Degradable antibacterial fiber and preparation method thereof

Abstract

The invention discloses a degradable antibacterial fiber and a preparation method thereof, and belongs to the field of environment-friendly materials. The invention aims to solve the problems that the antibacterial long-term effect and the degradability are unbalanced, and the toxicity of an antibacterial agent conflicts with the biocompatibility. The fiber is composed of bacteriophage antibacterial peptide, polyhydroxyalkanoate, sodium hypochlorite and the like, the antibacterial peptide is derived from a bacteriophage phi 87S / 06 genome, and a mineralizing solution is prepared according to a ratio of CaCl2 to Na2HPO4 to sodium alginate of 3: 2: 2. The preparation method comprises the following steps: constructing double-plasmid engineering bacteria through gene editing to realize synergistic expression of the antibacterial peptide and PHBV, performing fermentation separation to obtain a copolymer, and performing ionic liquid dissolution, boric acid crosslinking, electrostatic spinning and mineralized coating treatment. After the product is washed for five times, the antibacterial rate is greater than 99%, the weight loss rate in 90 days is 82%, the tensile strength is 18MPa, the elongation at break is 25%, the balance of antibacterial long-term effect, degradability and mechanical property is realized, and the antibacterial material is suitable for the fields of medical dressings and the like.

Description

Technical Field

[0001] The present invention belongs to the field of environmentally friendly materials, and in particular relates to a degradable antibacterial fiber and a preparation method thereof. Background Art

[0002] The research and development of degradable antimicrobial fibers focuses on solving the dual challenges of medical infection prevention and control and plastic pollution management, but has long faced two core contradictions. The first is the dynamic imbalance between the long-term antimicrobial effect and the degradability of the material. Traditional physically doped antimicrobial agents are prone to rapid loss, while the degradation rate of degradable materials is significantly affected by the environment and is difficult to match the antimicrobial cycle. The second is the conflict between the toxicity and biocompatibility of antimicrobial agents. Metal-based antimicrobial agents such as silver ions have cytotoxicity and ecological accumulation risks, and natural antimicrobial peptides face the problems of poor stability and easy loss of activity. These contradictions directly restrict their large-scale application in scenarios such as medical dressings and environmentally friendly packaging.

[0003] While existing solutions have their own breakthroughs, they all have significant limitations. Gene editing technology improves long-term efficacy by synergistically expressing antimicrobial peptides and PHBV, but is limited by the fermentation stability of engineered bacteria. Nanocarrier sustained-release systems can optimize release curves, but are difficult to promote due to high costs and lack of compatibility. Bionic mineralized coatings can delay degradation, but suffer from low production efficiency. Traditional strategies often focus on optimizing a single dimension and fail to systematically balance the triangular relationship between antimicrobial activity, degradation, and safety, resulting in compromised performance in practical applications.

[0004] Future breakthroughs will rely on multidisciplinary innovation, integrating technologies such as gene editing, nanocarriers, and biomimetic mineralization to build an integrated antimicrobial-degradation-repair system. The proposed approach of synergistic expression of bacteriophage antimicrobial peptides (PHBVs) combined with a mineralized coating, as described in the claim, achieves sustained release of the antimicrobial agent through gene regulation while balancing degradation rates through the mineralized layer, providing a new paradigm for resolving core challenges. As the technology matures and costs decrease, these fibers are expected to achieve breakthroughs in areas such as medical implants and environmentally friendly packaging, pushing the industry from functional stacking to systemic synergy. Summary of the Invention

[0005] To solve the problem of the difficulty in dynamically balancing the long-term effectiveness of antibacterial fibers and the degradability of materials, and the contradiction between the toxicity of antibacterial agents and biocompatibility.

