A near-infrared light-responsive porous membrane and a preparation method and application thereof

Abstract

This invention discloses a near-infrared light-responsive porous membrane, its preparation method, and its applications, relating to the field of dressing technology. The near-infrared light-responsive porous membrane is composed of polyurethane, PDA@ZnO nanoparticles, and the antibacterial agent QCS. Under near-infrared light excitation, this near-infrared light-responsive porous membrane can generate reactive oxygen free radicals and heat, and release biofunctional zinc ions. Addressing the clinical challenges of chronic wounds, such as their susceptibility to infection and slow healing, this invention provides a new approach to improving the clinical treatment of chronic wounds by using a PDA@ZnO / QCS / TPU porous membrane that achieves highly efficient and precise sterilization under the synergistic effect of specific wavelengths of light, thereby preventing wound infection and promoting wound healing.

Description

Technical Field

[0001] This invention relates to the field of dressing technology, and in particular to a near-infrared light-responsive porous membrane, its preparation method, and its application. Background Technology

[0002] With the continuous rise in the incidence of chronic diseases such as diabetes, hyperglycemia, and obesity, related wound healing problems are becoming increasingly prominent, placing a significant burden on social resources. Wounds in patients with chronic diseases, if not properly treated, are prone to developing into intractable chronic wounds. These wounds are often accompanied by complex problems such as bacterial infection and impaired angiogenesis, leading to slow or even stalled healing.

[0003] Dressings play a crucial role in clinical treatment to effectively prevent further wound deterioration and damage to deeper tissues. Traditional dressings, such as cotton wool and gauze, while providing basic physical protection, lack antibacterial and healing-promoting active ingredients, thus limiting their effectiveness in treating chronic wounds. These dressings also fail to provide a favorable wound microenvironment and lack anti-infection capabilities, further restricting their application in wound repair.

[0004] In light of these issues, the development of modern dressings increasingly emphasizes the integration of functionality and active ingredients, such as embedding antibacterial agents or bioactive substances, to improve the treatment outcomes of chronic wounds. These modern dressings actively participate in the wound repair process by providing a moist environment, promoting new blood vessel formation, and effectively resisting bacterial invasion, thereby accelerating the natural healing process. By using these advanced dressings, the treatment time for chronic wounds can be significantly reduced and treatment outcomes improved, thus alleviating patient suffering and financial burden. Summary of the Invention

[0005] Based on the above, this invention provides a near-infrared light-responsive porous membrane, its preparation method, and its application. This invention combines PDA@ZnO nanoparticles with near-infrared light-responsive function, antibacterial agent QCS, and polyurethane, and obtains a near-infrared light-responsive porous membrane through solvent exchange method, which has the functions of antibacterial and anti-infection and promoting wound healing.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] One of the technical solutions of the present invention is a near-infrared light-responsive porous film, wherein the near-infrared light-responsive porous film comprises polyurethane (TPU), polydopamine-encapsulated zinc oxide nanoparticles (PDA@ZnO), and chitosan quaternary ammonium salt (QCS, antibacterial agent), wherein the PDA@ZnO nanoparticles and QCS are encapsulated in the polyurethane, that is, the PDA@ZnO nanoparticles and QCS are loaded in the polyurethane.

[0008] Furthermore, other biologically functional components, such as drugs, amino acids, and growth factors, can be introduced into the near-infrared light-responsive porous film.

[0009] The near-infrared light-responsive porous film generates a photothermal effect under ultraviolet-visible-near-infrared light excitation, which can generate reactive oxygen free radicals and heat, controllably release biofunctional zinc ions, and polydopamine can effectively reduce the accumulation of reactive oxygen at the wound site and promote wound healing.

[0010] Furthermore, the content of PDA@ZnO nanoparticles in the near-infrared light-responsive porous film is 1-5 wt%.

[0011] Furthermore, the mass ratio of polyurethane to antibacterial agent QCS in the near-infrared light-responsive porous film is 1000 / 1 to 100 / 1.

