Long-term implanted multi-layer coated prostate stent

Abstract

The invention relates to the technical field of medical apparatus and instruments, in particular to a long-term implanted multilayer coated prostate stent which comprises a nickel-titanium stent, a crown head is mounted at one end of the nickel-titanium stent, inner-layer anti-calcification is arranged in the nickel-titanium stent and the crown head, and middle-layer polyurethane is arranged outside the nickel-titanium stent and the crown head. Outer-layer porous polyurethane is arranged outside the middle-layer polyurethane; according to the invention, the surface of the nickel-titanium stent is coated with the polyurethane material, so that the damage to tissues is reduced, a relatively strong supporting effect is achieved, and a layer of polyurethane material which is easy to endothelialize is additionally arranged at the contact position of the outer layer of the nickel-titanium stent and the tissues, so that the stent is tightly attached to the tissues, and the displacement risk of the stent is effectively reduced; the middle layer is used for providing connection force between the nickel-titanium stent meshes and the inner and outer layers and blocking hyperplasia tissues; and the inner layer is provided with a layer of anti-calcification polyurethane film material, so that the urine can be prevented from crusting or crystallizing when flowing in the body.

Description

Technical Field

[0001] The invention relates to the technical field of medical devices, and in particular to a long-term implanted multi-layer coated prostate stent. Background Art

[0002] The prostate is a gland in the male reproductive system, connected to the bladder and urethra, with a sphincter below. As people age, long periods of sitting or other reasons cause the prostate to hypertrophy, which puts pressure on the urethra and causes urination difficulties, which in turn damages bladder function, resulting in urination difficulties, frequent urination, and urinary retention. As the disease worsens, urethral stones, urethral infections, and even kidney damage may occur. The main treatment methods currently used are medication or surgery. Medication is often ineffective, while surgery is prone to complications. With the development of medical technology, the use of prostate stents has become increasingly widespread. Prostate stents are made of memory alloy materials. The stents are assembled in vitro and can expand and restore their shape after being delivered to the patient's affected area, thereby propping up the patient's tissues to achieve a therapeutic effect. The tissue cells propped up by the stent cannot obtain oxygen supply due to ischemia, which eventually leads to the death of the hyperplastic tissue in the affected area, reducing the impact on urine flow until it returns to its original state, thereby achieving a therapeutic effect; Currently, most prostate stents are made of pure nickel-titanium tube cutting or nickel-titanium wire weaving, and are in direct contact with tissues in the body. Over time, complications may occur in the supported parts, and the stents may shift, causing local inflammation or tissue fibrosis. At the same time, due to limited supporting points, the entire prostate cannot be expanded, and the tissue cannot be effectively expanded. Most importantly, the stent needs to be lowered and removed after surgery, which may cause scratches on the tissue, difficulty in removal or other unpredictable problems in the process. Therefore, a long-term implantable multi-layer coated prostate stent is proposed to address the above problems. Summary of the invention

[0003] The purpose of the present invention is to provide a long-term implantable multi-layer coated prostate stent to solve the problem that most current prostate stents are made by cutting pure nickel-titanium tubes or weaving nickel-titanium wires, which are in direct contact with tissues in the body. After a long time, complications may occur in the supported parts, and the stent may be displaced, causing local inflammation or tissue fibrosis of the tissue. At the same time, due to limited supporting points, the entire prostate cannot be expanded, and the tissue cannot be effectively expanded. Most importantly, since the stent needs to be lowered and removed after surgery, scratches on the tissue may occur in the process, making removal difficult or other unpredictable problems may occur.

[0004] To achieve the above object, the present invention provides the following technical solutions: A multi-layer coated prostate stent for long-term implantation, comprising a nickel-titanium stent, a crown head is installed at one end of the nickel-titanium stent, an inner layer of anti-calcification is arranged inside the nickel-titanium stent and the crown head, an intermediate layer of polyurethane is arranged outside the nickel-titanium stent and the crown head, and an outer layer of porous polyurethane is arranged outside the intermediate layer of polyurethane; The raw materials of the inner layer anti-calcification polyurethane, the middle layer polyurethane and the outer layer porous polyurethane include but are not limited to one or more of Pellethane® 81A~76D, Elast-Eon™ 50D~90A, Tecoflex™ TPU EG60D~100A, Tecoflex™ TPU SG60D~80A, Carbothane™ 69~90A, and the molecular weight is 4-6 million Daltons.

