporated into binary systems in a rational manner. We also examine the effect of nanoparticle characteristics (including size, shape, number of DNA per particle and DNA flexibility) on the phase behaviour of the heterosystems, and demonstrate that the assembled materials can have novel optical and field-responsive properties.
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TL;DR: This review discusses efforts to create next-generation materials via bottom-up organization of nanocrystals with preprogrammed functionality and self-assembly instructions, and explores the unique possibilities offered by leveraging nontraditional surface chemistries and assembly environments to control superlattice structure and produce nonbulk assemblies.
Abstract: Chemical methods developed over the past two decades enable preparation of colloidal nanocrystals with uniform size and shape. These Brownian objects readily order into superlattices. Recently, the range of accessible inorganic cores and tunable surface chemistries dramatically increased, expanding the set of nanocrystal arrangements experimentally attainable. In this review, we discuss efforts to create next-generation materials via bottom-up organization of nanocrystals with preprogrammed functionality and self-assembly instructions. This process is often driven by both interparticle interactions and the influence of the assembly environment. The introduction provides the reader with a practical overview of nanocrystal synthesis, self-assembly, and superlattice characterization. We then summarize the theory of nanocrystal interactions and examine fundamental principles governing nanocrystal self-assembly from hard and soft particle perspectives borrowed from the comparatively established fields of micro...
1,376 citations
TL;DR: The two main approaches to creating stiff bonds, based on DNA-based materials synthesis, are reviewed, offering perhaps the most versatile way of organizing optically active materials into architectures that exhibit unusual and deliberately tailorable plasmonic and photonic properties.
Abstract: For over half a century, the biological roles of nucleic acids as catalytic enzymes, intracellular regulatory molecules, and the carriers of genetic information have been studied extensively. More recently, the sequence-specific binding properties of DNA have been exploited to direct the assembly of materials at the nanoscale. Integral to any methodology focused on assembling matter from smaller pieces is the idea that final structures have well-defined spacings, orientations, and stereo-relationships. This requirement can be met by using DNA-based constructs that present oriented nanoscale bonding elements from rigid core units. Here, we draw analogy between such building blocks and the familiar chemical concepts of "bonds" and "valency" and review two distinct but related strategies that have used this design principle in constructing new configurations of matter.
1,081 citations
Cites background from "A general strategy for the DNA-medi..."
...Indeed, when loosely packed single-stranded oligonucleotides (78) or extremely long duplexed linker strands (93) are used to direct anisotropic particle association, assemblies that indicate isotropic interactions are observed because the DNA is too conformationally flexible to retain the symmetry of the rigid scaffold to which it is anchored; these conditions do not favor the use of anisotropic particles to create directional nanoscale bonds....
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TL;DR: In this paper, the authors describe recent progress in the area of metasurfaces formed from plasmonic meta-atoms and identify some areas ripe for future research and indicate likely avenues for future device development.
Abstract: Metamaterials enable the tailoring of properties like dielectric permittivity and magnetic permeability. Electromagnetic excitations of metamaterial constituents and their interactions are reviewed, as well as promising future directions. Despite the extraordinary degree of interest in optical metamaterials in recent years, the hoped-for devices and applications have, in large part, yet to emerge. It is becoming clear that the first generation of metamaterial-based devices will most probably arise from their two-dimensional equivalents — metasurfaces. In this Review, we describe recent progress in the area of metasurfaces formed from plasmonic meta-atoms. In particular, we approach the subject from the perspective of the fundamental excitations supported by the meta-atoms and the interactions between them. We also identify some areas ripe for future research and indicate likely avenues for future device development.
858 citations
TL;DR: The origin of DNA nanotechnology is reviewed, followed by summarizing state-of-the-art strategies for the construction of DNAnanostructures and drug payloads delivered by DNA nanovehicles and challenges and opportunities for DNA nanostructure-based drug delivery.
Abstract: Over the past decade, we have seen rapid advances in applying nanotechnology in biomedical areas including bioimaging, biodetection, and drug delivery. As an emerging field, DNA nanotechnology offers simple yet powerful design techniques for self-assembly of nanostructures with unique advantages and high potential in enhancing drug targeting and reducing drug toxicity. Various sequence programming and optimization approaches have been developed to design DNA nanostructures with precisely engineered, controllable size, shape, surface chemistry, and function. Potent anticancer drug molecules, including Doxorubicin and CpG oligonucleotides, have been successfully loaded on DNA nanostructures to increase their cell uptake efficiency. These advances have implicated the bright future of DNA nanotechnology-enabled nanomedicine. In this review, we begin with the origin of DNA nanotechnology, followed by summarizing state-of-the-art strategies for the construction of DNA nanostructures and drug payloads delivered ...