[0012] The second technical solution of the present invention is a method for preparing the above-mentioned near-infrared light-responsive porous thin film, comprising the following steps:

[0013] Step 1: Disperse zinc oxide (ZnO) nanoparticles in Tris-HCl buffer solution, add dopamine hydrochloride powder after ultrasonic dispersion, stir and react at room temperature, centrifuge, obtain precipitate and dry to obtain PDA@ZnO nanoparticles.

[0014] Step 2: After mixing tetrahydrofuran and N,N'-dimethylformamide, add polyurethane particles, stir evenly, add PDA@ZnO nanoparticles and QCS powder, and then use an ultrasonic pulverizer to ultrasonically disperse to obtain a uniform mixed solution.

[0015] Step 3: Dissolve a certain mass of KCl in deionized water to prepare a saturated KCl solution;

[0016] Step 4: Pour the mixed solution from Step 2 into a petri dish, place the petri dish in a water bath containing saturated KCl solution, and let it stand to obtain a near-infrared light-responsive porous membrane. Then, dry the porous membrane for later use.

[0017] Further, in step 1, the average particle size of the ZnO nanoparticles is 30–50 nm; the concentration of the Tris-HCl buffer solution is 0.01–0.02 mol / L, and the pH value is 7.5–9.0; the ratio of the amount of zinc oxide nanoparticles, dopamine hydrochloride powder, and Tris-HCl buffer solution is 10–20 mg:10–20 mg:80–120 mL. More preferably, the mass-to-volume ratio of the ZnO nanoparticles to the dopamine hydrochloride and the buffer solution is 100 mg:100 mg:100 mL to 200 mg:200 mg:100 mL. The concentration of dopamine hydrochloride and the stirring time will affect the thickness of the polydopamine layer in the PDA@ZnO nanoparticles.

[0018] Further, in step 2, the ratio of the amounts of tetrahydrofuran, N,N'-dimethylformamide, polyurethane, polydopamine-coated zinc oxide nanoparticles, and chitosan quaternary ammonium salt is 3-7 mL: 3-7 mL: 0.05-0.2 g: 0.005-0.03 g. More preferably, the volume ratio of tetrahydrofuran to N,N'-dimethylformamide is 1:0.5-1.5 (most preferably 1:1), and the mass concentration of polyurethane in the mixed solution is 15-20 wt%. If the polyurethane concentration is lower than the range described above, the resulting precursor solution has low viscosity, making it difficult to effectively form a film using the casting method; if the polyurethane concentration is higher than the range described above, the viscosity of the mixed solution becomes too high, affecting the subsequent process of pouring the precursor solution into the mold.

[0019] Further, in step 2, the ratio of the amounts of tetrahydrofuran, N,N'-dimethylformamide, polyurethane, polydopamine-coated zinc oxide nanoparticles, and chitosan quaternary ammonium salt is 3–7 mL: 3–7 mL: 0.05–0.2 g: 0.005–0.03 g. The PDA@ZnO nanoparticles account for 1–5 wt% of the total mixed solution, and the mass ratio of the polyurethane particles to the QCS powder is 1000 / 1 to 100 / 1.

[0020] Furthermore, in step 2, other biologically functional substances, such as drugs, amino acids, and growth factors, may be introduced into the mixed solution to obtain other target functions.

[0021] Furthermore, in step 4, the drying time is 12h to 48h, and the drying temperature is 30 to 40℃.

[0022] The third technical solution of the present invention is that the above-mentioned near-infrared light-responsive porous film has photoexcitation-enhanced antibacterial properties and zinc ion release properties, and is particularly suitable for preparing antibacterial medical dressings.

[0023] Containing zinc ions (Zn) 2+Zinc-based dressings have shown broad application potential in the medical field due to their versatility. Zinc is an essential trace element in the human body, with an average content of about 2-3 grams, and is crucial for human health. Zinc ions have low allergenicity, and the probability of adverse reactions after skin contact is extremely low. ZnO is a common antibacterial agent that can kill bacteria by releasing zinc ions and generating reactive oxygen free radicals. However, ZnO nanoparticles have physiological toxicity. A polydopamine composite strategy can effectively reduce the physiological toxicity of ZnO and increase its biocompatibility. In addition, zinc ions play a key role in promoting wound healing, especially in stimulating the functional activity of key vascular and tissue repair-related factors such as platelet-derived growth factor (PDGF) and transforming growth factor-β (TGF-β). Therefore, zinc-based oxide / sulfide-based dressing films indicate great potential for future application in wound management and treatment.

