US20140141211A1

US20140141211A1 - Method for self-assembly of arbitrary metal patterns on DNA scaffolds

Info

Publication number: US20140141211A1
Application number: US11/978,219
Authority: US
Inventors: Si-Ping Han; Robert Barish; Michael J. Hochberg; Saurabh Vyawahare; Hareem Maune
Original assignee: Individual
Current assignee: California Institute of Technology
Priority date: 2006-10-26
Filing date: 2007-10-26
Publication date: 2014-05-22

Abstract

The present invention relates to methods for self-assembly of arbitrarily-shaped metal nanostructures using specifically-designed patterns on nucleic acid scaffolds. The methods involve using the nucleic acid scaffolds as templates on which a second material patterned, as seed nuclei. The patterns are then selectively plated with metal using an electro-less plating process to create arbitrarily-shaped metal nanostructures that are not constrained by the structure of the scaffold. The methods herein use controlled-growth processes to actively select the dimensions, positions, and alignments of the patterns to create different arbitrary shapes of metal nanostructures.

Description

PRIORITY CLAIM

The present application claims the benefit of priority of U.S. Provisional Patent Application No. 60/854,595, filed Oct. 26, 2006, entitled “Method for self assembly of arbitrary contiguous metal patterns on DNA Scaffolds” and U.S. Provisional Patent Application No. 60/922,919, filed Apr. 11, 2007, entitled “Method for self assembly of arbitrary contiguous metal patterns on DNA scaffolds.”

STATEMENT OF GOVERNMENT INTEREST

The Unites States Government has certain rights in this invention pursuant to Grant No. FA9550-04-1-0434 awarded by the Air Force Office of Scientific Research (AFOSR).

BACKGROUND OF THE INVENTION

(1) Technical Field
The present invention relates to DNA-based nanotechnology. More specifically, the present invention relates to a method for the creation of arbitrarily-shaped metal nanostructures using DNA and other nucleic acid scaffolds.
(2) Description of Related Art
DNA-based nanotechnology is a growing field. The specificity and combinatorial programmability of the Watson-Crick binding interactions between the subunits of DNA makes the molecule an ideal candidate for creating nanostructures of set patterns. The nanometer scale structural geometry of the DNA self-assembled nanostructures also provides an ideal building block for directed self-assembly of nanometer-scale materials with sub-nanometer precision and programmability. The resulting nanostructures created from nanometer-scale materials such as metals may be used to construct devices in the fields of nanoelectronics and nanophotonics.
Previously in the field, those of ordinary skill in the art have used electroless plating techniques to plate metal upon the self-assembled DNA nanostructures. However, the metal plating is uncontrolled and results in metallization of the entire DNA nanostructure scaffold. More recently, nanowires have been fabricated using DNA scaffolds. However, no other specific shapes of metal nanostructures have been created upon DNA scaffolds that are not constrained by the structure of the scaffold itself.
Additionally, those of ordinary skill in the art have only plated metal upon double-stranded DNA scaffolds. Previous methods have not incorporated arranging seed nuclei such as nanoparticles, single-stranded DNA or any other single-stranded nucleic acid in specific patterns upon a scaffold prior to plating a metal on the scaffold and thus create arbitrarily-shaped metal nanostructures that are not constrained by the DNA scaffold itself.
The ability to form patterns upon a scaffold upon which electro-less metal plating can be directed allows for higher precision in the formation of specifically-shaped metal nanostructures. Methods with controlled-growth processes allow for active selection of the dimensions, positions, and alignments of patterns on scaffolds to create the different shapes of the metal nanostructures. Such metal nanostructures may provide for novel uses in the field of nanoelectronics and nanophotonics. Other applications include quantum electronic devices based on quantized conductance, control of electronic properties of patterned materials, plasmonic materials for concentration of light, plasmonic materials for waveguiding, plasmonic materials for nonlinear optics, X-ray and short-wavelength optics, including waveguides and gratings, semiconductor metrology standards, nanometer-scale non-local energy transport, microwave and terahertz applications including field effect transistors and emitters, coupling to quantum dots to make composite materials and/or circuits and/or luminescence enhancement, bright tags through plasmon enhancement of dies or q-dots, plasmonic circuits for light manipulation, and surface adsorption chemical sensors, surface enhanced raman scattering, etc.
Therefore, a need exists in the art for a method for self-assembly of arbitrarily-shaped metal nanostructures that uses a specifically-placed pattern of a material upon a nucleic acid scaffold as a template for plating metal.

