阅读说明：本技术 一种可降解壳聚糖基复合止血薄膜 (Degradable chitosan-based composite hemostatic film ) 是由 张正男 段书霞 潘红福 闫钧 付迎坤 常聪 周静 储旭 何孜翰 柳小军 田林奇 于 2020-12-30 设计创作，主要内容包括：本发明公开了一种可降解壳聚糖基复合止血薄膜,包括基材层和功能层,所述基材层为可降解纤维布；所述功能层为改性壳聚糖、聚乙二醇2000、明胶、黄原胶、Ag/Fe-2O-3磁性纳米粒子、锻制花蕊石、油酸酰胺制备得到的复合水凝胶,功能层通过聚多巴胺与基材层结合。本发明提供的可降解壳聚糖基复合止血薄膜具有柔软透气、安全性高、机械性能良好,吸水保水能力强,能够与伤口紧密贴合,容易剥离,止血、抗感染效果好,不会产生血管栓塞副作用。(The invention discloses a degradable chitosan-based composite hemostatic film, which comprises a substrate layer and a functional layer, wherein the substrate layer is degradable fiber cloth; the functional layer is modified chitosan, polyethylene glycol 2000, gelatin, xanthan gum, Ag/Fe 2 O 3 The functional layer of the composite hydrogel prepared from magnetic nanoparticles, forged ophicalcite and oleamide is polymerizedThe bamine is bonded to the substrate layer. The degradable chitosan-based composite hemostatic film provided by the invention has the advantages of softness, air permeability, high safety, good mechanical property, strong water absorption and retention capacity, capability of being tightly attached to a wound, easiness in stripping, good hemostatic and anti-infection effects and no side effect of vascular embolism.)

1. A degradable chitosan-based composite hemostatic film comprises a substrate layer and a functional layer, and is characterized in that the substrate layer is degradable fiber cloth; the functional layer is modified chitosan, polyethylene glycol 2000, gelatin, xanthan gum, Ag/Fe₂O₃The composite hydrogel is prepared from magnetic nanoparticles, forged ophicalcitum and oleamide, and the functional layer is combined with the base material layer through polydopamine.

2. The degradable chitosan-based composite hemostatic film according to claim 1, wherein the fiber used by the degradable fiber cloth is one or more of polylactic acid fiber, polycarbonate fiber, polyglycolic acid, polycaprolactone fiber, polybutylene succinate fiber, and polytrimethylene carbonate fiber.

3. The degradable chitosan-based composite hemostatic film according to claim 1, wherein the modified chitosan is prepared by the following steps: dissolving chitosan powder in 1wt% acetic acid to prepare 1wt% chitosan-acetic acid solution, adding alkyl aldehyde, stirring at room temperature for 12h, adjusting pH to 5 with NaOH solution, slowly adding sodium borohydride, then continuously stirring for 2h, adjusting pH to 7 with NaOH solution again, filtering and washing to neutrality after precipitation, repeatedly washing with ethanol, removing redundant aldehyde, freeze-drying and grinding to obtain the modified chitosan.

4. The degradable chitosan-based composite hemostatic film according to claim 1, wherein the Ag/Fe is₂O₃The preparation method of the magnetic nanoparticles comprises the following steps: mixing Fe₂O₃Preparing magnetic nano particles into suspension, adding 0.1% silver nitrate solution, oscillating for 20-30 min, adding trisodium citrate reducing agent, reacting for 5-15 min, adding 1% silver nitrate solution again, oscillating for 5-10 min, and coating the reduced nano silver on Fe₂O₃Performing magnetic separation on the surfaces of the magnetic nanoparticles, and repeatedly washing with deionized water to obtain Ag/Fe₂O₃Magnetic nanoparticles.

5. The degradable chitosan-based composite hemostatic film according to claim 1, wherein the preparation method of the forged ophicalcitum comprises the following steps: the ophicalcitum produced in Anhui Bozhou is subjected to superfine grinding, then is sieved by a 100-mesh sieve, is calcined at 400 ℃ for 4 hours, and is quenched by acetic acid and then is ground to obtain the ophicalcite.

6. The degradable chitosan-based composite hemostatic film according to claim 1, wherein the functional layer is prepared from the following raw materials in parts by weight: 90-150 parts of modified chitosan, 20006-10 parts of polyethylene glycol, 24-40 parts of gelatin, 12-20 parts of xanthan gum and Ag/Fe₂O₃Magnetic nanoparticles 614 parts of forged ophicalcitum, 12-25 parts of forged ophicalcitum and 0.1-0.2 part of oleamide.

7. The degradable chitosan-based composite hemostatic film according to claim 1, wherein the weight part ratio of the gelatin to the xanthan gum is 2: 1.

8. The degradable chitosan-based composite hemostatic film according to claim 1, wherein the weight part ratio of the modified chitosan, the polyvinyl alcohol 2000, the gelatin and the xanthan gum is 15:1:4: 2.

