A receiving device for electrospinning on a stent and application thereof

Abstract

The application provides a receiving device for electrospinning on a covered stent and application thereof, and belongs to the technical field of biological medicine. The receiving device comprises a base, fixed seats are arranged on both sides of the upper end of the base, a detachable seat is arranged on the other side of the base, a six-jaw chuck and a six-jaw driven wheel are arranged on the opposite sides of the upper part of the fixed seat and the detachable seat respectively, a driven shaft with a bearing is arranged at the connection between the six-jaw driven wheel and the detachable seat ， A tensioning rod is arranged on the front end of each claw of the six-jaw chuck, a clamping groove is arranged on each claw of the six-jaw driven wheel, each clamping groove is horizontally connected with the other side of the tensioning rod arranged on the front end of the claw of the six-jaw chuck, a wire insertion hole is arranged at the center of the bearing of the driven shaft connected with the detachable seat, a belt wheel is arranged on the other side of the fixed seat with the six-jaw chuck, and the belt wheel is coaxially connected with the six-jaw chuck. The receiving device can fix any straight pipe-shaped covered stent in the inner diameter range of the normal human aorta for electrospinning.

Description

Technical Field

[0001] This invention belongs to the field of biomedical technology, and in particular relates to a receiving device for electrospinning on a membrane-covered scaffold and its application. Background Technology

[0002] Aortic aneurysm and aortic dissection are two common aortic diseases that usually require surgical intervention. Compared to open-chest surgery, interventional therapy, which is less invasive, involves less blood loss, has lower risks, and is relatively safer, is a more sensible choice. For these aortic diseases, the corresponding interventional treatment involves delivering a endovascular stent graft to the lesion site to replace the blood vessel and restore vascular function, thereby improving the condition.

[0003] Conventional stents lack drug-carrying capacity, potentially leading to problems such as infection, inflammation, and stent displacement. To address these potential issues, drug-eluting stents were developed. Also known as drug-delivery stents, they utilize a polymer coating on the stent surface to carry medication. After the stent is placed at the lesion site, the drug is eluted from the polymer coating and released into the cardiovascular wall and other tissues, exerting its therapeutic effect.

[0004] As research into drug-eluting stents deepens, simply carrying the relevant drugs may no longer fully meet clinical requirements. Therefore, stents capable of controlled drug release, including sequential release and responsive release, have been developed based on drug-eluting stents. To achieve this, special structures or specific materials are required, such as multilayer composite membrane structures and responsive materials. Multilayer composite membrane structures enable sequential drug release from the outside in, while responsive release enables rapid drug release at the appropriate time to address adverse symptoms. Common response types include pH response, temperature response, light response, and ROS response, with ROS response receiving significant attention in recent years.

[0005] Electrospinning is a specialized fiber manufacturing process that produces polymer fiber films with advantages such as fine fibers, numerous pores, large specific surface area, and the ability to carry drugs, making it an excellent process for polymer film preparation. However, most research involving the preparation of drug-eluting stent fiber films using electrospinning employs traditional flat or roller receiving devices to receive the fibers. After the fiber film is formed, it is removed and then sewn or bonded to the stent. This approach requires a certain film thickness and may result in loosening. Therefore, if electrospinning could be performed directly on aortic endovascular stent grafts, this problem would be solved. Thus, it is necessary to design a receiving device for preparing fiber films for aortic endovascular stent grafts. Summary of the Invention

[0006] Therefore, the purpose of this invention is to provide a receiving device for electrospinning on a coated support and its application.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] This invention provides a receiving device for electrospinning on a coated support, comprising a base, with fixed seats integrally fixed to one side of the upper end of the base, and a detachable seat opposite the fixed seats on the other side of the base; a six-jaw chuck and a six-jaw driven wheel are respectively provided on opposite sides of the upper part of the fixed seats and the detachable seat; a driven shaft with a bearing is provided at the connection between the six-jaw driven wheel and the detachable seat, and the six-jaw driven wheel is rotatably connected to the detachable seat through the driven shaft; a tension rod is installed at the front end of each jaw of the six-jaw chuck; each jaw on the six-jaw driven wheel is provided with a groove, the width of which is the same as the diameter of each tension rod; each groove is horizontally threaded to the other side of the tension rod installed opposite the front end of the jaw of the six-jaw chuck, so that the six tension rods are parallel; a wire insertion hole is provided at the center of the bearing of the driven shaft connected to the detachable seat; a pulley is provided on the other side of the fixed seat with the six-jaw chuck, and the pulley is coaxially connected to the six-jaw chuck.

[0009] Preferably, the tensioning rod is a cylindrical metal rod; the diameter of the circle containing the center of the cross-section of the six tensioning rods is 23-35 mm.

[0010] Preferably, the detachable base is an L-shaped structure consisting of a vertical plate and a horizontal plate, the horizontal plate being provided with threaded holes for fixed connection with the base; the base is horizontally positioned, while the fixed base and the vertical plate are vertically positioned.

[0011] Preferably, the shape of the six-jaw driven wheel is the same as the shape formed by the jaws on the six-jaw chuck.

[0012] Preferably, the pulley drives the six-jaw chuck, tensioning rod, six-jaw driven wheel, and driven shaft to rotate synchronously; the opening and closing of the six jaws is controlled by the square hole of the six-jaw chuck on the base of the six-jaw chuck, which drives the tensioning rod to open and close, so as to realize the installation and tensioning of the film-coated bracket.

