DNA origami for nanomorse code and applications thereof

Abstract

This invention belongs to the fields of DNA nanotechnology and cryptography, and discloses a type of DNA origami representing nano Morse code and its application in encrypted secure communication. The main structure of the DNA origami representing nano Morse code is a two-dimensional nanostructure. The nano Morse code is constructed by arranging the dot and line patterns of each Morse code in the international Morse code in a 3x2 dot and line pattern from top to bottom and from left to right, and then using DNA self-assembly to map the nano Morse code pattern onto the main structure of the DNA origami. Two vertically distributed DNA dumbbell chains represent the dot symbols in the nano Morse code, and a segment of DNA double-stranded orbital formed by HCR components represents the long symbols in the nano Morse code table. This invention also discloses the application of the above-mentioned DNA origami representing nano Morse code in encrypted secure communication. In addition to achieving basic pattern encryption, the DNA origami representing nano Morse code can also achieve biological "multi-layer encryption," including biometric signature encryption and steganography encryption.

Description

Technical Field

[0001] This invention belongs to the fields of DNA nanotechnology and cryptography, specifically relating to a type of DNA origami representing nano Morse code and its application in encrypted secure communication. Background Technology

[0002] With the advent of the big data era, the secure storage and communication of massive amounts of data has become a major concern. Cryptography is a science that uses mathematical methods to design encryption algorithms to protect data and communication security. Traditional cryptography can be traced back to the Caesar cipher, where each letter in the plaintext is replaced by a letter in a specific position in the alphabet. Modern cryptography typically employs symmetric and asymmetric encryption algorithms, the strength of which depends on complex mathematical operations. However, the rapid development of computer science and the emergence of quantum computers have made current encryption protocols vulnerable to brute-force attacks, such as methods that traverse the entire key space, and the risk of interception.

[0003] Biomolecular cryptography utilizes specific biomolecular interactions for data encryption, offering a unique method for ensuring information security. For example, biocomputing based on proteins, aptamers, bacteria, and DNA has demonstrated its application in message protection techniques for secure communication. Due to the extremely high information density of DNA molecules and the parallelism of DNA computation, DNA cryptography has found widespread applications in encryption, authentication, and signatures. With the development of DNA nanotechnology, the structural potential of DNA molecules is also being utilized in DNA cryptography. DNA origami is a typical method in DNA nanotechnology, folding long single-stranded DNA scaffolds, such as the 7249-nucleotide M13mp18 bacteriophage, into nanostructures with pre-designed shapes and multiple functions using hundreds of short DNA chains, such as staple chains. Previous research has shown that steganography based on static DNA origami nanostructures can guarantee the confidentiality, integrity, and availability of information—the "CIA trinity"—as well as reconfigurable DNA origami domino arrays (DODA) for steganography and cryptography. However, constructing multi-key pair encryption protocols to ensure secure communication remains a significant challenge. Summary of the Invention

[0004] The purpose of this invention is to provide a type of DNA origami that characterizes nano Morse code and its application in encrypted secure communication, thereby solving the problem that existing technologies lack a secure communication system that can circumvent the risk of brute-force attacks caused by the rapid development of computer computing power, while the entire system possesses extremely high confidentiality, reliability, and availability.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] Firstly, this invention provides a type of DNA origami representing nano-Morse codes. The main structure of this type of DNA origami representing nano-Morse codes is a programmable two-dimensional nanostructure formed by using long-chain DNA as a scaffold and short-chain DNA as a co-strand to guide folding. The nano-Morse codes include the dot symbol "・" and the long symbol "—", with different sequences of these two signals representing different English letters, numbers, and punctuation marks. The nano-Morse code table of this invention is formulated by arranging the international Morse code table according to certain rules and mapping it onto the pattern on the main structure of the DNA origami, such as... Figure 1B The image shows the international Morse code table, as follows: Figure 1C The image shows a schematic diagram of the nano Morse code table and its pattern mapped onto the main structure of DNA origami, along with an AFM characterization diagram. Figure 1A The diagram shows the mapping method from international Morse code to nano Morse code. Figure 1A Taking the number "3" (··· —) as an example, other Morse codes use the same mapping method. The dot and line patterns of each Morse code in the international Morse code are arranged in a 3x2 dot and line pattern from top to bottom and from left to right as the nano Morse code. Then, following the above mapping method, the pattern of the nano Morse code is mapped onto the main structure of DNA origami using DNA self-assembly. The dot and line patterns of the nano Morse codes of the numbers 0~9 and the letters A~Z are collected to encode the nano Morse code table.