9. The preparation method of the degradable chitosan-based composite hemostatic film according to any one of claims 1 to 8, comprising the following steps:

step one, modifying the surface of a base material layer: preparing a Tris-HCl buffer solution containing hyaluronic acid and dopamine, respectively adding EDC and NHS, immersing the substrate layer in the buffer solution, reacting for 2 hours at room temperature, taking out, washing with deionized water for multiple times, immersing in the deionized water for 6 hours, and carrying out vacuum freeze drying to obtain a surface-modified substrate layer;

step two, preparation of a functional layer: dissolving modified chitosan in 3wt% acetic acid to prepare a solution; dissolving gelatin and xanthan gum in deionized water at 40 deg.C to obtain solutions, standing and swelling for 8 hr to obtain gelatin solution and xanthan gum solution; adding modified chitosan solution and oleamide into gelatin solution, rapidly stirring for 30s, adding polyethylene glycol 2000 and Ag/Fe₂O₃Carrying out ultrasonic treatment on the magnetic nanoparticles and the forged ophicalcitum for 40-60 s, then dropwise adding a xanthan gum solution, standing at room temperature for reaction for 12-24 h after dropwise adding, fully washing with deionized water, and carrying out freeze drying to obtain a composite hydrogel functional layer;

combining the functional layer with the substrate layer: and (3) overlapping and cold-pressing the functional layer and the substrate layer to obtain the degradable chitosan-based composite hemostatic film.

10. The preparation method of the degradable chitosan-based composite hemostatic film according to claim 9, wherein the pressure adopted in the cold pressing in the fourth step is 2-4 MPa, and the time is 10-20 min.

Technical Field

The invention relates to the technical field of biomedical materials, in particular to a degradable chitosan-based composite hemostatic film.

Background

The existing research shows that chitosan can adhere and aggregate red blood cells and blood platelets, activate a blood coagulation path through the activation of the blood platelets, accelerate the synthesis of fibrin glue, stimulate the vasoconstriction and finally seal wounds. Meanwhile, chitosan also has certain functions of resisting bacteria, relieving pain, promoting wound healing and reducing scars, and is an ideal hemostatic material. However, pure chitosan materials, including gels and fibers, tend to be mechanically weak. Therefore, the development of a chitosan-based composite hemostatic material with stable properties, safety, no toxicity and good mechanical strength is a hotspot. In the prior art, in order to improve the mechanical strength of the material when the chitosan composite material is prepared, a cross-linking agent such as terephthalaldehyde, adipic dialdehyde or glutaraldehyde is mostly needed, and the residual cross-linking agent can cause stimulation to wounds and is not beneficial to wound healing. The powdery mineral has good hemostasis and water absorption performances and is a common component for preparing the composite hemostasis material, but the powder is easy to gather to cause the reduction of the hemostasis effect, the risk of vascular embolism caused by the falling of the powder into blood vessels exists, the powder can be immobilized to play the role of hemostasis and blood coagulation, and the problem of leakage in the development of the composite hemostasis material is avoided. In order to improve the adhesion and adhesiveness of the composite hemostatic material and avoid leakage of powdery minerals, researchers and researchers often adopt methods of increasing the viscosity of the material or improving the compactness of the material, which causes the problems that the hemostatic material is difficult to separate from a wound, and secondary damage or poor comfort of the material is caused when the hemostatic material is removed.

Disclosure of Invention

The invention provides a degradable chitosan-based composite hemostatic film which can be directly used on a wound surface, cannot be bonded with the wound, has good mechanical property, is safe and nontoxic and resists infection and a preparation method thereof.

The purpose of the invention is realized by the following technical scheme:

a degradable chitosan-based composite hemostatic film comprises a substrate layer and a functional layer; the substrate layer is degradable fiber cloth; the functional layer is modified chitosan, polyethylene glycol 2000, gelatin, xanthan gum, Ag/Fe₂O₃The composite hydrogel is prepared from magnetic nanoparticles, forged ophicalcitum and oleamide, and the functional layer is combined with the base material layer through polydopamine.

Further, the fiber used by the degradable fiber cloth is one or more of polylactic acid fiber, polycarbonate fiber, polyglycolic acid, polycaprolactone fiber, polybutylene succinate fiber and polytrimethylene carbonate fiber.

Further, the preparation method of the modified chitosan comprises the following steps: dissolving chitosan powder in 1wt% acetic acid to prepare 1wt% chitosan-acetic acid solution, adding alkyl aldehyde, stirring at room temperature for 12h, adjusting pH to 5 with NaOH solution, slowly adding sodium borohydride, then continuously stirring for 2h, adjusting pH to 7 with NaOH solution again, filtering and washing to neutrality after precipitation, repeatedly washing with ethanol, removing redundant aldehyde, freeze-drying and grinding to obtain the modified chitosan.

Further, the alkyl aldehyde is one or more of hexanal, dodecanal and octadecanal.