[0006] In order to solve the above problems, the present invention provides the following technical solutions:

[0007] A degradable antibacterial fiber and a preparation method thereof, comprising the following components:

[0008] 8-10 parts of bacteriophage antimicrobial peptide, 65-70 parts of polyhydroxyalkanoate, 1-2 parts of sodium hypochlorite, 2-5 parts of 1-ethyl-3-methylimidazolium acetate, 0.5-1 part of boric acid, and 3-6 parts of CaCl2 / Na2HPO4 / sodium alginate mineralization solution.

[0009] Preferably, the gene of the phage antimicrobial peptide is cloned from the genome of bacteriophage φ87S / 06, and the antimicrobial peptide encoded by the gene is a natural antimicrobial peptide derived from bacteriophage.

[0010] Preferably, the main component of the polyhydroxyalkanoate is poly 3-hydroxybutyrate-co-3-hydroxyvalerate, and its main chain is a linear polyester.

[0011] Preferably, the ratio of CaCl2 / Na2HPO4 / sodium alginate mineralization solution is 3:2:2.

[0012] A method for preparing a degradable antibacterial fiber comprises the following steps:

[0013] S1: Recombinant Escherichia coli was constructed using gene editing technology. The phage-derived antimicrobial peptide gene and the polyhydroxyalkanoate synthesis gene cluster were integrated. The PHA synthesis inhibitory gene phaR was knocked out and the phaCAB operon was overexpressed. At the same time, an IPTG-inducible promoter was inserted before the antimicrobial peptide gene to achieve the coordinated expression of the antimicrobial peptide and PHBV, thus obtaining a dual-plasmid engineered bacterium.

[0014] S2: Fed-batch fermentation was performed in an optimized glucose-propionic acid medium to induce the bacteria to synthesize PHBV. The antimicrobial peptide-PHBV copolymer was then isolated by cell lysis with sodium hypochlorite, ultrasonic disruption, and ethanol precipitation.

[0015] S3: The antimicrobial peptide-PHBV copolymer was dissolved in the ionic liquid 1-ethyl-3-methylimidazolium acetate, followed by the addition of boric acid as a dynamic crosslinker and subsequent ultrasonic treatment to form a homogeneous solution;

[0016] S4: Prepare nanofiber membranes using electrospinning technology, control the average fiber diameter, and heat treat at 60°C for 2 hours;

[0017] S5: Soaking the fiber membrane in a CaCl2 / Na2HPO4 / sodium alginate mineralization solution, and then shaking for 24 hours to form a hydroxyapatite / alginate composite coating.

[0018] Preferably, after induction in S2, the bacterial cell concentration reaches 35 g / L and the PHBV accounts for 68% of the cells.

[0019] Preferably, in S3, the concentration of the antimicrobial peptide-PHBV copolymer in the solution is 8 wt %, and the amount of boric acid added is 0.5 wt %.

[0020] Preferably, the electrospinning technology used in S4 has a voltage of 18 kV, a receiving distance of 15 cm, and an average fiber diameter of 200-300 nm.

[0021] Preferably, in S4, the fiber membrane obtained by electrospinning is heat-treated at 60° C. for 2 hours.

[0022] Preferably, S5 is immersed in liquid at 37°C with shaking for 24 hours.

[0023] Effects and advantages of the degradable antibacterial fiber and its preparation method of the present invention:

[0024] 1. The present invention constructs a dual-plasmid engineered bacterium through gene editing, integrates the phage antimicrobial peptide and polyhydroxyalkanoate synthesis gene clusters, knocks out the PHA synthesis inhibitory gene phaR and overexpresses the phaCAB operon, and simultaneously inserts an IPTG-inducible promoter to achieve coordinated expression of the two.

[0025] 2. The present invention uses an optimized glucose-propionic acid medium for batch fed-batch fermentation. After induction, the bacterial concentration reaches 35 g / L and the PHBV cell ratio is 68%, resulting in high fermentation efficiency. The separation process uses sodium hypochlorite to dissolve cells, ultrasonic disruption, and ethanol precipitation to efficiently purify the antimicrobial peptide-PHBV copolymer, thereby ensuring the purity and activity of the product.

