Balloon microcatheter and preparation method thereof

Abstract

The invention relates to the field of medical instruments, in particular to a balloon microcatheter and a preparation method thereof, and the balloon microcatheter comprises a microcatheter and a balloon; the balloon is arranged at the far end of the micro catheter; the microcatheter comprises a lining layer, a reinforcing layer, a high-molecular polymerization layer, a protective layer and a hydrophilic layer, the lining layer, the reinforcing layer and the high-molecular polymerization layer are sequentially arranged from inside to outside in a sleeving manner; the high-molecular polymerization layer is coated with the protective layer; the protective layer is coated with the hydrophilic layer, and the hydrophilic layer is connected with the protective layer through molecular bonds; the protective layer is arranged between the hydrophilic layer and the high-molecular polymerization layer, so that the aging influence of light, oxygen, microorganisms, moisture and chemical media on the high-molecular polymerization layer is effectively relieved, the aging rate of the high-molecular polymerization layer is relieved, the service life of the high-molecular polymerization layer is prolonged, and then the service life of the microcatheter is prolonged; meanwhile, by adding the protective layer, the anti-aging capability of the microcatheter can still be kept when the thickness of the high-molecular polymerization layer is relatively thin.

Description

Technical Field

[0001] The present invention relates to the field of medical devices, and in particular to a balloon microcatheter and a preparation method thereof. Background Art

[0002] With the continuous improvement of medical technology, clinical requirements for the performance of medical catheters are becoming higher and higher, especially for microcatheters used in nerves and blood vessels. Due to the continuous improvement of clinical needs, the outer diameter of microcatheters needs to be made smaller while the inner diameter remains unchanged, resulting in the wall thickness of the outer layer of the tube becoming thinner and thinner.

[0003] The outer material of the microcatheter will inevitably undergo an aging process during processing and use. Too rapid aging will cause its physical properties to deteriorate, such as becoming hard, sticky, brittle, discolored or losing strength. The thinner the wall, the easier it is to age and degenerate, causing the microcatheter to be damaged and unusable, thereby shortening the service life of the microcatheter.

[0004] Based on the shortcomings of the existing technology, it is urgent to study a balloon microcatheter and a preparation method thereof to solve the above problems. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a balloon microcatheter and a preparation method thereof. The present invention effectively mitigates the aging effect by setting a protective layer between the hydrophilic layer and the polymer layer, thereby increasing the service life of the microcatheter.

[0006] The present invention provides a balloon microcatheter, comprising a microcatheter and a balloon;

[0007] The balloon is arranged at the distal end of the microcatheter;

[0008] The microcatheter comprises an inner lining layer, a reinforcing layer, a polymer layer, a protective layer and a hydrophilic layer; the inner lining layer, the reinforcing layer and the polymer layer are sequentially sleeved from the inside to the outside; the protective layer is coated on the polymer layer; the hydrophilic layer is coated on the protective layer and connected to the protective layer through a molecular bond.

[0009] Furthermore, the thickness of the protective layer is 5-10 um.

[0010] Furthermore, the material of the protective layer includes one or more of polyparaxylene or polyurethane.

[0011] Furthermore, the material of the hydrophilic layer can form a hydrogel when in contact with water.

[0012] Furthermore, the material of the hydrophilic layer includes any one or a combination of several of protein, collagen, albumin, fibrin, elastin, polypeptide, oligonucleotide, polysaccharide, hyaluronic acid, gelatin, chitosan, alginate, cellulose, carboxymethyl cellulose, hydroxymethyl cellulose, hydroxypropyl cellulose, dextran, polyether, polyethylene glycol, polyethylene oxide, polypropylene glycol, polylactam, polyvinyl pyrrolidone, polyacrylate, polyurethane, polyanhydride, polyamino acid, polycarboxylic acid, polyamide, polyvinyl alcohol, and polyphosphazene.

[0013] Furthermore, the thickness of the polymer layer is 0.001-0.005 inches.

[0014] Further, the bending diameter of the microcatheter is 4-6 mm;

[0015] The bending angle of the microcatheter is 0-180°.

[0016] Furthermore, the inner diameter of the lining layer ranges from 0.016 to 0.027 inches.

[0017] Furthermore, the protective layer has chemical stability to the components of the hydrophilic layer.

