A high molecular weight chitosan core-shell structured micro / nanofiber dressing

Abstract

The application provides a high-molecular-weight chitosan skin-core structure micro-nano fiber dressing, which is prepared by preparing a spinning solution from high-molecular-weight chitosan, polyethylene oxide, acetic acid and water, and then performing solution jet spinning. The skin-core structure is that the high-molecular-weight chitosan is used as an inner core, and the polyethylene oxide is used as an outer skin. The application solves the problem that the high-molecular-weight chitosan spinning solution has high viscosity and is difficult to be prepared into a micro-nano fiber dressing, and the prepared high-molecular-weight chitosan skin-core structure micro-nano fiber dressing can promote wound healing.

Description

(I) Technical Field:

[0001] This invention belongs to the field of medical materials technology, specifically relating to a high molecular weight chitosan core-shell structure micro / nanofiber dressing. (II) Background Technology:

[0002] Chitosan is a renewable natural polymer material widely found in nature. Due to its good biocompatibility and significant antibacterial properties, it is widely used in wound healing and other applications. [1-3] Chitosan is a linear polysaccharide composed of (1→4) linked 2-acetamido-2-deoxy-β-D-glucopyranase (GlcNAc) units and 2-amino-2-deoxy-beta-D-glucanopyranose (GlcN) units. The chitosan macromolecular chain contains many primary amine groups, which are positively charged under acidic conditions. These primary amine groups attract negatively charged bacteria, leading to cell wall dissolution and inhibiting bacterial growth. [4] Chitosan can be classified into three types: low molecular weight (below 190kDa), medium molecular weight (190kDa–310kDa), and high molecular weight (above 310kDa). [5] High molecular weight chitosan facilitates the action of platelet-derived growth factor (PDGF) on reactive cells, thereby increasing the proliferation rate of 3T3-L1 fibroblasts. [6] Studies have shown that, compared with the control group, wounds treated with high molecular weight chitosan had more epithelial tissue (p<0.05), better re-epithelialization, and a faster wound closure rate. Histological examination and collagenase activity studies showed that wounds treated with high molecular weight chitosan developed late granulation tissue (p<0.05). [7] Furthermore, the 2000kDa high molecular weight chitosan is significantly superior to other low molecular weight chitosans in terms of wound contraction and collagenase activity. [8] .

[0003] Due to the high specific surface area effect of micro / nanofibers, preparing high molecular weight chitosan into micro / nanofibers can further enhance its antibacterial function and accelerate wound healing. Electrospinning is a common method for preparing micro / nanofibers; however, the viscosity of the electrospinning solution generally does not exceed 5 Pas. [9-11] Due to the high viscosity of the spinning solution, it is difficult to prepare high molecular weight chitosan micro / nanofibers using conventional electrospinning methods.

[12] To prepare high molecular weight chitosan micro / nanofibers, new preparation methods need to be explored.

[0004] Polyethylene oxide (PEO) is a highly hydrophilic and non-toxic polymer.

[13] It has good blood compatibility and good anti-adhesion properties against proteins.

[14] Vigilon dressing contains 96% water and polyethylene oxide.TM Capable of absorbing its own weight in exudate and freely delivering oxygen, it exhibits better healing effects than other wound dressings. [15,16] If polyethylene oxide (PEO) is used as the outer layer of micro / nanofibers, and high-molecular-weight chitosan serves as the core, the PEO outer layer can absorb wound exudate and, supported by the high-molecular-weight chitosan micro / nanofibers core, transform into a three-dimensional network structure of physical hydrogel formed by hydrogen bonds between PEO and water, allowing oxygen diffusion to accelerate healing. The high-molecular-weight chitosan in the micro / nanofibers core, under the action of the PEO physical hydrogel in the outer layer, can exert antibacterial and healing-promoting effects.

[13] Currently, electrospinning can only prepare micro / nanofibers composed of low molecular weight chitosan and polyethylene oxide. For example, at temperatures below 70°C, micro / nanofibers with a low molecular weight chitosan skin and a polyethylene oxide core can be prepared by electrospinning.