[0007] The DNA origami characterizing nano Morse code provided by this invention utilizes the addressability and programmability of DNA origami, such as... Figure 2A As shown, the dotted-line pattern of nano Morse code is encoded by replacing the auxiliary strands at specific sites on its two-dimensional plane with DNA dumbbell strands or HCR components; where, for example, Figure 2B As shown, the two vertically distributed DNA dumbbell strands represent the dot symbol "・" in nano Morse code, and a DNA double-stranded orbital formed by the HCR component represents the long symbol "—" in the nano Morse code table.

[0008] The DNA dumbbell chain is a special DNA structure used to replace the original DNA staple chain, making it protrude on the DNA origami with closed loops at both ends and a linear double strand in the middle;

[0009] The HCR component is a chemical reaction in which two or more DNA hairpin structures achieve a cascade reaction through a strand displacement mechanism to generate a double-stranded DNA pathway structure. Specifically, in the DNA origami described in the first aspect of the present invention, the HCR component includes a DNA orbital strand, a DNA capture strand located at a specific site in the main structure of the DNA origami, an initiation strand, and a fuel strand; wherein, the DNA orbital strand includes hairpin DNA1, hairpin DNA2, and hairpin DNA3; the HCR component reaction mechanism is as follows: Figure 2C As shown, the DNA orbital strand is anchored to the DNA origami template through sticky ends complementary to the DNA capture strand, triggering the initiation of the corresponding HCR component, and the fuel strand drives the corresponding HCR component.

[0010] As a preferred embodiment of the first aspect of the present invention, the main structure of the DNA origami characterizing nano Morse code is a rectangular DNA origami structure. The rectangular DNA origami structure is formed by using the circular DNA single strand of M13mp18 bacteriophage as the main strand and an excess of DNA staple strands as auxiliary strands. The main strand and auxiliary strands are hybridized and complemented at specific positions to assemble a two-dimensional planar DNA origami structure.

[0011] The main structure of the DNA origami representing nano Morse code is a rectangular DNA origami structure. Furthermore, as a preferred embodiment of the first aspect of the present invention, the DNA origami also includes edge extension chains. The edge extension chains are extension chains that are free on the upper and lower edges of the rectangular DNA origami structure after the auxiliary chains at corresponding sites are replaced by DNA extension chains to assemble the rectangular DNA origami structure. Under the induction of DNA tubular chains, the edge extension chains can transform the rectangular DNA origami structure into a tubular origami structure. That is, the DNA origami representing nano Morse code can also embed identity information by modifying the auxiliary chains. The assembly process and the transformation process of the DNA origami ciphertext are both encryption processes.

[0012] As a preferred embodiment of the first aspect of the present invention, the DNA origami further includes a DNA linker strand, which is used to replace the auxiliary strand at the corresponding site for assembling a rectangular DNA origami structure. Free linker ends can be formed on one or both sides of the rectangular DNA origami structure. The linker ends are used for multiple DNA origami to form DNA origami polymers through orthogonal recognition assembly. The DNA origami polymers can represent multiple Morse codes.

[0013] Secondly, the present invention provides the application of the DNA origami characterizing nano Morse code described above in encrypted secure communication, the application comprising the following steps:

[0014] Step S1: The sender and receiver agree on the information encoding method and formulate a nanomorse cipher table as the key for symmetric encryption.

[0015] Step S2: The sender refers to the nano Morse code table, encrypts the plaintext information into a pattern in the nano Morse code table that is composed of several consecutive dot symbols "·" and long symbols "—", and maps the pattern onto the DNA origami structure template to generate a single DNA origami representing the nano Morse code or a polymer formed by multiple DNA origami representing the nano Morse code, as the DNA origami pattern ciphertext;

[0016] Step S3: The sender stores the DNA origami pattern ciphertext synthesized in step S2 in a test tube and transmits it to the receiver physically.

[0017] Step S4: The receiver characterizes the DNA origami pattern ciphertext using AFM and decrypts the pattern into plaintext information by referring to the nano Morse code table.

[0018] In step S2, the plaintext information is encoded using Morse code. Each character in the plaintext information is represented by a DNA origami unit encoded in Morse code. The sender holds all the DNA dumbbell strands, HCR components, DNA backbone strands, and DNA staple chains required to represent all the information. The sender selects the DNA strands needed to create the ciphertext based on the plaintext information. When the corresponding position in the pattern ciphertext shows the symbols "·" and "—", the sender needs to replace the DNA staple chain with the corresponding symbol's DNA dumbbell strand or HCR component at a specific position in the DNA origami.