SUMMARY OF THE INVENTION

The present invention overcomes the aforementioned limitations and fills the aforementioned needs by providing methods for assembly of arbitrarily-shaped metal nanostructures.
In one aspect, the method comprises acts of fabricating a scaffold, patterning a first material on a scaffold, and plating a metal on the first material, whereby an arbitrarily-shaped metal nanostructure is created based on a pattern formed by the first material on the scaffold and whereby the metal nanostructure is not constrained by a shape of the scaffold itself.
In another aspect, the scaffold is fabricated from a material selected from a group consisting of a plurality of nucleic acids, DNA origami, DNA ribbons, two-dimensional DNA crystals, and three-dimensional DNA constructions.
In another aspect, the plurality of nucleic acids is selected from a group consisting of a charged nucleic acid strands, an uncharged nucleic acid strands, DNA, PNA, RNA, LNA, chemically modified DNA, nucleoside analogues, and combinations thereof.
In another aspect, the act of plating comprises an electro-less plating process.
In another aspect, the first material comprises a single-stranded material selected from a group consisting of single-stranded forms of DNA, RNA, LNA, PNA, a nucleoside analogue, a polymer, and combinations thereof.
In another aspect, the first material has a first end and second end.
In another aspect, the act of patterning the first material on the scaffold further comprises an act of attaching the first material with the scaffold so that the first material projects from the scaffold.
In another aspect, the act of attaching the first material to the scaffold comprises an attachment mechanism selected from a group consisting of attaching the first end of the first material with the scaffold, attaching the first end and the second end of the first material with the scaffold, and a combination thereof, whereby a plurality of conformations of the first material are projected from the scaffold.
In another aspect, the plurality of conformations is selected from a group consisting of single open strands, loops, closed rings, a series of interlocking rings, and locked knotted topologies.
In another aspect, the electro-less plating process further comprises using a 2+ cationic solution whereby the solution blocks the plating of metal on the scaffold and thereby allows plating of metal on the first material.
In another aspect, the method further comprises an act of placing the scaffold on a negatively charged surface.
In another aspect, the negatively charged surface comprises a material selected from a group consisting of muscovite mica, cleaned silicon dioxide, and a surface that has been modified to display negatively charged groups at a specific surface density.
In another aspect, the first material is a nanowire.
In another aspect, the nanowire comprises metal.
In another aspect, the first material comprises a plurality of nanoparticles.
In another aspect, the nanoparticle comprises a metal nanoparticle selected from a group consisting of gold, silver, molybdenum, nickel, copper, and commercially-available nanoparticles.
In another aspect, the nanoparticle further comprises a nucleic acid strand, wherein the nucleic acid strand further comprises a linker, whereby the linker will bind to a complementary nucleic acid pattern on the scaffold.
In another aspect, the act of fabricating the scaffold further comprises the act of incorporating a plurality of nanoparticle attachment linker sites on the scaffold.
In another aspect, the plurality of nanoparticle attachment linker sites is selected from a group consisting of biotin, primary amines, thiols, and commercially-available nanoparticle attachment linker sites.
In another aspect, the act of patterning the first material on the scaffold further comprises the act of attaching the first material with the plurality of nanoparticle attachment linker sites.
In another aspect, the metal is selected from a group consisting of gold, silver, platinum, copper, titanium, nickel, zinc, lead, uranium, iron, palladium, and a metal structure.
Another method according to the present invention comprises the acts of fabricating a DNA scaffold, selecting a sequence-specific DNA hook projecting from the DNA scaffold, fabricating a single-stranded DNA lantern strand, attaching one or more single-stranded DNA lantern strands with two or more sequence-specific DNA hooks projecting from the DNA scaffold and plating a metal on the single stranded DNA lantern strand whereby an arbitrarily-shaped metal nanostructure may be created based on a pattern formed by the nanoparticles attached with the single-stranded DNA lantern strands and whereby the metal nanostructure is not constrained by a shape of the scaffold itself.
In another aspect, the single-stranded DNA lantern strand further comprises one or more nanoparticle attachment linker sites.
In another aspect, the method comprises the acts of attaching one or more nanoparticles with the nanoparticle attachment linker sites and plating a metal on the nanoparticles whereby an arbitrarily-shaped metal nanostructure may be created based on a pattern formed by the nanoparticles attached with the nanoparticle attachment linker sites and whereby the metal nanostructure is not constrained by the shape of the scaffold itself.
In another aspect, the method comprises the acts of attaching one or more nanowires with the nanoparticle attachment linker sites and plating a metal on the nanowires whereby an arbitrarily-shaped metal nanostructure may be created based on a pattern formed by the nanowires attached with the nanoparticle attachment linker sites and whereby the metal nanostructure is not constrained by the shape of the scaffold itself.
In another aspect, the scaffold is fabricated by a material selected from a group consisting of a plurality of nucleic acids, DNA origami, DNA ribbons, two-dimensional DNA crystals, and three-dimensional DNA constructions.
In another aspect, the plurality of nucleic acids is selected from a group consisting of a charged nucleic acid strands, an uncharged nucleic acid strands, DNA, PNA, RNA, LNA, chemically modified DNA, nucleoside analogues, and combinations thereof.
In another aspect, the act of plating comprises an electro-less plating process.
In another aspect, the nanoparticle comprises a metal nanoparticle selected from a group consisting of gold, silver, molybdenum, nickel, copper, and commercially-available nanoparticles.
In another aspect, the plurality of nanoparticle attachment linker sites is selected from a group consisting of biotin, primary amines, thiols, and commercially-available nanoparticle attachment linker sites.
In another aspect, the metal is selected from a group consisting of gold, silver, platinum, copper, titanium, nickel, zinc, lead, uranium, iron, palladium, and a metal structure.
Finally, the present invention includes an arbitrarily-shaped metal nanostructures formed according to all methods described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects, features and advantages of the present invention will be apparent from the following detailed descriptions of the preferred aspects of the invention in conjunction with reference to the following drawings, where:

FIG. 1A is an illustration a method for self-assembly of arbitrarily shaped metal nanostructures using single-stranded molecules patterned on nucleic acid scaffolds according to the present invention;

FIG. 1B is an illustration of a conformation formed by a single-stranded material on a scaffold according to the present invention;

FIGS. 2A and 2B are illustrations of a method for self-assembly of arbitrarily shaped metal nanostructures using metal nanoparticles patterned on nucleic acid scaffolds according to the present invention;

FIGS. 3A-3C are illustrations of a method for self-assembly of arbitrarily shaped metal nanostructures using sequence-specific DNA hooks patterned on nucleic acid scaffolds according to the present invention;

FIGS. 4A and 4B are illustrations of attachments of single-stranded DNA lantern strands with sequence-specific DNA hooks according to the present invention; and

FIGS. 5-8 are images of atomic force microscopy (AFM) scans of gold nanowire structures created according to the present invention.

DETAILED DESCRIPTION

The present invention relates to methods for creating self-assembled arbitrarily-shaped metal nanostructures. More specifically, the present invention relates to methods for self-assembly of arbitrarily-shaped metal nanostructure using patterns placed upon a nucleic acid scaffold. The following description, taken in conjunction with the referenced drawings, is presented to enable one of ordinary skill in the art to make and use the invention and to incorporate it in the context of particular applications. Various modifications, as well as a variety of uses in different applications, will be readily apparent to those skilled in the art, and the general principles, defined herein, may be applied to a wide range of aspects. Thus, the present invention is not intended to be limited to the aspects presented, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. Furthermore, it should be noted that unless explicitly stated otherwise, the figures included herein are illustrated diagrammatically and without any specific scale, as they are provided as qualitative illustrations of the concept of the present invention.
(1) Introduction
In the following detailed description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. However, it will be apparent to one skilled in the art that the present invention may be practiced without necessarily being limited to these specific details. In other instances, well-known structures and devices are shown in block diagram form, rather than in detail, in order to avoid obscuring the present invention.
The reader's attention is directed to all papers and documents which are filed concurrently with this specification and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference. All the features disclosed in this specification, (including any accompanying claims, abstract, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
Furthermore, any element in a claim that does not explicitly state “means for” performing a specified function, or “step for” performing a specific function, is not to be interpreted as a “means” or “step” clause as specified in 35 U.S.C. Section 112, Paragraph 6. In particular, the use of “step of or “act of in the claims herein is not intended to invoke the provisions of 35 U.S.C. 112, Paragraph 6.
The description outlined below sets forth methods for self-assembly of arbitrarily-shaped metal nanostructure patterned on nucleic acid scaffolds. The methods herein use controlled-growth processes to actively select the dimensions, positions, and alignments of patterns to create different shapes of metal nanostructures. Three methods according to the present invention are individually addressable.
(2) Method for self-assembly of arbitrarily shaped metal nanostructures using single-stranded molecules patterned on nucleic acid scaffolds.
This method, as illustrated in FIG. 1A, creates a specifically-designed pattern by placing a single-stranded material 102 upon a scaffold 104 and plating a metal 106 on the single-stranded material 102 to self-assemble arbitrarily-shaped metal nanostructures 108. The scaffold 104 used in the method according to the present invention is best as a nucleic acid scaffold. DNA origami, DNA ribbons, two-dimensional DNA crystals, and three-dimensional DNA constructions such as DNA tetrahedrals can be used as the scaffold 104 to either arbitrarily design a pattern or algorithmically grow a pattern with single-stranded material 102 upon. The scaffold 104 could also be made of PNA, RNA, LNA, chemically modified DNA such as methylated DNA, or the scaffold 104 could have portions that consist of other nucleoside analogues such as universal bases.
