CN113499469A

CN113499469A - Multifunctional antibacterial composite film and preparation method thereof

Info

Publication number: CN113499469A
Application number: CN202110481820.7A
Authority: CN
Inventors: 蔡芳昌; 叶琴; 马宁; 章雅; 阮波; 张鑫珂; 张逸捷; 蒋涛
Original assignee: Hubei University
Current assignee: Hubei University
Priority date: 2021-04-30
Filing date: 2021-04-30
Publication date: 2021-10-15
Anticipated expiration: 2041-04-30
Also published as: CN113499469B

Abstract

The invention discloses a multifunctional antibacterial composite film and a preparation method thereof, wherein the preparation method comprises the following steps: dissolving chitosan and polyvinyl alcohol in an acid solution, and stirring for reaction; adding lauramidopropyl betaine, reducing the temperature to 40-60 ℃, continuing to react, then adding a hydrogen bond organic frame, and stirring and mixing for reaction; after the mixture is placed to room temperature, air bubbles are removed, and then the film is dried and uncovered; then with NaHCO₃Washing the solution to be neutral and drying to obtain the multifunctional antibacterial composite film. Book (I)The invention selects chitosan, polyvinyl alcohol, lauramide propyl betaine and hydrogen bond organic framework as raw materials, so that the chitosan, the polyvinyl alcohol, the lauramide propyl betaine and the hydrogen bond organic framework interact to form a compact polymer network, and utilizes the inherent toughening mechanism of the materials to obviously enhance the mechanical property of the composite film from the microstructure.

Description

Multifunctional antibacterial composite film and preparation method thereof

Technical Field

The invention relates to the technical field of biomedical dressings, in particular to a multifunctional antibacterial composite film and a preparation method thereof.

Background

Medical dressings are articles for dressing wounds, for covering sores, wounds or other lesions of medical material. With the intensive research on the pathophysiology of the wound healing process, people understand the wound healing process more and more deeply, so that medical wound dressings are continuously improved and developed. Traditional medical dressings only have a simple protection function on wounds, such as early-stage flax and cotton dressings, cannot provide a moist environment, are easy to adhere to wounds, are not easy to replace, and cannot achieve a good treatment effect. Currently, polymer dressings capable of keeping skin wounds moist and antibacterial have become the mainstream of development of medical wound dressings. When the antibacterial dressing has more exudate, if the antibacterial dressing is not replaced in time, the skin around the wound is likely to be soaked, infected and ulcerated, so that the ideal medical dressing for the wound has the exudate absorption capacity; and has the performances of providing moist environment for wounds, sufficient oxygen permeability, good biocompatibility, proper swelling rate, excellent antibacterial activity and the like.

The hydrogel dressing prepared by the patent has excellent characteristics of diminishing inflammation, relieving wound pain, reducing scars, promoting wound healing, absorbing wound exudate, achieving biocompatibility and the like, but shows poor antibacterial performance and mechanical stability, is easy to cause wound infection, and is easy to curl edges, fall off and poor in using effect due to repeated friction. Therefore, a novel multifunctional composite film medical dressing with excellent mechanical properties and antibacterial effect, high swelling rate, oxygen transmission rate and biocompatibility is urgently needed to be designed.

Disclosure of Invention

The invention provides a multifunctional antibacterial composite film and a preparation method thereof aiming at the defects in the prior art, wherein chitosan, polyvinyl alcohol, lauramidopropyl betaine and a hydrogen bond organic framework are selected as raw materials and are interacted to form a compact polymer network, the inherent toughening mechanism of the materials is utilized, the mechanical property of the composite film is obviously enhanced from the microstructure, and meanwhile, the composite film also has the characteristics of air permeability, moisture absorption, antibacterial property, high-load medicine and the like, and the preparation method is simple, the materials are nontoxic and pollution-free, and the multifunctional antibacterial composite film has wide application prospect and application value.

