Bacterial surface modification method and application based on programmable pilus-like DNA nanowire rods

Abstract

The application discloses a bacterial surface modification method based on programmable pilus-like DNA nanowire rods and application. The method comprises the following steps: firstly, constructing a DNA nanowire rod structure with a three-dimensional structure by using a DNA origami technology; modifying functional molecules at the head end and the main body of the DNA nanowire rod structure respectively; and incubating bacteria modified with coupling groups with the DNA nanowire rod structure modified with the functional molecules, and the bacterial surface modification method based on the programmable pilus-like DNA nanowire rods is obtained. The DNA nanowire rod structure constructed by the application can be used to regulate the movement of bacteria, the behavior of the bacteria can be regularly regulated by adjusting the geometry and density of the DNA-based pilus analog, and gene operation is not needed. The DNA nanowire rod of the application has the characteristics of modifiability, low toxicity and low immunogenicity, can be used to analyze how the nanoscale appendage morphology controls the movement, and lays a foundation for future application in interface adaptability, colonization or engineering probiotic system.

Description

Technical Field

[0001] This application relates to a method and application for bacterial surface modification based on programmable pili-shaped DNA nanowires, belonging to the fields of DNA nanotechnology and microbial engineering technology. Background Technology

[0002] In 1982, Seeman et al. first proposed the rule of using Watson-Crick base pairing to construct DNA branching junctions, ushering in a new era of DNA nanotechnology. In the following decades, DNA has been widely recognized and applied as a universal polymer material for constructing more complex micro- and nanostructures in the material world. In 2006, Paul Rothemund first reported DNA origami, further advancing the research and application of DNA nanotechnology. Based on the advantages of DNA nanostructures, such as good biocompatibility, precise multi-site surface modification, and controllable size and shape, the nanostructures obtained by DNA self-assembly are similar to cellular substructures and bacterial appendages in terms of scale, morphology, and rigidity, exhibiting strong comparability and representing a cutting-edge approach for constructing biomimetic model systems. For example, significant progress has been made in recent years in using DNA-assembled framework structures to simulate transmembrane pores, cytoskeletal proteins, nuclear pore complexes, eukaryotic viruses, and bacteriophages.

[0003] Bacteria interact with their environment through a variety of surface appendages, among which pili are among the most multifunctional and evolutionarily conserved structures. These filamentous organelles, only a few nanometers in diameter and several micrometers in length, mediate key behaviors such as surface adhesion, twitching movement, biofilm formation, and horizontal gene transfer through dynamic stretching-contraction cycles. For example, the mechanical action of type IV pili can generate propulsive forces up to 100 pN, driving bacteria to move in confined or highly viscous environments. Such movement and adhesion processes are crucial for bacterial colonization, pathogenicity, and environmental adaptation. The artificial regulation of bacterial movement has become an emerging topic at the intersection of microbiology and materials science. Current research mainly uses synthetic coatings such as polymers, nanoparticles, and peptide conjugates to alter bacterial adhesion, biofilm formation, or population dynamics. However, these chemical strategies often lack structural precision, leading to uneven surface modification and unpredictable mechanical properties. While microfabrication environments or external fields can influence bacterial movement trajectories, they cannot replicate the nanoscale structural features of natural pili. Pili are both virulence factors for pathogens and adhesion mediators for probiotics, playing a role in both infection and beneficial colonization. Although biochemical and structural studies have elucidated the composition and assembly pathways of pili proteins, direct manipulation of pili geometric characteristics (such as length, diameter, or mechanical flexibility) remains a technological bottleneck. Traditional gene knockout or overexpression systems can only alter pili abundance, making it difficult to precisely regulate nanoscale structures or biomechanical responses.

[0004] Therefore, developing controllable and quantitative methods to simulate and regulate pili-like structures in live bacteria, and thus systematically studying how geometry regulates motility, remains a long-standing challenge.