[0005] As a further optimization of the present invention, the dissolving reagents for the inner layer anti-calcification polyurethane, the middle layer polyurethane and the outer layer porous polyurethane include but are not limited to a mixed solvent of one or more of N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran and dimethyl sulfoxide.

[0006] As a further optimization of the present invention, the tensile strength of the inner layer of anti-calcification polyurethane is 100-800Mpa, preferably 200-600Mpa, and most preferably 300-600Mpa. The inner layer of anti-calcification polyurethane is prepared by adding silicone and other fluorine-containing anti-calcification components during the preparation of the polyurethane film.

[0007] As a further optimized content of the present invention, wherein: the middle layer polyurethane is prepared by dipping method, natural leveling method or casting method, and the tensile strength of the middle layer polyurethane is 300-600Mpa.

[0008] As a further optimized content of the present invention, wherein: the outer layer of porous polyurethane is prepared by electrospinning, phase separation, dry method or weaving method, and the tensile strength of the outer layer of porous polyurethane is 300-500Mpa.

[0009] As a further optimization of the present invention, the outer layer of porous polyurethane is provided with a plurality of micropores inside, the pore size of the micropores is 20-60 microns, the porosity is 40%-90%, and the thickness of the outer layer of porous polyurethane is 10-200 microns.

[0010] As a further optimization of the present invention, the middle layer polyurethane is combined with the inner layer anti-calcification polyurethane and the outer layer porous polyurethane by a hot pressing coating method at a temperature of 120-150 degrees Celsius, and the middle layer polyurethane is combined with the nickel-titanium bracket by a hot pressing coating method at a temperature of 120-150 degrees Celsius.

[0011] As a further optimized content of the present invention, it includes a nickel-titanium stent, characterized in that a crown head is installed at one end of the nickel-titanium stent, an inner layer of anti-calcification is provided inside the nickel-titanium stent and the crown head, and an outer layer of porous polyurethane is provided outside the nickel-titanium stent and the crown head.

[0012] As a further optimized content of the present invention, the nickel-titanium stent and the outer layer of porous polyurethane are combined by a hot pressing coating method at a temperature of 120-150 degrees Celsius.

[0013] Compared with the prior art, the present invention has the following beneficial effects: 1. In the present invention, the surface of the nickel-titanium stent is coated with a polyurethane material, which contacts the tissue surface through the polymer material, reduces damage to the tissue, and plays a strong supporting role. A layer of polyurethane material that is easy to endothelialize is added at the contact position between the outer layer of the nickel-titanium stent and the tissue, so that the stent and the tissue fit closely, effectively reducing the risk of stent displacement; the middle layer provides a connection force between the nickel-titanium stent mesh and the inner and outer layers, and blocks the hyperplastic tissue; the inner layer has a layer of anti-calcification polyurethane coating material, which can ensure that urine flows in the body without crusting or crystallization; 2. In the present invention, the materials are all medical-grade materials that can be implanted for a long time and have almost no rejection reaction with the human body. Therefore, they can be implanted for a long time without being removed from the body, reducing secondary damage to the patient and effectively avoiding recurrence of the disease. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the film structure of the inner layer of anti-calcification polyurethane, the middle layer of polyurethane, and the outer layer of porous polyurethane; Figure 3 It is a schematic diagram of the inner layer of anti-calcification polyurethane and the outer layer of porous polyurethane coating structure of the present invention.

