A bilayer asymmetric patch material for preventing air leaks after lung surgery and its preparation method and application

Abstract

The application provides a double-layer asymmetric patch material for preventing air leakage after lung surgery and a preparation method and application thereof, and relates to the field of bioadhesive materials. The preparation method of the double-layer asymmetric patch material comprises the following steps: mixing a hydrophilic polymer compound, acrylic acid, an amine coupling group compound, alpha-ketoglutaric acid, a crosslinking agent and water to obtain a hydrogel precursor solution, performing 3D printing on the hydrogel precursor solution to obtain a 3D printed hydrogel patch; mixing polyester and an organic solvent to obtain an electrostatic spinning solution, performing electrostatic spinning to obtain a nanofiber membrane; and using the hydrogel precursor solution as an adhesive to bond the nanofiber membrane and the 3D printed hydrogel patch to obtain the double-layer asymmetric patch material. The material has strong tensile strength and fatigue resistance, can conform to lung respiratory movement, has an adhesive layer and an anti-adhesive layer, and can effectively solve the problem of postoperative pleural adhesion.

Description

Technical Field

[0001] This invention relates to the field of bioadhesion materials technology, and in particular to a bilayer asymmetric patch material for preventing air leakage after lung surgery, its preparation method and application. Background Technology

[0002] Pneumothorax (PAL) is a common postoperative pulmonary surgery condition. In most patients, the PAL heals spontaneously as the residual pleural cavity closes and the visceral pleura adheres. However, a small percentage develop persistent PAL. With the aging of pulmonary surgery patients and the increasing incidence of emphysema and chronic obstructive pulmonary disease (COPD), the challenges posed by persistent PAL in pulmonary surgery practice are becoming more pronounced. Persistent PAL leads to prolonged pleural drainage time, increasing the risk of intrathoracic infection, and also impacts hospitalization costs and length of stay.

[0003] Experimental and clinical research on persistent air leakage after lung surgery has been conducted for decades. Many methods are available for preventing or treating persistent air leakage, such as prolonging the indwelling time of chest drainage tubes, chemical pleurodesis, and autologous blood pleurodesis. While sutures and U-shaped staples are most commonly used in these surgeries for wound closure, hemostasis, and securing implantable devices to tissues, they suffer from complex application methods and poor airtightness and watertightness. Bioadhesives (including tissue adhesives, hemostatic agents, and tissue sealants) have been extensively studied for their potential advantages, such as ease of use, airtight or watertight seals, and minimal tissue damage. To date, clinically used adhesives are mainly classified into two categories based on their material properties: bioadhesives (such as fibrin derivatives, chitosan, and gelatin) and chemical adhesives (such as cyanoacrylates and polyethylene glycols). Recently, the U.S. Food and Drug Administration (FDA) approved commercial fibrin-based sealants (Tisseels, Evicels, Vitagert, etc.) for use in lung incisions, hernia repair, treatment of refractory chylous ascites, skin grafting in burn surgery, and cleft palate repair. Most commercial sealants lack sufficient adhesive strength and durability and are prone to inducing immune responses in vivo. Furthermore, adhesive patches used to prevent lung leakage need good compliance and tensile strength to adapt to lung contraction and relaxation, but existing technologies do not address this issue with bioadhesive patches. Moreover, existing technologies do not consider postoperative pleural adhesions caused by adhesive materials (most are monolayer hydrogel structures, which, while adhering to the wound for hemostasis and leak prevention, can cause postoperative adhesions by adhering to other tissues, such as the pleura). Therefore, those skilled in the art urgently need to disclose a patch material that can both adhere to wet tissue and provide physical support on the wound surface to accommodate lung respiration, possesses sufficient tensile strength, and whose outer layer does not easily adhere to other biological tissues. Summary of the Invention

[0004] The purpose of this invention is to provide a double-layer asymmetric patch material for preventing air leakage after lung surgery, as well as its preparation method and application, to solve the problems of poor bonding strength and durability of existing clinical adhesive materials, which cannot adapt to the contraction and relaxation of the lungs during respiration, and the outer layer of the patch material adhering to tissues, causing postoperative adhesion.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for preparing a bilayer asymmetric patch material for preventing air leakage after lung surgery, comprising the following steps:

[0007] 1) A hydrogel precursor solution is prepared by mixing a hydrophilic polymer compound, acrylic acid, a compound with an amine coupling group, α-ketoglutaric acid, a crosslinking agent and water. The hydrogel precursor solution is then used as a 3D printing ink for 3D printing to obtain a 3D printed hydrogel patch.

[0008] 2) Polyester is mixed with an organic solvent to obtain an electrospinning solution, and then electrospinned to obtain a nanofiber membrane;

[0009] 3) Using the hydrogel precursor solution described in step 1) as an adhesive, the nanofiber membrane is bonded to the 3D printed hydrogel patch to obtain a double-layer asymmetric patch material.

