Glycosyl dynamic polymer, preparation method and application

Abstract

The invention discloses a glycosyl dynamic polymer as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials. Aiming at the problems of drug resistance risk, biological safety hidden danger, complex preparation process and the like caused by the introduction of antibiotics in the existing acylhydrazone dynamic polymer, chitosan is used as a raw material, and a guanidino hydrazide monomer is prepared through esterification and hydrazide reaction of guanidino carboxylic acid; and carrying out hydrazone bond dynamic cross-linking on the glycosyl dynamic polymer and aldehyde chitosan according to a specific molar ratio in a weak acid system to prepare the glycosyl dynamic polymer with bacteriostatic activity and pH responsiveness. The polymer shows an obvious antibacterial effect on escherichia coli, the preparation process is simple and convenient to operate, the reaction condition is mild, and large-scale production is easy to realize. Based on the excellent performance of the glycosyl dynamic polymer, the glycosyl dynamic polymer can be applied to wound antibacterial dressings, medical instrument antibacterial coatings and other scenes, and a novel material solution which is safe, controllable and easy to apply on a large scale is provided for the antibacterial field.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a class of dynamic covalent polymers based on glycosylation, their preparation method, and their application in the field of antibacterial applications. Background Technology

[0002] Dynamic polymers, with their unique reversible covalent or non-covalent structures, possess excellent biocompatibility, biodegradability, and stimulus-responsiveness. Among them, acylhydrazone dynamic compounds, in particular, show great promise in the biomedical field due to their significant antibacterial, anti-infective, and antitumor activities. However, the preparation of acylhydrazone dynamic polymers often faces technical bottlenecks such as complex processes and low yields. Furthermore, some methods require the introduction of exogenous active ingredients to achieve specific functions, further raising biosafety concerns and hindering their clinical translation.

[0003] Chitosan, as a widely available and inexpensive natural polymer, has a large number of amino and hydroxyl groups in its structure that facilitate chemical modification, making it an ideal raw material for developing novel dynamic polymers. In existing technologies, there have been explorations related to dynamic polymers based on chitosan: Yun Liu et al. (Tobramycin crosslinking improves the colloidal stability of arginine chitosan biodynamers for safe and efficient siRNA delivery[J]. International Journal of Biological Macromolecules, 2025(Pt.1):311) disclosed a dynamic polymer in which aldehyde-based chitosan (ACh) is linked to arginine hydrazide (Arg) and tobramycin (Tob) through imine or acylhydrazone bonds. Tobramycin, as an antibiotic, provides amino groups as internal crosslinking agents to stabilize drug-loaded nanoparticles and also imparts specific biological activities to the material. The team subsequently reported a dynamic polymer covalently coupled to aldehyde-based chitosan via amide bonds (Design, synthesis and antibacterial evaluation of aldehyde chitosan-antibiotic conjugates[J]. New Journal of Chemistry, Issue 35, (2025), whose antibacterial activity depends on antibiotic monomers and antibiotic molecules released after polymer degradation.

[0004] While the aforementioned technologies offer insights for the development of chitosan-based dynamic polymers, key drawbacks remain: the crosslinking stability and antibacterial activity of existing polymers depend on the introduction of antibiotics. This not only poses a risk of antibiotic resistance due to overuse but also makes it difficult to fully guarantee biocompatibility, failing to meet the stringent biocompatibility requirements for clinical applications. Therefore, developing functional monomers that do not rely on antibiotics and possess inherent antibacterial capabilities, and preparing glycosylated dynamic covalent polymers based on these monomers to significantly improve biocompatibility while maintaining antibacterial activity, has become a pressing technical challenge in this field. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a class of glycosyl dynamic polymers that are antibiotic-free, possess high biocompatibility, and stable antibacterial activity. These polymers achieve antibacterial activity regulation through reversible dynamic covalent bonds. Simultaneously, this invention provides a simple and efficient preparation method for these polymers, overcoming the drawbacks of traditional processes being cumbersome and requiring stringent conditions. Furthermore, it expands the applications of these polymers in the antibacterial field, including wound dressings and medical device coatings. Ultimately, this invention provides the biomedical field with a safe, controllable, and easily scalable novel antibacterial material solution, meeting the urgent clinical demand for high-performance, high-safety antibacterial materials.