[0019] In step S3, the method by which the sender transmits the DNA origami ciphertext to the receiver includes: collecting the DNA origami ciphertext in a test tube and transmitting it directly to the receiver, or collecting it and dropping it onto absorbent paper for the receiver to collect.

[0020] like Figure 4A As shown, as a preferred application method, the main structure of the DNA origami representing nano Morse code is a rectangular DNA origami structure. The application also includes the following operations: In step S1, the sender designs and synthesizes a pair of keys for the signature algorithm, including a signature key and a verification key, and transmits the verification key to the receiver through a secure channel. The signature key is kept secret by the sender. In step S2, the sender uses the signature key to encrypt the DNA origami using a biometric signature algorithm and steganography, as the ciphertext of the DNA origami pattern. In step S4, the receiver adds the verification key to the ciphertext of the DNA origami pattern obtained in step S3, performs signature verification, and then uses AFM to characterize the ciphertext after cracking the steganography.

[0021] In step S1, the signature key is a set of edge extension strands of DNA origami and a set of DNA tubular strands that induce the rectangular DNA origami structure to conformate into a tubular DNA origami structure; the verification key is a set of DNA open strands that guide the tubular DNA origami structure to conformate back to a rectangular conformation.

[0022] In step S2, the biometric signature algorithm refers to the conformational change of DNA origami between a rectangle and a tubular shape under the action of a set of DNA key chains; the signature generation refers to the transformation of the rectangular DNA origami into a tubular shape under the action of the signature key; and the steganography refers to the fact that the nano Morse code pattern cipher modified on the surface of the DNA origami in the tubular conformation is invisible under AFM.

[0023] In step S4, the receiver first performs signature verification, uses AFM to observe the ciphertext, confirms that the ciphertext is in the form of tubular DNA origami, and ensures the authenticity and integrity of the information. Then, the verification key is added, and the tubular DNA origami ciphertext is transformed into rectangular DNA origami for signature verification and at the same time, the steganography is cracked. By characterizing the pattern ciphertext with AFM and referring to the nano Morse code table, the pattern can be decrypted into plaintext information.

[0024] The signature algorithm refers to a method for ensuring data integrity and authentication using a pair of keys. In this invention, the conformational change of DNA origami between a rectangle and a tubular shape serves as the biosignature, and the DNA tubular strand and the DNA open strand serve as the pair of keys. The signature generation refers to the reconstructing of the rectangular DNA origami into a tubular shape under the action of the signature key, i.e., the DNA tubular strand; the signature verification refers to the reconstructing of the tubular DNA origami into a rectangle under the action of the verification key, i.e., the DNA open strand. Figure 4A The diagram illustrates the allosteric principle and AFM characterization of DNA origami. The signature key comprises 12 edge extension strands and 6 DNA tube-forming strands, while the verification key comprises 6 DNA open strands complementary to the DNA tube-forming strands. Preferably, the DNA extension strands are distributed at the upper and lower edges of the rectangular DNA origami, with an extension length of 16 bases. Preferably, the DNA tube-forming strands are 48 bases long, comprising a 32-base complementary region to the edge extension strands and sticky end regions of 8 bases at each end. Preferably, the DNA open strands are 48 bases long.

[0025] As one implementation of the above application, if the plaintext information contains multiple ordered words, for example, the plaintext information "LIVE AND LEARN" contains three ordered words "LIVE", "AND", and "LEARN", it needs to be split into three groups of DNA origami polymers for encoding. The aforementioned DNA origami including the DNA linker strand needs to be selected. The ordinal number of each word in the sentence is represented by the number of sequence marker units on the first DNA origami monomer in the DNA origami polymer. These sequence marker units correspond to... Figure 1A The 1 in the bottom right corner of the mapping rule st , 2 nd , 3 rdIn the specified region, a single "·" in the sequence marker unit represents sequence number 1, two "·"s represent sequence number 2, and three "·"s represent sequence number 3. Therefore, the mapping method of the plaintext information "LIVE AND LEARN" on the DNA origami multimer and the AFM characterization diagram are as follows: Figure 1D As shown, in order to determine the word order, an extra "·" is added to the bottom right corner of the DNA origami monomer representing "L" in LIVE, two extra "·"s are added to the bottom right corner of the DNA origami monomer representing "A" in AND, and three extra "·"s are added to the bottom right corner of the DNA origami monomer representing "L" in LEARN.