[0010] There is no specific order requirement for steps 1) and 2).

[0011] Preferably, the hydrophilic polymer compound in step 1) includes one or more of the following: polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyhydroxyethyl methacrylate, polyethylene glycol, polyurethane, casein, albumin, gelatin, chitosan, hyaluronic acid, alginate, alginate, sodium oxidized alginate, cellulose, oxidized cellulose, polyvinylpyrrolidone, sodium polystyrene sulfonate, collagen, and pectin.

[0012] Preferably, the compound of the amine coupling group in step 1) includes one or more of N-hydroxysuccinimide acrylate, N-hydroxysuccinimide ester, N-hydroxysulfosuccinimide ester, aldehyde, epoxide, isocyanate and catechol.

[0013] The crosslinking agent includes one or more of polyethylene glycol dimethacrylate, methacrylamide gelatin, hyaluronic acid methacrylate, oxidized methacrylate alginate, N,N'-bis(acryloyl)cystamine, N,N'-methylenebis(acrylamide), and polyethylene glycol diacrylate.

[0014] Preferably, in step 1), the concentration of the hydrophilic polymer compound in the hydrogel precursor solution is 5-15 wt%, the concentration of acrylic acid is 20-40 wt%, the concentration of the amine coupling group compound is 0.5-2 wt%, the concentration of α-ketoglutarate is 0.05-1 wt%, and the concentration of the crosslinking agent is 0.01-0.1 wt%.

[0015] Preferably, the 3D printing conditions in step 1) are as follows:

[0016] The ambient temperature is 25℃, the ambient humidity is 40%, the needle temperature is 20~25℃, the platform temperature is 4~10℃, the line spacing is 0.8~1.2mm, the needle size is 0.21mm, the printing speed is 5~10mm / s, and the extrusion pressure is 0.3~0.5MPa;

[0017] Preferably, the polyester in step 2) comprises one or more of polylactic acid-glycolic acid copolymer, polycaprolactone, polylactic acid, and polyglycolic acid;

[0018] The concentration of polyester in the electrospinning solution is 10-30 wt%.

[0019] The organic solvent is a mixture of N,N-dimethylformamide and dichloromethane, with a volume ratio of N,N-dimethylformamide to dichloromethane of 1:10 to 10:1.

[0020] Preferably, the conditions for electrospinning in step 2) are as follows:

[0021] The ambient temperature is 20℃, the ambient humidity is 25%, the voltage is 15~25kV, the spinning extrusion speed is 0.001~0.005mm / s, and the needle size is 18~22G;

[0022] The thickness of the nanofiber membrane is 20–200 μm.

[0023] The present invention also provides a bilayer asymmetric patch material for preventing air leakage after lung surgery, prepared by the above preparation method.

[0024] The present invention also provides an application of a double-layer asymmetric patch material for preventing air leakage after lung surgery in the field of medical dressings.

[0025] The present invention has at least the following beneficial effects:

[0026] This invention designs an adhesive material specifically for the characteristics of lung tissue. A 3D-printed hydrogel patch, prepared using hydrophilic polymers, acrylic acid, compounds with amine coupling groups, and α-ketoglutaric acid, exhibits excellent adhesion properties. Meanwhile, an electrospun membrane prepared from polyester materials provides anti-adhesion capabilities. The combined material creates a bilayer asymmetric patch that effectively adheres to the wound surface while preventing adhesion to other biological tissues. This bilayer asymmetric patch also possesses high tensile strength and fatigue resistance, conforms to lung respiratory movements, and can be used to address air leakage after lung surgery, effectively preventing postoperative pleural adhesions. Attached Figure Description

[0027] Figure 1 The infrared characterization image of the PVA / PAA-NHS hydrogel prepared in step (1) of Example 1;

[0028] Figure 2 These are microstructure characterization images of the PCL / PLGA nanofiber membrane prepared in step (2) of Example 1 at different magnifications. Figure 2 Image (A) is a microscopic morphology image of the nanofiber membrane magnified 1000 times. Figure 2 Image (B) is a microscopic morphology of the nanofiber membrane magnified 7000 times.

[0029] Figure 3 This is a statistical graph showing the cell viability during biocompatibility testing of the bilayer asymmetric patch prepared in Example 1.