[0024] This invention relates to a near-infrared light-responsive porous membrane that, upon near-infrared light excitation, generates reactive oxygen species and heat, and releases biofunctional zinc ions. Addressing the clinical challenges of chronic wounds, such as their susceptibility to infection and slow healing, this invention provides a PDA@ZnO / QCS / TPU porous membrane that, under the synergistic effect of specific wavelengths of light, achieves highly efficient and precise sterilization, thereby preventing wound infection and promoting wound healing, offering a new approach to improving the clinical treatment of chronic wounds.

[0025] Polyurethane has a wide range of applications in medical dressings, mainly due to its excellent biocompatibility, breathability, and waterproof properties. Furthermore, polyurethane can be easily combined with other natural or synthetic polymers (such as starch, lignin, chitosan, and polyaniline), inorganic ceramics (such as hydroxyapatite), and inorganic nanoparticles. Through electrospinning and 3D printing, biodegradable, bio-friendly nanofibers or scaffolds can be obtained, showing great promise for applications in tissue repair and regeneration.

[0026] This invention combines PDA@ZnO nanoparticles, which possess excellent biocompatibility, photoresponsiveness, and reactive oxygen species scavenging capabilities, with polyurethane and the antibacterial agent QCS, and prepares near-infrared photoresponsive porous films through a casting method and solvent exchange strategy. The porous films involved in this invention, when used as skin wound dressings, can reduce bacterial colonization, prevent wound infection, and promote wound healing.

[0027] In terms of preparation technology, the near-infrared light-responsive porous thin film and its basic building blocks involved in this invention are simple to prepare and easy to promote on a large scale. The thin film is prepared by casting, which is easy to achieve industrial mass production. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a transmission electron microscope (TEM) image of the PDA@ZnO nanoparticles prepared in Example 1.

[0030] Figure 2 The images shown are physical images and scanning electron microscope images of the PDA@ZnO / QCS / TPU thin film prepared in Example 2.

[0031] Figure 3 The images shown are physical images and scanning electron microscope images of the PDA@ZnO / QCS / TPU porous film prepared in Example 3.

[0032] Figure 4 The graph shows the photothermal properties of the PDA@ZnO / QCS / TPU porous film prepared in Example 3.

[0033] Figure 5 The porous membranes prepared in Examples 3-6 are shown to have a bactericidal effect on Escherichia coli. Detailed Implementation

[0034] To facilitate understanding, the technical solutions and implementation methods of the present invention will be further described clearly, completely, and in detail below through specific embodiments and in conjunction with the accompanying drawings. It should be understood that the embodiments described herein are implemented based on the technical solutions of the present invention, providing detailed implementation methods and specific operating procedures, but are only some embodiments of the present invention, not all embodiments. The specific implementation methods described are limited to illustrating and explaining the present invention and do not limit the present invention. Based on the embodiments of the present invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the materials and reagents used in the examples are commercially available unless otherwise specified.

[0036] Example 1

[0037] A method for preparing PDA@ZnO nanoparticles, the specific steps of which are as follows:

[0038] 0.2 g of ZnO nanoparticles (average particle size 40 nm) were weighed and dispersed in 100 mL of Tris-HCl buffer (pH 8.5, 0.015 mol / L), and sonicated for 18 min. Then, 0.2 g of dopamine hydrochloride powder was added, and the mixture was stirred at 25 °C for 24 h. After centrifugation, the powder was washed three times with deionized water and dried in a 60 °C oven for 6–12 h to obtain black PDA@ZnO powder.