[0013] The present invention also provides an application of the above-described receiving device in preparing a film-coated scaffold covered with a fiber film.

[0014] This invention provides a method for preparing a membrane-covered stent with an outer fiber film, wherein the fiber film comprises an inner layer and an outer layer, the inner layer being a drug-loaded layer and the outer layer being a coagulation layer;

[0015] The drug-loaded layer includes antibacterial and anti-inflammatory drugs, and the coagulation layer includes coagulation drugs;

[0016] Then, using the aforementioned receiving device, a drug-loaded layer is electrospun onto the covered stent, followed by an electrospun coagulation layer.

[0017] Preferably, the drug-loaded layer includes a first fiber and a second fiber, wherein the first fiber includes a first fiber shell and a first fiber core; and the second fiber includes a second fiber shell and a second fiber core.

[0018] The first fibrous core layer includes an antibacterial drug; the second fibrous core layer includes an anti-inflammatory drug; the second fibrous shell layer includes a material with ROS-responsive properties.

[0019] The first fiber shell and the first fiber core are installed on one side of the receiving device by coaxial electrospinning, and the second fiber shell and the second fiber core are installed on the other side of the receiving device by coaxial electrospinning. Coaxial electrospinning is carried out on both sides of the receiving device at the same time to form conjugate electrospinning, thus obtaining the drug-loaded layer.

[0020] The antibacterial drug includes one or both of vancomycin and amoxicillin; the anti-inflammatory drug includes one or both of astragaloside A and cefadroxil.

[0021] The coagulation drugs include thrombin;

[0022] The membrane-covered scaffold is coated with bio-adhesive between itself and the drug-loaded layer, and between the drug-loaded layer and the coagulation layer.

[0023] Preferably, the first fiber shell layer comprises polycaprolactone and polyethylene oxide; the first fiber core layer comprises polyvinylpyrrolidone and vancomycin; the second fiber shell layer comprises polycaprolactone and polyamide thioketone polymer; and the second fiber core layer comprises polyvinylpyrrolidone and astragaloside A.

[0024] The coagulation layer comprises polycaprolactone, polyethylene oxide, and thrombin.

[0025] The present invention provides a fiber film coating on a membrane-coated scaffold prepared by the above-described preparation method.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] This invention provides a receiving device for electrospinning on a covered stent and its application. The invention utilizes this receiving device to spin a membrane onto the covered stent, creating a covered stent with self-fixation, antibacterial, anti-inflammatory, and ROS-responsive properties. This receiving device can fix any straight tubular covered stent within the normal aortic diameter range. The covered stent prepared using this receiving device, with its outer fiber membrane, not only replaces diseased blood vessels to maintain normal blood flow but also prevents stent displacement, provides local antibacterial properties, and releases anti-inflammatory drugs when inflammation occurs. Attached Figure Description

[0028] Figure 1 The main structural diagram of the receiving device for preparing electrospinning on a coated support is shown below; wherein, 1. base; 2. fixed base; 3. detachable base; 4. six-jaw chuck; 5. six-jaw driven wheel; 6. driven shaft; 7. chuck jaws; 8. tensioning rod; 9. square hole of the six-jaw chuck; 10. nut; 11. wire insertion hole; 12. pulley;

[0029] Figure 2 Left view of the receiving device for preparing electrospinning on a coated support;

[0030] Figure 3 A top view of the receiving device for preparing electrospinning on a coated support;

[0031] Figure 4 Axonometric view of the receiving device for preparing electrospinning on a coated support;

[0032] Figure 5 A schematic diagram of the installation method of a straight tubular film-coated support on the receiving device designed in this invention;

[0033] Figure 6 This is a flowchart illustrating the synthesis process of the PATK powder.

[0034] Figure 7 The simplified structural formula of PATK and its thioketone linkage are shown, where the structure in the red box is a thioketone linkage.

[0035] Figure 8 The cumulative release curves of the drug-loaded layer and coagulation layer prepared separately in Example 2 are shown, including the cumulative release curves of thrombin, vancomycin and astragaloside A in PBS buffer, the cumulative release curve of astragaloside A (10 μM) in 10 μM hydrogen peroxide, and the cumulative release curve of astragaloside A (25 μM) in 25 μM hydrogen peroxide. Detailed Implementation

[0036] To enable the electrospun fibers to be spun on the surface of a covered stent, allowing it to release drugs for antibacterial and anti-inflammatory effects in response to lesion inflammation, this invention provides a receiving device for electrospun fibers on a covered stent. This receiving device can fix the covered stent, rotate it, and, importantly, connect to a negative voltage power supply for conductivity, thereby ensuring that the electrospun fibers are smoothly and uniformly received on the outer surface of the covered stent. Furthermore, it is suitable for covered stents of different inner diameters.