[0018] Another aspect of the present invention also includes a method for preparing a balloon microcatheter, the method comprising:

[0019] Providing a prefabricated microcatheter; the prefabricated microcatheter comprises, from inside to outside, an inner lining layer, a reinforcement layer and a polymer layer;

[0020] Coating an adhesion enhancer on the side wall of the prefabricated microcatheter, uniformly coating the protective material on the side wall of the prefabricated microcatheter, and performing a curing treatment to form a protective layer outside the prefabricated microcatheter;

[0021] The hydrophilic material is evenly coated on the protective layer, and the protective layer and the hydrophilic layer are connected by molecular bonds through photocuring to form a microcatheter having a hydrophilic layer and a protective layer;

[0022] The balloon is arranged at the distal end of the microcatheter to form a balloon microcatheter.

[0023] Implementing the embodiments of the present invention has the following beneficial effects:

[0024] The present invention can effectively isolate the polymer layer from direct contact with the outside world by arranging a protective layer between the hydrophilic layer and the polymer layer, effectively slow down the aging effect of light, oxygen, microorganisms and chemical media on the polymer layer, slow down the aging rate of the polymer layer, and increase the service life of the polymer layer, thereby increasing the service life of the microcatheter; at the same time, by adding the protective layer, it is ensured that when the thickness of the polymer layer is relatively thin, the anti-aging ability of the microcatheter can still be maintained. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments or prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0026] Figure 1 is a structural diagram of the balloon microcatheter described in this embodiment;

[0027] Figure 2 Flow chart of the method for preparing the balloon microcatheter described in this embodiment.

[0028] Among them, the reference numerals in the figure correspond to:

[0029] 1- lining layer; 2- reinforcing layer; 3- polymer layer; 4- protective layer; 5- hydrophilic layer. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0032] In view of the defects of the prior art, the present invention provides a protective layer between the hydrophilic layer and the polymer layer, thereby effectively isolating the polymer layer from direct contact with the outside world, effectively slowing down the aging effects of light, oxygen, microorganisms and chemical media on the polymer layer, slowing down the aging rate of the polymer layer, and increasing the service life of the polymer layer, thereby increasing the service life of the microcatheter; at the same time, by adding a protective layer, it is ensured that when the thickness of the polymer layer is relatively thin, the anti-aging ability of the microcatheter can still be maintained, making the thickness adaptability of the microcatheter wider.

[0033] See attached Figure 1-2 The present embodiment provides a balloon microcatheter, comprising a microcatheter and a balloon; the balloon is arranged at the distal end of the microcatheter; the microcatheter comprises an inner lining layer 1, a reinforcing layer 2, a polymer layer 3, a protective layer 4 and a hydrophilic layer 5; the inner lining layer 1, the reinforcing layer 2, and the polymer layer 3 are sequentially sleeved from the inside to the outside; the protective layer 4 is coated on the polymer layer 3; the hydrophilic layer 5 is coated on the protective layer 4, and is connected to the protective layer 4 by molecular bonds to form a stable connection.

[0034] It should be noted that: with the continuous improvement of the performance of the microcatheter, the wall thickness of the existing polymer layer 3 is continuously reduced. Since the thinner the thickness, the easier it is for the polymer layer 3 to age, and the thinner the thickness, the lower the content of processing aids in the microcatheter, and the stabilizer in the microcatheter will continuously migrate to the surface of the microcatheter, the thinner the thickness, the shorter the residence time of the stabilizer on the microcatheter, and the faster the loss rate, which leads to a continuous decrease in the anti-aging ability of the polymer layer 3, and then leads to a significant shortening of the service life of the microcatheter.

[0035] It should also be noted that: in order to increase the service life of the microcatheter, this embodiment changes the microcatheter from an original four-layer structure to a five-layer structure, specifically, a protective layer 4 is set between the hydrophilic layer 5 and the polymer layer 3. The protective layer has good moisture resistance, chemical barrier properties, gas barrier properties, light barrier properties, chemical stability, ultraviolet stability, thermal stability and a certain mechanical tensile strength. By setting the protective layer 4, the polymer layer 3 can be effectively isolated from direct contact with the outside world, and the aging effects of light, oxygen, microorganisms and chemical media on the polymer layer 3 are effectively slowed down, the aging rate of the polymer layer 3 is shortened, and the service life of the polymer layer 3 is increased, thereby increasing the service life of the microcatheter; at the same time, by adding the protective layer 4, it is ensured that when the thickness of the polymer layer 3 is relatively thin, the anti-aging ability of the microcatheter can still be maintained, so that the thickness of the microcatheter is more adaptable.