[0030] Figure 4 These are cell fluorescence images taken during biocompatibility testing of the bilayer asymmetric patch prepared in Example 1. Figure 4 (A) in the image shows a cell photograph after 72 hours of culture without the addition of the bilayer asymmetric patch material extract. Figure 4 (B) is a cell photograph after 72 hours of incubation with the extract of the double-layer asymmetric patch material;

[0031] Figure 5 The figure shows the adhesion strength test results of the PVA / PAA-NHS hydrogel prepared in step (1) of Example 1;

[0032] Figure 6 The figure shows the tensile strength test results of the PVA / PAA-NHS hydrogel prepared in step (1) of Example 1;

[0033] Figure 7 The hydrophilicity test results of the PVA / PAA-NHS hydrogel prepared in step (1) of Example 1 and the PCL / PLGA nanofiber membrane prepared in step (2) of Example 1 are presented. Figure 7 (A) in the image is a photograph of the hydrophilicity test on one side of the PCL / PLGA nanofiber membrane. Figure 7 (B) in the image shows a hydrophilicity test photograph of one side of the PVA / PAA-NHS hydrogel. Figure 7 (C) in the figure represents the contact angle data for both sides;

[0034] Figure 8 The figure shows the in vivo hemostatic performance test results of the PVA / PAA-NHS hydrogel prepared in step (1) of Example 1;

[0035] Figure 9 The image shows the tissue adhesion test results of the PVA / PAA-NHS hydrogel prepared in step (1) of Example 1;

[0036] Figure 10 This is a microstructure diagram of the bilayer asymmetric patch prepared in Example 4. Detailed Implementation

[0037] This invention provides a method for preparing a bilayer asymmetric patch material for preventing air leakage after lung surgery, comprising the following steps:

[0038] 1) A hydrogel precursor solution is prepared by mixing a hydrophilic polymer compound, acrylic acid, a compound with an amine coupling group, α-ketoglutaric acid, a crosslinking agent and water. The hydrogel precursor solution is then used as a 3D printing ink for 3D printing to obtain a 3D printed hydrogel patch.

[0039] 2) Polyester is mixed with an organic solvent to obtain an electrospinning solution, and then electrospinned to obtain a nanofiber membrane;

[0040] 3) Using the hydrogel precursor solution described in step 1) as an adhesive, the nanofiber membrane is bonded to the 3D printed hydrogel patch to obtain a double-layer asymmetric patch material.

[0041] There is no specific order requirement for steps 1) and 2).

[0042] In this invention, the compound with the amine coupling group refers to a compound containing a group capable of undergoing a coupling reaction with an amino group.

[0043] In this invention, the hydrophilic polymer compound mentioned in step 1) includes one or more of the following: polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyhydroxyethyl methacrylate, polyethylene glycol, polyurethane, casein, albumin, gelatin, chitosan, hyaluronic acid, alginate, alginate, sodium oxidized alginate, cellulose, oxidized cellulose, polyvinylpyrrolidone, sodium polystyrene sulfonate, collagen, and pectin.

[0044] The alginate is calcium alginate, potassium alginate, or sodium alginate;

[0045] The method for preparing oxidized sodium alginate is to oxidize sodium alginate with sodium periodate at room temperature, wherein the molar ratio of sodium periodate to sodium alginate is 5:4, and the oxidation time is 8 to 24 hours.

[0046] In this invention, the compound of the amine coupling group in step 1) includes one or more of N-hydroxysuccinimide acrylate, N-hydroxysuccinimide ester, N-hydroxysulfosuccinimide ester (CAS 106627-54-7), aldehyde, epoxide, isocyanate and catechol.

[0047] The aldehyde is glutaraldehyde or furfural;

[0048] The epoxide is polyethylene glycol diglycidyl ether (CAS 39443-66-8) or epoxidized soybean oil (CAS8013-07-8);

[0049] The isocyanate is hexamethylene diisocyanate (CAS 822-06-0), toluene diisocyanate (CAS26471-62-5), isophorone diisocyanate (CAS 4098-71-9), polyethylene glycol diisocyanate (manufacturer: Meiluo Technology, catalog number 031303) or lysine diisocyanate (CAS 45172-15-4).

[0050] In this invention, the crosslinking agent includes one or more of polyethylene glycol dimethacrylate, methacrylamide gelatin, hyaluronic acid methacrylate, oxidized methacrylate alginate, N,N'-bis(acryloyl)cystamine, N,N'-methylenebis(acrylamide), and polyethylene glycol diacrylate.

[0051] In this invention, the concentration of the hydrophilic polymer compound in the hydrogel precursor solution in step 1) is 5-15 wt%, the concentration of acrylic acid is 20-40 wt%, the concentration of the amine coupling group compound is 0.5-2 wt%, the concentration of α-ketoglutaric acid is 0.05-1 wt%, and the concentration of the crosslinking agent is 0.01-0.1 wt%. Preferably, the concentration of the hydrophilic polymer compound is 8-13 wt%, the concentration of acrylic acid is 25-35 wt%, and the concentration of the amine coupling group compound is... The concentrations of the compound with the group are 0.8–1.8 wt%, the concentration of α-ketoglutaric acid is 0.1–0.8 wt%, and the concentration of the crosslinking agent is 0.02–0.08 wt%. More preferably, the concentrations of the hydrophilic polymer compound are 10 wt%, the concentration of acrylic acid is 30 wt%, the concentration of the compound with the amine coupling group is 1.2–1.5 wt%, the concentration of α-ketoglutaric acid is 0.2–0.5 wt%, and the concentration of the crosslinking agent is 0.04–0.6 wt%.