[0037] Given that covered stents come in various inner diameters, and since the inner diameter is generally different for different patients in clinical use, the receiving device of this invention can achieve stepless fixation, that is, it can fix stents of any aortic inner diameter. The receiving device of this invention features a six-jaw chuck with tensioning rods mounted on its jaws. Six tensioning rods are located at the front end of the jaws, their centers forming a regular hexagon. The cross-section of the tensioning rods is designed to be circular, with the diameter of the circle containing the centers of the six tensioning rods being 23-35 mm. The six jaws open and close via the square holes in the six-jaw chuck, causing the tensioning rods to move, thereby achieving stent installation and tensioning. The six-jaw chuck and pulley are coaxially mounted, so the pulley, acting as the driving pulley, rotates the six-jaw chuck. On the other side of the tensioning rod, a slotted six-jaw driven wheel is designed. The groove width is the same as the diameter of the tensioning rod. After the tensioning rod is installed on the six-jaw chuck, the six-jaw driven wheel is installed so that the tensioning rod is inserted through the groove of the six-jaw driven wheel. The part of the tensioning rod that passes through the six-jaw driven wheel is designed with threads. After the installation of the six-jaw driven wheel is completed, a nut is screwed on the thread of the tensioning rod to fix the tensioning rod and prevent the non-fixed end from swinging due to its excessive length during rotation.

[0038] As one embodiment, a tensioning rod 8 is installed at the front end of each jaw 7 of the six-jaw chuck 4. The installation can be performed by setting a threaded hole at the front end of the jaw for threaded installation, thereby facilitating disassembly.

[0039] The covered stent, specifically the aortic covered stent, is a straight tubular covered stent in terms of its shape.

[0040] Regarding the conductivity issue, a wire insertion hole is provided in the center of the bearing of the driven shaft connected to the detachable base. When in use, the negative wire of the electric spinning machine is inserted into the wire insertion hole, the plug contacts the bearing, the bearing contacts the driven shaft, and the six-jaw driven wheel contacts the tensioning rod, so that all six tensioning rods are connected to the negative voltage.

[0041] For safety and weight considerations, the base, fixed base, and detachable base can be made of non-conductive non-metallic materials (such as resin materials, such as polyvinyl chloride, polyethylene, polypropylene, or ABS), while the remaining parts are made of metallic materials, such as one or more of copper, aluminum, nickel, and steel.

[0042] The tensioning rod of the present invention is a cylindrical metal rod, wherein the metal has electrical conductivity and includes one or more of copper, aluminum, nickel and steel.

[0043] The present invention also provides an application of the above-described receiving device in preparing a film-coated scaffold covered with a fiber film.

[0044] This invention provides a method for preparing a membrane-covered stent with an outer fiber film, wherein the fiber film comprises an inner layer and an outer layer, the inner layer being a drug-loaded layer and the outer layer being a coagulation layer;

[0045] The drug-loaded layer includes antibacterial and anti-inflammatory drugs, and the coagulation layer includes coagulation drugs;

[0046] Then, using the aforementioned receiving device, a drug-loaded layer is electrospun onto the covered stent, followed by an electrospun coagulation layer.

[0047] In this invention, the drug-loaded layer has antibacterial and anti-inflammatory effects when local inflammation occurs, while the coagulation layer serves to fix the covered stent to the lesion site. The covered stent in this invention is a straight tubular covered stent.

[0048] In this invention, the drug-loaded layer is manufactured using a composite process of conjugate electrospinning and coaxial electrospinning, resulting in two different fibers, both of which have a core-shell coaxial structure. The first fiber has antibacterial properties, while the second fiber has inflammatory response capabilities. During inflammation, local reactive oxygen species (ROS) levels increase, and the second fiber of the drug-loaded layer can respond to ROS to achieve an inflammatory response.

[0049] In one embodiment of the present invention, the drug-loaded layer includes a first fiber and a second fiber, wherein the first fiber includes a first fiber shell and a first fiber core; and the second fiber includes a second fiber shell and a second fiber core.

[0050] The first fibrous core layer includes an antibacterial drug; the second fibrous core layer includes an anti-inflammatory drug; the second fibrous shell layer includes a material with reactive oxygen species (ROS) responsiveness.

[0051] The first fiber shell and the first fiber core are installed on one side of the receiving device by coaxial electrospinning. The second fiber shell and the second fiber core are installed on the other side of the receiving device by coaxial electrospinning. Coaxial electrospinning is carried out simultaneously on both sides of the receiving device to form conjugate electrospinning, thus obtaining the drug-loaded layer.

[0052] In this invention, the antibacterial drug includes one or both of vancomycin and amoxicillin; the anti-inflammatory drug includes one or both of astragaloside A and cefadroxil.

[0053] In one embodiment, the first fiber shell comprises polycaprolactone (PCL) and polyethylene oxide (PEO); the first fiber core layer comprises polyvinylpyrrolidone (PVP) and vancomycin. The reactive oxygen species (ROS) responsive material includes phenylboronic acid derivatives, thioketones, diselenides, peroxyoxalate, or vinyl disulfide, etc. In another embodiment, this invention uses a polyamide-thioketone polymer (PATK) as the ROS-responsive functional material. PATK is biodegradable and contains thioketone linkages, which break upon encountering ROS, causing the polymer to decompose and release the drug to achieve the response. PATK is also known as polyamide-thioketal, polyamide-ketone thioacetate, or polyamide-thioketone. The second fiber shell comprises polycaprolactone and a polyamide-thioketone polymer; the second fiber core layer comprises polyvinylpyrrolidone and astragaloside A.