[0005] In recent years, the rapid development of DNA nanotechnology has made it possible to achieve precise structural design and synthesis at the micro- and nanoscale. At the same time, the cross-disciplinary integration of nucleic acid nanotechnology and biomedicine is receiving increasing attention. Although numerous nanomaterials have been reported for modification of bacterial surfaces, research on the use of DNA nanostructures for bacterial modification is still in its early stages, with very limited related reports. Therefore, how to use DNA strategies to achieve controllable modification of bacterial surfaces, improve the bioavailability of bacterial preparations, and regulate bacterial motility is a pressing issue that needs to be addressed. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by designing a pili-like DNA rod structure using DNA origami technology and introducing its controllable shape, controllable length, and multi-site modification advantages to the bacterial surface. This proposes a simple and effective new strategy for controllable modification of bacterial surfaces. It can be used as an engineered bacterium to study the influence mechanism of pili on changes in bacterial motility, thus laying a theoretical foundation for improving bacterial bioavailability, colonization, or infection through biomimetic (pili-like) regulation of bacterial motility, ultimately improving disease treatment outcomes.

[0007] To achieve the above objectives, this application adopts the following technical solution:

[0008] This application provides a method for bacterial surface modification based on programmable pili-shaped DNA nanowires, the method comprising the following steps: Step 1: First, construct DNA nanowire or nanorod structures with a three-dimensional structure using DNA origami technology; Step 2: Modify the head end and body of the DNA nanowire or nanorod structure with functional molecules, respectively; Step 3: The bacteria modified with coupling molecules or groups are coupled with DNA nanowires or nanorods modified with functional molecules to graft the DNA nanowires or nanorods onto the bacterial surface. The coupling molecules or groups are molecules or groups that can bind to the functional molecules.

[0009] The DNA nanowire or nanorod structure is assembled from a long template and hundreds of short nucleic acid strands using DNA origami technology. The head end and the "staple chain" of the three-dimensional structure can be quantitatively selected as modification sites, and the selected modification sites extend an anchoring sequence outward for functional modification.

[0010] In some embodiments, the modification of the functional molecule is carried out by utilizing the principle of complementary DNA base pairing, hybridizing the complementary sequence of the modified functional molecule with the anchoring sequence extending from a selected site of the DNA nanowire or nanorod structure, thereby modifying the functional molecule to the head end and body of the DNA nanowire or nanorod structure respectively.

[0011] In some embodiments, the method for constructing the DNA nanowire or nanorod structure includes: Step A1: Construct DNA nanowire or nanorod structures and use 3D images to present schematic diagrams of the structures. Then, use caDNAno, a professional DNA nanostructure design software, to design DNA nanowire or nanorod structures. Step A2: Based on Step 1, further construct variants of DNA nanowire or nanorod structures and establish modification sites on the head end and body; Step A3: Perform structural assembly and purification of the DNA nanowire or nanorod structure constructed in Step 2.

[0012] In some embodiments, step 1 is further followed by obtaining the corresponding sequences of hundreds of staple chains through the input of template strand sequences, and performing sequence synthesis; in this invention, the long ssDNA template p7560 in the M13 phage genome is used as the template strand sequence for the DNA nanowire structure; the long ssDNA template p3024 in the M13 phage genome is used as the template strand sequence for the DNA nanorod structure. In some embodiments, step 3, the structural self-assembly and purification, specifically includes: annealing the template strand sequence and the synthesized staple strand sequence, base pairing self-assembly to obtain DNA nanowires or nanorods, and then separating and purifying them to obtain purified DNA nanowires or nanorods; the purification includes obtaining purified structural monomers using ultracentrifugation and ultrafiltration concentration methods, and removing unbound staple strands and impurities such as dimers and polymers.

[0013] In some embodiments, in step 3, the coupling molecule or group is covalently bonded to the functional molecule by a chemical bond, which is an amide bond, a thiol bond, or a biotin-streptavidin bond. The functional molecule also includes one or more of fluorescent molecules, nucleic acids, and biotin-streptavidin proteins.

[0014] In some embodiments, step 3 specifically includes: reacting bacteria with Sulfo-NHS-Biotin to modify its surface with biotin, then coupling it with streptavidin to obtain bacteria modified with biotin-streptavidin, and then coupling the bacteria modified with biotin-streptavidin with biotin-modified DNA nanowires or nanorods to graft the DNA nanowires or nanorods onto the bacterial surface. The bacteria are naked bacteria or fluorescently labeled bacteria.

[0015] In some embodiments, the concentration of DNA nanowires or nanorods grafted onto the bacterial surface is 0.5 to 40 nM.

[0016] This application also provides bacteria obtained by the above method.

[0017] This application also provides the application of the bacteria obtained by the above methods as tool strains in the study of bacterial biological behavior and mechanisms of action.