[17] Coaxial electrospinning can also prepare micro / nanofibers with low molecular weight chitosan as the outer skin and polyethylene oxide as the core, with fiber diameters of 150-190 nm.

[18] However, neither of these two methods can prepare micro / nanofibers with chitosan as the core and polyethylene oxide as the sheath.

[0005] Solution jet spinning is a spinning method that uses an injection pump to deliver a polymer solution into a concentric nozzle, where a high-speed airflow outside the nozzle stretches and whips the polymer solution into a jet, which is then solidified into fibers. During the spinning process, along with the jet's flight and stretching / whipping motion, the solvent components in the jet rapidly evaporate, and the polymer solidifies to form micro / nanofibers. [19-21] .

[0006] References:

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[0008] [2]WEIβPFLOG Janek,VEHLOW David, Martin et al. Characterization of chitosan with different degrees of deacetylation, solubility and solid viscosity: insights from various complementary methods [J]. International Journal of Biomacromolecules, 2021, 171: 242-261.

[0009] [3] Yu Ling, Dou Shubin, Ma Jinghan, et al. Preparation of antimicrobial peptide-supported chitosan / oxidized polyethylene nanofiber membranes by electrospinning [J]. Materials Frontiers, 2021, 8.

[0010] [4] Li Jianhui, Fu Jimin, Tian Xiao, et al. Properties of chitosan fiber and its effect on improving antibacterial activity [J]. Carbohydrate Polymer, 2022, 280:119031.

[0011] [5] MATICA, AACHMAN, TONDERVIK, et al. Antibacterial properties and mechanism of action of chitosan as a starting material for wound dressings [J]. International Journal of Molecular Sciences, 2019, 20(23): 5889.

[0012] [6]DI SANTO Mariana Carolina, ALAIMO Agustina, ACEBEDO Sofia Lorena et al. Biological responses induced by the combined application of high molecular weight chitosan and platelet-derived growth factor in different mammalian cell lines [J]. International Journal of Biological Macromolecules, 2020, 158: 953-967.

[0013] [7]ALSARRA Ibrahim A. Application of chitosan topical gel preparation in the treatment of burn wounds [J]. International Journal of Biological Macromolecules, 2009, 45(1): 16-21.

[0014] [8] JONES Mitchell, KUJUNDZIC Marina, JOHN Sabu, et al. Crabs and mushrooms: Research progress on the use of crustaceans and fungal chitin in wound treatment [J]. Marine Drugs, 2020, 18(1): 64.

[0015] [9] HIGASHI Shougo, HIRAI Takayuki, MATSUBARA Masato, et al. Dynamic viscosity recovery of electrospinning solution for TEMPO-CNF stabilized slender ultrafine polymer nanofibers [J]. Scientific Reports, 2020, 10(1): 13427.

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[10] TIWARI Sandeep Kumar, VENKATRAMAN Subbu S. The importance of viscosity parameters in electrospinning: monofilament fibers and core-shell fibers [J]. Materials Science and Engineering: C, 2012, 32(5): 1037-1042.

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[11] GREYLING Corinne Jean. Electrospun polyacrylonitrile nanofibers with additives: a study on orientation and crystallinity [D]. Stellenbosch: University of Stellenbossh, 2010: 229.

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[12] AMARIEI N, MANEA LR, BERTEA AP, et al. Effect of polymer solution on the properties of electrospun three-dimensional nanostructures [J]. IOP Conference Series: Materials Science and Engineering, 2017, 209: 012092.

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[13] Ma Lulu, Deng Li, Chen Jianming. A review of the application of polyethylene oxide in controlled-release tablet systems [J]. Drug Development and Industrial Pharmacy, 2013, 1-7.

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[14] LEE Jin Ho, LEE Hai Bang, ANDRADE Joseph D. Blood compatibility of polyoxyethylene surfaces [J]. Progress in Polymer Science, 1995, 20: 1043-1079.