[0054] In this invention, the preparation of the polyamide-thione polymer includes: (1) mixing 3-mercaptopropionic acid, acetone and trifluoroacetic acid, reacting in an ice bath to obtain reaction mixture 1, filtering and collecting the powder, washing with hexane and water to remove impurities, and obtaining TK compound; (2) mixing the TK compound and N-hydroxysuccinimide in MES buffer to obtain TK / NHS solution; then dissolving carbodiimide in MES buffer and reacting it with the TK / NHS solution in an ice bath to obtain reaction mixture 2, filtering and collecting the filtered white solid, then rinsing with water, dissolving the rinsed solid in dichloromethane, drying, recrystallizing the dried solid in isopropanol, filtering and collecting the solid, and drying to obtain TK-NHS powder; (3) mixing TK-NHS powder, polyetheramine and 1,6-diaminohexane in N,N-dimethylformamide, reacting to obtain crude PATK, then purifying by dialysis with a 3.5 kDa membrane, drying, and obtaining purified PATK powder.

[0055] In the preparation of the polyamide-thione polymer described above, in step (1), the mass-to-volume ratio of 3-mercaptopropionic acid, acetone, and trifluoroacetic acid is 6–6.5 g: 7–7.5 g: 20 mL; the reaction time is 10–14 h. In step (2), the mass-to-volume ratio of TK compound, N-hydroxysuccinimide, and MES buffer is 2.5–3.5 g: 3.2–3.6 g: 25–35 mL; the mass-to-volume ratio of carbodiimide to MES buffer is 5–6 g: 15–25 mL; the reaction temperature is room temperature; and the reaction time is 2–4 h. In step (3), the mass-to-volume ratio of TK-NHS powder, polyetheramine, 1,6-diaminohexane and N,N-dimethylformamide is 0.5-1.5g:2-2.5g:0.1-0.15g:15-25mL; the reaction temperature is 70-80℃ and the reaction time is 70-74h.

[0056] In this invention, to spin the first fiber, the first solvent is prepared by mixing dichloromethane (DCM) and N,N-dimethylformamide (DMF); polycaprolactone and polyethylene oxide are dissolved in the first solvent to obtain a first solution; polyvinylpyrrolidone and vancomycin are dissolved in anhydrous ethanol to obtain a second solution. The first solvent is prepared by mixing dichloromethane and N,N-dimethylformamide in a volume ratio of 4:1; the first solution is prepared by dissolving polycaprolactone and polyethylene oxide in the first solvent in a mass ratio of 9:1, and the mass concentration is within 12-16%, where the mass concentration refers to the mass ratio of polycaprolactone and polyethylene oxide in the first solution; the mass concentration of polyvinylpyrrolidone in the second solution (i.e., the mass ratio of polyvinylpyrrolidone in the second solution) is 38-42%, and it contains 450-500 mg of vancomycin.

[0057] In this invention, to spin the second fiber, the second solvent is prepared by mixing chloroform and N,N-dimethylformamide; PATK and polycaprolactone are dissolved in the second solvent to obtain a third solution; polyvinylpyrrolidone and astragaloside IV are dissolved in anhydrous ethanol to obtain a fourth solution. The second solvent is prepared by mixing chloroform and N,N-dimethylformamide in a volume ratio of 10:1; the third solution is prepared by dissolving polycaprolactone and PATK in equal masses in the second solvent, and the mass concentration (i.e., the mass ratio of polycaprolactone and PATK in the third solution) is within 16-20%; the mass concentration of polyvinylpyrrolidone in the fourth solution (i.e., the mass ratio of polyvinylpyrrolidone in the fourth solution) is 38-42%, and the concentration of astragaloside IV is 12-15 mg / mL.

[0058] In this invention, the coagulation drug includes thrombin, and the coagulation layer includes polycaprolactone, polyethylene oxide, and thrombin. The coagulation layer is manufactured using a uniaxial electrospinning process and is loaded with thrombin. When the covered stent is delivered to the lesion, the thrombin is rapidly released, causing localized coagulation between the outer surface of the covered stent and the stent wall, thereby fixing the covered stent in the designated position.

[0059] In this invention, the coagulation layer comprises polycaprolactone, polyethylene oxide, and thrombin. The mass ratio of polycaprolactone to polyethylene oxide is 7:3; the concentration of thrombin is 2–6 mg / mL. To spin the coagulation layer fibers, polycaprolactone and polyethylene oxide are dissolved in the first solvent, and then thrombin is added for further mixing and dissolution to obtain a fifth solution. The fifth solution is prepared by dissolving polycaprolactone and polyethylene oxide in the first solvent at a mass ratio of 7:3, achieving a mass concentration of 12–16%, and then adding 2–6 mg / mL of thrombin. The mass concentration refers to the percentage of polycaprolactone or polyethylene oxide by mass in the fifth solution.

[0060] In this invention, to enhance the bonding force between layers, a bio-adhesive is added between the layers; specifically, a bio-adhesive is coated between the membrane-covered scaffold and the drug-loaded layer, and between the drug-loaded layer and the coagulation layer. The bio-adhesive is dissolved in deionized water using polyvinyl alcohol (PVA-1788). This bio-adhesive has high viscosity and is relatively stable.

[0061] The covered stent of the present invention is covered with a fiber membrane, which consists of, from the inside out, a drug-loaded layer with antibacterial and inflammatory responses and a coagulation layer for fixing the covered stent to the lesion. After the covered stent is delivered to the lesion, the outer coagulation layer first releases thrombin, causing local coagulation at the lesion site's blood vessel wall, thereby achieving the purpose of fixing the stent. Then, the first fiber in the drug-loaded layer degrades and begins to release vancomycin, a glycopeptide antibiotic with strong antibacterial properties and a high killing effect on Gram-positive bacteria. When inflammation occurs at the lesion site, the local reactive oxygen species level increases, and the second fiber in the drug-loaded layer begins to degrade, at which point astragaloside A is released, which has anti-inflammatory, anti-apoptotic, and antioxidant effects.