[0018] Compared with the prior art, this application has the following beneficial effects: (1) This application utilizes DNA origami to construct a DNA nanorod structure whose length, stiffness, and aspect ratio can be precisely controlled. The structure is programmable and modifiable. The head and body of the structure can extend anchor sequences (A sequences) at selected sites. By combining functionalized complementary sequences (A' sequences) with the anchor sequences, the biocompatibility can be enhanced by localizing and quantitatively modifying the structure with short-chain nucleic acids. This provides an ideal platform for simulating biological filaments such as pili. Compared with various existing nanomaterials, this DNA nanorod structure has advantages such as design controllability, low toxicity, and low immunogenicity. (2) This application uses Bacillus subtilis as a model organism for experimental verification. The functionalized DNA rod structure, with its programmable sequence design and site-specific modification capabilities (such as biotinylation modification through specific hybridization of anchor sequence and staple chain), shows a highly tunable potential for bacterial engineering modification. This structure can precisely regulate bacterial motility through surface functionalization strategies. Attached Figure Description

[0019] Figure 1 This is a design diagram of the DNA nanowire / rod structure in the embodiment; Figure 2 The diagram shows the design structure of DNA nanowires / rods with fimbriae provided in the examples. In the diagram, 2HR represents DNA nanowires and 6HR represents DNA nanorods. Figure 3As an example, this diagram illustrates the stable and controllable grafting of DNA nanowires / rods onto the bacterial surface; wherein, A is a transmission electron microscope image showing the results of grafting different concentrations of DNA nanowires onto the bacterial surface; B is a transmission electron microscope image showing the results of grafting different concentrations of DNA nanorods onto the bacterial surface; C is a statistical graph of the FITC fluorescence intensity of grafted DNA nanowires onto the bacterial surface; and D is a statistical graph of the FITC fluorescence intensity of grafted DNA nanorods onto the bacterial surface.

[0020] Figure 4 In this embodiment, the plate viability diagrams of DNA nanowire / rod-modified bacteria are shown; wherein, A is the plate viability diagram of DNA nanowire-modified bacteria; B is the plate viability diagram of DNA nanorod-modified bacteria; BS: naked Bacillus subtilis; BS-Biotin: activated biotin-modified Bacillus subtilis; BS-SA: streptavidin-modified Bacillus subtilis; BS-2HR: nanowire-modified Bacillus subtilis; BS-6HR: nanorod-modified Bacillus subtilis. Figure 5 This is a schematic diagram illustrating the geometric dependence regulation of bacterial movement in a free-suspension state in the embodiments. A represents representative confocal fluorescence images (top) and corresponding single-cell movement trajectories (bottom) of Bacillus subtilis under different surface modification conditions, including untreated bacteria (natural Bacillus subtilis, Natural BS), streptavidin-modified bacteria (BS-SA), and BS-SA bacteria grafted with different concentrations of 2HR or 6HR; scale bar: 30 μm; BC are violin plots showing the distribution of bacterial movement rates as the modification concentration of 2HR (B) or 6HR (C) increases; D is a curve showing the change in average bacterial movement rate with nanowire surface coverage under 2HR and 6HR modifications, obtained based on quantitative analysis of fluorescence coverage.

[0021] Figure 6 This is a schematic diagram illustrating the verification of motility regulation in a microfluidic environment in the embodiments; wherein, A shows the changes in the motility trajectory of Bacillus subtilis modified with streptavidin (BS-SA) and bacteria modified with different concentrations of 2HR (0.5, 5, 10, 20 and 40 nM); B shows the quantitative statistics of the rate of change in motility of Bacillus subtilis modified with streptavidin (BS-SA) and bacteria modified with different concentrations of 2HR (0.5, 5, 10, 20 and 40 nM); C shows the changes in the motility trajectory of Bacillus subtilis modified with streptavidin (BS-SA) and bacteria modified with different concentrations of 6HR (0.5, 5, 10, 20 and 40 nM); D shows the quantitative statistics of the rate of change in motility of Bacillus subtilis modified with streptavidin (BS-SA) and bacteria modified with different concentrations of 6HR (0.5, 5, 10, 20 and 40 nM).

[0022] Figure 7 This example compares the zeta potentials of bacteria modified under different conditions with those of unmodified bacteria. Detailed Implementation

[0023] To make the technical solution of this application clearer and easier to understand, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0024] Unless otherwise specified, the experimental or testing methods described in the following examples are conventional methods; the reagents and materials described are obtained through conventional commercial channels unless otherwise specified.