628 citations
TL;DR: This work provides a theoretical foundation for X-ray scattering, considering both form factor and structure factor, as well as the use of correlation functions, which may be used to determine a particle's size, size distribution, shape, and organization into hierarchical structures.
Abstract: X-ray scattering is a structural characterization tool that has impacted diverse fields of study. It is unique in its ability to examine materials in real time and under realistic sample environments, enabling researchers to understand morphology at nanometer and angstrom length scales using complementary small and wide angle X-ray scattering (SAXS, WAXS), respectively. Herein, we focus on the use of SAXS to examine nanoscale particulate systems. We provide a theoretical foundation for X-ray scattering, considering both form factor and structure factor, as well as the use of correlation functions, which may be used to determine a particle’s size, size distribution, shape, and organization into hierarchical structures. The theory is expanded upon with contemporary use cases. Both transmission and reflection (grazing incidence) geometries are addressed, as well as the combination of SAXS with other X-ray and non-X-ray characterization tools. We conclude with an examination of several key areas of research w...
611 citations
References
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TL;DR: An exact derivation of the Scherrer equation is given for particles of spherical shape, values of the constant for half-value breadth and for integral breadth being obtained in this article, and various approximation methods which have been used are compared with the exact calculation.
Abstract: An exact derivation of the Scherrer equation is given for particles of spherical shape, values of the constant for half-value breadth and for integral breadth being obtained. Various approximation methods which have been used are compared with the exact calculation. The tangent plane approximation of v. Laue is shown to be quite satisfactory, but some doubt is cast on the use of approximation functions. It is suggested that the calculation for the ellipsoidal particle based on the tangent plane approximation will provide a satisfactory basis for future work.
6,907 citations
TL;DR: A method for assembling colloidal gold nanoparticles rationally and reversibly into macroscopic aggregates by using the specificity of DNA interactions to direct the interactions between particles of different size and composition is described.
Abstract: COLLOIDAL particles of metals and semiconductors have potentially useful optical, optoelectronic and material properties1–4 that derive from their small (nanoscopic) size. These properties might lead to applications including chemical sensors, spectro-scopic enhancers, quantum dot and nanostructure fabrication, and microimaging methods2–4. A great deal of control can now be exercised over the chemical composition, size and polydis-persity1,2 of colloidal particles, and many methods have been developed for assembling them into useful aggregates and materials. Here we describe a method for assembling colloidal gold nanoparticles rationally and reversibly into macroscopic aggregates. The method involves attaching to the surfaces of two batches of 13-nm gold particles non-complementary DNA oligo-nucleotides capped with thiol groups, which bind to gold. When we add to the solution an oligonucleotide duplex with 'sticky ends' that are complementary to the two grafted sequences, the nanoparticles self-assemble into aggregates. This assembly process can be reversed by thermal denaturation. This strategy should now make it possible to tailor the optical, electronic and structural properties of the colloidal aggregates by using the specificity of DNA interactions to direct the interactions between particles of different size and composition.
6,188 citations
IBM1
TL;DR: Thermal annealing converts the internal particle structure from a chemically disordered face- centered cubic phase to the chemically ordered face-centered tetragonal phase and transforms the nanoparticle superlattices into ferromagnetic nanocrystal assemblies that can support high-density magnetization reversal transitions.
Abstract: Synthesis of monodisperse iron-platinum (FePt) nanoparticles by reduction of platinum acetylacetonate and decomposition of iron pentacarbonyl in the presence of oleic acid and oleyl amine stabilizers is reported. The FePt particle composition is readily controlled, and the size is tunable from 3- to 10-nanometer diameter with a standard deviation of less than 5%. These nanoparticles self-assemble into three-dimensional superlattices. Thermal annealing converts the internal particle structure from a chemically disordered face-centered cubic phase to the chemically ordered face-centered tetragonal phase and transforms the nanoparticle superlattices into ferromagnetic nanocrystal assemblies. These assemblies are chemically and mechanically robust and can support high-density magnetization reversal transitions.
5,568 citations
TL;DR: In this article, the Scherrer constants of simple regular shapes have been determined for all low-angle reflections (h2 + k2 + l2 ≤ 100) for four measures of breadth.
Abstract: Existing knowledge about Scherrer constants is reviewed and a summary is given of the interpretation of the broadening arising from small crystallites. Early work involving the half-width as a measure of breadth has been completed and Scherrer constants of simple regular shapes have been determined for all low-angle reflections (h2 + k2 + l2 ≤ 100) for four measures of breadth. The systematic variation of Scherrer constant with hkl is discussed and a convenient representation in the form of contour maps is applied to simple shapes. The relation between the `apparent' crystallite size, as determined by X-ray methods, and the `true' size is considered for crystallites having the same shape. If they are of the same size, then the normal Scherrer constant applies, but if there is a distribution of sizes, a modified Scherrer constant must be used.
3,018 citations