As shown in FIG. 1A, the single-stranded material 102, for example, single-stranded DNA, with a first end 110 and a second end 112 can be attached to the scaffold 104 by the first end 110, leaving the second end 112 free from the scaffold 104. Or, both the first end 110 and the second end 112 of the single-stranded material 102 can be attached to the scaffold 104 to create a loop 114, as illustrated in FIG. 1B. Other shapes may be formed, including a closed ring, or a series of interlocking rings. The strand could be locked into knotted topologies to create differently shaped nanostructures when plated. Additionally, the strand could be free or under some sort of tension that either pulls the two ends apart or sets the two ends at a certain distance that is closer than statistically typical for free single stranded DNA. Other single-stranded nucleic acids may be used, including RNA, LNA, PNA, a different nucleoside analogue or a type of polymer such as polyethylene.
Referring again to FIG. 1A, the single-stranded material 102 of the specifically-designed pattern act as seed nuclei upon a scaffold 104 to which metal 106 may be plated to create the arbitrarily-shaped metal nanostructures 108 that are not constrained by the structure of the scaffold 104. A metal 106 may be plated on the single-stranded material 102 using an electro-less metal plating technique.
In this method, the definition of electro-less plating is the deposition of metal from metal ions dissolved in aqueous solution without use of electrodes. During the electro-less plating process, the metal begins as an ion in solution, but when it is deposited, it gains the missing electrons and becomes a metal. The chemistry for reduction of the positive metal ions on an existing metal surface or a seed nucleus is the mechanism that deposits the metal on the surface. The plating metal could be a variety of metals, including gold, silver, platinum, copper, titanium, nickel, zinc, lead, uranium, iron, palladium, and a metal structure. A metal structure can be an alloy, a mixture of metals, or a layered composition of metal.
The electro-less plating process is performed in a solution containing a source of metal ions, a reducing agent, a surfactant, and a buffer (to create the proper pH). When using a DNA scaffold, a pH buffer with an approximate pH of 5 prevents denaturing and provides for optimal performance. The buffer comprise of a mixture of a salt species to generate cations, for example, sodium chloride to generate sodium ions, magnesium acetate or magnesium chloride to generate magnesium ions, and nickel acetate to generate nickel ions, etc. The buffer could also contain a metal ion chelator, such as ethylenediamine tetraacetic acid, to act as a buffer for metal concentrations. A typical buffer used with nucleic acid-based scaffolds is magnesium acetate or magnesium chloride with a tris acetate base to buffer the pH and optional ethylenediamine tetraacetic acid to buffer ion concentrations.
Different monovalent, divalent, or multi-valent cationic species such as sodium chloride, nickel acetate, ammonium acetate, potassium chloride, calcium chloride, lithium chloride, organic zwitterions such as 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), and ionic liquids could be used as buffers to control the rate and specificity of deposition. The pH, salt concentrations, and concentrations of the metal ion species during plating can be used to adjust the rate of deposition.
As a non-limiting example, during electro-less plating of gold using gold chloride in a magnesium solution, gold preferentially nucleates on single-stranded DNA versus double stranded. The method is most effective when the scaffold is deposited on Muskovite mica using a 2+ cation as a salt bridge. The use of a multi-valent solution allows for selective deposition of metal on the single stranded DNA during electro-less plating because the monovalent (+) or multivalent (2+) cations in the solution form a charged layer that acts as diffusion barrier covering the scaffold, preventing access by metal ions used in the electro-less metal plating process from attaching to the scaffold itself The metal ions can then selectively attach on the single-stranded material or on other projected materials that have a lower charge concentration in its vicinity. The scaffold can be also placed on a negatively charged surface such as muscovite mica, cleaned silicon dioxide, or some other surface that has been modified to display negatively charged groups at some specific surface density, which can be adjusted to control the rate and the selectivity of metal deposition.