[0025] This application relates to the construction of a type of DNA rod structure using DNA origami, and the use of the programmability and modifiability of the DNA rod structure to modify and functionalize the bacterial surface in the form of pili. This application further explores the influence of the length and concentration of pili grafts on the bacterial surface on bacterial motility, providing an idealized tool bacteria for studying bacterial biological behavior.

[0026] Example 1: Design and Assembly of DNA Nanowire Rod Structures This embodiment describes a method for constructing a type of DNA nanowire / rod structure, which is a three-dimensional structure, specifically including the following steps: Step 1: Constructing DNA nanowire / rod structures. This step utilizes 3D images to visualize the structure, and then employs caDNAno, a professional DNA nanostructure design software, to design the nanowire / rod DNA. Figure 1 Step 1 is followed by the following steps: inputting the genome sequence of recombinant M13 phage p7560 (template strand of DNA nanowire) or p3024 (template strand of DNA nanorod) (the genome sequence is from the NCBI database), exporting the staple strand sequence generated by the software, and performing sequence synthesis.

[0027] Step 2: Based on Step 1, further design modification sites at the head and body of the DNA thread / rod structure for functional modification; Step 3: The functionalized DNA thread / rod structure (including stapled chains with anchored sequence extensions) constructed in Step 2 is assembled and purified. Differential ultracentrifugation combined with retention ultrafiltration is used to achieve efficient separation of structural monomers.

[0028] After the DNA thread / rod structure was assembled and purified, the structure was systematically identified using multi-scale characterization techniques, including preliminary screening by agarose gel electrophoresis, morphology and size verification by transmission electron microscopy, and surface morphology and integrity assessment by atomic force microscopy.

[0029] Ultracentrifugation is a technique that uses the powerful centrifugal force in an ultracentrifuge to separate, prepare, and purify substances. This method achieves separation through the difference in sedimentation velocities of particles in a gradient liquid: particles with different sedimentation velocities form a series of zones within a density gradient layer, thus separating from each other. Sedimentation velocity is affected by particle molecular size and density, and also depends on the molecular density, viscosity, and particle shape of the solution. The most commonly used techniques include sedimentation velocity methods and sedimentation equilibrium methods.

[0030] Ultrafiltration is a membrane separation method that utilizes the microporous structure of a semi-permeable membrane to achieve selective separation and recovery of substances. Ultrafiltration membranes have pore sizes between 0.001 and 0.1 μm, with a molecular weight cutoff of approximately 1,000 to 500,000 Daltons. The operating pressure for ultrafiltration is typically between 0.1 and 0.6 MPa. When a solution flows through the surface of an ultrafiltration membrane with a specific pore size at a certain flow rate, under external pressure, ultrafiltration allows small molecules, inorganic salts, and solutes smaller than the membrane's molecular weight cutoff to pass through, forming the filtrate. Simultaneously, it retains substances larger than the membrane's molecular weight cutoff, such as colloids, proteins, microorganisms, and large organic molecules, forming a concentrate, thus achieving the purpose of concentration.

[0031] Agarose gel electrophoresis, a fundamental technique in genetic engineering, has become a routine experimental method in nucleic acid research due to its ease of operation and short processing time. Under alkaline conditions (pH above the isoelectric point), DNA molecules carry a negative charge due to the dissociation of phosphate groups, thus migrating directionally towards the anode (positive electrode) under the drive of an electric field. It is noteworthy that because the sugar-phosphate backbone of the DNA double helix has a highly repetitive symmetrical structure, equal amounts of double-stranded DNA molecules carry essentially the same net charge, thus exhibiting a relatively consistent migration rate in an electric field.

[0032] Negative staining is an electron microscopy sample preparation method that enhances sample contrast through staining with metal salts. This technique is primarily used to observe the microstructures of particulate matter or biomolecules. In practice, the sample is spread on a grid and then stained with a heavy metal salt solution. Because the metal salts are uniformly deposited on the grid surface, and the raised areas of the sample particles block dye adhesion, a striking contrast is created: "no dye deposition in the particle areas, and dye coverage in the background areas." This staining method produces a unique effect during electron microscopy observation: the sample particles appear as bright, electron-dense regions, while the background appears as dark, electron-transparent regions, significantly improving the visualization of the target structure.