[0062] In this invention, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art.

[0063] 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.

[0064] Example 1

[0065] like Figures 1-4As shown, this embodiment provides a receiving device for electrospinning on a coated support, including a base 1. Fixed seats 2 are integrally fixed to one side of the base 1 on both sides of the upper end of the base 1. A detachable seat 3 is provided on the other side of the base 1, opposite to the fixed seat 2. The detachable seat 3 is an L-shaped structure composed of a vertical plate and a horizontal plate. The base 1 is horizontally positioned, while the fixed seat 2 and the vertical plate are vertically positioned. The horizontal plate has threaded holes and is fixedly connected to the base 1. A six-jaw chuck 4 and a six-jaw driven wheel 5 are respectively provided on opposite sides of the upper part of the fixed seat 2 and the detachable seat 3. A driven shaft 6 with a bearing is provided at the connection between the six-jaw driven wheel 5 and the detachable seat 3, and the six-jaw driven wheel 5 is rotatably connected to the detachable seat 3 through the driven shaft 6. A tensioning rod 8 is installed at the front end of each jaw 7 of the six-jaw chuck 4. The opening and closing of the six jaws 7 is controlled by the square hole 9 of the six-jaw chuck on the base of the six-jaw chuck 4, which drives the tensioning rod to open and close. The installation and tensioning of the film-coating bracket are achieved. The shape of the six-jaw driven wheel 5 is the same as the shape of the jaws 7 on the six-jaw chuck 4. Each jaw on the six-jaw driven wheel 5 is provided with a groove, and the width of the groove is the same as the diameter of each tensioning rod 8. Each groove is horizontally threaded to the other side of the tensioning rod 8 installed opposite to the front end of the jaw of the six-jaw chuck 4, so that the six tensioning rods 8 are parallel to each other. That is, the other side of the tensioning rod 8 installed at the front end of the jaw of the six-jaw chuck 4 is inserted into the groove. The tensioning rod part extending through and beyond the other side of the six-jaw driven wheel 5 is provided with threads. The nut 10 is tightened to fix the tensioning rod 8 and prevent it from swinging due to its excessive length during rotation. The bearing center of the driven shaft 6 connected to the detachable base 3 is provided with a wire insertion hole 11. When in use, the negative wire of the electrospinning machine is inserted into the wire insertion hole 11. The plug contacts the bearing, the bearing contacts the driven shaft 6, and the six-jaw driven wheel 5 contacts the tensioning rod 8, so that all six tensioning rods are connected to the negative voltage.

[0066] A tensioning rod 8 is installed at the front end of each jaw 7 of the six-jaw chuck 4. The installation can be carried out by threading through threaded holes at the front end of the jaws, which facilitates disassembly.

[0067] The square hole of the six-jaw chuck is located at the end of any jaw on the outer circumference of the six-jaw chuck.

[0068] On the other side of the fixed base 2 equipped with a six-jaw chuck, there is a pulley 12, which is coaxially connected to the six-jaw chuck. During operation, the electrospinning machine drives the six-jaw chuck 4, tensioning rod 8, six-jaw driven wheel 5, and driven shaft 6 to rotate synchronously via the pulley 12.

[0069] The tensioning rod 8 is a cylindrical steel rod. The six jaws of the six-jaw chuck are equidistantly distributed on the base of the six-jaw chuck. Therefore, the ends of the six tensioning rods connected to the six-jaw chuck together form a regular hexagon. Since the inner diameter of the aorta is generally 23-35 mm, and the inner diameter of the aortic endovascular stent graft is within this range, the diameter of the circle containing the center of the cross-section of the six tensioning rods can be within an appropriate range including 23-35 mm.

[0070] For safety and weight considerations, the base 1, fixed base 2, and detachable base 3 can be made of non-conductive non-metallic materials (such as polyethylene), while the remaining components are made of steel.

[0071] When preparing electrospinning on an aortic endovascular stent graft using a receiving device, before installing the stent graft, first remove the detachable base 3 (with its parts), insert a T-wrench into the square head hole 9 of the six-jaw chuck, and rotate the wrench to retract the six tension rods 8 on the six-jaw chuck 4 to a position smaller than the inner diameter of the stent graft; place the stent graft on the six tension rods 8 in the appropriate position, and then use the wrench to open the six tension rods 8 to tension the stent graft. The tension should not be too tight, just enough to allow the stent graft to rotate with the tension rods; then install the detachable base 3 on the base 1, tighten the screws, and screw the nut on the back of the six-jaw driven wheel 5; finally, insert the wire plug into the wire socket so that the receiving device can be connected to the negative voltage of the high-voltage power supply during electrospinning.

[0072] A schematic diagram of the installation method of the straight tubular film-coated support on the receiving device designed in this invention is shown below. Figure 5 .

[0073] Example 2

[0074] A method for preparing a membrane-coated scaffold covered with a fiber film includes the following steps:

[0075] Synthesis of S1, polyamide-thione polymer (PATK)

[0076] (1) Synthesis of ketethiocyanate (TK) compound: 6.1 g of 3-mercaptopropionic acid and 7.01 g of acetone were mixed in 20 mL of trifluoroacetic acid and reacted in an ice bath for 12 h to obtain reaction mixture 1. Then, reaction mixture 1 was filtered to obtain powder. The powder was washed with 25 mL of hexane each time for a total of 3 times to obtain the first solid powder after washing. Then, the powder was washed with 25 mL of water each time for a total of 3 times to obtain the second solid powder after washing. The powder was then dried under vacuum to obtain a white solid, namely the TK compound.