[0006] This invention is achieved as follows: a method for preparing a class of glycosyl dynamic polymers, the preparation route of which is as follows:

[0007] ;

[0008] Wherein, R is a C1~C4 straight-chain alkyl or phenyl group; n>50;

[0009] The specific preparation steps are as follows: 1) Under ice bath conditions, guanidinocarboxylic acid compound 1 was dissolved in organic solvent A, and then trimethylchlorosilane was added dropwise. After the addition was complete, the mixture was stirred at room temperature, filtered, rotary evaporated, and freeze-dried to obtain guanidinocarboxylic acid methyl ester compound 2. 2) Compound 2 was dissolved in organic solvent B, hydrazine hydrate solution was added, and the mixture was refluxed. After the reaction was completed, the mixture was cooled to room temperature and rotary evaporated to obtain guanidinohydrazide compound 3. 3) Compound 3 and compound 4 were mixed and dispersed in a weakly acidic system, stirred and reacted at room temperature, dialyzed, and lyophilized to obtain glycosyl dynamic polymer 5.

[0010] Further, in step 1), the organic solvent A is anhydrous methanol; the concentration of compound 1 dissolved in organic solvent A is 1~2 mol / L, the molar ratio of trimethylchlorosilane added dropwise to compound 1 is 2~4:1; the stirring reaction time at room temperature is 18~24 h.

[0011] Further, in step 2), the organic solvent B is at least one of anhydrous methanol and anhydrous ethanol; the concentration of compound 2 dissolved in organic solvent B is 0.04~0.1 mol / L; the molar ratio of hydrazine hydrate to compound 2 is 7~10:1; the reflux reaction temperature is 130℃ and the reaction time is 4~6 h.

[0012] Further, in step 3), the molar ratio of the aldehyde group in compound 4 to the hydrazide group in compound 3 is 1:1 to 1.5; the weakly acidic system is an acetic acid solution with a pH of 4.5 to 5.5; and the stirring reaction time is 60 to 72 h.

[0013] This application also claims protection for a glycosyl dynamic polymer prepared based on the above method, which is a glycosyl modified dynamic covalent polymer formed by dynamic cross-linking of aldehyde-modified chitosan and guanidinohydrazide compounds through hydrazone bonds, and the corresponding general structural formula is as follows:

[0014] ;

[0015] Wherein, R is a C1~C4 straight-chain alkyl or phenyl; n>50.

[0016] The aforementioned glycosyl dynamic polymers possess both pH-responsive dynamic characteristics, excellent biocompatibility, and highly efficient antibacterial activity, making them applicable in the antibacterial field. Specifically, they can be used to prepare antibacterial materials against Gram-negative bacteria (such as Escherichia coli). These antibacterial materials include, but are not limited to, antibacterial wound dressings and antibacterial coatings for medical devices.