[0033] Figure 2This is a schematic diagram of the DNA nanowire / rod structure constructed in this embodiment. Two nucleic acid nanostructures with different geometries—wires and rods—were designed to simulate the size of natural bacterial pili. The nanowires have a diameter of approximately 5 nm and a length of 1200 nm, with an aspect ratio greater than 200, exhibiting the characteristics of flexible, long, bendable wires; while the nanorods have a diameter of 7.5 nm and a length of 168 nm, with an aspect ratio of approximately 20, exhibiting the characteristics of straight, rigid, short rods. Figure 2 The uniform and monodisperse properties were confirmed by AGE, AFM, and TEM imaging. Visualization and quantitative analysis were achieved by hybridizing fluorescently labeled short nucleic acid strands with anchoring strands (selectable at specific sites) extending from the DNA nanowire / rod structure using base complementarity pairing. This demonstrates that programmable DNA nanowires / rods with linear and rod-like geometries have been successfully constructed, with structures similar to natural pili, and their length and rigidity can be controlled through pre-designed nanostructures and shapes. The DNA nanowire / rod structure realistically reproduces the nanoscale morphology of natural pili and provides a programmable handle for surface modification.

[0034] Example 2 Functionalization of DNA Nanowires / Rods on Bacterial Surfaces This embodiment relates to a method for functionalizing the surface of bacteria (taking Bacillus subtilis, BS, as an example) using the aforementioned DNA nanowires / rods: Step 1: Add 1 mg / mL of sulfonyl and biotin-modified NHS (sulfosuccinimide biotin, Sulfo-NHS-Biotin) to 100 μL OD. 600 The bacterial culture was activated by shaking at 600 rpm for 10 minutes at room temperature in a Cy5.5-NHS-labeled Bacillus subtilis culture with a concentration of 1.0. After the reaction was completed, an equal volume of PBS (pH 7.2-7.4) was added to the activated bacterial culture. The culture was centrifuged at 8000 rpm for 1 minute each time, and then washed with deionized water. This centrifugation and washing process was repeated three times. Then, an equal volume of PBS (pH 7.2-7.4) was added to resuspend and disperse the bacterial culture. Step 2: Based on Step 1, add streptavidin to the activated bacterial solution and shake at 300 rpm for 1 hour at 37°C. Centrifuge and wash as in Step 1, collect the bacterial precipitate, and record it as SA or BS-SA. Step 3: Add equal volumes of FITC and biotin-modified 2HR and 6HR line / rod structures of different concentrations to the bacterial precipitate obtained in Step 2 for resuspension and dispersion, and react with shaking at 300 rpm for 1 hour at 37°C in the dark. Step 4: Add TE buffer to the reaction bacterial solution obtained in step 3 and allow it to settle naturally at 4°C for about 6 hours to purify it, in order to remove the free fimbriae DNA thread / rod structure in the solution; Step 5: Characterize the bacteria modified with the fimbriae-like DNA rod structure using flow cytometry, transmission electron microscopy, and laser confocal microscopy to assess whether the modification effect has been achieved.

[0035] Figure 3 In this embodiment, confocal microscopy and flow cytometry results showed that the FITC fluorescence intensity increased with increasing concentration of grafted DNA thread / rod structures, indicating that the grafting density was controllable. Figure 3 C~D). Figure 3 Transmission electron microscopy (TEM) of samples A-B directly observed the DNA nanowires / rods grafted onto the bacterial surface. The fluorescence ratio tended to plateau above a concentration of 40 nM nanowires / rods, establishing the surface saturation threshold. The bacteria maintained normal viability, and the grafted nanowires / rods stably bound to bacteria for at least 24 hours in PBS or LB medium. This demonstrates that DNA nanowires / rods can be stably and quantitatively grafted onto live Bacillus subtilis without affecting bacterial viability. Figure 4 (A~B), thereby enabling precise control over the concentration of DNA nanowires / rods grafted onto the bacterial surface.

[0036] Example 3: Geometric Dependence Regulation of Bacterial Motion in Free Suspension In this embodiment, Figure 5 Time-stretched confocal tracking revealed that streptavidin modification alone slowed bacterial motility, likely due to increased surface friction. However, grafting DNA nanowires / rods significantly enhanced bacterial motility. Figure 5 A). Increased nanowire / rod concentration leads to increased velocity and trajectory complexity, and this effect is related to the aspect ratio of DNA nanostructures: linear coatings produce faster and more irregular trajectories, while rod coatings do not. Figure 5 A). Quantitative analysis of over 200 single bacterial trajectories confirmed a correlation between movement speed and grafting density, up to a point of saturation. Figure 5 (B~D). This demonstrates that synthetic fimbriae with a higher aspect ratio significantly enhance bacterial motility, revealing a strong coupling relationship between nanoscale geometry and dynamic behavior.

