Monomer dna framework-based metal nanoparticle superlattice and preparation method and application thereof

Abstract

The application belongs to the technical field of DNA nanomaterials, and particularly relates to a metal nanoparticle superlattice based on a monomer DNA framework as well as a preparation method and application thereof. The method comprises the following steps: synthesizing a micrometer-level monomer DNA framework template through one-step self-assembly of DNA bricks; mixing metal nanoparticles with a thiolated single-stranded DNA on the surface and the DNA framework template in a buffer containing sucrose to obtain the metal nanoparticle superlattice through sequence-specific hybridization. Compared with the prior art, the application solves the technical problems of structural defects caused by DNA template splicing and heavy metal particle assembly kinetic traps in the prior art. The rigid micrometer-level monomer DNA framework template is synthesized through one-step self-assembly of DNA bricks, and a sucrose-assisted assembly system (SAAS) is used to realize high-fidelity epitaxial assembly of the metal nanoparticles at preset sites of the DNA framework template.

Description

Technical Field

[0001] This invention belongs to the field of DNA nanomaterials technology, specifically relating to a metal nanoparticle superlattice based on a monomeric DNA framework, its preparation method, and its application. Background Technology

[0002] Metal nanoparticle superlattices endow materials with unique collective physicochemical properties through precise spatial arrangement, demonstrating significant application potential in fields such as metasurface optics, ultrasensitive biosensors, nanoelectronic devices, and heterogeneous catalysis. The performance of these devices is highly dependent on the precise control of nanoparticle spacing, geometric patterns, and material composition. In particular, when the spacing is reduced to sub-10 nm, the system not only generates strong plasmon coupling but also triggers a significant quantum tunneling effect, which is crucial for constructing single-electronic devices.

[0003] While photolithography can achieve patterned arrays at the micrometer scale, its resolution is limited by wavelength, making it difficult to consistently break through the sub-10 nm physical limit. Furthermore, it has poor compatibility with multi-component or complex interface metal nanoparticle systems. In recent years, bottom-up approaches based on DNA nanotechnology have provided alternatives for constructing high-precision arrays. For example, CN118497191A discloses a method for preparing a dynamically controllable nanoparticle superlattice based on a DNA origami crystal template, and CN119900093A discloses a method for constructing a two-dimensional chiral nanoparticle superlattice. However, existing technologies largely rely on the splicing of DNA tiles or origami modules to construct large-size templates. Due to the lack of sufficient rigid constraints between modules, the splicing process easily leads to lattice stress accumulation and structural curling, resulting in orderliness typically limited to within a few hundred nanometers, making it difficult to maintain sub-10 nm arrangement accuracy at the micrometer scale. Furthermore, during the aqueous phase assembly process, heavy metal particles often fall into kinetic traps due to excessively fast settling rates or non-specific adsorption, making it difficult for the particles to reach the thermodynamically stable preset sites, which severely limits the array's arrangement density and structural uniformity.

[0004] Therefore, how to simultaneously achieve sub-10 nm precision spacing control, high-density heterogeneous integration, and controlled quantum transport at the micrometer scale remains a technical challenge that urgently needs to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a metal nanoparticle superlattice based on a monomeric DNA framework, its preparation method, and its application, in order to solve at least one of the aforementioned problems. This addresses the technical issues of structural defects caused by DNA template splicing and the kinetic traps in the assembly of heavy metal particles in existing technologies. This method achieves high-fidelity epitaxial assembly of metal nanoparticles at predetermined sites on the DNA framework template through one-step self-assembly of DNA bricks.

[0006] The objective of this invention is achieved through the following technical solution: The first aspect of this invention discloses a method for preparing a metal nanoparticle superlattice based on a monomeric DNA framework, comprising the following steps: (1) Micron-sized (0.5-20 μm) monomeric DNA framework templates were synthesized by one-step self-assembly of DNA bricks; (2) Metal nanoparticles with thiolized single-stranded DNA on their surface are mixed with the DNA framework template prepared in step (1) in a sucrose-containing buffer solution. The metal nanoparticles are precisely anchored to the preset sites of the DNA framework template through sequence-specific hybridization to obtain a metal nanoparticle superlattice. The DNA bricks are formed by one-step self-assembly of single strands of DNA with a length of 48-56 nt. The DNA framework template is a rigid structure that is all solid and without cavities.