[0017] Beneficial effects: 1. This application constructs a dynamic polymer by introducing guanidinohydrazide monomers (GTH, GZH) with their own antibacterial activity, which can achieve antibacterial function without relying on antibiotics, effectively avoiding the risk of bacterial resistance and biosafety hazards caused by antibiotic use in the prior art; at the same time, glycosylation modification does not significantly affect the cell compatibility of the material. At the conventional application concentration (≤500 μg / mL), the material can maintain high cell activity and low cytotoxicity, and its biosafety is superior to many existing antibiotic-coupled dynamic polymers. 2. The dynamic polymer constructed in this application is based on a dynamic structure formed by acylhydrazone crosslinking, which has precise pH response characteristics and can adapt to the acid-base differences between the inflammatory microenvironment (pH 4.5~5.5) and the normal physiological environment (pH 7.4), laying the foundation for intelligent response applications in medical scenarios. 3. The glycosyl dynamic covalent polymers (ACs-GTH, ACs-GZH) prepared in this application have a significant inhibitory effect on the growth of bacteria such as Escherichia coli, and the antibacterial effect is clearly concentration-dependent. At high concentrations, they can effectively block bacterial proliferation, and at low concentrations, they can also effectively inhibit bacterial growth activity. Combined with pH-responsive characteristics, the material can undergo dynamic cleavage of acylhydrazone bonds in an acidic inflammatory microenvironment, promoting the directional release of guanidine antibacterial groups, further enhancing the local antibacterial effect, and achieving a synergistic function of environmental response and precise antibacterial action. 4. This application constructs a dynamic polymer using chitosan as a raw material. Relying on the biodegradable properties of chitosan's natural polymer, the material can be gradually degraded into non-toxic metabolites in vivo, with no residual risk. Glycosylation modification not only enhances cell affinity but also synergizes with pH response characteristics. Under specific pH conditions, the degradation rate of the material can be regulated, which not only meets the core requirements of bio-friendly materials in the biomedical field but also satisfies the dynamic needs of on-demand degradation and functional performance in the living environment, providing dual protection for its application in in vivo antibacterial scenarios. 4. The preparation process of this application simplifies the complex modification steps of existing dynamic polymers. Using chitosan as the basic raw material, the target product can be obtained through aldehyde modification, guanidinohydrazide monomer coupling, and dialysis freeze drying. The operation is simple and the reaction conditions are mild. At the same time, chitosan has the characteristics of wide availability and low cost, which helps to reduce the cost of large-scale production and meet the needs of industrial applications. 5. The glycosylated dynamic covalent polymer disclosed in this application combines stable antibacterial activity, excellent biosafety, pH intelligent responsiveness and biodegradability. It can be used alone as a high-performance antibacterial material for wound antibacterial care, antibacterial coating of medical devices and other scenarios, providing a new technical path and material selection for the research and development of antibacterial biomedicine, and has broad prospects for clinical translation. Attached Figure Description

[0018] Figure 1 The 1H NMR spectra of 4-guanidinobutyrylhydrazide (GTH) and glycosylated 4-guanidinobutyrylhydrazone (ACs-GTH) prepared in Example 1 are shown below. Figure 2 Infrared spectra of 4-guanidinobutyrylhydrazide (GTH) and glycosylated 4-guanidinobutyrylhydrazone (ACs-GTH) prepared in Example 1. Figure 3 The 1H NMR spectra of 4-guanidinobenzoylhydrazide (GZH) and 4-guanidinobenzoylhydrazone (ACs-GZH) prepared in Example 2 are shown below. Figure 4 The infrared spectra of 4-guanidinobenzoylhydrazide (GZH) and 4-guanidinobenzoylhydrazone (ACs-GZH) prepared in Example 2 are shown below. Figure 5Size exclusion chromatography (SEC) chromatograms of ACs-GTH and ACs-GZH in different pH buffers are shown. A is the SEC chromatogram of ACs-GTH in phosphate buffer at pH 7.4 and acetate buffer at pH 5.0; B is the SEC chromatogram of ACs-GZH in phosphate buffer at pH 7.4 and acetate buffer at pH 5.0. Figure 6 The graphs show the cell activity and cytotoxicity of each substance. In the graphs, A represents the cell activity detection results of GTH, GZH, ACs-GTH, and ACs-GZH (MTT method), and B represents the cytotoxicity detection results of GTH, GZH, ACs-GTH, and ACs-GZH (LDH method). Figure 7 The antibacterial effects of each substance are shown in Figure A, where GTH shows the inhibitory effect on Escherichia coli (E. coli), ACs-GTH shows the inhibitory effect on E. coli, GZH shows the inhibitory effect on E. coli, and ACs-GZH shows the inhibitory effect on E. coli. Detailed Implementation