Once the metal is deposited upon a single-stranded material as seed nuclei, one or more additional metals may be used to plate existing metallic structures. As many additional layers of metal may be plated as needed. The buffer used during the depositing of the first metal as seed nuclei on the single-stranded material can be different from the buffer used in the subsequent plating of metal upon the seed nuclei. Also, if using two metals that like to alloy, such as gold and silver, a layer of another metal may be placed in between the two metals to stop the alloying reaction.
(3) Method for self-assembly of arbitrarily shaped metal nanostructures using metal nanoparticles patterned on nucleic acid scaffolds.
This method, as illustrated in FIG. 2A, uses a pattern of nanoparticles 200 attached to the scaffold 104, as seed nuclei, for the subsequent deposition of metal 106 to create a metal nanostructures 108. In this method, the metal nanoparticles 200 are prefabricated and are attached with the scaffold 104 by specifically placed nanoparticle attachment linker sites 202 such as biotin, primary amines, thiols, or commercially-available nanoparticle attachment linker sites. By using modified bases with attachment chemistries such as thiol, biotin, or primary amine modifications, patterning of the scaffold 104 with nanoparticles, proteins, gold, or other materials is possible. Nanoparticles 200 (for example, gold nanoparticles) are attached to nanoparticle attachment linker sites 202 on a scaffold 104 in specific two-dimensional shapes. This creates the pattern of nanoparticles 200 as seed nuclei for electro-less metal plating. In addition, nanowires may be attached to the nanoparticle attachment linker sites 202. As in the previous method described, electro-less metal plating is a technique used to create contiguous patterns originating from the nanoparticles 200. Thus, the nanoparticle patterns are expanded in a controlled manner by the addition of metal 106 using an electro-less metal plating technique to create contiguous shapes on the nanoparticles 200.
There are a number of commercially-available metal nanoparticles. More commonly used metal nanoparticles are gold, silver, iron, molybdenum, nickel, and copper. Many other nanoparticles are suitable as long as the nanoparticle is small enough to reproduce a desired pattern with accuracy and there exists a suitable linker chemistry.
Another option is to coat the nanoparticles 200 first with a DNA strand that has a linker, as illustrated in FIG. 2B. The linker DNA 204 will bind to complementary DNA patterns 206 on the DNA scaffold 104. Advantages to using this process include the ability to control the interaction strength via the number of complementary bases and the ability to coat several different types of nanoparticles with different DNA sequences so that each can attach to a specific location on the scaffold that has the particular complementary DNA. Also, if the nanoparticle is large and may attach to several different parts of the scaffold, then the nanoparticle can be coated with DNA strands with different sequences to prevent the nanoparticle from attaching to more than one part of the scaffold.
(4) Method for self-assembly of arbitrarily shaped metal nanostructures using sequence-specific DNA hooks patterned on nucleic acid scaffolds.
Another method may be used for the arrangement of nanoparticle linker sites upon a DNA scaffold with reduced constraints from the shape and structure of the scaffold itself, for example, the dimensions of scaffolds such as DNA tiles in DNA ribbons. As illustrated in FIG. 3A, strands of DNA 300 within the DNA scaffold 104 that are projecting out and away from the DNA scaffold 104 are selected. These selected strands of DNA 300 are sequence-specific DNA hooks 300. In a separate step of the method, nanoparticle attachment linker sites 202 are incorporated into specific positions on single-stranded DNA strands 302. One or more of these single-stranded DNA strands 302 are attached with two or more of the sequence-specific DNA hooks 300 attached to the scaffold 104. The single-stranded DNA strands 302 have sequence-specific binding regions 304 that attach to complementary sequence-specific binding regions 306 on the sequence-specific DNA hooks 300. Thus, the single-stranded DNA strands 302 are called “lantern strands,” because when nanoparticles 200 attach with the nanoparticle attachment linker sites 202 on the lantern strands 302, the nanoparticles 200 resemble Chinese lanterns hanging on a line. In addition, nanowires may be attached to the nanoparticle attachment linker sites 202.