[0015] In the figure: 1. Inner layer of anti-calcification polyurethane; 2. Nickel-titanium stent; 3. Crown head; 4. Middle layer of polyurethane; 5. Outer layer of porous polyurethane. DETAILED DESCRIPTION

[0016] Embodiment 1: See also Figure 1-2 , the present invention provides a technical solution: A long-term implanted multi-layer coated prostate stent comprises a nickel-titanium stent 2, a crown head 3 is installed at one end of the nickel-titanium stent 2, an inner layer of anti-calcification 1 is arranged inside the nickel-titanium stent 2 and the crown head 3, an intermediate layer of polyurethane 4 is arranged outside the nickel-titanium stent 2 and the crown head 3, and an outer layer of porous polyurethane 5 is arranged outside the intermediate layer of polyurethane 4; the raw materials of the inner layer of anti-calcification polyurethane 1, the intermediate layer of polyurethane 4 and the outer layer of porous polyurethane 5 include but are not limited to one or more of Pellethane® 81A~76D, Elast-Eon™ 50D~90A, Tecoflex™ TPU EG60D~100A, Tecoflex™ TPU SG60D~80A, Carbothane™ 69~90A, and the molecular weight is 4-6 million Daltons.

[0017] The dissolving agents of the inner anti-calcification polyurethane 1, the middle layer polyurethane 4 and the outer porous polyurethane 5 include but are not limited to a mixed solvent of one or more of N,N-dimethylformamide DMF, N,N-dimethylacetamide DMAc, tetrahydrofuran THF and dimethyl sulfoxide DMSO. The tensile strength of the inner anti-calcification polyurethane 1 is 100-800Mpa, preferably 200-600Mpa, and most preferably 300-600Mpa. The inner anti-calcification polyurethane 1 is added with siloxane and other fluorine-containing anti-calcification components in the process of preparing the polyurethane film. The middle layer polyurethane 4 is prepared by dipping and natural leveling. The outer porous polyurethane 5 is prepared by electrospinning, phase separation, dry method or weaving method, the tensile strength of the outer porous polyurethane 5 is 300-500Mpa, the outer porous polyurethane 5 is provided with a plurality of micropores, the pore diameter of the micropores is 20-60 microns, the porosity is 40%-90%, the thickness of the outer porous polyurethane 5 is 10-200 microns, the middle layer polyurethane 4 is combined with the inner layer anti-calcification polyurethane 1 and the outer layer porous polyurethane 5 by hot pressing and coating method, the temperature is 120-150 degrees Celsius, the middle layer polyurethane 4 is combined with the nickel-titanium bracket 2 by hot pressing and coating method, the temperature is 120-150 degrees Celsius.

[0018] Preparation process: Preparation of outer thermoplastic polyurethane porous membrane: Carbothane™ 90A is dissolved in N,N-dimethylacetamide (DMAc) to prepare a 5-20% (m / v) thermoplastic polyurethane spinning solution. After filtering and degassing, the spinning solution is filled into a glass syringe of an electrospinning machine. The liquid discharge speed of the syringe is adjusted to 0.01 ml / s-0.5 ml / s, the needle tip is 15-25 cm away from the mandrel collector, the mandrel rotation speed is 30-70 rpm, and the voltage difference is set to 15-30 kV. After spinning for 4 hours, the membrane is placed in a vacuum oven at 60-100 ° C and dried for 8-12 hours. The formed polyurethane membrane is ultrasonically cleaned with purified water for 10 minutes, ultrasonically cleaned with ethanol for 10-30 minutes, and then placed in a 60-100 ° C oven for drying. The cleaned polyurethane membrane is subjected to low-temperature and low-pressure plasma treatment at a treatment temperature of 20-80 ° C, a treatment time of 2-10 minutes, an argon working gas, and a gas pressure of 10-250 Pa to obtain an outer layer of thermoplastic polyurethane porous membrane. Preparation of middle layer thermoplastic polyurethane film: Dissolve Carbothane™ 90A in tetrahydrofuran (THF) to prepare 8~15% (m / v) thermoplastic polyurethane solution, filter and degas, pour into the leveling mold, put into a vacuum oven for drying for 24~72 hours, take out, vacuum degree is 3*10-3~1*10-6Pa, temperature is 25~80℃, take out, soak in water and demould, and then get the middle layer thermoplastic polyurethane film; Preparation of inner anti-calcification thermoplastic polyurethane membrane and preforming of prostate stent: Dissolve Carbothane™ 90A in tetrahydrofuran (THF) and N,N-dimethylacetamide (DMAc) to prepare a 10-15% (m / v) thermoplastic polyurethane solution with a solvent ratio of 5:2. Add 0.3%-3% siloxane during the dissolution process for mixed dissolution. After sufficient dissolution, pour the solution into the mold with the bracket installed. Place the mold in an oven for drying at a temperature of 50-100°C for 24 hours. After complete drying, separate the mold for demoulding. Stent complete coverage: The combination of the inner anti-calcification polyurethane membrane and the stent, the middle polyurethane membrane, and the outer thermoplastic polyurethane porous membrane are arranged neatly in order. The outermost layer is fixed with a heat shrink tube and placed in a heat sealing machine for compression processing at a temperature of 130°C for 5 to 20 seconds. After the heat sealing is completed, the stent is taken out and the three-layer coated prostate stent is completed.