[0026] 3. The present invention uses the ionic liquid 1-ethyl-3-methylimidazolium acetate to dissolve the copolymer, avoiding pollution from traditional organic solvents, and adds boric acid as a dynamic crosslinker. The mechanical stability and degradability of the material are balanced through the reversible dissociation / binding properties, solving the problem of difficulty in balancing rigidity and toughness.

[0027] 4. In the present invention, electrospinning technology precisely controls the average fiber diameter. The porous structure of the nanofiber membrane is conducive to the release of antibacterial components and their contact with degradation media. Heat treatment at 60°C further stabilizes the structure. The mineralization step forms a hydroxyapatite / alginate composite coating through the CaCl2 / Na2HPO4 / sodium alginate system, which not only significantly improves the antibacterial performance but also regulates the degradation rate, thereby achieving synchronization between the antibacterial cycle and the degradation cycle.

[0028] 5. The present invention achieves long-lasting antibacterial effect, excellent degradability and balanced mechanical properties in the final product, overcoming the inherent defects of traditional methods and achieving a synergistic balance of antibacterial, degradation and mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a flow chart for preparing a degradable antibacterial fiber in the present invention. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus. In the absence of further restrictions, the elements defined by the sentence "include..." do not exclude the presence of other identical elements in the process, method, article or apparatus that includes the elements.

[0032] Example 1

[0033] This embodiment provides a method for preparing a degradable antibacterial fiber, using recombinant Escherichia coli as a production strain to prepare the degradable antibacterial fiber. The specific implementation content is as follows:

[0034] Purpose of the experiment:

[0035] Preparation of biodegradable antibacterial fibers

[0036] Experimental materials:

[0037] Phage antimicrobial peptides, polyhydroxyalkanoate, glucose-propionic acid medium, sodium hypochlorite, 1-ethyl-3-methylimidazolium acetate, boric acid, CaCl2 / Na2HPO4 / sodium alginate mineralization solution.

[0038] Experimental steps:

[0039] S1: Recombinant Escherichia coli was constructed using gene editing technology. The phage-derived antimicrobial peptide gene and the polyhydroxyalkanoate (PHA) synthesis gene cluster were integrated. The PHA synthesis inhibitory gene phaR was knocked out and the phaCAB operon was overexpressed. At the same time, an IPTG-inducible promoter was inserted before the antimicrobial peptide gene to achieve the coordinated expression of the antimicrobial peptide and PHBV, thus obtaining a dual-plasmid engineered bacterium.

[0040] S2: Fed-batch fermentation was performed in an optimized glucose-propionic acid medium. After induction, the bacterial cell volume reached 35 g / L and the PHBV ratio reached 68%. The antimicrobial peptide-PHBV copolymer was then isolated by lysing the cells with sodium hypochlorite, ultrasonication, and ethanol precipitation.

[0041] S3: dissolving the antimicrobial peptide-PHBV copolymer in the ionic liquid 1-ethyl-3-methylimidazolium acetate to prepare a solution with a concentration of 8 wt%, then adding 0.5 wt% boric acid as a dynamic crosslinker, and then sonicating to form a homogeneous solution;

[0042] S4: Nanofiber membranes with an average fiber diameter of 200-300 nm were prepared using electrospinning technology at 18 kV and a receiving distance of 15 cm, and heat-treated at 60°C for 2 hours.

[0043] S5: Soaking the fiber membrane in a CaCl2 / Na2HPO4 / sodium alginate mineralization solution, and then shaking at 37°C for 24 hours to form a hydroxyapatite / alginate composite coating.

[0044] Experimental results: See Table 1 for details.