[0036] In some possible embodiments, the thickness of the protective layer 4 is 5-10um, and the protective layer 4 protects the polymer layer 3 to prevent the polymer layer 3 from aging too quickly. At the same time, the thickness of the protective layer 4 is 5-10um, which will not have much impact on the size and performance of the microcatheter. That is, under the premise of avoiding the polymer layer 3 from aging too quickly, it will not have much impact on the size and performance of the microcatheter.

[0037] In some possible embodiments, the material of the protective layer 4 includes one or more of polyparaxylene or polyurethane. By setting the protective layer 4 to the above materials, it can be ensured that the protective layer 4 has good moisture resistance, chemical barrier properties, gas barrier properties, light barrier properties, chemical stability, UV stability, thermal stability and a certain mechanical tensile strength, so that the protective layer 4 can protect the polymer layer 3 and prevent the polymer layer 3 from aging too quickly.

[0038] In some possible embodiments, the material of the hydrophilic layer 5 can form a hydrogel when in contact with water, which has high lubricity and wear resistance, thereby reducing the friction between the microcatheter and the blood vessel; a protective layer 4 is added between the polymer layer 3 and the hydrophilic layer 5 to enhance the anti-aging ability of the polymer layer 3 while also connecting the hydrophilic layer 5.

[0039] In some possible embodiments, the material of the hydrophilic layer 5 includes any one or a combination of several of proteins, collagen, albumin, fibrin, elastin, polypeptides, oligonucleotides, polysaccharides, hyaluronic acid, gelatin, chitosan, alginate, cellulose, carboxymethyl cellulose, hydroxymethyl cellulose, hydroxypropyl cellulose, dextran, polyether, polyethylene glycol, polyethylene oxide, polypropylene glycol, polylactam, polyvinyl pyrrolidone, polyacrylate, polyurethane, polyanhydride, polyamino acid, polycarboxylic acid, polyamide, polyvinyl alcohol, and polyphosphazene.

[0040] In some possible embodiments, the thickness of the polymer layer 3 is 0.001-0.005 inches.

[0041] In some possible embodiments, the bending diameter of the microcatheter is 4-6 mm; under the premise that the bending diameter of the microcatheter is 4-6 mm, the bending angle of the microcatheter is 0-180°, and under the premise that the bending diameter of the microcatheter is 4-6 mm, the protective layer 4 will not break, which significantly improves the mechanical tensile strength of the microcatheter.

[0042] In some possible embodiments, the inner diameter of the liner layer 1 ranges from 0.016 to 0.027 inches.

[0043] In some possible embodiments, the protective layer 4 is chemically stable to the components of the hydrophilic layer 5 .

[0044] Another aspect of the present invention also includes a method for preparing a balloon microcatheter, the method comprising:

[0045] S101: providing a prefabricated microcatheter; the prefabricated microcatheter comprises, from inside to outside, an inner lining layer, a reinforcement layer and a polymer layer;

[0046] S102: coating an adhesion enhancer on the side wall of the prefabricated microcatheter, uniformly coating a protective material on the side wall of the prefabricated microcatheter, and performing a curing treatment to form a protective layer outside the prefabricated microcatheter;

[0047] S103: uniformly coating a hydrophilic material on the protective layer, and the protective layer and the hydrophilic layer are connected by a molecular bond through a photocuring process, so as to form a microcatheter having a hydrophilic layer and a protective layer;

[0048] S104: Disposing a balloon at the distal end of the microcatheter to form a balloon microcatheter.

[0049] Embodiment 1

[0050] See attached Figure 1-2 The present embodiment provides a balloon microcatheter, comprising a microcatheter and a balloon; the microcatheter comprises, from the inside to the outside, an inner lining layer 1, a reinforcing layer 2, a polymer layer 3, a protective layer 4 and a hydrophilic layer 5. The balloon microcatheter in the present embodiment can not only slow down the erosion of the polymer layer 3 by the external environment by setting the protective layer 4, but also isolate the polymer layer 3 from the contact with the solvent, reduce the leaching of the anti-aging agent from the surface of the polymer layer 3, reduce the consumption rate of the anti-aging agent, and thus indirectly enhance the anti-aging ability of the microcatheter.

[0051] In some possible implementations, the lining layer 1 is made of polytetrafluoroethylene; and the reinforcement layer 2 is formed by weaving or winding metal wires.