[0019] Embodiment 2: See also Figure 1 and Figure 3 , the present invention provides a technical solution: A long-term implanted multi-layer coated prostate stent includes a nickel-titanium stent 2, characterized in that a crown head 3 is installed at one end of the nickel-titanium stent 2, an inner layer of anti-calcification 1 is provided inside the nickel-titanium stent 2 and the crown head 3, an outer layer of porous polyurethane 5 is provided outside the nickel-titanium stent 2 and the crown head 3, and the nickel-titanium stent 2 and the outer layer of porous polyurethane 5 are combined by a hot pressing coating method at a temperature of 120-150 degrees Celsius.

[0020] Preparation process: Preparation of outer thermoplastic polyurethane porous membrane: Pellethane®81A was dissolved in a mixed solvent of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF) to prepare a 10-20% (m / v) thermoplastic polyurethane casting solution. After filtering and degassing, an appropriate amount of the casting solution was cast on a polytetrafluoroethylene plate, and a 400um film was scraped with a scraper, and then immersed in a gradient temperature ethanol coagulation bath for 10-30 minutes. The solution was then immersed in deionized water for 1 hour, and then taken out and placed in a vacuum oven at 60-80°C for 8-12 hours for drying. The formed polyurethane film was ultrasonically cleaned with purified water for 10 minutes, and then ultrasonically cleaned with one or more reagents of ethanol, methanol, and acetone for 10-30 minutes, and then placed in a 60-100°C oven for drying. The cleaned polyurethane film was subjected to low-temperature and low-pressure plasma treatment at a treatment temperature of 20-100°C, a treatment time of 2-10 minutes, an argon gas, and a gas pressure of 10-250Pa, to obtain a thermoplastic polyurethane porous membrane. Preparation of inner anti-calcification thermoplastic polyurethane membrane and preforming of prostate stent: Pellethane®70A was dissolved in tetrahydrofuran (THF) and N,N-dimethylacetamide (DMAc) to prepare a 10~15% (m / v) thermoplastic polyurethane solution with a solvent ratio of 3:2. During the dissolution process, 0.3%~3% siloxane was added for mixed dissolution. After sufficient dissolution, the solution was poured into the mold with the bracket installed. The mold was placed in an oven for drying at a temperature of 50~100℃ for 24 hours. After complete drying, the mold was separated for demoulding. Stent complete coverage: The combination of the inner anti-calcification polyurethane membrane and the stent, the middle polyurethane membrane, and the outer thermoplastic polyurethane porous membrane are arranged neatly in order. The outermost layer is fixed with a heat shrink tube and placed in a heat sealing machine for compression processing at a temperature of 130°C for 5 to 20 seconds. After the heat sealing is completed, the stent is taken out and the three-layer coated prostate stent is completed.