[0007] Preferably, the DNA framework template is asymmetric step-like, comprising: a one-dimensional step-like structure periodically assembled along the Y-axis, or a two-dimensional channel-like structure periodically assembled along the XY plane; or... The DNA framework template has a double-step channel structure, consisting of a bottom base, a middle layer, and a top layer; The DNA framework template has a trapping strand extending from its sidewall, which is used to connect the thiolized single-stranded DNA of the metal nanoparticles and anchor the metal nanoparticles.

[0008] Preferably, when the DNA framework template is a double-step channel structure, the capture strands extending from the sidewalls of different levels in the middle and top layers are orthogonal capture strands, which are used to anchor different types and / or morphologies of metal nanoparticles.

[0009] Preferably, the metal nanoparticles include at least one of gold nanospheres, gold nanorods, and silver nanospheres; The number of thiolized single-stranded DNA molecules distributed along the axial direction of the gold nanorods is greater than the number of thiolized single-stranded DNA molecules distributed along the radial direction.

[0010] Preferably, the metal nanoparticles hybridize with the capture strand of the DNA framework template via single-stranded DNA with a hybridization domain length of T4-T12.

[0011] Preferably, in the sucrose-containing buffer solution: The mass-volume concentration of sucrose is 15-25%; Buffer solution containing Mg 2+ TAE buffer.

[0012] Preferably, after the metal nanoparticles are mixed with the DNA framework template, programmed cooling annealing is used to ensure that the hybridization reaction proceeds fully and reaches a thermodynamically stable state. The programmed cooling annealing is as follows: annealing from 40-50℃ to 20-30℃ at a rate of 0.1-0.5℃ / 5 min.

[0013] The second aspect of this invention discloses a metal nanoparticle superlattice based on a monomeric DNA framework, which is prepared by the preparation method described in any of the preceding claims; The superlattice has an array structure that is homogeneous, homogeneous, heterogeneous, or heterogeneous.

[0014] Preferably, the superlattice is a binary heterogeneous superlattice, a binary heteromorphic superlattice, a binary heterogeneous heteromorphic superlattice, or a ternary heterogeneous heteromorphic superlattice; and / or, The spacing between adjacent metal nanoparticles in the superlattice is 4-10 nm.

[0015] The third aspect of this invention discloses the application of a metal nanoparticle superlattice based on a monomeric DNA framework as described above in the fabrication of single-electronic devices, quantum logic circuits, optoelectronic integrated circuits, metasurface optical devices, or ultrasensitive biosensors.

[0016] The working principle of this invention is as follows: (1) Construction principle of the rigid framework: Traditional DNA tiles or Origami templates rely on multi-step splicing, and the lack of rigid constraints between modules makes it easy for stress concentration and structural distortion to occur at the splicing interface, resulting in the decay of order at the scale of hundreds of nanometers. This invention adopts the DNA brick strategy, which uses DNA single strands of 48-56 nt in length to form a rigid structure that is all-solid and without cavities through one-step self-assembly. The smallest nucleation site of this structure consists of only four DNA single strands, and each hybridization domain is 12-16 nt in length, which significantly enhances the thermodynamic stability of base pairing and the mechanical rigidity of the structure. Since there is no need for splicing between modules, the interface discontinuity and stress accumulation are fundamentally eliminated, so that the framework can still maintain sub-nanometer structural fidelity at the micrometer scale (0.5-20 μm).

[0017] (2) Working principle of sucrose-assisted assembly system (SAAS): In an aqueous environment, the array structure of heavy metal nanoparticles such as gold and silver, assembled by micron-sized DNA templates, tends to settle rapidly to the bottom of the container under gravity due to its large molecular weight. This results in insufficient reaction between the metal nanoparticles and the DNA template, leading to a "kinetic trap". This invention introduces 15-25% (w / v) sucrose as a molecular congestion agent, exerting a dual physicochemical effect: First, eliminating the volume effect—sucrose molecules occupy the free volume in the solution, effectively increasing the local collision frequency and effective concentration between the DNA capture strand and the DNA on the surface of the metal nanoparticles, significantly accelerating sequence-specific hybridization kinetics; Second, density matching effect—sucrose increases the density of the buffer solution, reducing the density difference between the metal nanoparticles and the medium, thereby slowing down the sedimentation rate and providing sufficient reaction time window for the particles to cross the energy barrier and accurately settle to the preset site of the DNA template. The synergistic effect of the two enables the particles to successfully reach the thermodynamically stable preset site, achieving high-fidelity epitaxial assembly.