[0019] The preferred embodiments of the present invention will now be described in detail so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0020] Example 1

[0021] This embodiment discloses a glycosylated 4-guanidinobutyrylhydrazone compound, the preparation route of which is as follows:

[0022] ;

[0023] The specific preparation steps are as follows: 1) Preparation of methyl 4-guanidinobutyrate (GTM): 1.452 g of 4-guanidinobutyric acid (GTA, 0.01 mol) was dissolved in 10 mL of anhydrous methanol under -5~0℃ conditions. After magnetic stirring until completely dissolved, 3.8 mL of trimethylchlorosilane (TMSCL, 0.03 mol) was added dropwise to the above solution. After the addition was completed, the ice bath was removed, and the reaction was carried out under magnetic stirring at room temperature (25±2℃) for 24 h. After the reaction was completed, the insoluble byproducts were removed by filtration, the organic solvent in the filtrate was removed by rotary evaporation, and the solution was freeze-dried to obtain methyl 4-guanidinobutyrate.

[0024] 2) Preparation of 4-guanidinobutyrylhydrazine (GTH): 100 mg of methyl 4-guanidinobutyrate (0.6 mmol) was dissolved in 10 mL of anhydrous methanol and stirred magnetically until completely dissolved. Then, 306 µL of 80% hydrazine hydrate solution (4.8 mmol) was added. A reflux apparatus was set up and the reaction was carried out under sealed reflux at 130 °C for 5 h. After the reaction was completed, the mixture was cooled to room temperature and methanol was removed by rotary evaporation to obtain 4-guanidinobutyrylhydrazine with a yield >95%.

[0025] 3) Preparation of glycosylated 4-guanidinobutyrylhydrazone (ACs-GTH): Weigh out aldehyde-modified chitosan (ACs-GTH). S For n>50, the preparation method is described in the literature: doi: 10.3390 / pharmaceutics14061197, section 2.2, paragraph 2), according to AC. S The molar ratio of the aldehyde group to the hydrazide group in 4-guanidinobutyrylhydrazide was 1:1.2. The corresponding amounts of GTH were weighed and dispersed together in 10 mM acetic acid solution (pH 5.0). The reaction was carried out under magnetic stirring at room temperature for 72 h. After the reaction was completed, deionized water containing 0.01% triethylamine (TEA) was used as the dialysis medium. The dialysis solution was changed every 8 h and dialyzed continuously for 3 days. Finally, the dialysate was transferred to a lyophilization bottle and lyophilized at -50℃ and 10 Pa for 24 h to obtain a white solid product, which is glycosylated 4-guanidinobutyrylhydrazone, with a yield >20%.

[0026] The proton NMR spectra of the 4-guanidinobutyrylhydrazide (GTH) and glycosylated 4-guanidinobutyrylhydrazone (ACs-GTH) prepared in this embodiment are as follows: Figure 1 As shown, the infrared spectra of GTH and ACs-GTH are as follows: Figure 2 As shown.

[0027] Example 2

[0028] This embodiment discloses a glycosylated 4-guanidinobenzoylhydrazone compound, the preparation route of which is as follows:

[0029]

[0030] The specific preparation steps are as follows: (1) Preparation of methyl 4-guanidinobenzoate (GZM): 1.800 g of 4-guanidinobenzoic acid (GZA, 0.01 mol) was dissolved in 10 mL of anhydrous methanol under -5~0℃ conditions. After magnetic stirring until completely dissolved, 2.538 mL of trimethylchlorosilane (TMSCL, 0.02 mol) was added dropwise to the above solution. After the addition was completed, the ice bath was removed and the reaction was continued to be carried out under magnetic stirring at room temperature (25±2℃) for 24 h. After the reaction was completed, the insoluble byproducts were removed by filtration, the organic solvent was removed by rotary evaporation, and the product was freeze-dried to obtain methyl 4-guanidinobenzoate.