[0052] In some possible implementations, when the thickness of the polymer layer 3 is 0.001 inches, since the thickness of the polymer layer 3 is relatively thin relative to the thickness of the existing polymer layer 3, this will result in a lower content of processing aids in the polymer layer 3, and the stabilizer of the polymer layer 3 will continuously migrate to the surface of the polymer layer 3, which will result in an accelerated loss rate, and further result in a significant shortening of the service life of the polymer layer 3; and by providing a protective layer 4 on the outer surface of the polymer layer 3, it is possible to slow down the erosion of the polymer layer 3 by the outside world, and it is also possible to isolate the polymer layer 3 from contact with the solvent, thereby reducing the leaching of the anti-aging agent from the surface of the polymer layer 3, and reducing the anti-aging agent. The consumption rate of the aging agent is reduced, thereby improving the anti-aging ability of the polymer layer 3; at the same time, by setting a protective layer 4 with good moisture resistance, chemical barrier properties, gas barrier properties, light barrier properties, chemical stability, ultraviolet stability, thermal stability and a certain mechanical tensile strength, the aging effects of light, oxygen, microorganisms and chemical media on the polymer layer 3 are effectively slowed down, the aging rate of the polymer layer 3 is shortened, the service life of the polymer layer 3 is increased, and the service life of the microcatheter is increased; at the same time, by adding the protective layer 4, it is ensured that when the thickness of the polymer layer 3 is relatively thin, the anti-aging ability of the microcatheter can still be maintained, so that the thickness of the microcatheter is more adaptable.

[0053] In another possible embodiment, when the thickness of the polymer layer 3 is 0.005 inches, although it is the maximum thickness of the polymer layer 3, there will be a problem of too fast aging of the polymer layer 3. By setting the protective layer 4, the aging effects of light, oxygen, microorganisms and chemical media on the polymer layer 3 are effectively slowed down, and the aging rate of the polymer layer 3 is shortened. At the same time, by setting the protective layer 4 on the outer surface of the polymer layer 3, the erosion of the polymer layer 3 by the outside world is further slowed down and the contact between the polymer layer 3 and the solvent is isolated, thereby reducing the leaching of the anti-aging agent from the surface of the polymer layer 3 and reducing the consumption rate of the anti-aging agent, thereby improving the anti-aging ability of the polymer layer 3.

[0054] In some other possible embodiments, the protective layer 4 has good chemical stability, UV stability, thermal stability and a certain mechanical tensile strength.

[0055] The protective layer 4 has thermal stability, which means that the protective layer 4 has thermal stability under the condition of not higher than 60 degrees for a long time.

[0056] In some possible embodiments, the protective layer 4 is chemically stable to the components of the hydrophilic layer 5 .

[0057] In some other possible embodiments, after the protective layer 4 is cured, a dense protective film is formed on the outer surface of the polymer layer 3 , and the protective film has moisture-proof, chemical barrier, gas barrier and light barrier properties.

[0058] Specifically, moisture resistance means that the protective film can block or slow down the effect of moisture in the air on the polymer layer 3; chemical barrier property means that the protective film can block or reduce the erosion of the polymer layer 3 by the chemical components in the hydrophilic layer liquid; gas barrier property means that the protective film has a low permeability to oxygen in the air, thereby reducing the aging rate of the polymer layer 3; light barrier property means that the protective film can block the direct exposure of ultraviolet rays to the polymer layer 3, thereby reducing the aging rate of the polymer layer 3; it can be seen that by forming a dense protective film on the outer surface of the polymer layer 3, the polymer layer 3 can be protected in many ways, thereby improving the anti-aging ability of the polymer layer 3.

[0059] Specifically, the thickness of the protective layer 4 can be 5-6um, 5-7um, 5-8um, 5-9um, 5-10um, 6-8um, 6-9um, 7-10um or 8-10um, etc.

[0060] Specifically, the thickness of the polymer layer 3 can be 0.001-0.002 inches, 0.001-0.003 inches, 0.001-0.004 inches, 0.001-0.005 inches, 0.002-0.003 inches, 0.002-0.004 inches, 0.002-0.005 inches, 0.003-0.004 inches or 0.003-0.005 inches, etc.

[0061] Specifically, when the thickness of the polymer layer 3 is 0.002-0.003 inches and the thickness of the protective layer 4 is 10um, the aging time corresponding to the polymer layer 3 is more than 36 months; when the thickness of the polymer layer 3 is 0.001-0.002 inches and the required thickness of the protective layer 4 is 10um, the aging time corresponding to the polymer layer 3 is 22-28 months; obviously, when the thickness of the protective layer 4 is the same, the thicker the polymer layer 3, the longer the corresponding aging time, that is, the better the anti-aging ability.