[0018] (3) Physical mechanism of room temperature collective Coulomb blockade: When the spacing between adjacent metal nanoparticles is reduced to sub-10 nm, the quantum tunneling probability between particles is significantly enhanced, and electrons can undergo sequential hopping between discrete nanoparticle energy levels. For a single-row metal nanoparticle array, due to the limited tunneling channels, the system exhibits quasi-linear electron hopping transport. When expanded to a multi-row parallel array, the number of particles and the number of gaps increase simultaneously, and the charging energy of a single nanoparticle (Ec = e) increases. 2 / 2C, where C is the interparticle capacitance, increases significantly with increasing gap size. When Ec is much greater than the room temperature thermal noise (k_BT≈25.7 meV, T=298 K), thermal fluctuations are insufficient to overcome the charging energy barrier, and electron transport is collectively suppressed, forming a Coulomb gap near zero bias, i.e., the Collective Coulomb Blockade (CCB) effect is observed. This invention achieves a relatively uniform interparticle gap through the high structural consistency of the DNA template, making the charging energy distribution of each tunneling channel concentrated, thus allowing this quantum transport phenomenon to be clearly observed at room temperature without the need for an extremely low temperature environment.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) This scheme breaks through the size limit of traditional splicing templates: it adopts one-step self-assembly to construct micron-scale monomer DNA framework, which fundamentally solves the problems of interface discontinuity, stress accumulation and structural curling caused by multi-step splicing, and realizes cross-scale unification of micron scale and sub-nanometer precision.

[0020] (2) This scheme overcomes the kinetic bottleneck of heavy metal particle assembly: the SAAS strategy, by eliminating the dual effects of volume effect and sedimentation regulation, increases the linear density of AuNP array by 68%, reduces the spacing between adjacent particles by 37%, improves uniformity by 69%, and achieves the highest AuNR array yield of 93.8%.

[0021] (3) This scheme realizes true multi-dimensional heterogeneous programming: through the double-sided differential capture chain and multi-level step design, the resolution is doubled in the XY plane (~101 nm → ~50 nm), and three-cycle heterogeneous integration is realized in the Z axis, with the line spacing finely controlled to 14-30 nm.

[0022] (4) This scheme achieves room temperature collective coulomb blocking for the first time: the constructed sub-5 nm extreme gap superlattice exhibits clear coulomb gap and electron jumping behavior at 298 K, laying the physical foundation for single-electron devices operating under environmental conditions.

[0023] (5) This solution is highly versatile and scalable: it is applicable to a variety of materials such as gold nanospheres, gold nanorods, and silver nanospheres, supports two-dimensional large-area arrays and three-dimensional multi-level structures, and is seamlessly compatible with traditional semiconductor micro-nano processing technology. Attached Figure Description

[0024] Figure 1 Morphological characterization of one-dimensional step-like DNA framework: Schematic diagram of one-dimensional DNA step structure (a) and its corresponding size information (b); AFM characterization diagram (c) and TEM characterization diagram (d) of one-dimensional DNA step structure.

[0025] Figure 2 Morphological characterization of two-dimensional channel DNA framework: Schematic diagram of two-dimensional DNA channel structure (a) and its corresponding size information (b); AFM characterization diagram (c) and TEM characterization diagram (d) of two-dimensional DNA channel structure.