In order to achieve the purpose, the invention adopts the technical scheme that:

the invention provides a preparation method of a multifunctional antibacterial composite film, which comprises the following steps:

step 1, dissolving chitosan and polyvinyl alcohol in an acid solution, and stirring for reaction at 70-90 ℃;

step 2, adding lauramidopropyl betaine, reducing the temperature to 40-60 ℃, continuing to react for 1-3 hours, then adding a hydrogen bond organic frame, and stirring and mixing to react for 8-12 hours;

step 3, after the mixture is placed to room temperature, air bubbles are removed, drying is carried out, and the film is uncovered;

step 4, NaHCO is used for the uncovered membrane₃Washing the solution to neutralityAnd then drying the film at 35-40 ℃ for 8-12 hours to obtain the multifunctional antibacterial composite film.

Further, the mass ratio w/w of the chitosan, the polyvinyl alcohol and the lauramidopropyl betaine is 1: 1-3: 1 to 3.

Further, the mass ratio w/w of the chitosan, the polyvinyl alcohol and the lauramidopropyl betaine is 1: 2: 2.

further, the addition amount of the hydrogen bond organic framework is 3 wt% of the total mass.

Further, the hydrogen bond organic framework is a 2-dimensional-hydrogen bond organic framework, and the preparation method of the 2-dimensional-hydrogen bond organic framework comprises the following steps:

weighing melamine, pyromellitic dianhydride and zinc chloride, mixing, grinding, sealing in a high-temperature resistant tube, reacting at 200-400 ℃, and then reacting with HCl and H₂And (3) washing with O, activating with tetrahydrofuran, performing Soxhlet extraction with methanol, and finally drying to obtain the 2-dimensional-hydrogen bond organic framework.

Further, in the preparation method of the 2-dimensional-hydrogen bond organic framework, the w/w of melamine, pyromellitic dianhydride and zinc chloride is 1: 2.59: 13.53.

further, the acid solution in step 1 is selected from any one or more of hydrochloric acid, sulfuric acid, formic acid and acetic acid.

Further, the acid solution in step 1 is an acetic acid solution with a concentration of 2 wt%.

Further, in step 1, chitosan and polyvinyl alcohol were dissolved in a 2 wt% acetic acid solution at a volume ratio v/v 1: 50.

The invention also provides a multifunctional antibacterial composite film which is prepared by the preparation method.

Compared with the prior art, the invention has the beneficial effects that:

(1) according to the invention, on the basis of the traditional chitosan/polyvinyl alcohol hydrogel film, the lauramidopropyl betaine and the hydrogen bond organic framework are added, so that functional groups of all components interact to form a compact polymer network, the mechanical property of the composite film is enhanced, meanwhile, the toughness of the composite film is enhanced by a toughening mechanism caused by the hydrogen bond organic framework, the maximum tensile strength of the composite film can reach 29MPa, and the maximum loading capacity can reach 3700g, namely the mechanical property of the composite film is remarkably improved;

(2) the chitosan and the lauramidopropyl betaine in the composite film are both polycationic compounds, and the bacteria are polyanions, so that the composite film has stronger antibacterial activity due to the hydrogen bond effect formed by the chitosan, the lauramidopropyl betaine, the polyvinyl alcohol and a hydrogen bond organic frame;

(3) the composite film also has excellent hydrophilicity, swelling rate, oxygen transmission rate and biocompatibility, namely the multifunctional antibacterial composite film has multiple excellent performances, and meanwhile, the preparation method is simple, the material cost is low, and the multifunctional antibacterial composite film is non-toxic, pollution-free and nuisanceless and has wide application prospects.

Drawings

FIG. 1 is a CS/PVA/LPB/2D-HOF composite membrane prepared in example 1 of the present invention;

FIG. 2 is a diagram illustrating the measurement of the bacteriostatic effect of the CS/PVA/LPB/2D-HOF composite membrane in example 1 of the present invention;

FIG. 3 is a graph showing the results of measuring the antibacterial properties of different films in example 1 of the present invention and comparative examples 1 to 4;

FIG. 4 shows the results of the biocompatibility measurements of different films of example 1 of the present invention and comparative examples 1 to 4;

FIG. 5 is a graph showing the results of measuring the tensile strength and elongation at break of different films in example 1 of the present invention and comparative examples 1 to 4;

FIG. 6 is an FESEM image before and after stretching of a CS/PVA/LPB/2D-HOF composite film according to the present invention;