[0021] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. The above is only a preferred implementation of the present invention. It should be pointed out that due to the limitations of textual expression and the objective existence of infinite specific structures, ordinary technicians in this technical field can make several improvements, modifications or changes without departing from the principles of the present invention, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the inventive concept and technical solution to other occasions without improvement, should be regarded as the protection scope of the present invention.

Claims

1. A multi-layer coated prostate stent for long-term implantation, comprising a nickel-titanium stent (2), characterized in that: A crown head (3) is installed at one end of the nickel-titanium stent (2); an inner layer of anti-calcification (1) is provided inside the nickel-titanium stent (2) and the crown head (3); an intermediate layer of polyurethane (4) is provided outside the nickel-titanium stent (2) and the crown head (3); and an outer layer of porous polyurethane (5) is provided outside the intermediate layer of polyurethane (4); The raw materials of the inner layer anti-calcification polyurethane (1), the middle layer polyurethane (4) and the outer layer porous polyurethane (5) include but are not limited to one or more of Pellethane® 81A~76D, Elast-Eon™ 50D~90A, Tecoflex™ TPU EG60D~100A, Tecoflex™ TPU SG60D~80A, and Carbothane™ 69~90A, and the molecular weight is 4-6 million Daltons.

2. A long-term implantable multi-layer coated prostate stent according to claim 1, characterized in that: The dissolving reagents for the inner layer anti-calcification polyurethane (1), the middle layer polyurethane (4) and the outer layer porous polyurethane (5) include but are not limited to a mixed solvent of one or more of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), tetrahydrofuran (THF) and dimethyl sulfoxide (DMSO).

3. The multi-layer coated prostate stent for long-term implantation according to claim 1, characterized in that: The tensile strength of the inner layer anti-calcification polyurethane (1) is 100-800Mpa, preferably 200-600Mpa, and most preferably 300-600Mpa. The inner layer anti-calcification polyurethane (1) is prepared by adding siloxane and other fluorine-containing anti-calcification components during the preparation of the polyurethane film.

4. The multi-layer coated prostate stent for long-term implantation according to claim 1, characterized in that: The intermediate layer polyurethane (4) is prepared by a dipping method, a natural leveling method or a casting method, and the tensile strength of the intermediate layer polyurethane (4) is 300-600 Mpa.

5. The multi-layer coated prostate stent for long-term implantation according to claim 1, characterized in that: The outer layer of porous polyurethane (5) is prepared by electrostatic spinning, phase separation, dry method or weaving method, and the tensile strength of the outer layer of porous polyurethane (5) is 300-500Mpa.

6. The multi-layer coated prostate stent for long-term implantation according to claim 1, characterized in that: The outer layer of porous polyurethane (5) is provided with a plurality of micropores therein, the micropores have a pore diameter of 20-60 micrometers, a porosity of 40%-90%, and the thickness of the outer layer of porous polyurethane (5) is 10-200 micrometers.

7. The multi-layer coated prostate stent for long-term implantation according to claim 1, characterized in that: The middle layer polyurethane (4) is combined with the inner layer anti-calcification polyurethane (1) and the outer layer porous polyurethane (5) by a hot pressing coating method at a temperature of 120-150 degrees Celsius. The middle layer polyurethane (4) is combined with the nickel-titanium stent (2) by a hot pressing coating method at a temperature of 120-150 degrees Celsius.

8. The multi-layer coated prostate stent for long-term implantation according to claim 1, characterized in that: The invention comprises a nickel-titanium stent (2), characterized in that a crown head (3) is installed at one end of the nickel-titanium stent (2), an inner layer of anti-calcification (1) is provided inside the nickel-titanium stent (2) and the crown head (3), and an outer layer of porous polyurethane (5) is provided outside the nickel-titanium stent (2) and the crown head (3).

9. The multi-layer coated prostate stent for long-term implantation according to claim 1, characterized in that: The nickel-titanium stent (2) and the outer layer of porous polyurethane (5) are combined by a hot pressing coating method at a temperature of 120-150 degrees Celsius.

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