[0026] Figure 3 : Optimization effect of sucrose-assisted assembly system on the arrangement of metal nanoparticles (comparison with traditional assembly system, and yield results for different hybridization domain lengths): (a) Schematic diagram of gold nanosphere array constructed using two-dimensional DNA channel template; (b) Using traditional assembly system (1×TAE-Mg 2+ (c) Construction of a two-dimensional gold nanosphere array and its TEM characterization; (d) Assembly of a sucrose-assisted system (1×TAE-Mg) 2+(d) Schematic diagram of two-dimensional gold nanorod array; (e) Side view of two-dimensional gold nanorod array, where the dashed box is a schematic diagram of hybridization between gold nanorods and DNA channel template, and Tn represents the length of the hybridization domain, which are T12, T10, T8, T6 and T4 respectively; (f) Statistical analysis of the yield of two-dimensional gold nanorod array structures with different hybridization domain lengths, which are non-defect rate, misalignment defect rate and vacancy defect rate respectively.

[0027] Figure 4 Morphological characterization of one-dimensional and two-dimensional metal nanoparticle arrays with various structural forms.

[0028] Figure 5 Morphological characterization of the double-step DNA channel structure and the three-period superlattice: (a) Schematic diagram of the double-step DNA channel structure, consisting of a base plate, an intermediate layer Step 1, and a top layer Step 2; (b) TEM characterization of the double-step DNA channel structure; (c) Schematic diagram of the 2D AuNR-AgNP-AuNP array (Separated); (d) TEM characterization of the 2D AuNR-AgNP-AuNP array (Separated).

[0029] Figure 6 Electrical performance testing of two-dimensional gold nanorod arrays: Schematic diagram (a), top view (b), SEM image (c), and IV curve (d) of the conductivity test of the two-dimensional gold nanorod array structure (e.g., electrode deposition on only one gold rod line, within the dashed box); Schematic diagram (e), top view (f), SEM image (g), and IV curve (h) of the conductivity test of the two-dimensional gold nanorod array structure (e.g., electrode deposition on only five gold rod lines, within the dashed box).

[0030] Figure 7 : Schematic diagram of the preparation method and superlattice structure of the present invention. Detailed Implementation

[0031] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0032] Unless otherwise specified in the following description, the reagents used are conventional commercial products, the methods used are well-known in the art, and any other matters not covered herein may be handled using existing technologies.

[0033] This invention discloses a metal nanoparticle superlattice based on a monomeric DNA framework, its preparation method, and its applications. The method involves a one-step self-assembly of a DNA brick to synthesize a micrometer-scale rigid monomeric DNA framework template, with a pre-set trapping strand on the step sidewalls. Further, utilizing a sucrose-assisted assembly system (SAAS), metal nanoparticles with surface-modified thiolized single-stranded DNA are sequence-specifically hybridized with the DNA framework template in a sucrose-containing buffer, achieving high-fidelity epitaxial assembly of the metal nanoparticles at pre-set sites on the DNA framework template. This invention overcomes the structural defects and kinetic traps of heavy particles caused by traditional multi-step splicing, achieving sub-5 nm precision, high density, and multi-component heterogeneous integration, and for the first time, a clear collective Coulomb blockage effect is observed at room temperature. This invention provides a novel material platform and physical basis for single-electronic devices, optoelectronic integrated circuits, and programmable nanofabrication.

[0034] Specifically, a method for preparing a metal nanoparticle superlattice, such as... Figure 7 As shown, it includes the following steps: (1) A micron-sized monomeric DNA framework template is synthesized by one-step self-assembly of DNA brick. The DNA framework template has an asymmetric step-like structure with a trapping strand pre-set on the sidewall of the step for anchoring metal nanoparticles. (2) Metal nanoparticles with thiolized single-stranded DNA on their surface are mixed with DNA framework template in a sucrose buffer solution. The metal nanoparticles are precisely anchored to the preset sites on the DNA framework template by sequence-specific hybridization to obtain a metal nanoparticle superlattice.

[0035] Preferably, in step (1), the DNA brick uses a single strand of DNA with a length of 48-56 nt (preferably 52 nt), and each hybridization domain is 12-16 nt (preferably 13 nt) in length, forming a rigid, all-solid-state structure without cavities through one-step self-assembly. This design significantly enhances the thermodynamic stability and mechanical rigidity of the structure, effectively suppresses the accumulation of defects during long-range assembly, and the smallest nucleation site consists of only four single strands of DNA.