[0026] This invention provides a type of DNA origami representing nano-Morse code, which, in a preferred application, can achieve "multiple encryption." Specifically, the "multiple encryption" includes: 1. Pattern encryption: The sender encrypts the plaintext information into a pattern formed by a continuous arrangement of dot symbols "·" and long symbols "—". The receiver decrypts the pattern ciphertext back to the plaintext information. The key is a nano-Morse code table; 2. Biometric signature encryption: The sender prepares a set of keys, divided into a signature key and a verification key. The signature key contains all the extended DNA strands and all the tubular DNA strands that transform the DNA origami into tubular DNA origami. The verification key contains all the open DNA strands that transform the tubular DNA origami into rectangular DNA origami. The verification key is publicly transmitted to the sender, while the signature key is secretly kept by the sender. Let n represent the length of the DNA tubular sequence, and the key length is 4. 6n When using a 48-base tube sequence, the key length is 2. 576 3. Steganography encryption: The ciphertext of the pattern cannot be directly observed by AFM under the tubular DNA origami conformation.

[0027] It should be understood that the DNA origami representing nano Morse code provided by this invention and its application in encrypted secure communication have universal applicability. Results show that this invention provides a reliable secure communication method that integrates pattern ciphers, signature algorithms, and steganography, and can obtain a vast key space by utilizing the specific identification of DNA sequences. This invention uses DNA as the medium for information transmission, offering strong concealment and is not threatened by the increasing processing speed of electronic computers. As a novel secure communication method, it provides more possibilities for future information encryption methods. Attached Figure Description

[0028] Figure 1A A mapping method from international Morse code to nano Morse code;

[0029] Figure 1B For international Morse code;

[0030] Figure 1CA schematic diagram of a nano Morse code table and its pattern mapped onto the main structure of DNA origami, and an AFM characterization diagram;

[0031] Figure 1D The mapping method of the plaintext information "LIVE AND LEARN" on DNA origami polymers and the AFM characterization diagram;

[0032] Figure 2A The paper demonstrates the origami representation of the dot symbol "·" and the long symbol "—". The dot symbol "·" is represented by two DNA dumbbell strands, and the long symbol "—" is represented by a double-stranded DNA path formed by HCR components.

[0033] Figure 2B A diagram showing the position of the dot symbol "·" represented by two DNA dumbbell strands;

[0034] Figure 2C The reaction mechanism of the HCR component was demonstrated;

[0035] Figure 3A This is a schematic diagram of the encryption and decryption process and secure communication of text "DNA" information through pattern ciphertext in Example 1;

[0036] Figure 3B The AFM characterization results of the ciphertext "DNA" pattern are shown, with a scale bar corresponding to 200 nm.

[0037] Figure 4A It demonstrates how rectangular DNA origami is folded into a tubular shape by DNA tubular strands, and how tubular DNA origami is restored to a rectangle by DNA open strands, with the scale bar corresponding to 100 nm;

[0038] Figure 4B This is a schematic diagram of the secure transmission of the text "6" based on signature algorithms and steganography in Example 2, with the scale bar corresponding to 100 nm. Detailed Implementation

[0039] To further illustrate the technical means and effects of this invention, the following description, in conjunction with embodiments and accompanying drawings, provides a further explanation of the invention. It is understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it.

[0040] In the description of this specification, it should be understood that the terms "upper," "lower," "left," and "right" are based on the orientation or positional relationship shown in the accompanying drawings, or the orientation relationship of the product in its usual use state. They are used only for the convenience of describing the invention and simplifying the description, and are not intended to indicate or imply that the product referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.

[0041] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels.

[0042] 1×TAE-Mg 2+ Buffer components: 40 mM Tris, 20 mM acetate, 2 mM EDTA, 12.5 mM magnesium acetate, pH: 8.0;

[0043] The following Examples 1 and 2 use rectangular DNA origami as the main structure as specific embodiments of the application of DNA origami representing nano Morse code in encrypted secure communication. That is, the main structure of the DNA origami in Examples 1 and 2 uses the circular DNA single strand of M13mp18 bacteriophage as the main strand and an excess of DNA staple strands as auxiliary strands. The two-dimensional rectangular DNA origami structure is formed by the hybridization and complementary assembly of the main strand and auxiliary strands at specific positions.