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[15] MANDY Stephen H. A novel polyoxyethylene gel primary wound dressing [J]. Journal of Dermatologic Surgery & Oncology, 1983, 9:2.

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[16] SALASSA John R., PEARSON Bruce W. Polyethylene oxide gel: a novel intranasal dressing after septoplasty [J]. Archives of Otorhinolaryngology Head and Neck Surgery, 1991, 117:1365-1367.

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[17] Zhang Jianfeng, Yang Dongzhi, Xu Fei, et al. Electrospun core-shell nanofibers in homogeneous solution of polyethylene oxide / chitosan [J]. Macromolecule, 2009, 42(14): 5278-5284.

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[18] PAKRAVAN Mehdi, HEUZEY Marie Claude, AJJI Abdelah. Preparation of core-shell structured PEO chitosan nanofibers by coaxial electrospinning [J]. Biomacromolecules, 2012, 13(2): 412-421.

[0025]

[19] MEDEIROS Eliton S, GLENN Gregory M, KLAMCZYNSKI Artur P, et al. Solution jet spinning: a new method for producing micro and nanofibers from polymer solutions [J]. Journal of Applied Polymer Science, 2009, 113(4): 2322-2330.

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[20] Deodor Grebert, Ali, Gijin Leonard, et al. Solution jet spinning (SBS) and SBS-spun nanofibers: materials, methods and applications [J]. Materials Today, 2020, 25: 101656.

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[21] Huang Ya, Bai Xiaopeng, Zhou Ming, et al. Large-scale spinning of silver nanofibers as flexible and reliable conductors [J]. Nano Letters, 2016, 16(9): 5846-5851.

[0028]

[22] MURPHY Ryan, TURCOTT Ashley, BANUELOS Leo, et al. SIMPoly: An image analysis tool based on Matlab for measuring the diameter of electrospun polymer scaffold fibers [J]. Tissue Engineering Part C: Methods, 2020, 26(12): 628-636. (III) Summary of the Invention:

[0029] The purpose of this invention is to prepare a high molecular weight chitosan core-shell structured micro / nanofiber dressing, which can overcome the shortcomings of the existing technology. The high molecular weight chitosan core-shell structured micro / nanofiber dressing prepared by this invention can promote wound healing.

[0030] The technical solution of the present invention is a high molecular weight chitosan core-shell structure micro / nanofiber dressing, characterized in that it is prepared by a spinning solution of high molecular weight chitosan, polyethylene oxide, acetic acid and water, and then obtained by solution jet spinning.

[0031] The core-shell structure consists of a high molecular weight chitosan core and a polyethylene oxide outer shell, with a core diameter of 10-400 nm and an outer shell thickness of 60-500 nm.

[0032] The diameter of the core-sheath structure micro / nanofibers ranges from 100 nm to 3000 nm.

[0033] The mass ratio of the high molecular weight chitosan, polyethylene oxide, acetic acid, and water is 1.6:2.5-5:50:45.9-43.4.

[0034] The high molecular weight chitosan is made from chitosan powder or flakes with a molecular weight of 460,000, or from chitosan powder or flakes with a dynamic viscosity of 850 cp in a 2% w / w acetic acid aqueous solution containing 1% w / w chitosan.

[0035] The acetic acid was of 99% w / w analytical grade.

[0036] The polyethylene oxide has a molecular weight of 100,000 and is a powdered raw material.

[0037] The water used is double-distilled water.

[0038] The preparation process of the spinning solution is as follows: high molecular weight chitosan raw material and polyethylene oxide are dissolved in acetic acid and water in a certain proportion to prepare a mixture. After being stirred thoroughly at room temperature, a homogeneous spinning solution is prepared and the solution is degassed.