[0052] In this invention, the conditions for 3D printing in step 1) are as follows:

[0053] The ambient temperature is 25℃, the ambient humidity is 40%, the needle temperature is 20-25℃, the platform temperature is 4-10℃, the line spacing is 0.8-1.2mm, the needle size is 0.21mm, the printing speed is 5-10mm / s, and the extrusion pressure is 0.3-0.5MPa. Preferably, the ambient temperature is 25℃, the ambient humidity is 40%, the needle temperature is 21-24℃, the platform temperature is 5-8℃, the line spacing is 0.9-1.1mm, the needle size is 0.21mm, the printing speed is 6-9mm / s, and the extrusion pressure is 0.35-0.45MPa. More preferably, the ambient temperature is 25℃, the ambient humidity is 40%, the needle temperature is 22-23℃, the platform temperature is 6-7℃, the line spacing is 1mm, the needle size is 0.21mm, the printing speed is 7-8mm / s, and the extrusion pressure is 0.4MPa.

[0054] In this invention, the height of the 3D printed support is 20-1000 μm, preferably 40-800 μm, more preferably 60-500 μm, and even more preferably 100-400 μm.

[0055] In this invention, the concentration of polyester in the electrospinning solution in step 2) is 10-30 wt%, preferably 14-26 wt%, more preferably 18-22 wt%, and even more preferably 20 wt%.

[0056] The organic solvent is a mixture of N,N-dimethylformamide and dichloromethane, wherein the volume ratio of N,N-dimethylformamide to dichloromethane is 1:10 to 10:1, preferably 1:8 to 8:1, more preferably 1:5 to 5:1, and even more preferably 1:3 to 3:1.

[0057] In this invention, the conditions for electrospinning in step 2) are as follows:

[0058] The ambient temperature is 20℃, the ambient humidity is 25%, the voltage is 15-25kV, the spinning extrusion speed is 0.001-0.005mm / s, and the needle size is 18-22G. Preferably, the ambient temperature is 20℃, the ambient humidity is 25%, the voltage is 17-23kV, the spinning extrusion speed is 0.002-0.004mm / s, and the needle size is 19-21G. More preferably, the ambient temperature is 20℃, the ambient humidity is 25%, the voltage is 19-20kV, the spinning extrusion speed is 0.003mm / s, and the needle size is 20G.

[0059] In this invention, the thickness of the nanofiber membrane is 20-200 μm, preferably 40-180 μm, more preferably 60-150 μm, and even more preferably 80-120 μm.

[0060] The present invention also provides a bilayer asymmetric patch material for preventing air leakage after lung surgery, prepared by the above preparation method.

[0061] The present invention also provides an application of a double-layer asymmetric patch material for preventing air leakage after lung surgery in the field of medical dressings.

[0062] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0063] Example 1

[0064] (1) Prepare an aqueous solution containing 8wt% polyvinyl alcohol (PVA), 40wt% acrylic acid (AAc), 2wt% N-hydroxysuccinimide acrylate (AA-NHS), 0.2wt% α-ketoglutarate, and 0.05wt% polyethylene glycol dimethacrylate (PEGDMA) to obtain 3D printing ink. Place the 3D printing ink in a special syringe, connect the printing needle (0.1G), and perform 3D printing under ambient temperature of 25℃ and humidity of 40%. Set the 3D printer parameters as follows: needle temperature 37℃, platform temperature 10℃, printing speed 6mm / s, extrusion speed 7mm / s, pullback (SK) 0.25mm, lift (HP) 0.2mm, size 10×10mm, line spacing 1.2mm, and support height 0.4mm (the size is the length and width of the 3D printed hydrogel patch, and the support height is the thickness of the 3D printed hydrogel patch). After printing, the material is cured by irradiation under a 365nm UV lamp for 30 minutes to obtain a polyvinyl alcohol (PVA) and PAA-NHS composite 3D printed hydrogel patch, denoted as PVA / PAA-NHS.