Further, the Ag/Fe₂O₃The preparation method of the magnetic nanoparticles comprises the following steps: mixing Fe₂O₃Preparing magnetic nano particles into suspension, adding 0.1% silver nitrate solution, oscillating for 20-30 min, adding trisodium citrate reducing agent, reacting for 5-15 min, adding 1% silver nitrate solution again, oscillating for 5-10 min, and coating the reduced nano silver on Fe₂O₃Performing magnetic separation on the surfaces of the magnetic nanoparticles, and repeatedly washing with deionized water to obtain Ag/Fe₂O₃Magnetic nanoparticles.

Further, the preparation method of the forged ophicalcitum comprises the following steps: the ophicalcitum produced in Anhui Bozhou is subjected to superfine grinding, then is sieved by a 100-mesh sieve, is calcined at 400 ℃ for 4 hours, and is quenched by acetic acid and then is ground to obtain the ophicalcite.

Further, the functional layer is prepared from the following raw materials in parts by weight: 90-150 parts of modified chitosan, 20006-10 parts of polyethylene glycol, 24-40 parts of gelatin, 12-20 parts of xanthan gum and Ag/Fe₂O₃6-14 parts of magnetic nanoparticles, 12-25 parts of forged ophicalcitum and 0.1-0.2 part of oleamide.

Further, the weight part ratio of the gelatin to the xanthan gum is 2: 1.

Further, the weight part ratio of the modified chitosan, the polyvinyl alcohol 2000, the gelatin and the xanthan gum is 15:1:4: 2.

A preparation method of the degradable chitosan-based composite hemostatic film comprises the following steps:

step one, modifying the surface of a base material layer: preparing a Tris-HCl buffer solution containing hyaluronic acid and dopamine, respectively adding EDC and NHS, immersing the substrate layer in the buffer solution, reacting for 2 hours at room temperature, taking out, washing with deionized water for multiple times, immersing in the deionized water for 6 hours, and carrying out vacuum freeze drying to obtain a surface-modified substrate layer;

step two, preparation of a functional layer: dissolving modified chitosan in 3wt% acetic acid to prepare a solution; dissolving gelatin and xanthan gum in deionized water at 40 deg.C to obtain solutions, standing and swelling for 8 hr to obtain gelatin solution and xanthan gum solution; adding modified chitosan solution and oleamide into gelatin solution, rapidly stirring for 30s, adding polyethylene glycol 2000 and Ag/Fe₂O₃Carrying out ultrasonic treatment on the magnetic nanoparticles and the forged ophicalcitum for 40-60 s, then dropwise adding a xanthan gum solution, standing at room temperature for reaction for 12-24 h after dropwise adding, fully washing with deionized water, and carrying out freeze drying to obtain a composite hydrogel functional layer;

combining the functional layer with the substrate layer: and (3) overlapping and cold-pressing the functional layer and the substrate layer to obtain the degradable chitosan-based composite hemostatic film.

Further, in the first step, the concentration of the Tris-HCl buffer solution is 10mM, and the pH value is 8.5.

Further, the pressure adopted in the cold pressing in the fourth step is 2-4 MPa, and the time is 10-20 min.

The surface of the substrate layer can be grafted with hyaluronic acid, so that on one hand, the mechanical property of the substrate layer is improved due to the strong hydrogen bond effect among hyaluronic acid molecules, and on the other hand, the hyaluronic acid has a very excellent water retaining effect and further improves the water absorbing and retaining properties of the substrate layer. In addition, dopamine molecules can be self-assembled on the surface of the substrate, and the surface of the substrate is modified through self-polymerization and reaction with amino groups of hyaluronic acid, so that the modified surface of the substrate has good adhesion and hydrophilic water retention. After the surface of the base material layer is modified, the base material layer can be combined with the functional layer at normal temperature and under a small pressure condition without using an adhesive, and the combination is firm, so that the stimulation of the adhesive to a wound is effectively avoided.

The chitosan, the gelatin and the xanthan gum used in the functional layer are natural biological macromolecules, have good biocompatibility and no toxic or side effect, the hemostatic function and the antibacterial property of the chitosan are improved through alkylation modification, and the chitosan has positive charges in an acidic aqueous solution and can react with the gelatinCross-linking to Ag/Fe together with polyethylene glycol₂O₃The magnetic nano particles and the forged ophicalcitum are subjected to preliminary cross-linking fixation to avoid aggregation of the magnetic nano particles and the forged ophicalcitum, when anionic polysaccharide xanthan gum with negative charges is dripped in the magnetic nano particles and the forged ophicalcitum, the xanthan gum forms cogel through polyelectrolyte complexation between the xanthan gum and chitosan, and the cogel is formed for Ag/Fe₂O₃The magnetic nano particles and the forged ophicalcitum are secondarily fixed, so that the side effect of vascular embolism possibly caused by leakage of the magnetic nano particles and the forged ophicalcitum is avoided, and meanwhile, the three-dimensional spiral structure of the gelatin has certain rigidity and can penetrate through a gel system, so that the porous structure of the composite gel can be ensured, and the mechanical property of the hydrogel can be improved.