[0039] The solution jet spinning process is as follows: the prepared spinning solution is added to a syringe, and a syringe pump is used to advance the syringe for feeding. The feeding rate of the syringe pump is 2-4 mL / h. The distance between the nozzle and the mesh receiver ranges from 21 cm to 33 cm. A stable airflow shear force is provided using an air pressure of 0.04 MPa to 0.1 MPa. The area of ​​the micro / nanofiber membrane jetted from the high molecular weight chitosan solution is 1000-3000 cm². 2 The spinning time is 30-60 minutes, and the spinning is carried out at 24-35℃ with a relative humidity of 20%-25%.

[0040] The solution jet spinning process is achieved through a solution jet spinning device, which includes an air compressor with a capacity of 60-130L, a precision pressure control valve, a three-way connector with an outer diameter of 2.5 cm and an inner diameter of 2.3 cm, a 20G needle, and an injection pump.

[0041] The precision pressure control valve has an accuracy of 0.001 MPa;

[0042] The minimum feed rate of the syringe pump is less than 2 ml / hr;

[0043] The mesh of the mesh receiver is made of Teflon.

[0044] The solution jet spinning device is a model JNS-SBS-01 manufactured by Nanjing Genus New Materials Co., Ltd.

[0045] Advantages of this invention: This invention prepares a core-shell structured micro / nanofiber dressing with high molecular weight chitosan in the inner core and polyethylene oxide in the outer layer; this invention solves the problem that the high viscosity of high molecular weight chitosan spinning solution makes it difficult to prepare into micro / nanofibers, and the prepared high molecular weight chitosan core-shell structured micro / nanofiber dressing can promote wound healing. (iv) Description of the attached drawings:

[0046] Figure 1 Scanning electron microscopy (SEM) images of core-skin structured micro / nanofibers prepared using 1.6% w / w high molecular weight chitosan and different polyethylene oxides.

[0047] Figure 2 Diagram showing the diameter distribution of core-skin structured micro / nanofibers prepared using 1.6% w / w high molecular weight chitosan and different polyethylene oxides.

[0048] Figure 3 X-ray photoelectron spectra of pure polyethylene oxide, pure high molecular weight chitosan, and micro / nanofibers with different high molecular weight chitosan-polyethylene oxide core-shell structures.

[0049] Figure 4 Transmission electron microscopy (TEM) images of core-skin structured micro / nanofibers prepared using 1.6% w / w high molecular weight chitosan and 2.5% w / w polyethylene oxide before and after immersion in water.

[0050] Figure 5 This study serves as a control for the wound healing effect of core-skin structured micro / nanofibers prepared using 1.6% w / w high molecular weight chitosan and 2.5% w / w polyethylene oxide in SD rats. (V) Specific Implementation Methods:

[0051] Example: To further understand the present invention, the preparation method of the high molecular weight chitosan core-shell structured micro / nanofiber dressing provided by the present invention will be described below with reference to the examples. The scope of protection of the present invention is not limited to the following examples.

[0052] The raw materials selected were high molecular weight chitosan flakes with a dynamic viscosity of 850 cp in a 2% w / w acetic acid aqueous solution (1% w / w solid), polyethylene oxide powder with a molecular weight of 100,000, and analytical reagent-grade glacial acetic acid (99.5% w / w).

[0053] 3.2 g of high molecular weight chitosan and different masses of polyethylene oxide (5 g, 6 g, 7 g, 10 g) were dissolved in 100 g of acetic acid and deionized water, respectively. After stirring thoroughly at room temperature for 10 hours, 200 g of homogeneous spinning solution was prepared, namely, mixed solutions prepared by mixing 1.6% w / w high molecular weight chitosan with 2.5%, 3%, 3.5%, and 5% w / w polyethylene oxide, respectively. The solution was degassed for 12 hours before the solution jet spinning process. The stirring speed during the stirring process was 200 rpm.