[0065] (2) Mix polylactic acid-glycolic acid copolymer (PLGA) and polycaprolactone (PCL) in a certain proportion, and add them to a blended solution of N,N-dimethylformamide (DMF) and dichloromethane (DCM) in a volume ratio of 3:7. Stir magnetically at room temperature (24h) until the solute is completely dissolved. Then place the solution in a cleaning machine and sonicate for 20min to remove air bubbles in the solution. Prepare an electrospinning solution (pale yellow) with a PLGA concentration of 9wt% and a PCL concentration of 9wt%. The electrospinning solution was placed in a special syringe (20 mL), and a polytetrafluoroethylene tubing (1 m) and a spinning needle (21 G) were connected by an adapter. Electrospinning was carried out continuously for 6 h under the conditions of ambient temperature of 20℃, humidity of 25%, spinning voltage of 24 kV, roller speed of 300 r / min, and spinning extrusion speed of 0.003 mm / s. The obtained nanofiber membrane was collected on a grounded rotating roller (40 mm in diameter, 300 r / min), wrapped on aluminum foil, and then placed in a fume hood to dry for 24 h to allow the residual solvent to fully evaporate, resulting in a polycaprolactone (PCL) / polylactic acid (PLA) composite electrospinned nanofiber membrane with a thickness of 200 μm, which can be abbreviated as PCL / PLGA or PLGA / PCL.

[0066] (3) Use a special syringe (1 mL) to apply the 3D printing ink prepared in step (1) between the electrospun film and the 3D printed hydrogel patch (100 μL of 3D printing ink is used per square centimeter patch). Then, use a 365 nm ultraviolet lamp to irradiate the connection for 30 min until the solution forms a hydrogel. Adhere the two together to obtain a double-layer asymmetric patch material.

[0067] The PVA / PAA-NHS hydrogel was characterized using a transmission Fourier transform infrared spectrometer (FTIR6700, Thermo Fisher) with a germanium attenuated total reflectance (ATR) crystal (55°). The infrared spectrum is shown below. Figure 1 As shown.

[0068] Figure 2 These are scanning electron microscope (SEM) images of the PCL / PLGA nanofiber membrane prepared in step (2) of this embodiment at different magnifications (1000x, 7000x). Figure 2 As can be seen, the PLGA / PCL film obtained by electrospinning exhibits a densely connected nanofiber network structure.

[0069] Biocompatibility of the bilayer asymmetric patch material was tested:

[0070] The cell compatibility of the bilayer asymmetric patch material was evaluated using a cell viability assay kit (CCK-8). Culture medium was added to the bilayer asymmetric patch material at a ratio of 10 mg: 1 mL, and the material was extracted for 24 hours to prepare an extract. After human umbilical vein endothelial cells (HUVECs) adhered and grew, they were incubated with the extract for 24, 48, and 72 hours. Then, an appropriate amount of CCK-8 solution was added, and cell viability was measured at 450 nm to calculate the cell viability. Figure 3 As shown, at all times (24 hours, 48 ​​hours, and 72 hours), the OD values ​​of each experimental group increased with the extension of incubation time, indicating that the number of cells increased significantly over time under these conditions; at fixed time points, there was no significant difference in absorbance values ​​between the experimental group and the control group.

[0071] The cell compatibility of the bilayer asymmetric patch material was evaluated using a cell viability and cytotoxicity assay kit. The bilayer asymmetric patch material was extracted with culture medium at a ratio of 10 mg: 1 mL for 24 hours to prepare the extract. After human umbilical vein endothelial cells (HUVECs) adhered and grew, two groups of cells were incubated with the bilayer asymmetric patch material extract and untreated culture medium for 72 hours, respectively. Then, Calcein AM and PI dyes were added for 30 minutes, and observation and photography were performed using a fluorescence microscope at 488 nm and 620 nm, respectively. Figure 4 As shown, Figure 4 In the diagram, A represents the control group, which is the culture medium added without extracting the bilayer asymmetric patch material. Figure 4 In the diagram, group B represents the experimental group with the addition of the extract from the bilayer asymmetric patch material. Under a fluorescence microscope, the survival rate of HUVECs when co-cultured with the material extract was similar to that of the control group. The experimental results indicate that the bilayer asymmetric patch prepared in this embodiment is more conducive to the activity of human umbilical vein endothelial cells, has no obvious cytotoxic effect, and exhibits good cell compatibility, which is consistent with the results of CCK-8 mentioned above.

[0072] The adhesion strength of the PVA / PAA-NHS prepared in step (1) was tested:

[0073] The adhesion strength of the PVAPAAA-NHS hydrogel was quantitatively determined using a universal testing machine. Fresh pigskin was used as the adhesion medium; a 25mm × 25mm × 2mm hydrogel was adhered between two pieces of pigskin. The force and displacement during the movement of the clamp were recorded. Figure 5 As shown, the material's adhesion strength to pigskin can reach 66 kPa.

[0074] The tensile strength of the PVA / PAA-NHS hydrogel was tested:

[0075] The tensile strength of the PVA / PAA-NHS hydrogel was quantitatively determined using a universal testing machine. A dumbbell-shaped hydrogel sample was placed on a fixture for a tensile test. Figure 6 The tensile strength of the hydrogel shown is 0.4 MPa.