[0031] (2) Preparation of 4-guanidinobenzoyl hydrazine (GZH): 100 mg of methyl 4-guanidinobenzoate (0.5 mmol) was dissolved in 10 mL of anhydrous methanol, followed by the addition of 243 µL of 80% hydrazine hydrate solution (3.8 mmol). A reflux apparatus was set up and the reaction was carried out under sealed reflux at 130 °C for 5 h. After the reaction was completed, the mixture was cooled to room temperature and methanol was removed by rotary evaporation to obtain 4-guanidinobenzoyl hydrazine with a yield of >95%.

[0032] (3) Preparation of glycosylated 4-guanidinobenzoylhydrazone (ACs-GZH): Weigh out aldehyde-modified chitosan (ACs-GZH) S ), press AC S The molar ratio of the aldehyde group to the acyl group in 4-guanidinobenzoylhydrazone was 1:1.2. The corresponding amounts of GZH were weighed and dispersed together in 10 mM acetic acid solution (pH 5.0). The reaction was carried out under magnetic stirring at room temperature for 72 h. After the reaction was completed, deionized water containing 0.01% triethylamine (TEA) was used as the dialysis medium. The dialysis solution was changed every 8 h and dialyzed continuously for 3 days. Finally, the dialysate was transferred to a lyophilization bottle and lyophilized at -50℃ and 10 Pa for 24 h to obtain a white solid product, which is glycosylated 4-guanidinobenzoylhydrazone, with a yield >20%.

[0033] The proton NMR spectra of the 4-guanidinobenzoylhydrazine (GZH) and glycosylated 4-guanidinobenzoylhydrazone (ACs-GZH) prepared in this embodiment are as follows: Figure 3 As shown, the infrared spectra of GZH and ACs-GZH are as follows: Figure 4 As shown.

[0034] Related performance tests

[0035] 1) pH-responsive changes in dynamic polymers

[0036] ACs-GTH and ACs-GZH were dissolved in 10 mM pH 7.4 phosphate buffer and 10 mM pH 5.0 acetate buffer, respectively, to prepare solutions with a concentration of 0.1 mg / mL. Size exclusion chromatography (SEC) was used to analyze and compare the hydrodynamic dimensional changes of both solutions under different pH conditions.

[0037] The chromatographic conditions were set as follows: Thermo Acclaim SEC-300 column (4.6×300 mm; packing particle size 5µm, pore size 300 ˚A), mobile phase 10 mM pH 7.4 phosphate buffer, and flow rate 0.3 mL / min.

[0038] Because these glycosyl dynamic polymers exist in dynamic equilibrium and multiple molecular arrangements in solution, their absolute molecular size cannot be accurately quantified by a single parameter. Therefore, in the experiment, the retention time of the first chromatographic peak was used to characterize the relative hydrodynamic size.

[0039] Combination Figure 5 The chromatograms and retention time data in Table 1 clearly demonstrate the pH response characteristics of both: For ACs-GTH: at pH 7.4 (neutral environment), the retention time of the first chromatographic peak is 10.3 min; at pH 5.0 (acidic environment), the retention time is shortened to 9.8 min, corresponding to an increase in hydrodynamic size; For ACs-GZH: the retention time was 10.6 min at pH 7.4 and shortened to 10.3 min at pH 5.0, also showing a trend of increasing molecular size under acidic conditions.

[0040] Meanwhile, combined with the results of a series of concentration experiments, it can be seen that as the solution concentration decreases, the molecular volume of ACs-GTH and ACs-GZH also decreases accordingly, further demonstrating the concentration-dependent equilibrium characteristics of dynamic polymers.