As illustrated in FIGS. 4A and 4B, this method allows lantern strands 302 to be drawn across sequence-specific DNA hooks 300 defined by any two anchor points on the DNA scaffold 104. Along each lantern strand 302, there is almost complete freedom to incorporate one-dimensional patterns of nanoparticle attachment linker sites 202 that accommodate one or more types of nanoparticles 200, upon which metals 106 can be plated to allow for arbitrary design freedom of metal nanostructures 108 on the scaffolds 104.
As a non-limiting example, this method can be used to create gold nanowires on DNA ribbon. As illustrated in FIG. 3B, three nanoparticle attachment linker sites 202, for example, three modified thymine bases, were incorporated in 28 nm long DNA lantern strands 302. The nanoparticle attachment linker sites 202 were separated by approximately 2 nm, in this case, each having a primary amine available as the covalent linkage site, for attachment of nanoparticles 200.
The single-stranded DNA lantern strands 302 attach to the sequence-specific DNA hooks 300 via complementary sequence-specific binding regions 304 on the single-stranded DNA lantern strands 302 and sequence-specific binding regions 306 on the sequence-specific DNA hooks 300. This creates a string of binding regions down the scaffold 104 with approximately 2 nm inter-site spacing. To prevent spurious attachment, two different sequence-specific single-stranded DNA hooks (i.e., having different sequences) can be projected from two different tiles on the DNA ribbon (the tiles repeat periodically down the length of the ribbon).
Optionally, as illustrated in FIG. 3B nanoparticles 200, for example, commercially-bought 0.8 nm gold nanoparticles consisting of 11 gold atoms (Undecagold from Nanoprobes, Incorporated, 95 Horse Block Road, Unit 1, Yaphank, N.Y. 11980-9710, USA) are attached to the nanoparticle attachment linker sites 202. As an example, each nanoparticle 200 can have a single sulfo-N-Hydroxysuccinimide-ester group on its surface, which covalently links to the primary amine of the nanoparticle attachment linker site 202 that is incorporated into the DNA lantern strand 302 assembled on the DNA scaffold 104, for example, a ribbon. This attachment proceeds in a buffer free of competing primary amine sites, such as a buffer containing tris acetate. This is one non-limiting example of the many different linkage chemistries available for attachment of various nanoparticles to specific bases of a DNA strand.
After incubating using standard procedures known in the art, the DNA scaffold 104 with or without docked nanoparticles 200 can be deposited on a negatively charged surface 312, for example, a mica substrate, as illustrated in FIG. 3C. Deposition of the scaffold 104 to silicon dioxide, gold, and other surfaces is also possible. A commercially available gold deposition process (Gold Enhance LM from Nanoprobes, Incorporated, 95 Horse Block Road, Unit 1, Yaphank, N.Y. 11980-9710, USA) can be used to deposit metal 106, in this example, gold, for two and a half minutes, at which time, deposition was stopped by washing the substrate with buffer. When gold nanoparticles are present, because the electro-less plating step enlarges the gold nanoparticles uniformly, the size and shape of gold nanoparticles and the achievable inter-particle spacing creates the lower bound for the smallest achievable feature size in the method. A metal nanostructure 108 is formed after the metal 106 is continuously added by an electro-less metal plating process.
FIGS. 5-8 are images of atomic force microscopy (AFM) scans of gold nanowire structures created according to the present invention. In the images shown, nanoparticles were not attached to the lantern strands. Gold deposition nucleated directly on the single stranded portions of the lantern strands. The images are taken on an atomically flat mica surface and are colored according to the height of the structures above the surface. In the example shown, the structure consists of a continuous gold wire composed of ˜28 nm lantern segments that merged together after deposition.