[0045] Table 1: Test results of Example 1

[0046] 5 times antibacterial rate 90-day weight loss rate tensile strength Elongation at break Example 1 ＞99％ 82％ 18MPa 25％

[0047] In Example 1, recombinant Escherichia coli was constructed to achieve the coordinated expression of phage antimicrobial peptides and polyhydroxyalkanoates. After fermentation separation, ionic liquid dissolution and cross-linking, electrospinning and mineralization treatment, a degradable antimicrobial fiber was successfully prepared. The test results showed that the fiber had an antibacterial rate of over 99% after 5 times and a weight loss rate of 82% in 90 days. It also had a tensile strength of 18 MPa and an elongation at break of 25%, which not only verified the feasibility of the preparation method in the claims of the present invention, but also demonstrated excellent long-term antibacterial effect, degradability and mechanical properties, achieving an effective balance between antibacterial function and material degradability.

[0048] Comparative Example 1

[0049] This embodiment provides a method for preparing an antimicrobial agent-degradable polymer by melt blending and spinning, and the following implementation contents are provided:

[0050] Purpose of the experiment:

[0051] The antibacterial fiber was prepared by melt blending spinning method.

[0052] Experimental materials:

[0053] Natural antimicrobial agents (such as chitosan, plant essential oils), biodegradable polymers (polylactic acid PLA, polybutylene succinate PBS), solubilizers (maleic anhydride PLA), lubricants (magnesium stearate)

[0054] Experimental steps:

[0055] S1: Chitosan powder and PLA particles are mixed at a ratio of 5-10%, a compatibilizer is added, and the mixture is fed into a twin-screw extruder and melt-blended at 170-190°C to fully disperse the antimicrobial agent in the PLA matrix to prepare an antimicrobial masterbatch;

[0056] S2: The masterbatch is passed through a melt spinning machine, the spinning temperature is set to 160-180°C, the draft ratio is 3-5, and the fiber is spun into fibers, which are then heat-set to obtain antibacterial fibers.

[0057] Experimental results: See Table 2 for details.

[0058] Table 2: Test results of Comparative Example 1

[0059] 5 times antibacterial rate 90-day weight loss rate tensile strength Elongation at break Comparative Example 1 ＞45％ 55％ 49MPa 2.5％

[0060] Comparative Example 1 demonstrates a typical drawback of the melt-blending spinning method: poor compatibility between the antimicrobial agent and the PLA matrix. This results in a sharp drop in antimicrobial efficacy to 45% after five uses, coupled with rapid precipitation of the antimicrobial agent. The 90-day weight loss rate of 55% indicates a mismatch between the fiber degradation rate and the antimicrobial cycle. While the tensile strength of 49 MPa is higher than that of Example 1, the elongation at break is only 2.5%, demonstrating significant material brittleness and poorly balanced mechanical properties, in stark contrast to the high toughness of Example 1.

[0061] Comparative Example 2

[0062] A method for preparing a degradable antibacterial fiber by a surface coating method is provided, and the following implementation contents are provided:

[0063] Experimental materials:

[0064] Polyhydroxyalkanoate fiber (PHBV), silver nanoparticles (antimicrobial agent), polyvinyl alcohol (PVA), ethanol.

[0065] Purpose of the experiment:

[0066] The biodegradable antibacterial fiber was prepared by surface coating method.

[0067] Experimental steps:

[0068] S1: When preparing PHBV fibers through melt spinning, the spinning temperature is set at 140-150°C, and the fibers are washed with water to remove surface impurities and then dried;

[0069] S2: Prepare an ethanol solution containing 0.5-1% silver nanoparticles and 5% PVA, immerse the PHBV fiber in it for 30 minutes, take it out and dry it in an oven at 60°C to make the PVA-silver nanoparticle coating adhere to the fiber surface.

[0070] Experimental results: See Table 3 for details.