[0054] Microfibers and nanofibers were prepared using a solution jet spinning apparatus: different prepared spinning solutions were added to syringes using a micro-injection pump at a feed rate of 4 mL / h. The distance between the nozzle and the mesh receiver ranged from 21 cm to 33 cm. A stable airflow shear force was provided using an air pressure of 0.09 MPa. The area of ​​the solution-jet microfibers and nanofibers was 20¹⁰ cm². 2 The spinning time for all four spinning solutions was 45 min. Solution jet spinning was carried out at 24℃ and a relative humidity of approximately 20%, yielding different high molecular weight chitosan core-shell structured micro / nanofiber dressings. The ratios of high molecular weight chitosan to polyethylene oxide in the prepared high molecular weight chitosan core-shell structured micro / nanofibers were 1.6:2.5, 1.6:3, 1.6:3.5, and 1.6:5, respectively.

[0055] The morphology of micro- and nanofibers was observed using scanning electron microscopy, and the average diameter distribution of the micro- and nanofibers was calculated using MATLAB (R2022a version).

[22] ,like Figure 1 and Figure 2 As shown.

[0056] from Figure 1 It can be seen that all micro / nanofibers are linear. The calculated diameter distribution was fitted with a Gaussian function to obtain the average diameter. The core-skin structure micro / nanofibers prepared using 1.6% w / w high molecular weight chitosan and 2.5% w / w polyethylene oxide had an average diameter of 133 nm. Figure 2 (a)). Increasing the polyethylene oxide concentration to 3%, 3.5%, and 5% w / w resulted in fiber average diameters of 172 nm, 198 nm, and 210 nm, respectively. Figure 2 (b)-(d)).

[0057] X-ray photoelectron spectroscopy was used to analyze micro / nanofiber samples, pure high molecular weight chitosan, and polyethylene oxide samples to compare the chemical elements on the surfaces of the objects.

[0058] like Figure 3 As shown, pure polyethylene oxide (PEO) and high molecular weight chitosan-PEO core-shell structure micro / nanofibers (PEO concentrations of 2.5%, 3%, 3.5%, and 5% w / w, respectively) exhibit only two peaks: one is an oxygen peak in the 520–540 eV binding energy range, and the other is a carbon peak in the 280–290 eV range. The X-ray photoelectron spectrum of the pure high molecular weight chitosan sample contains oxygen and carbon peaks, as well as a nitrogen peak in the 390–400 eV range. Compared to the pure high molecular weight chitosan sample, the X-ray photoelectron spectrum of the high molecular weight chitosan-PEO core-shell structure micro / nanofibers does not contain a nitrogen peak. Since the penetration depth of X-ray photoelectrons is typically no more than 5 nm, it can be concluded that high molecular weight chitosan is not present on the surface of the high molecular weight chitosan-PEO core-shell structure micro / nanofibers; the only substance present on the surface is polyethylene oxide.

[0059] The micro / nanofiber structure of the high molecular weight chitosan-polyoxyethylene core-shell structure was observed using a transmission electron microscope (TEM) at 80.0 kV. After TEM imaging, the copper mesh was immersed in deionized water for 1 second, removed, and infrared dried for 30 minutes before its morphology was observed again using a TEM.

[0060] like Figure 4 As shown. The bright and dark areas represent the core and outer sheath of the micro / nanofiber, respectively. The diameters of the outer sheath and core are approximately 340 nm and 35 nm, respectively. Figure 4 As shown in (b), the outer skin of the micro-nanofibers becomes significantly thinner after being soaked in water, further confirming that the water-soluble polymer polyethylene oxide is the outer skin of the high molecular weight chitosan polyethylene oxide core-skin structure micro-nanofibers, and the high molecular weight chitosan constitutes the inner core of the micro-nanofibers.

[0061] Eight-month-old female SD rats weighing 230-240 grams were used as an animal model. The rats were first anesthetized, and then the hair on their backs was removed using a shaver. Two adjacent circular skin wounds, each 1 cm in diameter, were made on the backs of the rats using a punch. One wound served as a control group, covered only with gauze, while the other wound was dressed with a 2.5% w / w polyethylene oxide and 1.6% w / w high molecular weight chitosan core-shell structured micro / nanofiber dressing. The gauze and dressing were changed every three days. Wound photographs were taken every three days, and the wound area was calculated. The wound healing rate was calculated using the following formula: Wound healing rate (%) = (C0 - C...) t ) / C0×100, where C0 is the initial area of ​​the wound, C t It is the wound area after time t.