Claims

What is claimed is:

1. A method for assembly of arbitrarily-shaped metal nanostructures, the method comprising acts of:

fabricating a scaffold;

patterning a first material on a scaffold; and

plating a metal on the first material whereby an arbitrarily-shaped metal nanostructure is created based on a pattern formed by the first material on the scaffold and whereby the metal nanostructure is not constrained by a shape of the scaffold itself.

2. The method of claim 1, wherein the scaffold is fabricated from a material selected from a group consisting of a plurality of nucleic acids, DNA origami, DNA ribbons, two-dimensional DNA crystals, and three-dimensional DNA constructions.

3. The method of claim 2, wherein the plurality of nucleic acids is selected from a group consisting of a charged nucleic acid strands, an uncharged nucleic acid strands, DNA, PNA, RNA, LNA, chemically modified DNA, nucleoside analogues, and combinations thereof.

4. The method of claim 3, wherein the act of plating comprises an electro-less plating process.

5. The method of claim 4, wherein the first material comprises a single-stranded material selected from a group consisting of single-stranded forms of DNA, RNA, LNA, PNA, a nucleoside analogue, a polymer, and combinations thereof.

6. The method of claim 5, wherein the act of patterning the first material on the scaffold further comprises an act of attaching the first material with the scaffold so that the first material projects from the scaffold.