[0036] Preferably, in step (1), the DNA framework template is periodically assembled along the Y-axis to form a one-dimensional step-like structure or a two-dimensional channel-like structure periodically assembled along the XY plane.

[0037] Specifically, the basic unit has a base plate length of 312 bp (approximately 101 nm), a height of 8 DNA double helices (approximately 20 nm), and a width of 4 DNA double helices; the step has a length of 130 bp (approximately 42 nm), a height of 4 DNA double helices (approximately 10 nm), and a width of 4 DNA double helices. The one-dimensional step-like structure is formed by growing the basic unit along the Y-axis, with a width of 95-110 nm (preferably 101 nm). The two-dimensional channel-like structure is formed by the co-growth of the basic unit along the X / Y axes to form a parallel channel array, with a period span of 95-110 nm (preferably 101 nm).

[0038] Preferably, in step (1), the DNA framework template is a double-step channel structure, consisting of a bottom base, a middle layer Step 1 and a top layer Step 2. The widths of Step 1 and Step 2 are precisely controlled to be 50 nm and 25 nm, respectively, and the sidewalls of different layers extend with orthogonal capture chains, which are used to anchor metal nanoparticles of different types or morphologies, thereby achieving precise integration of complex three-period heterogeneous superlattices.

[0039] Preferably, in step (2), the sucrose concentration in the sucrose-containing buffer solution is 15-25% (w / v), more preferably 20% (w / v), and the buffer solution contains Mg. 2+ The TAE buffer significantly improved the collision probability and effective local concentration between the DNA capture strand and the DNA on the surface of the metal nanoparticles by eliminating the volume effect. At the same time, it reduced the sedimentation rate of the sample by increasing the density of the medium, providing a sufficient reaction window for the precise positioning of particles on the framework and effectively overcoming the "kinetic trap" of heavy metal particles.

[0040] Preferably, the metal nanoparticles in step (2) include at least one of gold nanospheres, gold nanorods, and silver nanospheres. For gold nanorods, the number of thiol DNA single strands distributed axially is greater than radially, thus they tend to align axially on the DNA template. The metal nanoparticles hybridize with the capture strand through a DNA strand with a hybridization domain length of T4-T12 (preferably T6), at which point the correct alignment yield is as high as 93.8%, and the misalignment defect rate is reduced to 5%.

[0041] Preferably, in step (2), after mixing, a programmed cooling annealing is performed, annealing from 40-50℃ to 20-30℃ at a rate of 0.1-0.5℃ / 5 min (preferably from 45℃ to 25℃ at a rate of 0.1℃ / 5 min) to ensure that the hybridization reaction proceeds fully and reaches a thermodynamically stable state.

[0042] Preferably, the spacing between adjacent metal nanoparticles in the metal nanoparticle superlattice is 4-10 nm, more preferably 4-5 nm, to achieve strong quantum tunneling coupling under extreme gap conditions.

[0043] The present invention also provides a metal nanoparticle superlattice prepared by the above method, comprising: a micron-sized monomeric DNA framework template having an asymmetric step-like or double-step channel-like structure; metal nanoparticles anchored to the step sidewalls of the DNA framework template, wherein the metal nanoparticles and the template are connected by sequence-specific DNA hybridization; wherein the superlattice has a homomorphic, homo-isomorphic, heteromorphic, or heteromorphic array structure.

[0044] Preferably, the superlattice exhibits collective Coulomb blockade and / or electronic hopping transport behavior at room temperature (298 K). Thanks to the extreme inter-space of 4–10 nm and high structural uniformity provided by the DNA template, the charging energy of a single particle significantly exceeds the room temperature thermal noise (Ec ≫ kBT), making the collective charge correlation behavior clearly visible under environmental conditions.

[0045] Preferably, the superlattice can be a binary heterogeneous superlattice (such as AuNP-AgNP), a binary heterogeneous superlattice (such as AuNR-AuNP), a binary heterogeneous heterogeneous superlattice (such as AuNR-AgNP), or a ternary heterogeneous heterogeneous superlattice (such as AuNR-AuNP / AgNP).

[0046] The present invention also provides the application of the above-mentioned metal nanoparticle superlattice in the preparation of single electronic devices, quantum logic circuits, optoelectronic integrated circuits, metasurface optical devices or ultrasensitive biosensors.