[0077] (2) Activation of TK compound: 3g of the TK compound and 3.43g of N-hydroxysuccinimide were mixed in 30mL of 2-(N-morpholine)ethanesulfonic acid buffer (MES buffer) at pH 6.5 to obtain a TK / NHS solution. Then, 5.71g of carbodiimide was dissolved in 20mL of MES buffer and added to the TK / NHS solution in an ice bath. The reaction was continued at room temperature for 3h to obtain reaction mixture 2. The white solid after filtration of reaction mixture 2 was collected. The white solid after filtration was washed with 25mL of water each time for a total of 3 washes to obtain the washed solid. The washed solid was then dissolved in 10mL of dichloromethane and dried on Na2SO4. The dichloromethane was evaporated to obtain the dried solid. The dried solid was then added to isopropanol to dissolve. The mixture was heated and stirred to 60-75℃. The amount of dried solid added was increased until it was difficult to dissolve. The mixture was cooled to room temperature, and crystals were precipitated. The solid was collected by filtration and dried under vacuum to obtain a white powder, namely TK-NHS powder.

[0078] (3) Synthesis of PATK: 1g of the TK-NHS powder was mixed with 2.24g of polyetheramine (JA) 2k 0.12 g of 1,6-diaminohexane (HMDA) was mixed in 20 mL of dry N,N-dimethylformamide and reacted at 75 °C for 72 h to obtain crude PATK. The crude PATK was purified by dialysis in water using a 3.5 kDa membrane, and then freeze-dried to obtain purified PATK powder.

[0079] The synthesis flowchart for PATK powder is shown below. Figure 6 The structural formula of PATK and its chemically cleavable bonds are shown in [link to PATK structure]. Figure 7 .

[0080] S2. Install the straight tubular film-coated support onto the tension rod of the receiving device in accordance with the method of Example 1.

[0081] S3. Preparation of the drug-carrying layer

[0082] Preparation of electrospinning solution:

[0083] (1) Preparation of the electrospinning solution for the first fiber: Using a dropper, 8 mL of dichloromethane and 2 mL of N,N-dimethylformamide were added to the same beaker and mixed to prepare the first solvent. Then, 1.35 g of polycaprolactone granules and 0.15 g of polyethylene oxide powder were added to the first solvent, and a magnetic rotor was placed in the beaker. The mouth of the beaker was sealed with plastic wrap or aluminum foil to ensure a tight seal. The mixture was magnetically stirred at room temperature for about 2 hours at a speed of 400 r / min to obtain the first solution.

[0084] Dissolve 4g of polyvinylpyrrolidone and 500mg of vancomycin powder in 10mL of anhydrous ethanol, place the mixture in a magnetic rotor, seal the mouth of the beaker with plastic wrap or aluminum foil to ensure a tight seal, and stir magnetically at room temperature for about 1 hour at a speed of 500r / min to obtain the second solution.

[0085] (2) Preparation of the electrospinning solution for the second fiber: Using a dropper, 10 mL of chloroform and 1 mL of N,N-dimethylformamide were added to the same beaker and mixed to prepare the second solvent. Then, 1 g of polycaprolactone granules and 1 g of PATK powder prepared in step S1 were added to the second solvent. The beaker was placed in a magnetic rotor, and the mouth of the beaker was sealed with plastic wrap or aluminum foil to ensure a tight seal. The mixture was magnetically stirred at room temperature for about 3 hours at a speed of 400 r / min to obtain the third solution.

[0086] Dissolve 4g of polyvinylpyrrolidone and 150mg of astragaloside A in 10mL of anhydrous ethanol, place the mixture in a magnetic rotor, seal the mouth of the beaker with plastic wrap or aluminum foil to ensure a tight seal, and stir magnetically at room temperature for about 1 hour at a speed of 500r / min to obtain the fourth solution.

[0087] (3) Conjugate coaxial composite electrospinning:

[0088] The four solutions described above are respectively loaded into medical syringes. Two syringes containing the first and second solutions are placed on one side of the straight tubular covered support of the receiving device in Example 1 to form a coaxial electrospinning device. The syringe containing the first solution is connected to the shell channel of the coaxial electrospinning nozzle, and the syringe containing the second solution is connected to the core channel of the coaxial electrospinning nozzle. Two syringes containing the third and fourth solutions are placed on the other side of the receiving device in Example 1 to form a coaxial electrospinning device. The syringe containing the third solution is connected to the shell channel of the coaxial electrospinning nozzle, and the syringe containing the fourth solution is connected to the core channel of the coaxial electrospinning nozzle. Both coaxial nozzles are 17 / 22G specification, with a horizontal distance of 16cm from the receiver axis. The voltage is set to 16kV, and the receiver rotation speed is set to 600r / min. The liquid supply rate is set to 0.5mL / h for the core layer and 0.8mL / h for the shell layer. This rate can be fine-tuned as needed, but the core layer supply rate should not exceed that of the shell layer. Electrospinning time is 8–10 hours. After this process, the drug-loaded layer preparation is complete.