According to the invention, firstly, a chitosan solution is added into a gelatin solution, so that a gelatin three-dimensional structure and a chitosan skeleton are crosslinked to form a first network structure, the hydrogel has good toughness, the first network structure crosslinked skeleton can slide in the hydrogel under the action of external force without causing the integral displacement of the hemostatic film, and the hemostatic film can be always contacted with a wound; the oleamide has no toxicity, stable property and good biocompatibility, and the invention firstly disperses the oleamide in the system evenly, and then adds Ag/Fe₂O₃The magnetic nanoparticles and the forged ophicalcitum mineral components, the oleamide can promote the dispersion of the mineral components in a system in the ultrasonic treatment process, and the aggregation is avoided, so that the dispersion and the immobilization of the mineral components are realized; the polyethylene glycol 2000 used in the invention can improve the ductility and the tear resistance of the composite hydrogel, so that the composite hydrogel can contain a high content of mineral components, and cannot be subjected to Ag/Fe₂O₃The magnetic nano particles and the forged ophicalcitum are added to become hard and fragile. The xanthan gum is compounded with the gelatin and the modified chitosan to form a second network structure in a dripping mode, the prepared composite hydrogel can be tightly attached to a wound, has high viscosity, can absorb seepage and promote wound healing, has small peel strength and can be easily torn off, and secondary damage to the wound can be avoided when the composite hydrogel is peeled off from the wound.

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

(1) the degradable chitosan-based composite hemostatic film base material layer provided by the invention adopts a degradable fiber material, can meet the requirements of the hemostatic film on mechanical properties, has the properties of softness and air permeability, has strong water absorption and retention capacity by grafting hyaluronic acid on the surface, and can absorb tissue seepage of a functional layer to the base material layer, so that the functional layer keeps proper humidity and promotes wound healing; the surface of the base material layer is also provided with a polydopamine layer generated by self-assembly polymerization and reaction with hyaluronic acid, the polydopamine has adhesiveness, the functional layer and the base material layer can be firmly bonded together, and Ag/Fe can be further prevented₂O₃Leakage of magnetic nano particles and forged ophicalcitum can avoid vascular embolism.

(2) Ag/Fe for use in the present invention₂O₃Magnetic nanoparticles with nano-silver supported on Fe₂O₃The surface of the magnetic nano particle has larger specific surface area, compared with the conventional nano silver particle, the sterilization efficiency is higher, and the composite hemostatic film has excellent anti-infection function; fe₂O₃The magnetic nano-particles have magnetic responsiveness and superparamagnetism, can absorb electromagnetic waves to generate heat under the action of an alternating magnetic field, and can participate in regulating and controlling cell functions under the action of an external magnetic field to promote wound healing.

(3) The degradable chitosan-based composite hemostatic film provided by the invention does not use any cross-linking agent and can not stimulate wounds, a first network structure is formed by cross-linking gelatin and chitosan, a second network structure is formed by the gelation of xanthan gum and chitosan, the double-network structure composite hydrogel is prepared, the ductility and tear resistance of the composite hydrogel are improved by adding a proper amount of polyvinyl alcohol 2000, simultaneously mineral components can be effectively fixed, the porous structure of the composite hydrogel can ensure the hemostasis and antibiosis of the mineral components and the promotion of the healing efficacy of the wounds, and simultaneously the cross-linking effect and the fixation of the polyvinyl alcohol 2000 can prevent the leakage of the mineral components and avoid the occurrence of side effects.

Drawings

FIG. 1 shows the results of cytotoxicity test.

FIG. 2 shows the results of an in vitro whole blood coagulation test.

Detailed Description

To further illustrate the technical means and effects of the present invention, the following detailed description is given with reference to specific embodiments.

Example 1

A degradable chitosan-based composite hemostatic film comprises a substrate layer and a functional layer; the substrate layer is polycarbonate fiber cloth; the functional layer is modified chitosan, polyethylene glycol 2000, gelatin, xanthan gum, Ag/Fe₂O₃The composite hydrogel is prepared from magnetic nanoparticles, forged ophicalcite and oleamide, and the functional layer is combined with the base material layer through polydopamine; the functional layer is prepared from the following raw materials in parts by weight: 150 parts of modified chitosan, 200010 parts of polyethylene glycol, 40 parts of gelatin, 20 parts of xanthan gum and Ag/Fe₂O₃14 parts of magnetic nano particles, 25 parts of forged ophicalcitum and 0.2 part of oleamide.

The preparation method of the modified chitosan comprises the following steps: dissolving chitosan powder in 1wt% acetic acid to prepare 1wt% chitosan-acetic acid solution, adding hexanal, stirring at room temperature for 12h, adjusting pH to 5 with NaOH solution, slowly adding sodium borohydride, stirring for 2h, adjusting pH to 7 with NaOH solution again, filtering and washing to neutrality after precipitation, repeatedly washing with ethanol to remove excessive aldehyde, freeze-drying and grinding to obtain the modified chitosan.