[0047] Example 1 Synthesis of a one-dimensional step-shaped DNA framework: The designed 52 nt long DNA single-stranded library (13 nt per hybridization domain) was mixed in 100 μL of 1×TAE-Mg 2+ In the reaction system, the final Mg 2+ The concentration was 20 mM. The sample was incubated at 50°C for 48 hours to directly construct a one-dimensional step-shaped monomeric DNA framework via one-step self-assembly. Characterization was performed using atomic force microscopy (AFM) and transmission electron microscopy (TEM), as shown below. Figure 1 As shown, the results indicate that the average frame length reaches 2-4 µm, and the geometric parameters are in high agreement with the theoretical model.

[0048] Furthermore, tests were conducted under the following preparation conditions: 50-100 μL of 1×TAE-Mg 2+ In the reaction system, the final Mg 2+ The results of using a concentration of 10-50 mM and heat preservation at 50-60℃ for 24-72 hours yielded a frame with performance that was basically equivalent to that of Example 1, and will not be further elaborated here.

[0049] Example 2 Synthesis of two-dimensional channeled DNA frameworks: The programming logic of the DNA single-stranded library from Example 1 was further extended to the XY plane, using the same one-step self-assembly conditions as in Example 1 (50°C, Mg). 2+ Two-dimensional channel-like monomer structures were directly synthesized using a method involving 20 mM. These structures were co-grown along the X / Y axes to form a parallel channel array with a period span of 101 nm. AFM and TEM characterization revealed a highly ordered macroscopic channel pattern, such as... Figure 2 As shown, the average length is 2-6 µm and the average width is 0.3-1 µm, exhibiting obvious growth anisotropy.

[0050] Furthermore, tests were conducted under the following self-assembly conditions: 50-60℃, Mg 2+ The frame performance obtained from 10-50 mM is basically the same as that of Example 2, and will not be further elaborated here.

[0051] Example 3 Two-dimensional gold nanosphere arrays constructed using a sucrose-assisted assembly system (SAAS): Gold nanospheres (AuNP, 10 nm) were surface-modified with thiolized single-stranded DNA using a salt aging method and then purified to remove excess thiolized single-stranded DNA. The two-dimensional DNA channel template prepared in Example 2 was mixed with AuNP in a specific ratio (volume ratio controlled at 1:1 to ensure AuNP excess) in 1×TAE-Mg containing 20% ​​(w / v) sucrose. 2+ In a buffer solution, anneal the mixture from 45°C to 25°C at a rate of 0.1°C / 5 min.

[0052] Furthermore, tests were conducted under the following self-assembly conditions: the two-dimensional DNA channel template prepared in Example 2 was mixed with AuNP in a specific ratio (volume ratio controlled at 1:0.8 to 1:1.5, ensuring AuNP excess) in 1×TAE-Mg containing 15-25% (w / v) sucrose. 2+ In the buffer solution, the performance of the obtained framework is basically the same as that of Example 3, and will not be elaborated further here.

[0053] Comparative Example 1 Constructing a two-dimensional gold nanosphere array using a traditional buffer system The two-dimensional DNA channel template prepared in Example 2 was mixed with AuNP in a specific ratio (consistent with Example 3) in sucrose-free 1×TAE-Mg. 2+ In the buffer solution, all other conditions were exactly the same as in Example 3 (including mixing ratio, annealing procedure, washing and dispersion and characterization methods).

[0054] After washing and redispersing the bottom precipitate, it was characterized by TEM, such as... Figure 3 As shown. The results show that the AuNP linear density of Example 3 reaches 30-45 particles / 500 nm; compared with the conventional 1×TAE-Mg of Comparative Example 1. 2+ The system (15-25 particles / 500nm) improved by 50-80%; and the center distance between adjacent particles in Example 3 was 10-16 nm, which was 30-45% lower than the traditional system (18-25nm) in Comparative Example 1; and the standard deviation of Example 3 was significantly reduced, and the uniformity was significantly improved.