FIG. 7 is a measurement result of the maximum loading amount of the CS/PVA/LPB/2D-HOF composite membrane according to the present invention;

FIG. 8 is a graph showing the results of measuring the oxygen transmission rate of various films in example 1 of the present invention and comparative examples 1 to 4;

FIG. 9 is a measurement result of swelling ratios of different films in example 1 of the present invention and comparative examples 1 to 4;

FIG. 10 shows the result of measuring the hydrophilic contact angle of the CS/PVA/LPB/2D-HOF composite membrane of the present invention.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

The embodiment provides a multifunctional antibacterial composite film and a preparation method thereof, and the multifunctional antibacterial composite film comprises the following specific steps:

step 1, synthesis of 2-dimensional-hydrogen bond organic framework (2D-HOF): 0.0723g of Melamine (MA), 0.1869g of pyromellitic dianhydride (PMDA) and 0.978g of zinc chloride (ZnCl) were weighed into a glove box₂) Mixing, grinding, adding into quartz tube, sealing, and reacting at 300 deg.C in furnace for 72 hours. After the reaction is finished, 1M HCl and H are used in sequence₂Washing with O, activating with Tetrahydrofuran (THF), performing Soxhlet extraction with methanol, and drying in oven at 85 deg.C overnight to obtain 2D-HOF;

step 2, adding 1g of Chitosan (CS),2g of polyvinyl alcohol (PVA) and 150mL of 2 wt% acetic acid (HAc) solution into a three-neck flask, stirring for 2 hours at 80 ℃, then adding 2g of lauramidopropyl betaine (LPB), reducing the temperature to 55 ℃, continuing to react for 2 hours, adding 3% of 2D-HOF by mass, and stirring for 8-12 hours;

step 3, after the mixed solution is placed at room temperature, vacuumizing the reaction solution for 30min to remove air bubbles in the reaction solution, pouring the solution into a polytetrafluoroethylene disc by a natural salivation method, drying the polytetrafluoroethylene disc in an oven at 50 ℃ for 20 hours, and then uncovering the film;

step 4, NaHCO is used for the uncovered mixed membrane₃Washing the solution to be neutral to remove the residual acetic acid on the surface of the membrane, and finally drying the membrane at 37 ℃ for 8-12 hours to finally prepare the CS/PVA/LPB/2D-HOF composite membrane, namely the multifunctional antibacterial composite membrane, which is shown in figure 1.

The specific action mechanism of the composite membrane is as follows: a hydrogen bond network is formed between the amido of the CS and the hydroxyl of the PVA, LPB contains amido and-COO-, a polymer network is formed between the LPB and the hydroxyl of the CS and the PVA through the action of the hydrogen bond, and a compact polymer network is formed through the interaction between the polymers by the 2D-HOF of a two-dimensional layered structure embedded in the polymer network, so that the mechanical property of the composite film is enhanced. Further, the composite film, during stretching, the 2D-HOF slides between the polymer chains, hydrogen bonds start to break and absorb the breaking energy, and some unbroken HOF and polymer chains cause crack bridging, thereby further enhancing energy consumption and load transfer. Therefore, the mechanical property of the composite film is obviously improved under the combined action of the toughening mechanism caused by the 2D-HOF and the hydrogen bond between the polymers, and the problem of edge curling caused by repeated friction of the traditional dressing is effectively solved.

CS and LPB are both polycationic compounds, and bacteria are polyanionic compounds, and the hydrogen bond interaction between the bacteria and PVA and 2D-HOF causes the composite membrane to have strong antibacterial activity. Further, CS and PVA contain a large number of hydrophilic groups (-OH, -NH)₂) After the addition of LPB, more groups interact (-OH, -NH) due to the presence of amide groups and-COO-groups of LPB₂COOH and amido group), the intermolecular force is strengthened, the multi-network structure formed by a plurality of polymers enhances the absorption of water molecules so as to enhance the hydrophilicity of the composite membrane, the adhesive force of human skin fiber cells on the surface of the dressing film is increased, and heat and sweat generated by a human body can be rapidly absorbed and diffused to the outside; meanwhile, the 2D-HOF is a porous material and can increase the oxygen permeability of the composite membrane, so that the composite membrane also has excellent oxygen permeability.