The Ag/Fe₂O₃The preparation method of the magnetic nanoparticles comprises the following steps: mixing Fe₂O₃Preparing magnetic nanoparticles into suspension, adding 0.1% silver nitrate solution, oscillating for 20min, adding trisodium citrate as reducer, reacting for 5min, adding 1% silver nitrate solution again, oscillating for 5min to coat the reduced nano-silver on Fe₂O₃Performing magnetic separation on the surfaces of the magnetic nanoparticles, and repeatedly washing with deionized water to obtain Ag/Fe₂O₃Magnetic nanoparticles.

The preparation method of the forged ophicalcitum comprises the following steps: the ophicalcitum produced in Anhui Bozhou is subjected to superfine grinding, then is sieved by a 100-mesh sieve, is calcined at 400 ℃ for 4 hours, and is quenched by acetic acid and then is ground to obtain the ophicalcite.

A preparation method of the degradable chitosan-based composite hemostatic film comprises the following steps:

step one, modifying the surface of a base material layer: preparing a Tris-HCl buffer solution (the concentration of the Tris-HCl buffer solution is 10mM, and the pH value is 8.5) containing hyaluronic acid and dopamine, respectively adding EDC and NHS, immersing the substrate layer in the solution, reacting for 2 hours at room temperature, taking out the substrate layer, washing the substrate layer with deionized water for multiple times, immersing the substrate layer in the deionized water for 6 hours, and carrying out vacuum freeze drying to obtain a surface-modified substrate layer;

step two, preparation of a functional layer: dissolving modified chitosan in 3wt% acetic acid to prepare a solution; dissolving gelatin and xanthan gum in deionized water at 40 deg.C to obtain solutions, standing and swelling for 8 hr to obtain gelatin solution and xanthan gum solution; adding modified chitosan solution and oleamide into gelatin solution, rapidly stirring for 30s, adding polyethylene glycol 2000 and Ag/Fe₂O₃Carrying out ultrasonic treatment on magnetic nanoparticles and forged ophicalcitum for 60s, then dropwise adding a xanthan gum solution, standing at room temperature for 24h after dropwise adding, fully washing with deionized water, and carrying out freeze drying to obtain a composite hydrogel functional layer;

combining the functional layer with the substrate layer: and (3) overlapping and cold-pressing a functional layer and a base material layer at the pressure of 2MPa for 10min to obtain the degradable chitosan-based composite hemostatic film.

Example 2

A degradable chitosan-based composite hemostatic film comprises a substrate layer and a functional layer; the substrate layer is polylactic acid fiber cloth; the functional layer is modified chitosan, polyethylene glycol 2000, gelatin, xanthan gum, Ag/Fe₂O₃The composite hydrogel is prepared from magnetic nanoparticles, forged ophicalcite and oleamide, and the functional layer is combined with the base material layer through polydopamine; the functional layer is prepared from the following raw materials in parts by weight: 120 parts of modified chitosan, 20008 parts of polyethylene glycol, 32 parts of gelatin, 16 parts of xanthan gum and Ag/Fe₂O₃10 parts of magnetic nano particles and forging18 parts of prepared ophicalcitum and 0.15 part of oleamide.

The preparation method of the modified chitosan comprises the following steps: dissolving chitosan powder in 1wt% acetic acid to prepare 1wt% chitosan-acetic acid solution, adding dodecanal, stirring at room temperature for 12h, adjusting pH to 5 with NaOH solution, slowly adding sodium borohydride, then stirring for 2h, adjusting pH to 7 with NaOH solution again, filtering and washing to neutrality after precipitation, repeatedly washing with ethanol to remove excessive aldehyde, freeze-drying and grinding to obtain the modified chitosan.

The Ag/Fe₂O₃The preparation method of the magnetic nanoparticles comprises the following steps: mixing Fe₂O₃Preparing magnetic nanoparticles into suspension, adding 0.1% silver nitrate solution, oscillating for 25min, adding trisodium citrate as reducer, reacting for 10min, adding 1% silver nitrate solution again, oscillating for 8min, and coating the reduced nano-silver in Fe₂O₃Performing magnetic separation on the surfaces of the magnetic nanoparticles, and repeatedly washing with deionized water to obtain Ag/Fe₂O₃Magnetic nanoparticles.

The preparation method of the forged ophicalcitum comprises the following steps: the ophicalcitum produced in Anhui Bozhou is subjected to superfine grinding, then is sieved by a 100-mesh sieve, is calcined at 400 ℃ for 4 hours, and is quenched by acetic acid and then is ground to obtain the ophicalcite.