[0044] Example 1: Secretly transmitting information "DNA" via pattern encryption

[0045] The DNA sequence involved in this Example 1 is specifically set as follows: M13 phage single-stranded DNA product - M13mp18 ssDNA was purchased from BioBio Biotechnology Co., Ltd., and the sequence can be obtained from the company's official website;

[0046] The original DNA staple strands were cited from the "Sequence of staplestrands used in the assembly of basic rectangular DNA origami" in the published document 1, "Chenqi, Shen, Xiang, et al. Tuning the structural asymmetries of three-dimensional gold nanorod assemblies.[J]. Chemical Communications, 2015.DOI:10.1039 / c5cc05295e". The DNA dumbbell strand sequences are shown in Table 1 below, and the DNA dumbbell strand sequences in Table 1 were used to replace the DNA staple strands in the "Sequence of staple strands used in the assembly of basic rectangular DNA origami" for assembly. The DNA capture strand sequences are shown in Table 2 below, and similarly, the DNA capture strand sequences in Table 2 were used to replace the DNA staple strands in the "Sequence of staple strands used in the assembly of basic rectangular DNA origami" for assembly. The DNA linker strands were cited from the previously published document 2, "Artificial molecular communication network based on...". "Supplementary Table 2. Sequences for connectors." from "DNA nanostructures recognition (Nature Communications, 2025, 16 1: 244.)" Following the DNA connector strand substitution sites and base sequences in published reference 2, the original DNA staple strands were replaced for assembly. The DNA orbital strand, initiator strand, and fuel strand were all referenced from our previously published reference 3, "Solving mazes with single-molecule DNA navigators (Nature Mater 2018, 18, 273–279)". Hairpin DNA1 and hairpin DNA2 in the DNA orbital strand were both T1 from reference 3; hairpin DNA3 was T1 from reference 3. exit -a and T1 exit -b; the initiation chain is I in the literature, and the fuel chain is T2 in literature 3.

[0047] Table 1:

[0048]

[0049] Table 2:

[0050]

[0051] The encryption and decryption diagram of secure communication using pattern ciphertext in Embodiment 1 is shown below. Figure 3A As shown, it includes the following steps:

[0052] First, Alice encrypts each letter in the text message into a continuous nano-Morse code pattern: Alice, the sender, follows... Figure 1C The given correspondence will convert the letters “D”, “N”, and “A” in the information into corresponding nano Morse code patterns in sequence.

[0053] The sender, Alice, encrypted the symbolic pattern of the letters in the text message into a DNA origami unit: the design diagram of the symbolic pattern is shown below. Figure 3A As shown. Different patterns require different DNA staple chains, DNA linker chains, DNA dumbbell chains, DNA capture chains, and DNA orbital chains (hairpin DNA1, hairpin DNA2, hairpin DNA3). The corresponding DNA dumbbell chain, DNA capture chain, and DNA orbital chain are added based on the pattern symbol at a certain position on the ciphertext. "·" symbol: DNA dumbbell chain added at the corresponding site; "—" symbol: DNA capture chain and DNA orbital chain added at the corresponding site; blank: no addition. The molar ratio of the backbone chain to the DNA staple chain, DNA linker chain, DNA dumbbell chain, DNA capture chain, and DNA orbital chain is 1:10:10:10:10:100. The mixture of the backbone strand and short DNA strands described above was slowly annealed using a gradient PCR instrument. In Example 1, the short DNA strands included DNA staple strands, DNA linker strands, DNA dumbbell strands, and DNA capture strands. The annealing conditions were: starting temperature 95°C, held for 3 min, ending temperature 25°C, with each 1°C increment representing a 100-second hold at each temperature. Annealing was performed from 95°C to 25°C over two hours. The reaction buffer was 1×TAE-Mg. 2+ Buffer solution; remove the sample and centrifuge using a 100 kDa centrifuge tube to remove excess short DNA strands; centrifugation conditions: add 300 μL of 1× TAE-Mg to 100 μL of sample. 2+ The buffer solution was centrifuged at 3000 rcf for 10 min, and the centrifugation was repeated 3 times to obtain the centrifuged purified DNA origami monomer.

[0054] Alice, the sender, assembled the DNA origami monomers into DNA origami polymers: the three DNA origami monomers with patterned symbols prepared above were mixed in an equimolar ratio, with each monomer having a concentration of 3 nM. The resulting solution was 90 µL and placed in a water bath for annealing, slowly reducing the temperature from 45°C to 25°C. After the annealing process was completed, DNA origami trimers were obtained.