[0055] Example 4 Constructing a two-dimensional gold nanorod array by optimizing the hybridization domain length: Thiolized single-stranded DNA was modified onto the surface of gold nanorods (AuNR, aspect ratio 5-10:1, length 60-100 nm, diameter 8-15 nm), and the hybridization domain lengths were set to T4 to T12 (i.e., 4-12 nt). The nanorods were mixed with the two-dimensional DNA channel template from Example 2 under the SAAS conditions of Example 3 and annealed.

[0056] like Figure 3 As shown, statistical results indicate that as the hybridization domain length decreases from T12 to T4, the yield gradually increases and the misalignment defect rate gradually decreases. The optimal hybridization domain length range is determined to be T5-T7, at which point the correct alignment yield reaches 90-95%, the misalignment defect rate drops to 3-8%, and the areal density remains at approximately 80-120 grains / µm. 2 .

[0057] Example 5 Construction of multi-component heterogeneous superlattices: Differential trapping chains are extended on both sides of the step in a two-dimensional channel template through sequence orthogonality design. Two or three of AuNP, AgNP, and AuNR are assembled according to the method in Example 3, successfully constructing binary heterostructures (AuNP-AgNP), binary heterostructures (AuNR-AuNP), binary heterostructures (AuNR-AgNP), and ternary heterostructures (AuNR-AuNP / AgNP) superlattices, such as... Figure 4 As shown. FFT analysis revealed the linear superposition of diffraction characteristics of each component, and EDS mapping confirmed that the distribution of metal elements perfectly matched the preset pattern. Bilateral programming reduced the array line spacing from 95-110 nm to 45-55 nm, achieving a doubling of spatial resolution.

[0058] Example 6 Construction of a double-step, three-period superlattice: A double-step channel-like DNA framework was designed and synthesized, consisting of a bottom pedestal (95-110 nm period), a middle layer Step 1 (45-55 nm wide), and a top layer Step 2 (20-30 nm wide). Orthogonal capture strands were pre-set on both sides of Step 1 and on one side of Step 2 to anchor AuNP, AgNP, and AuNR, respectively.

[0059] It is performed using the same method as in Example 3.

[0060] TEM showed the coordinated arrangement of the three types of particles on the sidewalls of the framework, such as Figure 5 As shown, the line spacing was finely controlled to P1≈10-18 nm, P2≈25-35 nm, and P3≈20-30 nm. The FFT pattern showed nested diffraction points and diffraction rings, confirming the long-range ordered arrangement of the ternary components.

[0061] Example 7 Electrical performance testing and observation of collective Coulomb blockage effect at room temperature: The two-dimensional AuNR array with the preferred hybridization domain length (T6) prepared in Example 4 was deposited on a SiO2 surface. Gold electrodes (50-100 nm thick, with a Ti adhesion layer) were fabricated by electron beam lithography. Pt electrodes were then deposited at both ends of the array using FIB-SEM to construct microelectrode pathways. The I / V curves were measured using a semiconductor parameter analyzer at room temperature (293-303 K) and in a vacuum environment. Figure 6 As shown.

[0062] For single-row AuNR arrays (1-3 AuNR lines, containing 4-8 gaps, with an average spacing of 3-6 nm), the I / V curves exhibit quasi-linear characteristics, and the dI / dV curves show periodic oscillations, confirming electron hopping transport. For multi-row parallel AuNR arrays (3-8 AuNR lines, containing 20-40 gaps, with an average spacing of 8-12 nm), clear Coulomb gaps are observed near V=0, with almost zero conductivity, exhibiting significant nonlinear transport behavior and a collective Coulomb blockage effect. A steep single-step characteristic is observed near the turn-on voltage, suggesting a confined stochastic percolation mechanism.

[0063] The above results show that the superlattice constructed in this invention generates charging energy that significantly exceeds room temperature thermal energy due to its sub-4-10 nm extreme gap, making the collective charge correlation behavior clearly visible under environmental conditions.