[0039] The prepared PDA@ZnO powder was dispersed in anhydrous ethanol, then dropped onto a copper grid and observed under a transmission electron microscope. Figure 1 As shown, we can observe that a polydopamine layer with a thickness of about ten nanometers was successfully coated around the ZnO nanoparticles.

[0040] Example 2

[0041] 2g of polyurethane particles (Bayer, 8795A) were weighed and dissolved in 10mL of a mixed solvent of tetrahydrofuran and N,N'-dimethylformamide (volume ratio 1:1). Then, 0.1g of PDA@ZnO nanoparticles and 0.01g of QCS (chitosan quaternary ammonium salt, Aladdin) powder were added. The particles and polyurethane solution were thoroughly mixed using an ultrasonic pulverizer to obtain a homogeneous solution. The ultrasonic dispersion process was carried out in an ice-water bath. 5mL of the homogeneous solution was poured into a 90mm diameter petri dish and allowed to spread evenly. The petri dish was then placed in a 40℃ oven for 12h to obtain a PDA@ZnO / QCS / TPU film.

[0042] like Figure 2 As shown, the formed film has a smooth surface, and no obvious pore structure was observed under a scanning electron microscope.

[0043] Example 3

[0044] 2g of polyurethane particles (Bayer, 8795A) were weighed and dissolved in 10mL of a mixed solvent of tetrahydrofuran and N,N'-dimethylformamide. Then, 0.1g of PDA@ZnO nanoparticles and 0.01g of QCS (chitosan quaternary ammonium salt, Aladdin) powder were added. The particles and polyurethane solution were thoroughly mixed using an ultrasonic pulverizer to obtain a homogeneous solution. The ultrasonic dispersion process was carried out in an ice-water bath. 5mL of the homogeneous solution was poured into a 90mm diameter petri dish to spread it evenly. The petri dish was then placed in a glass water bath containing saturated KCl solution and allowed to stand for 24h. After standing, the petri dish was removed and placed in a 40℃ oven for 12h to obtain a PDA@ZnO / QCS / TPU porous film.

[0045] like Figure 3 As shown, the surface of the formed film is porous, and obvious pore structures were observed under a scanning electron microscope.

[0046] The photothermal properties of the PDA@ZnO / QCS / TPU porous film prepared in Example 3 are shown in the figure below. Figure 4 As shown.

[0047] Example 4

[0048] 2g of polyurethane particles (Bayer, 8795A) were weighed and dissolved in 10mL of a mixed solvent of tetrahydrofuran and N,N'-dimethylformamide. Then, 0.1g of PDA@ZnO nanoparticles were added. The particles and polyurethane solution were thoroughly mixed using an ultrasonic pulverizer to obtain a homogeneous solution. The ultrasonic dispersion process was carried out in an ice-water bath. 5mL of the homogeneous solution was poured into a 90mm diameter petri dish to spread it evenly. The petri dish was then placed in a glass water bath containing saturated KCl solution and allowed to stand for 24 hours. After standing, the petri dish was removed and placed in a 40℃ oven for 12 hours to obtain a PDA@ZnO / TPU porous film.

[0049] Example 5

[0050] 2g of polyurethane particles (Bayer, 8795A) were weighed and dissolved in 10mL of a mixed solvent of tetrahydrofuran and N,N'-dimethylformamide. Then, 0.01g of QCS (chitosan quaternary ammonium salt, Aladdin) powder was added. The particles and polyurethane solution were thoroughly mixed using an ultrasonic pulverizer to obtain a homogeneous solution. The ultrasonic dispersion process was carried out in an ice-water bath. 5mL of the homogeneous solution was poured into a 90mm diameter petri dish and allowed to spread evenly. The petri dish was then placed in a glass water bath containing saturated KCl solution and allowed to stand for 24 hours. After standing, the petri dish was removed and placed in a 40℃ oven for 12 hours to obtain a QCS / TPU porous film.