[0055] Alice, the sender, prepares the DNA origami pattern ciphertext: The DNA origami trimer is diluted to 1 nM. According to the molar concentration ratio of the ciphertext solution, initiator chain I, and fuel chain H2 of 1:50:500, initiator chain I and fuel chain H2 are added to the ciphertext solution. The mixed solution is placed at room temperature for 2 hours to prepare the DNA origami pattern ciphertext. Then the DNA origami pattern ciphertext is collected and passed to Bob, the receiver.

[0056] The recipient, Bob, characterized and decrypted the DNA origami pattern ciphertext using AFM: 5 µL of sample was dropped onto freshly peeled mica, and after adsorption for 2 min, characterization was performed using a Multimode Nanoscope VIIIAFM (Bruker) in Tapping mode. The probe used was SNL-10 (Bruker). The AFM characterization results are as follows: Figure 3B As shown. During decryption, Bob... Figure 1C The corresponding letter is found in the nano Morse code table shown, and then decryption is performed.

[0057] Example 2: Secure transmission of the text "6" based on signature algorithms and steganography

[0058] This Example 2 uses the same M13 phage single-stranded DNA, the same original DNA staple strand, the same DNA capture strand sequence, the same DNA orbital strand, the same initiation strand, and the same fuel strand as in Example 1. In addition to the DNA dumbbell strands listed in Example 1, this Example 2 also requires replacing four original staple strands with the DNA dumbbell strands shown in Table 3 below:

[0059] Table 3:

[0060]

[0061] The DNA extension strands involved in this embodiment 2 are shown in Table 4 below. The DNA extension strand sequences in Table 4 are used to replace the DNA staple strands in the above "Sequence of staple strands used in the assembly of basic rectangular DNA origami" for assembly. For example, T-180 represents replacing the original DNA staple strand No. 180, T-156 represents replacing the original DNA staple strand No. 156, and so on.

[0062] Table 4:

[0063]

[0064] The DNA tubular strands involved in this Example 2 are shown in Table 5 below:

[0065] Table 5:

[0066]

[0067] The DNA open strands involved in this Example 2 are shown in Table 6 below:

[0068] Table 6:

[0069]

[0070] The encryption and decryption diagram of secure communication using signature algorithms and steganography in Embodiment 2 is shown below. Figure 4A As shown, it includes the following steps:

[0071] The sender, Alice, designs, synthesizes, and distributes the keys: such as Figure 4A The DNA keychain shown includes a DNA extension strand, a DNA tube forming strand, and a DNA opening strand. The DNA extension strand and the DNA tube forming strand serve as signature keys, secretly kept by Alice, while the DNA opening strand serves as the verification key. Alice stores the verification key in test tubes, with each DNA strand having a concentration of 1 µM. The test tubes can be stored in a freezer, and then the test tubes are transmitted to the recipient, Bob, via a secure channel.

[0072] The sender, Alice, created a DNA origami cipher and embedded her identity information: Alice followed... Figure 1CThe given correspondence converts the text "6" into a corresponding nanometer Morse code pattern. Different patterns require different DNA staple chains, DNA dumbbell chains, DNA capture chains, and DNA orbital chains. The presence or absence of a specific site on the ciphertext determines whether to add the corresponding DNA dumbbell chain, DNA capture chain, or DNA orbital chain. The molar ratio of the backbone chain to the DNA staple chain, DNA extension chain, DNA dumbbell chain, DNA capture chain, and DNA orbital chain is 1:10:10:10:10:100. The mixture of the backbone chain and DNA staple chain, DNA extension chain, DNA dumbbell chain, DNA capture chain, and DNA orbital chain is slowly annealed using a gradient PCR instrument. The annealing conditions are: initial temperature 95 °C, hold for 3 min, final temperature 25 °C, with each °C increment representing a 100 s hold, and annealing from 95 °C to 25 °C over two hours. The reaction buffer is 1×TAE-Mg. 2+ Buffer solution. Remove the sample and centrifuge using a 100 kDa centrifuge tube to remove excess short DNA strands; centrifugation conditions: add 300 μL of 1×TAE-Mg to 100 μL of sample. 2+ The buffer was centrifuged at 3000 rcf / min for 10 min, and the centrifugation was repeated 3 times to obtain the centrifuged and purified rectangular DNA origami ciphertext containing the identity information.