[0064] In summary, this invention discloses a metal nanoparticle superlattice based on a monomeric DNA framework and its preparation method. This method synthesizes a micron-scale rigid monomeric DNA framework template through one-step self-assembly of a 52-nt DNA brick. A sucrose-assisted assembly system (SAAS) is then used to perform sequence-specific hybridization between surface-modified thiolized single-stranded DNA metal nanoparticles and the template, achieving high-fidelity epitaxial assembly. This invention overcomes the structural defects of traditional splicing templates and the kinetic traps of heavy particles, achieving sub-5 nm precision, high density, and multi-component heterogeneous integration. A collective Coulomb blockage effect was observed at room temperature, making it applicable to single-electronic devices, optoelectronic integrated circuits, and other fields.

[0065] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for preparing a metal nanoparticle superlattice based on a monomeric DNA framework, characterized in that, Includes the following steps: (1) Micron-sized monomeric DNA framework templates were synthesized through one-step self-assembly of DNA bricks; (2) Metal nanoparticles with thiolized single-stranded DNA on their surface are mixed with the DNA framework template prepared in step (1) in a sucrose-containing buffer solution. The metal nanoparticles are precisely anchored to the preset sites of the DNA framework template through sequence-specific hybridization to obtain a metal nanoparticle superlattice. The DNA bricks are formed by one-step self-assembly of single strands of DNA with a length of 48-56 nt. The DNA framework template is a rigid structure that is all solid and without cavities.

2. The method for preparing a metal nanoparticle superlattice based on a monomeric DNA framework according to claim 1, characterized in that, The DNA framework template is asymmetric step-like, comprising: a one-dimensional step-like structure periodically assembled along the Y-axis, or a two-dimensional channel-like structure periodically assembled along the XY plane; or... The DNA framework template has a double-step channel structure, consisting of a bottom base, a middle layer, and a top layer; The DNA framework template has a trapping strand extending from its sidewall, which is used to connect the thiolized single-stranded DNA of the metal nanoparticles and anchor the metal nanoparticles.

3. The method for preparing a metal nanoparticle superlattice based on a monomeric DNA framework according to claim 2, characterized in that, When the DNA framework template is a double-step channel structure, the capture strands extending from the sidewalls of different levels in the middle and top layers are orthogonal capture strands, which are used to anchor different types and / or morphologies of metal nanoparticles.

4. The method for preparing a metal nanoparticle superlattice based on a monomeric DNA framework according to claim 1, characterized in that, The metal nanoparticles include at least one of gold nanospheres, gold nanorods, and silver nanospheres; The number of thiolized single-stranded DNA molecules distributed along the axial direction of the gold nanorods is greater than the number of thiolized single-stranded DNA molecules distributed along the radial direction.

5. The method for preparing a metal nanoparticle superlattice based on a monomeric DNA framework according to claim 1, characterized in that, The metal nanoparticles hybridize with the capture strand of the DNA framework template via a single-stranded DNA with a hybridization domain length of T4-T12.

6. The method for preparing a metal nanoparticle superlattice based on a monomeric DNA framework according to claim 1, characterized in that, In the sucrose-containing buffer solution: The mass-volume concentration of sucrose is 15-25%; Buffer solution containing Mg 2+ TAE buffer.

7. The method for preparing a metal nanoparticle superlattice based on a monomeric DNA framework according to claim 1, characterized in that, After mixing the metal nanoparticles with the DNA framework template, programmed cooling annealing was used to ensure that the hybridization reaction proceeded fully and reached a thermodynamically stable state. The programmed cooling annealing is as follows: annealing from 40-50℃ to 20-30℃ at a rate of 0.1-0.5℃ / 5 min.

8. A metal nanoparticle superlattice based on a monomeric DNA framework, characterized in that, It is prepared by the preparation method according to any one of claims 1-7; The superlattice has an array structure that is homogeneous, homogeneous, heterogeneous, or heterogeneous.

9. The metal nanoparticle superlattice based on a monomeric DNA framework according to claim 8, characterized in that, The superlattice is a binary heterogeneous superlattice, a binary heteromorphic superlattice, a binary heterogeneous superlattice, or a ternary heterogeneous superlattice; and / or, The spacing between adjacent metal nanoparticles in the superlattice is 4-10 nm.

10. The application of the metal nanoparticle superlattice based on the monomer DNA framework as described in claim 8 in the fabrication of single-electronic devices, quantum logic circuits, optoelectronic integrated circuits, metasurface optical devices, or ultrasensitive biosensors.

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