[0062] When the thickness of the polymer layer 3 is 0.001-0.002 inches, the thickness of the protective layer 4 is 8um, and the corresponding aging time of the polymer layer 3 is 16-24 months; when the thickness of the polymer layer 3 is 0.001-0.002 inches, the thickness of the protective layer 4 is 6um, and the corresponding aging time of the polymer layer 3 is 14-20 months; obviously, when the thickness of the polymer layer 3 is the same, the thicker the protective layer 4, the longer the corresponding aging time, that is, the better the anti-aging ability.

[0063] Specifically, when the thickness of the polymer layer 3 is the same, the anti-aging ability of the polymer layer 3 can be improved by increasing the thickness of the protective layer 4; when the thickness of the protective layer 4 is the same, the thicker the polymer layer 3 is, the better the anti-aging ability of the polymer layer 3 is.

[0064] In some possible embodiments, the bending diameter of the microcatheter is 4-6 mm; under the premise that the bending diameter of the microcatheter is 4-6 mm, the bending angle of the microcatheter is 0-180°, and under the premise that the bending diameter of the microcatheter is 4-6 mm, the protective layer 4 will not break, which significantly improves the mechanical tensile strength of the microcatheter.

[0065] Specifically, the tensile strength of the microcatheter provided with the protective layer 4 is 5-10N.

[0066] Specifically, the tensile strength of the protective layer 4 is 6000-10000 psi.

[0067] When the thickness of the polymer layer 3 is 0.002-0.003 inches and the thickness of the protective layer 4 is 10um, the tensile strength of the microcatheter is 8-10N; when the thickness of the polymer layer 3 is 0.001-0.002 inches and the thickness of the protective layer 4 is 10um, the tensile strength of the microcatheter is 5-8N; obviously, when the thickness of the protective layer 4 is the same, the thicker the polymer layer 3, the better the corresponding tensile strength.

[0068] When the thickness of the polymer layer 3 is 0.002-0.003 inches, the thickness of the protective layer 4 is 8um, and the tensile strength of the microcatheter is 8-9N; when the thickness of the polymer layer 3 is 0.002-0.003 inches, the thickness of the protective layer 4 is 10um, and the tensile strength of the microcatheter is 8-10N; obviously, when the thickness of the polymer layer 3 is the same, the thicker the thickness of the protective layer 4, the better the corresponding tensile strength.

[0069] Specifically, the anti-aging ability of the polymer layer 3 can be improved by increasing the UV blocking rate, density and thickness of the protective layer 4; this embodiment gradually improves the protective ability of the protective layer 4 while ensuring the tensile strength of the protective layer 4 by successively increasing the UV blocking rate, density and thickness, thereby gradually improving the anti-aging ability of the polymer layer 3, avoiding the loss of the polymer layer 3, and extending the life of the polymer layer 3.

[0070] Another aspect of the present invention also includes a method for preparing a balloon microcatheter, the method comprising:

[0071] S101: providing a prefabricated microcatheter; the prefabricated microcatheter comprises, from inside to outside, an inner lining layer, a reinforcement layer and a polymer layer;

[0072] S102: coating an adhesion enhancer on the side wall of the prefabricated microcatheter, uniformly coating a protective material on the side wall of the prefabricated microcatheter, and performing a curing treatment to form a protective layer outside the prefabricated microcatheter;

[0073] S103: uniformly coating a hydrophilic material on the protective layer, and the protective layer and the hydrophilic layer are connected by a molecular bond through a photocuring process, so as to form a microcatheter having a hydrophilic layer and a protective layer;

[0074] S104: Disposing a balloon at the distal end of the microcatheter to form a balloon microcatheter.

[0075] In some other possible embodiments, step S102 includes:

[0076] An adhesion enhancer is coated on the side wall of the prefabricated microcatheter, and a protective material is coated on the surface of the polymer layer by physical vapor deposition, physical dipping, brushing or spraying, and then cured to form a protective layer outside the prefabricated microcatheter; the protective layer prepared by the above method has good performance and good adhesion.

[0077] Specifically, the adhesion enhancer is a silane coupling agent.

[0078] In some possible embodiments, the step of providing a prefabricated microcatheter includes:

[0079] S1011: Provide mandrel and prefabricated microcatheter;

[0080] S1012: coating a lubricating material on the outer side of the mandrel to form a mandrel having a lubricating layer;

[0081] S1013: placing the prefabricated microcatheter on the outside of the core shaft;

[0082] S1014: placing a thermoplastic tube sleeve on the outer surface of the prefabricated microcatheter, and fixing the prefabricated microcatheter to a catheter forming device to fuse the prefabricated microcatheter, cooling for a period of time, and peeling off the heat shrink tube.