[0041] The above results indicate that both ACs-GTH and ACs-GZH possess pH-responsive degradation characteristics. Under acidic conditions, acylhydrazone bonds undergo dynamic cleavage, leading to the disintegration of the polymer's crosslinking network and a more dispersed molecular arrangement, ultimately resulting in an increase in hydrodynamic size. In contrast, under neutral conditions, the crosslinking network remains stable, and the molecular size is smaller. This characteristic is highly compatible with the response requirements of medical applications (such as the acidic conditions of the inflammatory microenvironment).

[0042] Table 1. Retention times of the first peak in SEC chromatography for ACs-GTH and ACs-GZH under different pH conditions

[0043] 2) Biosafety testing

[0044] The biosafety of GTH, GZH, ACs-GTH, and ACs-GZH was assessed using the MTT assay (to assess cell viability) and the LDH assay (to assess cytotoxicity). The test results are as follows: Figure 6 As shown in the figure (Note: "50~1000" indicates the concentration of the test substance, in μg / mL).

[0045] from Figure 6As shown in A (cell viability results), the cell viability of GTH, GZH, ACs-GTH, and ACs-GZH remained at a high level. When the concentration was ≤500 μg / mL, the cell viability of each substance did not decrease significantly, indicating that these substances had a weak inhibitory effect on cell growth within this concentration range, and the cells could still maintain a good active state after contact.

[0046] Let's look again. Figure 6 B (Cytotoxicity Results): The overall LDH activity of all substances was at a low level; at concentrations ≤500 μg / mL, the LDH activity of none of the four substances showed a significant increase, and only at concentrations ≥800 μg / mL did the LDH activity of GZH and ACs-GZH show a significant increase. This indicates that within the low concentration range commonly used in applications, these substances cause minimal damage to the cell membrane and exhibit low cytotoxicity.

[0047] In summary, GTH, GZH, ACs-GTH, and ACs-GZH all exhibit good biocompatibility, demonstrating high cell activity and low cytotoxicity. Their safety is particularly superior in the application range of concentrations ≤500 μg / mL, and glycosylation modification does not have a significant adverse impact on the biocompatibility of the materials.

[0048] 3) Evaluation of antibacterial properties

[0049] A single colony of *E. coli* was picked from an agar plate and inoculated into 50 mL of LB broth. The culture was incubated overnight at 37°C and 180 rpm with shaking. 50 µL of the overnight culture was then transferred to 50 mL of fresh LB broth and cultured until the logarithmic growth phase (OD200). 600 Values ​​were 0.6-0.8, and they were kept for later use. GTH, GZH, ACs-GTH, and ACs-GZH were serially diluted twofold using LB medium. 50 μL of each dilution was added to a 96-well plate, and then 50 μL of bacterial suspension (initial concentration 2 × 10⁻⁶) was inoculated into each well. 4 (CFU / mL), making the total system volume 100 μL and the final bacterial concentration 1×10⁻⁶. 4 CFU / mL. After incubating the 96-well plate overnight at 37°C with shaking at 180 rpm, the group containing only the culture medium served as a blank control, showing no significant OD compared to the control group. 600 The lowest compound concentration at which the value increases is the minimum inhibitory concentration (MIC). All experiments were repeated twice to ensure reproducibility of results.

[0050] Using OD 600 Methods for evaluating antibacterial efficacy (Note: Figure 7 In the figure, "0.00625~1024" represents the concentration of the test substance (unit: μg / mL). The results are as follows: Figure 7As shown, GTH, GZH, ACs-GTH, and ACs-GZH all exhibited significant growth-inhibiting effects on Escherichia coli.

[0051] Specifically:

[0052] For GTH ( Figure 7 (A) All concentrations showed some inhibitory effect on the growth of *E. coli*, and the antibacterial effect was significantly concentration-dependent; as the concentration increased, the OD of *E. coli* decreased. 600 The rate of increase in the value gradually decreased, and bacterial proliferation was significantly inhibited at high concentrations (≥32 μg / mL).