[0073] The sender signs and steganographically encrypts the DNA origami ciphertext: the purified DNA origami ciphertext is diluted to approximately 1 nM, then mixed with DNA origami at a molar ratio of 1:40 and annealed in a 100 μL volume. The annealing conditions are: from 45 ℃ to 25 ℃, with each 1 ℃ increment representing a gradient, and each gradient residence time being 5 min, for 5 cycles, to obtain tubular DNA origami, which is then collected and delivered to the recipient Bob.

[0074] Recipient Bob verifies the signature and deciphers the steganography: Bob uses AFM to observe the ciphertext, drops 5 μL of sample onto freshly peeled mica, allows it to adsorb for 2 min, and then characterizes it using the Tapping mode of a Multimode Nanoscope VIIIAFM (Bruker). The probe used is SNL-10 (Bruker). The AFM characterization results are as follows: Figure 4BAs shown. After confirming that the information had not been corrupted, Bob mixed the verification key with the ciphertext folded from the tubular DNA at a molar ratio of DNA open strand to DNA tubular strand of 2:1. The mixture was allowed to react at room temperature for 5 minutes, and the ciphertext was observed again using AFM. It is worth noting that if the recipient observes that the DNA ciphertext is still in a tubular form, it indicates that the verification key and the signature key do not match, and the signature verification has failed. In this case, the recipient cannot determine the authenticity of the information, thus avoiding the risk of being deceived by forged information.

[0075] Recipient Bob identified the DNA origami pattern ciphertext using AFM: Bob based on Figure 4B The AFM characterization diagram shown is used to obtain the ciphertext of the pattern and compare it. Figure 1C The nano Morse code table shown decrypts the ciphertext of the pattern into plaintext information.

Claims

1. A class of DNA origami representing nanomorse code, characterized in that, The main structure of the DNA origami representing the nano-Morse code is a programmable two-dimensional nanostructure formed by using long-chain DNA as a scaffold and short-chain DNA as auxiliary strands to guide folding. The nano-Morse code is constructed by arranging the dot-line pattern of each Morse code in the international Morse code in a 3x2 dot-line pattern from top to bottom and from left to right, and then mapping the nano-Morse code pattern onto the main structure of the DNA origami using DNA self-assembly. The method of mapping the nano-Morse code pattern onto the main structure of the DNA origami is as follows: the auxiliary strands at specific sites on the two-dimensional nanostructure are replaced with DNA dumbbell strands or HCR components to encode the dot-line pattern of the nano-Morse code as ciphertext. Two vertically distributed DNA dumbbell strands represent the dot symbols in the nano-Morse code, and a segment of DNA formed by the HCR component... NA double-stranded orbitals represent long symbols in a nano Morse code table; the DNA dumbbell chain is a special DNA structure used to replace the original DNA staple chain, causing it to protrude on the DNA origami with closed loops at both ends and a linear double strand in the middle; the HCR assembly consists of all the components that generate a double-stranded DNA pathway structure through a cascade reaction of two or more DNA hairpin structures via a strand substitution mechanism. The HCR assembly includes a DNA orbital chain, a DNA capture chain located at a specific site in the main structure of the DNA origami, an initiation chain, and a fuel chain; wherein, the DNA orbital chain includes hairpin DNA1, hairpin DNA2, and hairpin DNA3; the DNA orbital chain is anchored to the DNA origami template through sticky ends complementary to the DNA capture chain, the initiation chain corresponds to the initiation of the HCR assembly, and the fuel chain corresponds to the driving of the HCR assembly.

2. The class of DNA origami representing nanomorse code of claim 1, wherein, The main structure of the DNA origami representing nano Morse code is a rectangular DNA origami structure. The rectangular DNA origami structure uses the circular DNA single strand of M13mp18 bacteriophage as the main strand and an excess of DNA staple strands as auxiliary strands. The main strand and auxiliary strands are hybridized and complemented at specific positions to assemble a two-dimensional planar DNA origami structure.

3. The DNA origami characterizing nano Morse code as described in claim 2, characterized in that, The DNA origami also includes edge extension chains, which are extension chains that replace the auxiliary chains at corresponding sites with DNA extension chains to assemble rectangular DNA origami structures and are free on the upper and lower edges of the rectangular DNA origami structure. Under the induction of DNA tubular chains, the edge extension chains can transform the rectangular DNA origami structure into a tubular origami structure.

4. The DNA origami characterizing nano Morse code as described in claim 1, characterized in that, The DNA origami also includes a DNA linker strand, which is used to replace the auxiliary strand at the corresponding site to assemble a rectangular DNA origami structure. Free linker ends can be formed on one or both sides of the rectangular DNA origami structure. The linker ends are used to assemble multiple DNA origami into DNA origami polymers through orthogonal recognition. The DNA origami polymers can represent multiple Morse codes.