[0089] S4. Preparation of the coagulation layer

[0090] ① Preparation of electrospinning solution:

[0091] Dissolve 1.05g of polycaprolactone and 0.45g of polyethylene oxide in 10mL of the first solvent in step S3, then add 1mL of 4mg / mL thrombin solution to it, place it in a magnetic rotor, seal the mouth of the beaker with plastic wrap or aluminum foil to ensure a tight seal, and stir magnetically at room temperature for about 2 hours at a speed of 300r / min to obtain the fifth solution.

[0092] ② Uniaxial electrospinning:

[0093] The fifth solution was loaded into a medical syringe and placed on one side of the receiving device. Monoaxial electrospinning was then initiated on a straight tubular covered support with a drug-loaded layer on its surface. A 21G nozzle was selected, with a horizontal distance of 16 cm from the axis of the receiving device. The voltage was set to 13 kV, and the receiver rotation speed was set to 600 r / min. The electrospinning solution supply rate was set to 0.7 mL / h, and the electrospinning time was 6 hours. After this process, the preparation of the coagulation layer was completed.

[0094] Considering the non-conductivity of electrospun membranes and the bonding strength between spun membranes, a method is proposed here to enhance the bonding reliability of composite membranes by coating the layers, namely between the membrane-coated scaffold layer and the drug-loaded layer, and between the drug-loaded layer and the coagulation layer.

[0095] Preparation of homemade bio-adhesive (sixth solution): Dissolve 1.6g of type 1788 polyvinyl alcohol in 20mL of deionized water, stir with a magnetic stirrer for 1-2 hours at 300r / min, and obtain an 8% (w / v) polyvinyl alcohol solution, which is the sixth solution, for later use.

[0096] To enhance the interlayer bonding force, before the electrospinning begins in steps S3 and S4, the sixth solution is uniformly coated on the outer surface of the covered stent and the surface of the drug-loaded layer, respectively, with a thickness not exceeding 0.5 mm, to prepare the aortic covered stent with an outer fiber film.

[0097] Example 3

[0098] The difference between this embodiment and Example 2 lies in the preparation method. In step (1) and (2) of S3 in Example 2, polyvinylpyrrolidone is replaced with a 15% (w / v) aqueous solution of polyvinyl alcohol type 1788 (PVA-1788). For drug loading, vancomycin is replaced with 500 mg amoxicillin, and astragaloside IV is replaced with 300 mg cephalexin. Other steps follow the method of Example 2 for preparing the aortic endovascular stent graft with an external fiber membrane.

[0099] The differences between the above substitutions are as follows: Regarding the drug delivery system, amoxicillin is a broad-spectrum penicillin antibiotic with strong antibacterial and bacteriostatic effects against both Gram-positive and Gram-negative bacteria; cefadroxil, a first-generation semi-synthetic cephalosporin, has similar antibacterial activity to cephalexin, good absorption, and high blood concentrations. It is characterized by its resistance to β-lactamases and has rapid and reliable bactericidal effects against drug-resistant Staphylococcus aureus and many other bacilli resistant to broad-spectrum antibiotics. Regarding the core polymer material, type 1788 polyvinyl alcohol is safe, water-soluble, and rapidly releases the drug upon exposure in vivo.

[0100] Experimental Example 1

[0101] The cumulative release rate is a measure of the ratio of the total amount of substance released from a system over a certain period of time to the initial total amount. This ratio can be used to assess the release characteristics of drugs or other substances.

[0102] By measuring the concentration of a substance in a solution at different times, the cumulative release curve of that substance can be plotted.

[0103] According to Beer-Lambert's law, the absorbance of a solution is directly proportional to the concentration of a solute (at low concentrations). Therefore, by measuring the absorbance of the solution at different times using a spectrophotometer, the solution concentration at different times can be obtained. This method is used to obtain the drug concentration in the PBS buffer (pH = 7.4) of the electrospun fiber membrane at different times. The total drug amount is determined by multiplying the solution volume consumed by electrospinning by the solution concentration. The initial drug amount is determined by multiplying the ratio of the area of ​​the membrane used in the experiment to the area of ​​the spun membrane by the total drug amount. To achieve the experimental objectives, the receiving device of Example 1 was used to receive the coagulation layer and drug-loaded layer membranes respectively, so as to cut the membranes and calculate their areas.

[0104] The specific procedure involved cutting the woven film into several 1cm × 1cm square samples. The separately prepared coagulation layer and drug-loaded layer films from Example 2 were placed in centrifuge tubes containing 50mL of PBS buffer. At regular intervals, 5mL samples were collected in empty centrifuge tubes for absorbance testing. Each time a sample was collected, 5mL of pure PBS buffer was added back in. Time points were recorded at 0.5h, 1h, 2h, 4h, 8h, 12h, 24h, 48h, 72h, 120h, and 168h. After all time points had been collected, absorbance tests were performed. Following the experiments, the cumulative drug release curves were calculated and processed to obtain the cumulative release curves of thrombin, vancomycin, and astragaloside IV in PBS buffer.

[0105] Since the individual drug-loaded layer prepared in Example 2 contains ROS-responsive material, to verify the response characteristics of the drug-loaded layer, the above-mentioned 1cm×1cm square sample of the drug-loaded layer needs to be placed in 10μM and 25μM hydrogen peroxide, respectively. 5mL samples are taken at intervals and collected in empty centrifuge tubes for absorbance testing. After each collection, 5mL of 10μM and 25μM hydrogen peroxide are added again. Absorbance tests are conducted at time points of 0.5h, 1h, 2h, 4h, 8h, 12h, 24h, 48h, 72h, 120h, and 168h.