Further, the embodiment also verifies the antibacterial performance of the CS/PVA/LPB/2D-HOF composite membrane prepared by the method, which is specifically as follows: sterilizing composite membrane, and adding into Staphylococcus aureus (S.aureus) (1X 10)⁷CFU/mL) bacterial suspension, and culturing 48hour at 37 ℃ by taking no composite membrane as a blank control, then diluting the bacterial suspension by 100 ten thousand times, respectively coating the bacterial suspension in LB culture medium, culturing 48hour at 37 ℃, counting the number of bacterial colonies in the two culture media,the results are shown in FIG. 2. The result shows that almost no bacteria grow after the composite membrane bacterial liquid is added and the composite membrane bacterial liquid is coated, and the CS/PVA/LPB/2D-HOF composite membrane prepared by the invention is proved to have excellent bactericidal and bacteriostatic activity.

Comparative example 1

This comparative example differs from example 1 in that: in the comparative example, the CS film was prepared only from CS as a raw material, and the preparation method thereof was: adding 1g of CS and 150mL of 2 wt% HAc solution into a three-neck flask, stirring for 2 hours at 80 ℃, then reducing the temperature to 55 ℃, and stirring for 8-12 hours; subsequent steps were the same as steps 3 and 4 in example 1, and a CS film was synthesized.

Comparative example 2

This comparative example differs from example 1 in that: in the comparative example, the PVA film is prepared only by taking PVA as a raw material, and the preparation method comprises the following steps: 2g of PVA and 150mL of 2 wt% HAc solution are added into a three-neck flask, 2hour is stirred at 80 ℃, then the temperature is reduced to 55 ℃, and 8-12hour is stirred; the subsequent steps were the same as in steps 3 and 4 of example 1, and a PVA film was synthesized.

Comparative example 3

This comparative example differs from example 1 in that: the comparative example only takes CS and PVA as raw materials to prepare the CS/PVA film, and the preparation method comprises the following steps: 1g of CS, 2g of PVA and 150mL of 2 wt% HAc solution are added into a three-neck flask, 2hour is stirred at 80 ℃, then the temperature is reduced to 55 ℃, and 8-12hour is stirred; the subsequent steps were the same as in steps 3 and 4 of example 1, and a CS/PVA film was synthesized.

Comparative example 4

This comparative example differs from example 1 in that: in the comparative example, the CS/PVA/LPB film is prepared only by taking CS, PVA and LPB as raw materials, and the preparation method comprises the following steps: adding 1g of CS, 2g of PVA and 150mL of 2 wt% HAc solution into a three-neck flask, stirring for 2 hours at 80 ℃, then adding 2g of LPB, reducing the temperature to 55 ℃, and stirring for 8-12 hours; the subsequent steps were the same as in steps 3 and 4 of example 1, and a CS/PVA/LPB film was synthesized.

Evaluation protocol

1. Antibacterial property

Get implementationA total of 4 membranes of example 1 and comparative examples 1, 3 and 4 were cut into a circle with a diameter of 1cm, 4 samples were sterilized with absolute ethanol, then soaked in PBS solution for 12 hours, and finally the experimental equipment and membrane samples used were sterilized under an ultraviolet lamp for 30 min. 20 μ L of bacteria (S.aureus) (1X 10)⁷CFU/mL)) was diluted with 180 μ L of PBS solution and then added to a 96-well plate, and the sterilized film sample was placed in the 96-well plate containing the bacterial suspension, and the PBS bacterial suspension without the film sample was used as a control group. Culturing 48hour at 37 ℃, then diluting the bacterial suspension by 100 ten thousand times, coating the bacterial suspension in LB culture medium, culturing 48hour at 37 ℃, and recording the number of bacterial colonies containing CS/PVA/LPB/HOF film samples; meanwhile, optical density values (OD) of a control group and an experimental group were measured at a wavelength of 570nm using a microplate reader (Bio Tek, ELX800, USA), and six groups of experiments were performed in parallel for one sample. The antibacterial rate was calculated using the following formula:

the measurement results are shown in FIG. 3. The results show that 4 films have excellent antibacterial activity, the antibacterial rate is more than 90%, the antibacterial rates of the CS/PVA film and the CS/PVA/LPB/2D-HOF composite film are relatively high and reach 95%, wherein the antibacterial rate of the CS/PVA/LPB/2D-HOF composite film can reach 95.76%