A preparation method of the degradable chitosan-based composite hemostatic film comprises the following steps:

step one, modifying the surface of a base material layer: preparing a Tris-HCl buffer solution (the concentration of the Tris-HCl buffer solution is 10mM, and the pH value is 8.5) containing hyaluronic acid and dopamine, respectively adding EDC and NHS, immersing the substrate layer in the solution, reacting for 2 hours at room temperature, taking out the substrate layer, washing the substrate layer with deionized water for multiple times, immersing the substrate layer in the deionized water for 6 hours, and carrying out vacuum freeze drying to obtain a surface-modified substrate layer;

step two, preparation of a functional layer: dissolving modified chitosan in 3wt% acetic acid to prepare a solution; dissolving gelatin and xanthan gum in deionized water at 40 deg.C to obtain solutions, standing and swelling for 8 hr to obtain gelatin solution and xanthan gum solution; adding modified chitosan solution and oleamide into gelatin solution, rapidly stirring for 30s, adding polyethylene glycol 2000 and Ag/Fe₂O₃Carrying out ultrasonic treatment on magnetic nanoparticles and forged ophicalcitum for 50s, then dropwise adding a xanthan gum solution, standing at room temperature for reacting for 18h after dropwise adding, fully washing with deionized water, and carrying out freeze drying to obtain a composite hydrogel functional layer;

combining the functional layer with the substrate layer: and (3) overlapping and cold-pressing a functional layer and a base material layer, wherein the pressure adopted in the cold pressing is 3MPa, and the time is 15min, so that the degradable chitosan-based composite hemostatic film is obtained.

Example 3

A degradable chitosan-based composite hemostatic film comprises a substrate layer and a functional layer; the substrate layer is polycaprolactone fiber cloth; the functional layer is modified chitosan, polyethylene glycol 2000, gelatin, xanthan gum, Ag/Fe₂O₃The composite hydrogel is prepared from magnetic nanoparticles, forged ophicalcite and oleamide, and the functional layer is combined with the base material layer through polydopamine; the functional layer is prepared from the following raw materials in parts by weight: 90 parts of modified chitosan, 20006 parts of polyethylene glycol, 24 parts of gelatin, 12 parts of xanthan gum and Ag/Fe₂O₃6 parts of magnetic nano particles, 12 parts of forged ophicalcitum and 0.1 part of oleamide.

The preparation method of the modified chitosan comprises the following steps: dissolving chitosan powder in 1wt% acetic acid to prepare 1wt% chitosan-acetic acid solution, adding octadecanal, stirring at room temperature for 12h, adjusting pH to 5 with NaOH solution, slowly adding sodium borohydride, then continuously stirring for 2h, adjusting pH to 7 with NaOH solution again, filtering and washing to neutrality after precipitation, repeatedly washing with ethanol, removing redundant aldehyde, freeze-drying and grinding to obtain the modified chitosan.

The Ag/Fe₂O₃The preparation method of the magnetic nanoparticles comprises the following steps: mixing Fe₂O₃Preparing magnetic nanoparticles into suspension, adding 0.1% silver nitrate solution, oscillating for 30min, adding trisodium citrate as reducer, reacting for 15min, adding 1% silver nitrate solution again, oscillating for 10min, and coating the reduced nano-silver in Fe₂O₃Magnetically separating the surface of the magnetic nanoparticles, and repeatedly washing with deionized water to obtain the final productAg/Fe₂O₃Magnetic nanoparticles.

The preparation method of the forged ophicalcitum comprises the following steps: the ophicalcitum produced in Anhui Bozhou is subjected to superfine grinding, then is sieved by a 100-mesh sieve, is calcined at 400 ℃ for 4 hours, and is quenched by acetic acid and then is ground to obtain the ophicalcite.

A preparation method of the degradable chitosan-based composite hemostatic film comprises the following steps:

step one, modifying the surface of a base material layer: preparing a Tris-HCl buffer solution (the concentration of the Tris-HCl buffer solution is 10mM, and the pH value is 8.5) containing hyaluronic acid and dopamine, respectively adding EDC and NHS, immersing the substrate layer in the solution, reacting for 2 hours at room temperature, taking out the substrate layer, washing the substrate layer with deionized water for multiple times, immersing the substrate layer in the deionized water for 6 hours, and carrying out vacuum freeze drying to obtain a surface-modified substrate layer;

step two, preparation of a functional layer: dissolving modified chitosan in 3wt% acetic acid to prepare a solution; dissolving gelatin and xanthan gum in deionized water at 40 deg.C to obtain solutions, standing and swelling for 8 hr to obtain gelatin solution and xanthan gum solution; adding modified chitosan solution and oleamide into gelatin solution, rapidly stirring for 30s, adding polyethylene glycol 2000 and Ag/Fe₂O₃Carrying out ultrasonic treatment on magnetic nanoparticles and forged ophicalcitum for 60s, then dropwise adding a xanthan gum solution, standing at room temperature for 24h after dropwise adding, fully washing with deionized water, and carrying out freeze drying to obtain a composite hydrogel functional layer;

combining the functional layer with the substrate layer: and (3) overlapping and cold-pressing a functional layer and a base material layer, wherein the pressure adopted by the cold pressing is 4MPa, and the time is 20min, so that the degradable chitosan-based composite hemostatic film is obtained.