[0062] from Figure 5 As can be seen, compared with the control group, the core-skin structured micro / nanofiber dressing containing 1.6% w / w high molecular weight chitosan and 2.5% w / w polyethylene oxide significantly accelerated the wound healing rate. On the 3rd day post-surgery, the wound healing rate of the control group was only 22.2%, while the healing rate of the high molecular weight chitosan core-skin structured micro / nanofiber dressing reached 40.4%, far exceeding that of the control group. On the 6th day post-surgery, the healing rate of the high molecular weight chitosan core-skin structured micro / nanofiber dressing was 55.7%, still far exceeding the 27.0% of the control group. This preliminary animal experiment result verifies the effect of the polyethylene oxide-based, high molecular weight chitosan-based micro / nanofiber dressing on promoting wound healing.

Claims

1. A high molecular weight chitosan core-sheath micro- and nanofiber dressing characterized by It is prepared by dissolving high molecular weight chitosan, polyethylene oxide, acetic acid and water into a spinning solution, and then performing solution jet spinning; the core-sheath structure is that high molecular weight chitosan is the inner core and polyethylene oxide is the outer sheath; the high molecular weight chitosan adopts chitosan powder or flaky raw material with a molecular weight of 460,000 or 1% w / w chitosan in 2% w / w acetic acid aqueous solution dynamic viscosity of 850 cp chitosan powder or flaky raw material.

2. The high molecular weight chitosan core-shell structure micro-nanofiber dressing according to claim 1, characterized in that The inner core diameter is 10-400 nm, and the outer sheath thickness is 60-500 nm.

3. The high molecular weight chitosan core-shell structure micro-nanofiber dressing according to claim 1, characterized in that The diameter of the core-sheath structure micro-nano fiber is 100 nm to 3000 nm.

4. The high molecular weight chitosan core-shell structure micro-nanofiber dressing according to claim 1, characterized in that The mass ratio of the high molecular weight chitosan, polyethylene oxide, acetic acid and water is 1.6:2.5-5:50:45.9-43.

4.

5. The high molecular weight chitosan core-shell structure micro-nanofiber dressing according to claim 1, characterized in that The acetic acid is 99% w / w analytical pure grade.

6. The high molecular weight chitosan core-shell structure micro-nanofiber dressing according to claim 1, characterized in that The polyethylene oxide has a molecular weight of 100,000 and is a powder raw material.

7. The high molecular weight chitosan core-shell structure micro-nanofiber dressing according to claim 1, characterized in that The water is double distilled water.

8. The high molecular weight chitosan core-shell structure micro-nanofiber dressing according to claim 1, characterized in that The preparation process of the spinning solution is that high molecular weight chitosan raw material and polyethylene oxide are dissolved in acetic acid and water according to the proportion to prepare a mixture, and after sufficient stirring at room temperature, a homogeneous spinning solution is prepared, and the solution is degassed.

9. The high molecular weight chitosan core-shell structure micro-nanofiber dressing according to claim 1, characterized in that The process of the solution jet spinning is as follows: the prepared spinning solution is added into a syringe, a syringe pump is used to push the syringe for feeding, the feeding rate of the syringe pump is 2-4 mL / h, the distance between the nozzle and the mesh receiver ranges from 21 cm to 33 cm, a stable air flow shear force is provided by using an air pressure of 0.04 MPa to 0.1 MPa, the area of the high molecular weight chitosan solution jet micro-nano fiber membrane is 1000-3000 cm 2 , the spinning time is 30-60 min, and the spinning is carried out at 24-35℃ and a relative humidity of 20 % - 25 %.

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