[0071] Table 3: Comparative Example 2 test results

[0072] 5 times antibacterial rate 90-day weight loss rate tensile strength Elongation at break Comparative Example 2 ＞35％ 53％ 15MPa 12％

[0073] The results in Comparative Example 2 reflect the typical shortcomings of the surface coating method. Due to the weak bonding between the PVA-silver nanoparticle coating and the PHBV fiber, the antibacterial rate after five uses was only 35%, significantly insufficient for long-term antibacterial efficacy. The coating hinders the fiber's contact with the environment, resulting in a 90-day weight loss of only 53%, and its degradation performance is suppressed. The tensile strength of 15 MPa is slightly lower than that of Example 1, and the elongation at break of 12% is also lower than the 25% of Example 1. This indicates that the brittle nature of the coating affects the overall toughness of the fiber, resulting in poor balance of mechanical properties. This further highlights the limitations of the surface coating method in terms of antibacterial durability, degradation compatibility, and mechanical coordination.

[0074] refer to Figure 1 The preparation flow chart shows that in Example 1, a dual-plasmid engineered bacterium was constructed using gene editing. By integrating antimicrobial peptide and polyhydroxyalkanoate synthesis gene clusters, an antimicrobial peptide-PHBV copolymer was obtained through batch fermentation and separation and purification. This copolymer was then dissolved in an ionic liquid, crosslinked with boric acid, electrospun, and treated with a mineral coating to successfully produce a biodegradable antimicrobial fiber. Test results showed that the fiber exhibited an antimicrobial efficacy exceeding 99% after five exposures and a weight loss rate of 82% over 90 days. It also exhibited a tensile strength of 18 MPa and an elongation at break of 25%, achieving an effective balance of long-term antimicrobial efficacy, biodegradability, and mechanical properties.

[0075] Comparative Example 1 employed an antimicrobial agent-degradable polymer melt blending spinning method, melt-blending chitosan with PLA and other materials before spinning. Results showed a five-shot antimicrobial efficacy of only 45%, a 90-day weight loss of 55%, and a tensile strength of 49 MPa but a mere 2.5% elongation at break. This method suffers from drawbacks such as poor compatibility between the antimicrobial agent and the substrate, easy precipitation of the antimicrobial agent, a mismatch between the degradation rate and the antimicrobial cycle, significant material brittleness, and poorly balanced mechanical properties.

[0076] Comparative Example 2 employed a surface coating method, applying a PVA coating containing silver nanoparticles to the surface of PHBV fibers. Test results showed a 35% antibacterial rate after five exposures, a 53% weight loss rate after 90 days, a tensile strength of 15 MPa, and an elongation at break of 12%. However, the coating exhibited shortcomings, including weak adhesion to the fiber, resulting in insufficient long-term antibacterial efficacy; a low weight loss rate due to the coating's degradation resistance; and a brittle coating that compromised the fiber's overall toughness, resulting in poorly balanced mechanical properties.

[0077] Comparison shows that Example 1 demonstrates comprehensive advantages over Comparative Examples 1 and 2 in key performance, which is directly related to its innovative technological approach. In terms of long-term antibacterial efficacy, Example 1 still maintains an antibacterial rate of >99% after 5 uses, which is much higher than the 45% of Comparative Example 1 and the 35% of Comparative Example 2. This is due to the molecular-level compounding of antimicrobial peptides and PHBV achieved through gene editing, which avoids the rapid precipitation caused by the poor compatibility of the antimicrobial agent with the matrix in Comparative Example 1, and the loss of antimicrobial components caused by coating shedding in Comparative Example 2, ensuring the long-term stability of the antimicrobial function. In terms of degradability, Example 1 achieved a weight loss rate of 82% in 90 days, significantly higher than the 55% of Comparative Example 1 and the 53% of Comparative Example 2. Because its integrated structure is not hindered by physical mixing or surface coating, it can more fully contact and degrade with the environment, meeting the core requirements of environmentally friendly materials. In terms of mechanical properties, the tensile strength of 18 MPa and the elongation at break of 25% in Example 1 form a better balance, which not only overcomes the high brittleness of Comparative Example 1 caused by the agglomeration of the antibacterial agent, but also improves the insufficient toughness of Comparative Example 2 caused by the poor bonding between the coating and the substrate, fully demonstrating its significant technical advantages in antibacterial durability, degradation matching and mechanical coordination.