2. Biocompatibility

In order to detect the biocompatibility of different films, a cytotoxicity test was performed by using the MTT method. The cytocompatibility of MC3T3-E1 cells was determined using 3- [4,5-220 dimethylthiazol-2-yl ] -2, 5-diphenyltetrazolium bromide (MTT, Alad-221din reagent, Inc., China) (Wuhan Union Hospital).

The film samples were round with a diameter of 1cm and were soaked in PBS (pH 7.4) in advance at a concentration of 1X10⁴Cells/cm ²200. mu.L of the cell suspension and the membrane sample (CS membrane, PVA membrane, CS/PVA/LPB/HOF membrane) were cultured together in a 96-well plate for 3 days (37 ℃ incubator), and the cell suspension without the addition of the sample was used as a control group. Removing finesCell culture Medium, 200. mu.L MTT solution (0.5mg mL) was added to each well^-1) After 4 hours of incubation at 37 ℃ in a cell incubator, the MTT solution was aspirated by a pipette gun, 200. mu.L of dimethyl sulfoxide (DMSO) was added to each group, and the resulting mixture was centrifuged for 15min to obtain a supernatant, and finally the Optical Density (OD) was measured at a wavelength of 570nm using a microplate reader (Bio Tek, ELX800, USA). Six sets of parallel tests were performed on one sample. Cell activity was calculated using the following formula:

the detection results are shown in fig. 4, and the results show that different films have an effect on cell survival rates, wherein the cell survival rates of the CS film, the PVA film and the CS/PVA film are significantly lower than those of the CS/PVA/LPB film and the CS/PVA/LPB/2D-HOF composite film, i.e., the composite film of the invention has excellent biocompatibility, is non-toxic to cells, and can be directly applied to wounds.

3. Tensile strength, elongation at break and maximum load

A total of 5 film samples of example 1 and comparative examples 1-4 were prepared in a dumbbell shape, and the mechanical properties of the different polymer film samples were characterized by an electronic universal (tensile) tester (CMT4104), with an original gauge length of 20mm and a rate of 2 mm/min.

The measurement result is shown in fig. 5, where 5- (a) is tensile strength, and 5- (b) is elongation at break, and the result shows that the tensile strength of the CS/PVA/LPB/2D-HOF composite film of the present invention is significantly improved compared with other film samples, the maximum tensile strength thereof can reach 29MPa, and the elongation at break thereof is also significantly higher than other films, and is as high as 450%, which indicates that the toughness of the CS/PVA/LPB/2D-HOF composite film of the present invention is also significantly improved.

The surface morphology of the CS/PVA/LPB/2D-HOF composite film of the present invention was analyzed using a Field Emission Scanning Electron Microscope (FESEM) (Zeiss Sigma 500) during stretching, the surface morphology of the composite film before stretching and the morphology of the broken portion of the film after stretching with a tensile machine were observed using a field emission scanning electron microscope under a voltage of 15KV for 120sec, and the results of the observation are shown in FIG. 6. In fig. 6, the upper graph is before stretching and the lower graph is after stretching, cracks can be observed in the graphs, i.e. the crack toughening mechanism described in the principle part in example 1 is confirmed.

The maximum loading of the CS/PVA/LPB/2D-HOF composite membrane is measured, the result is shown in figure 7, and the result shows that the maximum loading of the composite membrane can reach 3700g, namely the composite membrane has excellent mechanical properties.

4. Oxygen transmission rate

A total of 5 film samples of example 1 and comparative examples 1 to 4 were taken, prepared in a circular shape having a diameter of 4cm, and each film sample was tested for oxygen permeability (cm) by a differential pressure gas permeameter (VAC-V2)³/m²24hour 0.1MPa), each test was performed 6 times, and the measurement results are shown in FIG. 8.