[0051] Example 6

[0052] 2g of polyurethane particles (Bayer, Germany, 8795A) were weighed and dissolved in 10mL of a mixed solvent of tetrahydrofuran and N,N'-dimethylformamide. The solution was stirred at room temperature (25°C) to obtain a homogeneous solution. 5mL of the homogeneous solution was poured into a 90mm diameter petri dish and allowed to spread evenly. The petri dish was then placed in a glass water bath containing saturated KCl solution and allowed to stand for 24 hours. After standing, the petri dish was removed and placed in an oven at 40°C for 12 hours to obtain a TPU porous film.

[0053] Performance testing

[0054] The antibacterial activity of the films prepared in Examples 3-6 was tested using the agar plate dilution method: the *E. coli* suspension was diluted to an appropriate concentration (1×10⁻⁶) in LB medium. 5 ~1×10 6CFU / mL), and were incubated separately with 10 mm diameter film discs at 37°C for 6 hours (the control group did not add film). The bacterial suspension was then diluted 10% with physiological saline. 5 100 μL of bacterial dilution solution was added to LB agar plates. The plates were then incubated at 37°C for 24 h. The growth of colonies on the plates was observed and counted to evaluate the antibacterial effect of the film. For the light-treated group, after 6 h of incubation with bacteria, the film was irradiated for 10 min with a laser at a wavelength of 808 nm and a power of 1 W. Subsequent treatment was the same as for the non-light-treated group.

[0055] like Figure 5 As shown, compared with the control group, the TPU group and the PDA@ZnO / TPU group did not show significant antibacterial activity, while the QCS / TPU group and the PDA@ZnO / QCS / TPU group both showed significant antibacterial activity. Among the PDA@ZnO / QCS / TPU groups, the group subjected to light showed more significant antibacterial performance than the group without light, with almost no bacterial growth on the plate of the light-treated group. This indicates that the PDA@ZnO / QCS / TPU film mainly exerts its antibacterial effect through the antibacterial agent QCS and the photothermal effect.

Claims

1. A method for preparing a near-infrared light-responsive porous membrane, characterized by, Includes the following steps: Step 1: Disperse zinc oxide nanoparticles in Tris-HCl buffer solution, add dopamine hydrochloride powder after ultrasonic dispersion, stir and react, centrifuge, obtain precipitate and dry to obtain polydopamine-coated zinc oxide nanoparticles. Step 2: After mixing tetrahydrofuran and N,N'-dimethylformamide, add polyurethane particles, stir evenly, add zinc oxide nanoparticles coated with polydopamine and chitosan quaternary ammonium salt powder, and then use an ultrasonic pulverizer to ultrasonically disperse to obtain a uniform mixed solution. Step 3: Prepare a saturated KCl solution; Step 4: Pour the mixed solution from Step 2 into a petri dish, place the petri dish in a water bath containing saturated KCl solution, let it stand to obtain a membrane, and then dry it to obtain a near-infrared light-responsive porous membrane. The near-infrared light-responsive porous membrane includes polyurethane and polydopamine-encapsulated zinc oxide nanoparticles and chitosan quaternary ammonium salt. The polydopamine-encapsulated zinc oxide nanoparticles and chitosan quaternary ammonium salt are loaded in the polyurethane. The content of polydopamine-coated zinc oxide nanoparticles in the near-infrared light-responsive porous membrane is 1-5 wt%. The mass ratio of the polyurethane to the chitosan quaternary ammonium salt is 1000 / 1 to 100 / 1.

2. The production method according to claim 1, wherein In step 1, the stirring reaction time is 18 h ~ 48 h.

3. The preparation method according to claim 1, characterized in that, In step 2, ultrasonic dispersion is performed in an ice-water bath.

4. The production method according to claim 1, characterized by, In step 3, a saturated KCl solution is prepared by adding solid KCl to deionized water until the KCl residue cannot be dissolved, thus obtaining a saturated KCl solution.

5. The method of claim 1, wherein, In step 4, the resting time is 12 h to 48 h, and the drying temperature is 30 to 40 ℃.

6. The application of the near-infrared light-responsive porous membrane prepared by the preparation method according to any one of claims 1-5 in the preparation of antibacterial medical dressings.

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