[0053] For ACs-GTH ( Figure 7 (B in the sample): All concentrations showed an inhibitory effect on the growth of Escherichia coli, and bacterial growth was restricted.

[0054] For GZH ( Figure 7 C): Different concentrations of the substance can inhibit the growth of Escherichia coli, and its antibacterial effect tends to increase with increasing concentration; under high concentration conditions (≥128 μg / mL), the OD of Escherichia coli... 600 The upward trend was significantly suppressed, and the bacterial proliferation capacity was significantly reduced.

[0055] For ACs-GZH ( Figure 7 D in the formula: It inhibits the growth of Escherichia coli at low concentrations (≥2 μg / mL) with a prominent concentration dependence. Under high concentration conditions (≥512 μg / mL), the inhibitory effect on the proliferation of Escherichia coli is very significant.

[0056] In summary, GTH, GZH, ACs-GTH, and ACs-GZH can all effectively inhibit the growth of Escherichia coli, and the antibacterial effect increases with their concentration, proving that these substances have good antibacterial capabilities.

[0057] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the protection scope of the present invention.

Claims

1. A method for preparing a class of glycosyl dynamic polymers, characterized in that, Its preparation route is as follows: ； Wherein, R is a C1~C4 straight-chain alkyl or phenyl group; n>50; The specific preparation steps are as follows: 1) Under ice bath conditions, guanidinocarboxylic acid compound 1 was dissolved in organic solvent A, and then trimethylchlorosilane was added dropwise. After the addition was complete, the mixture was stirred at room temperature, filtered, rotary evaporated, and freeze-dried to obtain guanidinocarboxylic acid methyl ester compound 2. 2) Compound 2 was dissolved in organic solvent B, hydrazine hydrate solution was added, and the mixture was refluxed. After the reaction was completed, the mixture was cooled to room temperature and rotary evaporated to obtain guanidinohydrazide compound 3. 3) Compound 3 and compound 4 were mixed and dispersed in a weakly acidic system, stirred and reacted at room temperature, dialyzed, and lyophilized to obtain glycosyl dynamic polymer 5.

2. The method for preparing a type of glycosyl dynamic polymer as described in claim 1, characterized in that, In step 1), the organic solvent A is anhydrous methanol; the concentration of compound 1 dissolved in organic solvent A is 1~2 mol / L, the molar ratio of trimethylchlorosilane added dropwise to compound 1 is 2~4:1; the reaction time at room temperature is 18~24 h.

3. The method for preparing a type of glycosyl dynamic polymer as described in claim 1, characterized in that, In step 2), the organic solvent B is at least one of anhydrous methanol and anhydrous ethanol; the concentration of compound 2 dissolved in organic solvent B is 0.04~0.1 mol / L; the molar ratio of hydrazine hydrate to compound 2 is 7~10:1; the reflux reaction temperature is 130℃ and the reaction time is 4~6h.

4. The method for preparing a type of glycosyl dynamic polymer as described in claim 1, characterized in that, In step 3), the molar ratio of the aldehyde group in compound 4 to the hydrazide group in compound 3 is 1:1 to 1.5; the weakly acidic system is an acetic acid solution with a pH of 4.5 to 5.5; and the stirring reaction time is 60 to 72 h.

5. A class of glycosyl dynamic polymers, characterized in that, It is prepared by the method described in any one of claims 1-4, and is a dynamic covalent polymer formed by crosslinking aldehyde-modified chitosan and guanidinohydrazide compounds via hydrazone bonds, with the corresponding general structural formula as follows: ； Wherein, R is a C1~C4 straight-chain alkyl or phenyl; n>50.

6. The application of the glycosyl dynamic polymer as described in claim 5 in the field of antibacterial agents, characterized in that, This glycosyl dynamic polymer was used to prepare antimicrobial materials against Gram-negative bacteria.

7. The application as described in claim 6, characterized in that, The antibacterial material includes wound dressings or antibacterial coatings for medical devices.

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