The results show that compared with 4 film samples in comparative examples 1-4, the CS/PVA/LPB/2D-HOF composite film provided by the invention has significantly improved oxygen transmission rate, and the oxygen transmission rate is as follows: 800cm³/m²24hour 0.1 MPa. Therefore, when the air-permeable dressing is used for wounds, the air permeability is better, and the wound healing is more facilitated.

5. Swelling degree and hydrophilicity measurement

A total of 5 film samples of example 1 and comparative examples 1 to 4 were taken, cut into 1cm × 1cm size, soaked in PBS buffer (pH 7.4, 37 ℃), taken out every 1d, and water on the surface of the dry film was slowly sucked up with a quantitative filter paper and then weighed. One sample, six sets of parallel runs, was run to calculate the swelling ratio using the following formula: (wherein W_dBefore soaking in PBS solution, W_wIs measured after soaking)

The result is shown in fig. 9, and the result shows that compared with other films, due to the addition of LPB and HOF, the hydrophilic functional groups are increased, and the hydrogen bond acting force is improved, so that the CS/PVA/LPB/2D-HOF composite film disclosed by the invention still maintains a higher swelling rate after being soaked in the buffer solution for 7 days, thereby facilitating the absorption of tissue fluid exuded from the wound and providing a moist environment for the wound, promoting the wound healing, providing a clean and clean environment for the wound surface, and simultaneously, the high swelling rate can also contain more drugs or antibacterial agents, thereby facilitating the wound treatment.

Furthermore, a CS/PVA/LPB/2D-HOF composite membrane sample prepared in the embodiment 1 of the invention is prepared into a square with the size of 2 x 2cm, the hydrophilicity of the composite membrane is characterized by a contact angle measuring instrument (POWEREACH JC2000D1), and the detection result is shown in figure 10.

According to the invention, by combining the determination results, chitosan, polyvinyl alcohol, lauramidopropyl betaine and a hydrogen bond organic framework are selected as raw materials, so that the chitosan, the polyvinyl alcohol, the lauramidopropyl betaine and the hydrogen bond organic framework are interacted to form a compact polymer network, the inherent toughening mechanism of the materials is utilized, the mechanical property of the composite film is obviously enhanced from the aspect of microstructure, and meanwhile, the composite film has the characteristics of air permeability, moisture absorption, antibiosis, high-load medicine and the like, and has wide application prospect and higher application value.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.

Claims

1. A preparation method of a multifunctional antibacterial composite film is characterized by comprising the following steps:

step 4, NaHCO is used for the uncovered membrane₃Washing the solution to be neutral, and then drying the solution at 35-40 ℃ for 8-12 hours to obtain the multifunctional antibacterial composite film.

2. The method according to claim 1, wherein the w/w ratio of the chitosan, polyvinyl alcohol and lauramidopropyl betaine is 1: 1-3: 1 to 3.

3. The method of claim 2, wherein the w/w ratio of the chitosan, polyvinyl alcohol and lauramidopropyl betaine is 1: 2: 2.

4. the method according to claim 1, wherein the hydrogen bonding organic framework is added in an amount of 3 wt% based on the total mass.

5. The method of claim 1, wherein the hydrogen bonding organic framework is a 2-dimensional hydrogen bonding organic framework, and the 2-dimensional hydrogen bonding organic framework is prepared by a method comprising:

6. The method according to claim 5, wherein the w/w ratio of melamine, pyromellitic dianhydride, and zinc chloride in the 2-dimensional hydrogen bonding organic framework is 1: 2.59: 13.53.

7. the method according to claim 1, wherein the acid solution in step 1 is selected from any one or more of hydrochloric acid, sulfuric acid, formic acid, and acetic acid.

8. The method according to claim 7, wherein the acid solution in step 1 is an acetic acid solution having a concentration of 2 wt.%.

9. The method according to claim 8, wherein the chitosan and the polyvinyl alcohol are dissolved in a 2 wt% acetic acid solution at v/v 1:50 in step 1.

10. A multifunctional antibacterial composite film characterized by being produced by the production method as claimed in claims 1 to 9.