[0083] In some possible implementations, step S103 includes:

[0084] The hydrophilic material is evenly coated on the protective layer, and the protective layer and the hydrophilic layer are connected by molecular bonds through photocuring;

[0085] The core shaft is removed from the prefabricated microcatheter to form a microcatheter having a hydrophilic layer and a protective layer; by using the core shaft, deformation of the lining layer, the reinforcing layer, the polymer layer, the protective layer and the hydrophilic layer during preparation can be avoided, the lining layer, the reinforcing layer, the polymer layer, the protective layer and the hydrophilic layer are ensured to be concentrically arranged, and the mechanical properties of the microcatheter are further ensured.

[0086] Although the present invention has been described through preferred embodiments, the present invention is not limited to the embodiments described herein but includes various changes and modifications that may be made without departing from the scope of the present invention.

[0087] In this document, the directional words such as front, back, top, and bottom are defined by the positions of the components in the drawings and the positions of the components relative to each other, and are only for the sake of clarity and convenience in expressing the technical solution. It should be understood that the use of the directional words should not limit the scope of protection claimed in the present invention.

[0088] In the absence of conflict, the above embodiments and features in the embodiments can be combined with each other.

[0089] The above disclosure is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A balloon microcatheter, characterized in that: Includes microcatheters and balloons; The balloon is arranged at the distal end of the microcatheter; The microcatheter comprises an inner lining layer (1), a reinforcing layer (2), a polymer layer (3), a protective layer (4) and a hydrophilic layer (5); the inner lining layer (1), the reinforcing layer (2) and the polymer layer (3) are sequentially sleeved from the inside to the outside; the protective layer (4) is coated on the polymer layer (3); the hydrophilic layer (5) is coated on the protective layer (4) and is connected to the protective layer (4) via a molecular bond.

2. The balloon microcatheter according to claim 1, characterized in that: The thickness of the protective layer (4) is 5-10 um.

3. The balloon microcatheter according to claim 1, characterized in that: The material of the protective layer (4) includes one or more of polyparaxylene or polyurethane.

4. The balloon microcatheter according to claim 1, characterized in that: The material of the hydrophilic layer (5) can form a hydrogel when in contact with water.

5. The balloon microcatheter according to claim 4, characterized in that: The material of the hydrophilic layer (5) includes any one or a combination of several of proteins, collagen, albumin, fibrin, elastin, polypeptides, oligonucleotides, polysaccharides, hyaluronic acid, gelatin, chitosan, alginate, cellulose, carboxymethyl cellulose, hydroxymethyl cellulose, hydroxypropyl cellulose, dextran, polyether, polyethylene glycol, polyethylene oxide, polypropylene glycol, polylactam, polyvinyl pyrrolidone, polyacrylate, polyurethane, polyanhydride, polyamino acid, polycarboxylic acid, polyamide, polyvinyl alcohol, and polyphosphazene.

6. The balloon microcatheter according to any one of claims 1 to 5, characterized in that: The thickness of the polymer layer (3) is 0.001-0.005 inches.

7. The balloon microcatheter according to any one of claims 1 to 5, characterized in that: The bending diameter of the microcatheter is 4-6 mm; The bending angle of the microcatheter is 0-180°.

8. The balloon microcatheter according to any one of claims 1 to 5, characterized in that: The inner diameter of the lining layer (1) ranges from 0.016 to 0.027 inches.

9. The balloon microcatheter according to any one of claims 1 to 5, characterized in that: The protective layer (4) is chemically stable to the components of the hydrophilic layer (5).

10. A method for preparing a balloon microcatheter, characterized in that: The method comprises: Providing a prefabricated microcatheter; the prefabricated microcatheter comprises, from inside to outside, an inner lining layer, a reinforcement layer and a polymer layer; Coating an adhesion enhancer on the side wall of the prefabricated microcatheter, uniformly coating the protective material on the side wall of the prefabricated microcatheter, and performing a curing treatment to form a protective layer outside the prefabricated microcatheter; The hydrophilic material is evenly coated on the protective layer, and the protective layer and the hydrophilic layer are connected by molecular bonds through photocuring to form a microcatheter having a hydrophilic layer and a protective layer; The balloon is arranged at the distal end of the microcatheter to form a balloon microcatheter.

Images