[0078] Those skilled in the art will appreciate that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented with electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0079] In addition, the functional modules in the various embodiments of the present application may be integrated into one processing module, or each module may exist physically separately, and two or more modules may be integrated into one module.

[0080] The above is only a specific implementation method of the present application, but the scope of protection of the present application is not limited to this. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed in this application, which should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

[0081] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection of the present invention.

Claims

1. A degradable antibacterial fiber, characterized in that: Includes the following components: 8-10 parts of bacteriophage antimicrobial peptide, 65-70 parts of polyhydroxyalkanoate, 1-2 parts of sodium hypochlorite, 2-5 parts of 1-ethyl-3-methylimidazolium acetate, 0.5-1 part of boric acid, and 3-6 parts of CaCl2 / Na2HPO4 / sodium alginate mineralization solution.

2. The degradable antibacterial fiber according to claim 1, characterized in that: The gene of the bacteriophage antimicrobial peptide is cloned from the genome of bacteriophage φ87S / 06, and the antimicrobial peptide encoded by the bacteriophage is a natural antimicrobial polypeptide derived from bacteriophage.

3. The degradable antibacterial fiber according to claim 1, characterized in that: The main component of the polyhydroxyalkanoate is poly 3-hydroxybutyrate-co-3-hydroxyvalerate, and the main chain thereof is a linear polyester.

4. The degradable antibacterial fiber according to claim 1, characterized in that: The ratio of CaCl2 / Na2HPO4 / sodium alginate mineralization solution is 3:2:

2.

5. A method for preparing a degradable antibacterial fiber, characterized in that: The following steps are involved: S1: Recombinant Escherichia coli was constructed using gene editing technology. The phage-derived antimicrobial peptide gene and the polyhydroxyalkanoate synthesis gene cluster were integrated. The PHA synthesis inhibitory gene phaR was knocked out and the phaCAB operon was overexpressed. At the same time, an IPTG-inducible promoter was inserted before the antimicrobial peptide gene to achieve the coordinated expression of the antimicrobial peptide and PHBV, thus obtaining a dual-plasmid engineered bacterium. S2: Fed-batch fermentation was performed in an optimized glucose-propionic acid medium to induce the bacteria to synthesize PHBV. The antimicrobial peptide-PHBV copolymer was then isolated by cell lysis with sodium hypochlorite, ultrasonic disruption, and ethanol precipitation. S3: The antimicrobial peptide-PHBV copolymer was dissolved in the ionic liquid 1-ethyl-3-methylimidazolium acetate, followed by the addition of boric acid as a dynamic crosslinker and subsequent sonication to form a homogeneous solution; S4: Prepare nanofiber membranes using electrospinning technology, control the average fiber diameter, and heat treat at 60°C for 2 hours; S5: Soaking the fiber membrane in a CaCl2 / Na2HPO4 / sodium alginate mineralization solution, and then shaking for 24 hours to form a hydroxyapatite / alginate composite coating.

6. The method for preparing a degradable antibacterial fiber according to claim 5, characterized in that: After induction, the bacterial cell content in S2 reached 35 g / L and the proportion of PHBV in the cells was 68%.

7. The method for preparing a degradable antibacterial fiber according to claim 5, characterized in that: In the above-mentioned S3, the concentration of the antimicrobial peptide-PHBV copolymer in the solution is 8 wt %, and the amount of boric acid added is 0.5 wt %.

8. The method for preparing a degradable antibacterial fiber according to claim 5, characterized in that: The electrospinning technology used in S4 has a voltage of 18 kV and a receiving distance of 15 cm, and the average fiber diameter is 200-300 nm.

9. The method for preparing a degradable antibacterial fiber according to claim 5, characterized in that: In the above-mentioned S4, the fiber membrane obtained by electrospinning is heat-treated at 60° C. for 2 hours.

10. The method for preparing a degradable antibacterial fiber according to claim 5, characterized in that: The S5 was immersed in liquid at 37°C and shaken for 24 hours.

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