[0076] The hydrophilicity of the double-layer asymmetric patch material was tested:

[0077] The hydrophilicity of the bilayer asymmetric patch was evaluated using a static contact angle tester. Figure 7 (A) in the image is a photograph of the hydrophilicity test on one side of the PCL / PLGA nanofiber membrane. Figure 7 (B) in the image shows a hydrophilicity test photograph of one side of the PVA / PAA-NHS hydrogel. Figure 7 (C) in the figure shows the contact angle data for both sides. It can be seen from the figure that the PVA / PAA-NHS hydrogel side is hydrophilic, while the PCL / PLGA nanofiber membrane side is hydrophobic. Figure 7 As can be seen from (C) in the figure, the contact angle of the PCL / PLGA nanofiber membrane is 120 degrees.

[0078] The in vivo hemostatic properties of hydrogel PVA / PAA-NHS were tested:

[0079] Anesthetized mice were exposed to expose their livers. A 10G needle was used to puncture the livers of the mice. The control group received no treatment, while the experimental group had a 3D-printed hydrogel patch (PVA / PAA-NHS) prepared in step (1) adhered to the liver wound. Liver bleeding was recorded at different time points. Figure 8 As shown, from Figure 8 The results show that the bleeding was significantly reduced in the hydrogel patch group compared with the control group, indicating that the 3D printed hydrogel patch PVA / PAA-NHS has in vivo hemostatic ability.

[0080] The tissue adhesion properties of the PVA / PAA-NHS hydrogel were tested.

[0081] The 3D-printed hydrogel patch PVA / PAA-NHS prepared in step (1) was placed subcutaneously in mice, as follows: Figure 9 As shown, the hydrogel adheres to the tissue and cannot be peeled off after applying pressure for several seconds, indicating that the hydrogel has tissue adhesion properties.

[0082] Example 2

[0083] A 3D printing ink was prepared by mixing an aqueous solution containing 5 wt% polyvinyl alcohol (PVA), 50 wt% acrylic acid (AAc), 1.5 wt% N-hydroxysuccinimide acrylate (AA-NHS), 0.2 wt% α-ketoglutarate, and 0.05 wt% polyethylene glycol dimethacrylate (PEGDMA). This 3D printing ink was placed in a dedicated syringe, connected to a 0.1G printing needle, and 3D printing was performed at an ambient temperature of 25℃ and a humidity of 40%. The 3D printer parameters were set as follows: needle temperature 37℃, platform temperature 10℃, printing speed 6 mm / s, extrusion speed 7 mm / s, pullback (SK) 0.25 mm, lift-off (HP) 0.2 mm, dimensions 15 × 15 mm, line spacing 1.2 mm, and support height 0.4 mm. After printing, the material was cured by irradiation under a 365nm UV lamp for 30 minutes to obtain a polyvinyl alcohol (PVA) and PAA-NHS composite 3D printed hydrogel mesh scaffold, denoted as PVA / PAA-NHS.

[0084] (2) Mix polylactic acid-glycolic acid copolymer (PLGA) and polycaprolactone (PCL) in a certain proportion, and add them to a blended solution of N,N-dimethylformamide (DMF) and dichloromethane (DCM) in a volume ratio of 3:7. Stir magnetically at room temperature (24h) until the solute is completely dissolved. Then place the solution in a cleaning machine and sonicate for 20min to remove air bubbles in the solution. Prepare an electrospinning solution (pale yellow) with a PLGA concentration of 10wt% and a PCL concentration of 8wt%. The electrospinning solution was placed in a special syringe (20 mL), and a polytetrafluoroethylene tubing (1 m) and a spinning needle (21 G) were connected by an adapter. Electrospinning was carried out continuously for 6 h under the conditions of ambient temperature of 20 °C, humidity of 25%, spinning voltage of 24 kV, roller speed of 300 r / min, and spinning extrusion speed of 0.003 mm / s. The obtained nanofiber membrane was collected on a grounded rotating roller (40 mm in diameter, 300 r / min), wrapped on aluminum foil, and then placed in a fume hood to dry for 24 h to allow the residual solvent to fully evaporate, resulting in a polycaprolactone (PCL) / polylactic acid (PLA) composite electrospinned nanofiber membrane with a thickness of 200 μm, denoted as PCL / PLGA.

[0085] (3) Use a special syringe (1 mL) to apply the 3D printing ink prepared in step (1) between the electrospun film and the 3D printed hydrogel mesh support (80 μL of 3D printing ink is used per square centimeter patch). Then, use a 365nm ultraviolet lamp to irradiate the connection for 30 minutes until the solution forms a hydrogel. Then, bond the two together to obtain a double-layer asymmetric patch material.