The peel strength and tack strength of the composite hemostatic film samples obtained in examples 1 to 3 and A, B, C, D obtained under the same conditions as in example 2 by separately adjusting the weight ratio of gelatin to xanthan gum to 1:2, 1:1, 3:1, and 4:1, respectively, were measured, and the results are shown in table 1 below.

TABLE 1

As can be seen from table 1, the ratio of gelatin to xanthan gum has a large influence on the peel strength and the tack of the composite hemostatic film, and the composite hemostatic films prepared in examples 1 to 3 have a small peel strength and a good tack, that is, when the weight ratio of gelatin to xanthan gum is 2:1, the composite hemostatic film can be tightly attached to a wound to avoid displacement, and can be easily torn off, so that secondary damage to the wound is not caused during peeling.

Comparative example 1

The same procedure as in example 2 was repeated, except that the functional layer contained no xanthan gum.

Comparative example 2

The same procedure as in example 2 was repeated, except that the functional layer contained no gelatin.

Comparative example 3

The same procedure as in example 2 was repeated, except that the functional layer did not contain polyethylene glycol 2000.

Comparative example 4

Except the functional layer, the preparation raw materials in parts by weight are as follows: 160 parts of modified chitosan, 20008 parts of polyethylene glycol, 32 parts of gelatin, 16 parts of xanthan gum and Ag/Fe₂O₃The procedure of example 2 was repeated, except for using 10 parts of magnetic nanoparticles, 18 parts of calcined ophicalcitum, and 0.15 part of oleamide.

Comparative example 5

Except the functional layer, the preparation raw materials in parts by weight are as follows: 120 parts of modified chitosan, 20008 parts of polyethylene glycol, 20 parts of gelatin, 10 parts of xanthan gum and Ag/Fe₂O₃The procedure of example 2 was repeated, except for using 10 parts of magnetic nanoparticles, 18 parts of calcined ophicalcitum, and 0.15 part of oleamide.

Tensile Property test

The samples were tested for tensile properties using a universal material tester according to the method of GB/T1040.3-2006. The test was divided into a dry sample and a swollen sample (swollen for 1h in 0.05M, pH7.4 PBS buffer), and 3 replicates of each sample were tested and the tensile strength and elongation at break were recorded. The mechanical property test results of the composite hemostatic films prepared in examples 1 to 3 and comparative examples 1 to 5 are shown in the following table 2:

TABLE 2

Determination of porosity

Adding a certain volume of absolute ethyl alcohol into the measuring cylinder, wherein the volume is marked as V₁Putting the sample into the sample, standing for 5min to make the sample completely soaked by absolute ethyl alcohol and have no obvious air bubbles on the surface, and recording the total volume at the moment as V₂(ii) a The sample was removed and the volume of absolute ethanol remaining in the cylinder was recorded as V₃. The porosity P of the sample is calculated according to the following formula: p ═ V₁－V₃)/(V₂－V₃) X 100%, each sample was tested in parallel 3 times and the average was taken.

Water absorption test

Cutting the sample into the same size, fully drying, and respectively weighing the initial weight of each sample by an electronic balance to be recorded as m₀Then, each sample was placed in a petri dish, redistilled water was added to the petri dish, the samples were taken out at different times with tweezers, surface moisture was wiped off with absorbent paper, weighed with an electronic balance, and recorded as m_t. The water absorption was calculated by the following formula

Bacterial inhibition test

Samples were tested for bacteriostatic properties using staphylococcus aureus (ATCC 25923) and escherichia coli (ATCC 25922). After two strains are respectively cultured for 24h, the two strains are diluted to 1 × 10⁶CFU/mL. The same weight of sample (test group) and sterile gauze for medical use (control group) were placed in 48-well plates in triplicate, and 1mL of the bacterial suspension was added to each well and incubated at 37 ℃. The absorbance values at 6h, 12h and 24h were determined using an MTT cell proliferation assay kit. Using gauze control group as reference standard, and making into gauze of the formula W_{Rate of inhibition of bacteria}＝(A_{Control group}－A_{Test group})/(A_{Test group}-0.04), wherein 0.04 is sterileThe OD of the culture medium was 600.

The composite hemostatic films prepared in examples 1 to 3 and comparative examples 1 to 5 were tested for porosity, water absorption and antibacterial property, and the results are shown in table 3:

TABLE 3

As can be seen from Table 3, the composite hemostatic film samples prepared in the embodiments 1 to 3 of the present invention have high porosity and water absorption, and strong antibacterial activity. The porosity of comparative examples 1 and 2 is low, and the water absorption is greatly reduced, which is presumably caused by that the comparative example 1 only has a first network structure formed by crosslinking gelatin and chitosan, the comparative example 2 only has a second network structure formed by gelation of xanthan gum and chitosan, both of which are single network structures, and the obtained composite hydrogel has a small number of pores and a large pore diameter; comparative example 3, which contained no polyethylene glycol 2000, was less bacteriostatic, probably due to aggregation of the mineral components, resulting in Ag/Fe₂O₃The bacteriostatic effect of the magnetic nanoparticles cannot be fully exerted; comparative example 4 the amount of the modified chitosan was more than 150 parts, the bacteriostatic rate was inferior to that of example 2, it is concluded that the amount of the modified chitosan had an important effect on the double-network structure of the composite hydrogel, which could affect Ag/Fe₂O₃The dispersion and fixation of the magnetic nano particles and the forged ophicalcitum show that the bactericidal property of the composite hemostatic film is not only combined with the modified chitosan and Ag/Fe₂O₃The dosage of the magnetic nano particles and the forged ophicalcitum is related to the distribution of the magnetic nano particles and the forged ophicalcitum in the composite hydrogel; and in the comparative example 5, the use amount of the gelatin is less than 24 parts, the porosity of the composite hemostatic film is increased, the water absorption is reduced, and the antibacterial activity is reduced to a certain extent, so that the double-network structure of the composite hydrogel has a specific structure, and the use amount of each component plays a key role in forming the structure.

Cytotoxicity assays

NIH3T3 fibroblasts were cultured in 96-well plates, divided into ten groups of 5 duplicate wells. Replacing a normal culture medium with a sample leaching solution during experimental group change, wherein the numbers of examples 1-3 are T1, T2 and T3 in sequence, and the numbers of comparative examples 1-5 are D1, D2, D3, D4 and D5 in sequence; the positive control group uses DMEM high-sugar complete medium containing 0.64% phenol, and is marked as PC; the negative control was normal DMEM high-glucose complete medium, noted NC. After 24 hours of culture, the detection was performed 3 times, and the average value was calculated. The detection method comprises the following steps: 0.02mL of 5mg/mL MTT solution was added to each well, incubated at 37 ℃ for 4 hours, aspirated, and 0.1mL of DMSO was added to each well and mixed well. The absorbance (wavelength 570nm) was measured and the cell viability was calculated according to the following formula:

cell survival rate (%) ═ a_{Sample (I)}-A_{Blank 1})/(A_{Negative of}-A_{Blank 2})×100％

In the formula, A_{Sample (I)}: adding the absorbance value of the hole of the sample leaching solution;

A_{blank 1}: absorbance values of the solution in wells with only the extract but no cells inoculated;

A_{negative of}: adding the absorbance value of the solution in the holes of the DMEM complete culture medium;

A_{blank 2}: absorbance values of the solution in wells with DMEM complete medium only and no cells inoculated.

The test results are shown in fig. 1, and it can be seen from fig. 1 that the composite hemostatic membrane leaching solutions prepared in the examples and the comparative examples have cell survival rates of over 90% in 24 hours and no cytotoxicity.

In vitro whole blood coagulation test

Taking healthy New Zealand white-ear rabbits, taking blood from heart, and mixing the blood and anticoagulant citric acid at a ratio of 9:1 to obtain anticoagulant whole blood. Numbering samples A-H in examples 1-3 and comparative examples 1-5, setting Blank (Blank) as control group, placing sample in test tube, pre-heating at 37 deg.C for 5min, adding 1mL anticoagulated rabbit blood, incubating at 37 deg.C for 3min, and adding 500 μ L CaCl₂Timing after the solution (concentration is 25mM), taking out the test tube every 10s, inclining, observing whether the blood flows until the blood is completely coagulated, and recording the blood coagulation time when the blood is inclined at 90 ℃ without blood flow, namely the whole bloodThe coagulation time BCT.

The test results are shown in FIG. 2. As can be seen from FIG. 2, the blood coagulation time of the composite hemostatic film sample groups prepared in the embodiments 1 to 3 of the present invention is less than 100s, which is far lower than that of the blank group. The blood coagulation time of the sample groups of comparative examples 1-2 is significantly longer than that of the sample groups of examples 1-3, which is probably caused by the deterioration of the water absorption of the two groups of samples; comparative example 3 polyethylene glycol 2000, blood clotting time exceeded 150s, which is probably due to aggregation of the mineral components, resulting in a fraction of the mineral components failing to have hemostatic efficacy; comparative example 4 the amount of the modified chitosan is more than 150 parts, and the blood coagulation time is longer than that of examples 1-3, which shows that the hemostatic film has promotion effect on blood coagulation and is related to the components contained in the hemostatic film and the specific double-network structure of the composite hydrogel; comparative example 5 the gelatin amount is less than 24 parts, the blood coagulation time reaches 160s, and the specific double-network structure of the composite hydrogel can be shown to be matched with Ag/Fe₂O₃The magnetic nanoparticles and the forged ophicalcitum synergistically promote blood clotting.

The above description is only for the specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and other modifications or equivalent substitutions made by the technical solution of the present invention by the ordinary skilled in the art should be covered within the scope of the claims of the present invention without departing from the spirit and scope of the technical solution of the present invention.