7. The method of claim 6, wherein the first material has a first end and second end, and wherein the act of attaching the first material to the scaffold comprises an attachment mechanism selected from a group consisting of attaching the first end of the first material with the scaffold, attaching the first end and the second end of the first material with the scaffold, and a combination thereof, whereby a plurality of conformations of the first material are projected from the scaffold.

8. The method of claim 7, wherein the plurality of conformations is selected from a group consisting of single open strands, loops, closed rings, a series of interlocking rings, and locked knotted topologies.

9. The method of claim 8, wherein the electro-less plating process further comprises using a 2+ cationic solution whereby the solution blocks the plating of metal on the scaffold and thereby allows plating of metal on the first material.

10. The method of claim 5, wherein the method further comprises an act of placing the scaffold on a negatively charged surface.

11. The method of claim 4, wherein the first material is a nanowire.

12. The method of claim 4, wherein the first material comprises a plurality of nanoparticles.

13. The method of claim 12, wherein the nanoparticle further comprises a nucleic acid strand, wherein the nucleic acid strand further comprises a linker, whereby the linker will bind to a complementary nucleic acid pattern on the scaffold.

14. The method of claim 12, wherein the act of fabricating the scaffold further comprises the act of incorporating a plurality of nanoparticle attachment linker sites on the scaffold.

15. The method of claim 14, wherein the plurality of nanoparticle attachment linker sites is selected from a group consisting of biotin, primary amines, thiols, and commercially-available nanoparticle attachment linker sites.

16. The method of claim 14, wherein the act of patterning the first material on the scaffold further comprises the act of attaching the first material with the plurality of nanoparticle attachment linker sites.

17. An arbitrarily-shaped metal nanostructure formed according to the method of claim 1.

18. A method for assembly of arbitrarily-shaped metal nanostructures, the method comprising acts of:

fabricating a DNA scaffold;

selecting a sequence-specific DNA hook projecting from the DNA scaffold;

fabricating a single-stranded DNA lantern strand;

attaching one or more single-stranded DNA lantern strands with two or more sequence-specific DNA hooks projecting from the DNA scaffold; and

plating a metal on the single stranded DNA lantern strand whereby an arbitrarily-shaped metal nanostructure may be created based on a pattern formed by the nanoparticles attached with the single-stranded DNA lantern strands and whereby the metal nanostructure is not constrained by a shape of the scaffold itself.

19. The method of claim 18, wherein the single-stranded DNA lantern strand further comprises one or more nanoparticle attachment linker sites.

20. The method of claim 19, further comprising the acts of:

attaching one or more nanoparticles with the nanoparticle attachment linker sites; and

plating a metal on the nanoparticles whereby an arbitrarily-shaped metal nanostructure may be created based on a pattern formed by the nanoparticles attached with the nanoparticle attachment linker sites and whereby the metal nanostructure is not constrained by the shape of the scaffold itself.

21. The method of claim 19, further comprising the acts of:

attaching one or more nanowires with the nanoparticle attachment linker sites; and

plating a metal on the nanowires whereby an arbitrarily-shaped metal nanostructure may be created based on a pattern formed by the nanowires attached with the nanoparticle attachment linker sites and whereby the metal nanostructure is not constrained by the shape of the scaffold itself.

22. The method of claim 18, wherein the scaffold is fabricated by a material selected from a group consisting of a plurality of nucleic acids, DNA origami, DNA ribbons, two-dimensional DNA crystals, and three-dimensional DNA constructions.

23. The method of claim 18, wherein the plurality of nucleic acids is selected from a group consisting of a charged nucleic acid strands, an uncharged nucleic acid strands, DNA, PNA, RNA, LNA, chemically modified DNA, nucleoside analogues, and combinations thereof.

24. The method of claim 18, wherein the act of plating comprises an electro-less plating process.

25. The method of claim 19, wherein the nanoparticle attachment linker site is selected from a group consisting of biotin, primary amines, thiols, and commercially-available nanoparticle attachment linker sites.