[0086] Example 3

[0087] A 3D printing ink was prepared by mixing an aqueous solution containing 10 wt% polyvinyl alcohol (PVA), 30 wt% acrylic acid (AAc), 2 wt% N-hydroxysuccinimide acrylate (AA-NHS), 0.2 wt% α-ketoglutarate, and 0.05 wt% polyethylene glycol dimethacrylate (PEGDMA). This 3D printing ink was placed in a dedicated syringe, connected to a 0.1G printing needle, and 3D printing was performed at an ambient temperature of 25℃ and a humidity of 40%. The 3D printer parameters were set as follows: needle temperature 37℃, platform temperature 10℃, printing speed 6 mm / s, extrusion speed 7 mm / s, pullback (SK) 0.25 mm, lift-off (HP) 0.2 mm, dimensions 10 × 10 mm, line spacing 1.2 mm, and support height 0.4 mm. After printing, the material was cured by irradiation under a 365nm UV lamp for 30 minutes to obtain a polyvinyl alcohol (PVA) and PAA-NHS composite 3D printed hydrogel mesh scaffold, denoted as PVA / PAA-NHS.

[0088] (2) Mix polylactic acid-glycolic acid copolymer (PLGA) and polycaprolactone (PCL) in a certain proportion, and add them to a blended solution of N,N-dimethylformamide (DMF) and dichloromethane (DCM) in a volume ratio of 3:7. Stir magnetically at room temperature (24h) until the solute is completely dissolved. Then place the solution in a cleaning machine and sonicate for 20min to remove air bubbles in the solution. Prepare an electrospinning solution (pale yellow) with a PLGA concentration of 8wt% and a PCL concentration of 10wt%. The electrospinning solution was placed in a special syringe (20 mL), and a polytetrafluoroethylene tubing (1 m) and a spinning needle (21 G) were connected by an adapter. Electrospinning was carried out continuously for 6 h under the conditions of ambient temperature of 20 °C, humidity of 25%, spinning voltage of 24 kV, roller speed of 300 r / min, and spinning extrusion speed of 0.003 mm / s. The obtained nanofiber membrane was collected on a grounded rotating roller (40 mm in diameter, 300 r / min), wrapped on aluminum foil, and then placed in a fume hood to dry for 24 h to allow the residual solvent to fully evaporate, resulting in a polycaprolactone (PCL) / polylactic acid (PLA) composite electrospinned nanofiber membrane with a thickness of 200 μm, denoted as PCL / PLGA.

[0089] (3) Use a special syringe (1 mL) to apply the 3D printing ink prepared in step (1) between the electrospun membrane and the 3D printed hydrogel mesh support (150 μL of 3D printing ink is used per square centimeter patch). Then, use a 365 nm ultraviolet lamp to irradiate the connection for 30 min until the solution forms a hydrogel. Adhere the two together to obtain a double-layer asymmetric patch material.

[0090] Example 4

[0091] (1) Prepare an aqueous solution containing 8 wt% polyvinyl alcohol (PVA), 40 wt% acrylic acid (AAc), 2 wt% N-hydroxysuccinimide acrylate (AA-NHS), 0.2 wt% α-ketoglutarate, and 0.05 wt% polyethylene glycol dimethacrylate (PEGDMA) to obtain 3D printing ink. Place the 3D printing ink in a special syringe, connect the printing needle (0.1G), and perform 3D printing under ambient temperature of 25℃ and humidity of 40%. Set the 3D printer parameters as follows: needle temperature 37℃, platform temperature 10℃, printing speed 6mm / s, extrusion speed 7mm / s, pullback (SK) 0.25mm, lift-up (HP) 0.2mm, size 10×10mm, line spacing 1.2mm, and support height 40μm (the size is the length and width of the 3D printed hydrogel patch, and the support height is the thickness of the 3D printed hydrogel patch). After printing, the material is cured by irradiation under a 365nm UV lamp for 30 minutes to obtain a polyvinyl alcohol (PVA) and PAA-NHS composite 3D printed hydrogel patch, denoted as PVA / PAA-NHS.

[0092] (2) Mix polylactic acid-glycolic acid copolymer (PLGA) and polycaprolactone (PCL) in a certain proportion, and add them to a blended solution of N,N-dimethylformamide (DMF) and dichloromethane (DCM) in a volume ratio of 3:7. Stir magnetically at room temperature (24h) until the solute is completely dissolved. Then place the solution in a cleaning machine and sonicate for 20min to remove air bubbles in the solution. Prepare an electrospinning solution (pale yellow) with a PLGA concentration of 9wt% and a PCL concentration of 9wt%. The electrospinning solution was placed in a special syringe (20 mL), and a polytetrafluoroethylene tubing (1 m) and a spinning needle (21 G) were connected by an adapter. Electrospinning was carried out continuously under the conditions of an ambient temperature of 20 °C, humidity of 25%, spinning voltage of 24 kV, roller speed of 300 r / min, and spinning extrusion speed of 0.003 mm / s. The obtained nanofiber membrane was collected on a grounded rotating roller (40 mm in diameter, 300 r / min), wrapped on aluminum foil, and then placed in a fume hood to dry for 24 h to allow the residual solvent to fully evaporate, resulting in a polycaprolactone (PCL) / polylactic acid (PLA) composite electrospinned nanofiber membrane with a thickness of 30 μm, which can be abbreviated as PCL / PLGA or PLGA / PCL.