[0037] Example 4: Verification of motion regulation in a microfluidic environment To study bacterial motility under specific spatial constraints, individual bacteria were monitored in custom-designed microfluidic channels (mesh size 100 nm). Figure 6Similar trends were observed: both nanostructures (wire / rod structures) accelerated bacterial motility. Figure 6 A, C), while linear structures produce greater displacement and velocity fluctuations (A, C), Figure 6 B, D). Figure 7 Dynamic light scattering data showed no significant change in the Zeta potential among the samples, ruling out electrostatic effects as the primary cause. This indicates that the enhanced motion originates from geometrically mediated mechanical interactions, rather than changes in surface charge, and persists under confined microfluidic conditions.

[0038] The above description is merely a preferred embodiment of this application and is not intended to limit this application in any form or substance. It should be noted that those skilled in the art can make several improvements and additions without departing from this application, and these improvements and additions should also be considered within the scope of protection of this application.

Claims

1. A method for bacterial surface modification based on programmable pili-shaped DNA nanowires, characterized in that, The method includes the following steps: Step 1: First, DNA nanowires or nanorods with three-dimensional structures are constructed using DNA origami techniques; wherein, the DNA nanowires use the long ssDNA template p7560 from the M13 phage genome as the template strand sequence; and the DNA nanorods use the long ssDNA template p3024 from the M13 phage genome as the template strand sequence. Step 2: Modify the head end and body of the DNA nanowire or nanorod structure with functional molecules, respectively; Step 3: The bacteria modified with coupling molecules or groups are coupled with DNA nanowires or nanorods modified with functional molecules to graft the DNA nanowires or nanorods onto the bacterial surface. The coupling molecules or groups are molecules or groups that can bind to the functional molecules.

2. The method according to claim 1, characterized in that, The modification of the functional molecules utilizes the principle of complementary DNA base pairing. The complementary sequence of the modified functional molecule is hybridized with the anchoring sequence extending from a selected site in the DNA nanowire or nanorod structure, thereby modifying the functional molecule to the head and body of the DNA nanowire or nanorod structure, respectively.

3. The method according to claim 1, characterized in that, The method for constructing the DNA nanowire or nanorod structure includes: Step A1: Construct DNA nanowire or nanorod structures and use 3D images to present schematic diagrams of the structures. Then, use caDNAno, a professional DNA nanostructure design software, to design DNA nanowire or nanorod structures. Step A2: Based on step A1, further construct variants of DNA nanowire or nanorod structures and establish modification sites on the head end and body; Step A3: Perform structural self-assembly and purification on the DNA nanowire or nanorod structure constructed in step A2.

4. The method according to claim 3, characterized in that, Step A1 is followed by obtaining the corresponding sequences of hundreds of staple chains through the input of the template chain sequence, and then performing sequence synthesis.

5. The method according to claim 4, characterized in that, The structural self-assembly and purification in step A3 specifically includes: annealing the template strand sequence and the synthesized staple strand sequence, base pairing self-assembly to obtain DNA nanowires or nanorods, and then separating and purifying them to obtain purified DNA nanowires or nanorods; the purification includes obtaining purified structural monomers by ultracentrifugation and ultrafiltration concentration, and removing unbound staple strands as well as dimer and multimer impurities.

6. The method according to claim 1, characterized in that, In step 3, the coupling molecule or group is covalently bonded to the functional molecule through a chemical bond, which is an amide bond, a thiol bond, or a biotin-streptavidin bond. The functional molecule also includes one or more of fluorescent molecules, nucleic acids, and biotin-streptavidin proteins.

7. The method according to claim 1, characterized in that, Step 3 specifically includes: reacting bacteria with Sulfo-NHS-Biotin to modify its surface with biotin, and then performing a coupling reaction with streptavidin to obtain bacteria modified with biotin-streptavidin. Then, the bacteria modified with biotin-streptavidin are coupled with biotin-modified DNA nanowires or nanorods to graft DNA nanowires or nanorods onto the bacterial surface.

8. The method according to claim 1, characterized in that, The concentration of the DNA nanowires or nanorods grafted onto the bacterial surface is 0.5~40 nM.

9. The bacteria obtained by the method according to any one of claims 1 to 5.

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