5. The application of the DNA origami characterizing nano Morse code as described in claim 1 in encrypted secure communication, the application comprising the following steps: Step S1: The sender and receiver agree on the information encoding method and formulate a nano-Morse cipher table as the key for symmetric encryption. Step S2: The sender refers to the nano Morse code table, encrypts the plaintext information into a pattern in the nano Morse code table that is composed of several consecutive dot symbols and long symbols, and maps the pattern onto the DNA origami structure template to generate a single DNA origami representing the nano Morse code or a polymer formed by multiple DNA origami representing the nano Morse code, as the DNA origami pattern ciphertext. Step S3: The sender stores the encrypted DNA origami pattern synthesized in step S2 in a test tube and transmits it to the receiver physically. Step S4: The receiver characterizes the DNA origami pattern ciphertext using AFM and decrypts the pattern into plaintext information by referring to the nano Morse code table; wherein In step S2, all plaintext information is encoded using Morse code. Each character in the plaintext information is represented by a DNA origami monomer encoded in Morse code. The sender holds all the DNA dumbbell strands, HCR components, DNA backbone strands, and DNA staple chains required to represent all the information. The sender selects the DNA strands needed to create the ciphertext based on the plaintext information. When dot symbols and long symbols appear at the corresponding positions in the pattern ciphertext, the sender needs to replace the DNA staple chains with DNA dumbbell strands or HCR components with the corresponding symbols at specific sites in the DNA origami. In step S3, the method by which the sender transmits the DNA origami ciphertext to the receiver includes: collecting the DNA origami ciphertext in a test tube and transmitting it directly to the receiver, or collecting it and dropping it onto absorbent paper for the receiver to collect.

6. The use according to claim 5, wherein the compound is ###0002### The main structure of the DNA origami representing nano Morse code is a rectangular DNA origami structure. The application also includes the following operations: In step S1, the sender designs and synthesizes a pair of keys for the signature algorithm, including a signature key and a verification key, and transmits the verification key to the receiver through a secure channel. The signature key is kept secret by the sender. In step S2, the sender uses the signature key to encrypt the DNA origami using a biometric signature algorithm and steganography, as the ciphertext of the DNA origami pattern. In step S4, the receiver adds the verification key to the ciphertext of the DNA origami pattern obtained in step S3, performs signature verification, and simultaneously decrypts the steganography before representing the ciphertext of the pattern through AFM. In step S1, the signature key is a set of edge extension strands of DNA origami and a set of DNA tubular strands that induce the rectangular DNA origami structure to transform into a tubular DNA origami structure; the verification key is a set of DNA open strands that guide the tubular DNA origami structure to transform back into a rectangular conformation. In step S2, the biosignature algorithm refers to the conformational change of DNA origami between a rectangle and a tubular shape under the action of a set of DNA key chains; the signature generation refers to the transformation of the rectangular DNA origami into a tubular shape under the action of the signature key; the steganography refers to the fact that the nano Morse code pattern cipher modified on the surface of the DNA origami in the tubular conformation is invisible under AFM. In step S4, the receiver first performs signature verification, uses AFM to observe the ciphertext, confirms that the ciphertext is in the form of tubular DNA origami, and ensures the authenticity and integrity of the information. Then, the verification key is added, and the tubular DNA origami ciphertext is transformed into rectangular DNA origami for signature verification and at the same time, the steganography is cracked. By characterizing the pattern ciphertext with AFM and referring to the nano Morse code table, the pattern can be decrypted into plaintext information.

7. Use according to claim 6, wherein The signature key contains 12 edge extension strands of DNA origami and 6 DNA tube strands, and the verification key contains 6 DNA open strands that are complementary to the DNA tubes.

8. The application as described in claim 7, characterized in that, The DNA extension strands are distributed in six strands on the upper and lower edges of the rectangular DNA origami, with an extension length of 16 base pairs.

9. The use according to claim 7, wherein the compound is ###0002### The DNA tubular strand is 48 bases long, including a 32-base complementary region to the edge extension strand, and a sticky end region of 8 bases at each end; the DNA open strand is 48 bases long.

10. The use according to claim 6, wherein If the plaintext contains multiple ordered words, select a DNA origami with a DNA linker strand. The ordinal number of each word in the sentence is represented by the number of sequence marker units on the first DNA origami monomer in the DNA origami polymer.

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