[0093] (3) Use a special syringe (1 mL) to apply the 3D printing ink prepared in step (1) between the electrospun film and the 3D printed hydrogel patch (100 μL of 3D printing ink is used per square centimeter patch). Then, use a 365 nm ultraviolet lamp to irradiate the connection for 30 min until the solution forms a hydrogel. Adhere the two together to obtain a double-layer asymmetric patch material.

[0094] Figure 10 The image shows the microstructure of the bilayer asymmetric patch prepared in this embodiment. It has a bilayer asymmetric structure, with an upper layer of PLC / PLGA with a thickness of 36.4 μm and a lower layer of PVA / PAA-NHS with a thickness of 46.7 μm.

[0095] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a bilayer asymmetric patch material for preventing air leakage after lung surgery, characterized in that, Includes the following steps: 1) A hydrogel precursor solution is prepared by mixing a hydrophilic polymer compound, acrylic acid, a compound with an amine coupling group, α-ketoglutaric acid, a crosslinking agent and water. The hydrogel precursor solution is then used as a 3D printing ink for 3D printing to obtain a 3D printed hydrogel patch. 2) Polyester is mixed with an organic solvent to obtain an electrospinning solution, and then electrospinned to obtain a nanofiber membrane; 3) Using the hydrogel precursor solution described in step 1) as a binder, the nanofiber membrane is bonded to the 3D printed hydrogel patch to obtain a double-layer asymmetric patch material; There is no specific order requirement for steps 1) and 2). The compounds with amine coupling groups mentioned in step 1) include one or more of N-hydroxysuccinimide acrylate, N-hydroxysuccinimide ester, N-hydroxysulfosuccinimide ester, aldehydes, epoxides, isocyanates, and catechol; The crosslinking agent mentioned in step 1) includes one or more of polyethylene glycol dimethacrylate, methacrylamide gelatin, hyaluronic acid methacrylate, oxidized methacrylate alginate, N,N'-bis(acryloyl)cystamine, N,N'-methylenebis(acrylamide), and polyethylene glycol diacrylate. In step 1), the hydrogel precursor solution contains 5-15 wt% hydrophilic polymer, 20-40 wt% acrylic acid, 0.5-2 wt% amine coupling group compound, 0.05-1 wt% α-ketoglutaric acid, and 0.01-0.1 wt% crosslinking agent. The conditions for 3D printing described in step 1) are as follows: The ambient temperature is 25℃, the ambient humidity is 40%, the needle temperature is 20~25℃, the platform temperature is 4~10℃, the line spacing is 0.8~1.2mm, the needle size is 0.21mm, the printing speed is 5~10mm / s, and the extrusion pressure is 0.3~0.5Mpa; The polyester mentioned in step 2) includes one or more of polylactic acid-glycolic acid copolymer, polycaprolactone, polylactic acid, and polyglycolic acid; The concentration of polyester in the electrospinning solution is 10~30wt%.

2. The method for preparing a double-layer asymmetric patch material for preventing air leakage after lung surgery according to claim 1, characterized in that, The hydrophilic polymeric compounds mentioned in step 1) include one or more of the following: polyvinyl alcohol, polyacrylic acid, polyacrylamide, polyhydroxyethyl methacrylate, polyethylene glycol, polyurethane, casein, albumin, gelatin, chitosan, hyaluronic acid, alginate, alginate, sodium oxidized alginate, cellulose, oxidized cellulose, polyvinylpyrrolidone, sodium polystyrene sulfonate, collagen, and pectin.

3. The method for preparing a double-layer asymmetric patch material for preventing air leakage after lung surgery according to claim 2, characterized in that, The organic solvent mentioned in step 2) is a mixed solvent of N,N-dimethylformamide and dichloromethane, and the volume ratio of N,N-dimethylformamide to dichloromethane is 1:10 to 10:

1.

4. The method for preparing a double-layer asymmetric patch material for preventing air leakage after lung surgery according to claim 3, characterized in that, The conditions for electrospinning described in step 2) are as follows: The ambient temperature is 20℃, the ambient humidity is 25%, the voltage is 15~25kV, the spinning extrusion speed is 0.001~0.005mm / s, and the needle size is 18~22G; The thickness of the nanofiber membrane is 20~200μm.

5. The double-layer asymmetric patch material for preventing air leakage after lung surgery, prepared by the method of any one of claims 1 to 4.

6. The application of the double-layer asymmetric patch material for preventing air leakage after lung surgery as described in claim 5 in the field of medical dressings.

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