[0106] Figure 8 The results showed that thrombin had the fastest release rate in PBS buffer. This is because the polymer carrying it has a high content of polyethylene oxide (PEO), which is water-soluble and has a uniaxial structure, allowing it to release thrombin relatively quickly and exert its coagulation effect immediately. Vancomycin had the second fastest release rate, which is why it can play an antibacterial or infection-preventing role. Due to its core-shell structure, the drug is encapsulated in the shell, and the PEO content is even lower, resulting in a slower release but also a longer release time. Astragaloside A had a slow release rate in PBS buffer but a faster release rate in hydrogen peroxide, reflecting its reactive oxygen species response characteristics.

[0107] Based on the above-described release characteristics, it can be seen that the aortic endovascular stent covered with a fibrous membrane provided by the present invention has coagulation, antibacterial, and inflammatory response effects.

[0108] 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 receiving device for electrospinning on a coated support, characterized in that, Includes a base (1), with fixed seats (2) integrally fixed to one side of the base (1) on both sides of the upper end of the base (1), and a detachable seat (3) opposite to the fixed seat (2) on the other side of the base (1); a six-jaw chuck (4) and a six-jaw driven wheel (5) are respectively provided on opposite sides of the upper part of the fixed seat (2) and the detachable seat (3); a driven shaft (6) with bearings is provided at the connection between the six-jaw driven wheel (5) and the detachable seat (3), and the six-jaw driven wheel (5) is rotatably connected to the detachable seat (3) through the driven shaft (6); each of the six-jaw chuck (4) Each jaw (7) has a tension rod (8) installed at its front end; each jaw on the six-jaw driven wheel (5) has a groove, the width of which is the same as the diameter of each tension rod (8); each groove is horizontally threaded to the other side of the tension rod (8) installed opposite to the front end of the jaw of the six-jaw chuck (4), so that the six tension rods (8) are parallel to each other; the bearing center of the driven shaft (6) connected to the detachable base (3) has a wire insertion hole (11); the other side of the fixed base (2) with the six-jaw chuck is provided with a pulley (12), and the pulley (12) is coaxially connected to the six-jaw chuck; The tensioning rod (8) is a cylindrical metal rod; the diameter of the circle containing the center of the cross-section of the six tensioning rods is 23-35 mm; The pulley (12) drives the six-jaw chuck (4), tensioning rod (8), six-jaw driven wheel (5), and driven shaft (6) to rotate synchronously; the six jaws (7) are controlled to open and close through the six-jaw chuck square hole (9) on the base of the six-jaw chuck (4), thereby driving the tensioning rod to open and close, so as to realize the installation and tensioning of the film-coated bracket; The installation is performed by threading through a threaded hole at the front end of the jaw; The aforementioned endovascular stent is an aortic endovascular stent. The detachable base (3) is an L-shaped structure consisting of a vertical plate and a horizontal plate. The horizontal plate is provided with threaded holes and is fixedly connected to the base (1). The base (1) is set horizontally, and the fixed base (2) and the vertical plate are set vertically.

2. The receiving device according to claim 1, characterized in that, The shape of the six-jaw driven wheel (5) is the same as the shape of the jaws (7) on the six-jaw chuck (4).

3. An application of the receiving device of claim 2 in preparing a film-coated scaffold covered with a fiber film.

4. A method for preparing a fiber film coating on a membrane-coated scaffold, characterized in that, The fiber film includes an inner layer and an outer layer, the inner layer being a drug-loaded layer and the outer layer being a coagulation layer; the drug-loaded layer includes antibacterial and anti-inflammatory drugs, and the coagulation layer includes coagulation drugs; then, using the receiving device of claim 2, the drug-loaded layer is electrospun onto the covered support, and then the coagulation layer is electrospun onto it. The drug-loaded layer includes a first fiber and a second fiber, wherein the first fiber includes a first fiber shell and a first fiber core. The second fiber includes a second fiber shell and a second fiber core; the first fiber core includes an antibacterial drug; the second fiber core includes an anti-inflammatory drug; and the second fiber shell includes a material with ROS-responsive properties. The first fiber shell and the first fiber core are mounted on one side of the receiving device using a coaxial electrospinning process. The second fiber shell and the second fiber core are mounted on the other side of the receiving device using the same coaxial electrospinning process. Coaxial electrospinning is performed simultaneously on both sides of the receiving device to form a conjugate electrospinning process, resulting in the drug-loaded layer. The antibacterial drug includes one or both of vancomycin and amoxicillin; the anti-inflammatory drug includes one or both of astragaloside A and cefadroxil. The coagulation drugs include thrombin; The membrane-covered stent is coated with bio-adhesive between the drug-loaded layer and the coagulation layer; The first fiber shell comprises polycaprolactone and polyethylene oxide; the first fiber core comprises polyvinylpyrrolidone and vancomycin; the second fiber shell comprises polycaprolactone and polyamide thioketone polymer; the second fiber core comprises polyvinylpyrrolidone and astragaloside A. The coagulation layer comprises polycaprolactone, polyethylene oxide, and thrombin; The mass ratio of polycaprolactone to polyethylene oxide is 7:3; the concentration of thrombin is 2~6 mg / mL.

5. A fiber film covering a membrane-coated scaffold prepared by the preparation method of claim 4.

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