A flexible pressure guide wire for real-time intravascular blood pressure monitoring and its preparation method

Abstract

The present invention discloses a flexible pressure guide wire for real-time intravascular blood pressure monitoring and a preparation method thereof, belonging to the technical field of medical devices. The preparation method includes the following steps: preparing a flexible composite material containing modified piezoelectric particles; preparing an ultra-thin flexible pressure guide wire coating; preparing a flexible pressure guide wire. The flexible pressure guide wire prepared by the above preparation method has high-precision mechanical sensing ability. When detecting minute changes in force, it can more effectively transmit stress and strain, can provide more reliable sensing data more timely, improves the overall response ability and structural stability, and thus improves the safety and effectiveness of the guide wire in clinical applications.

Description

Technical Field

[0001] The present invention belongs to the technical field of medical equipment, and in particular relates to a flexible pressure guide wire for real-time blood pressure monitoring in a blood vessel and a preparation method thereof. Background Art

[0002] In recent years, thanks to the emergence of new materials and innovations in manufacturing processes, guidewire technology has developed rapidly. In the medical field, traditional guidewires are only used as mechanical guidance tools, while the introduction of pressure guidewires enables them to have real-time feedback functions. This makes pressure guidewires an indispensable and important part of medical interventional surgery.

[0003] The core principle of pressure guidewire is based on the piezoelectric effect, that is, the property of certain materials (such as quartz, PDVF film, piezoelectric ceramics, etc.) to generate electric charges under mechanical stress, or to deform under the action of electric field. By integrating piezoelectric materials into the guidewire structure, the mechanical force exerted on the guidewire in blood vessels, cavities and other environments can be converted into electrical signals to achieve real-time monitoring.

[0004] At present, traditional pressure guidewires usually use piezoresistive or capacitive technology. Although they perform well in some clinical scenarios, they have certain limitations in the detection and response speed of small deformations. In addition, traditional pressure guidewires are usually relatively rigid and large in size, making it difficult to adapt to the complex microenvironment within the blood vessels. During use, they may cause stress concentration or friction within the blood vessels, thereby causing vascular damage. Therefore, it is necessary to provide a flexible pressure guidewire for real-time blood pressure monitoring within blood vessels to solve the problems existing in traditional rigid pressure guidewires. Summary of the invention

[0005] The purpose of the present invention is to solve the deficiencies in the prior art and to provide a flexible pressure guide wire for real-time blood pressure monitoring in blood vessels and a preparation method thereof, so that the prepared flexible pressure guide wire has high-precision mechanical sensing capability, can more effectively transmit stress and strain when detecting slight changes in force, and provide more reliable sensing data in a more timely manner, thereby improving the overall response capability and structural stability, thereby improving the safety and effectiveness of the guide wire in clinical applications.

[0006] In order to solve the above technical problems, one of the technical solutions adopted by the present invention is to provide a method for preparing a flexible pressure guide wire for real-time blood pressure monitoring in a blood vessel, comprising the following steps:

[0007] S1. Preparation of flexible composite material containing modified piezoelectric particles: Mix piezoelectric particle powder and absolute ethanol in proportion, filter out the piezoelectric particles after ultrasonic gradient dispersion, and dry them until no moisture remains; Add the dried piezoelectric particles into the acetone solution of silane coupling agent, disperse and modify them by ultrasonic gradient, then transfer them to a magnetic rotating table. After the fluid state of the solution is stable, gradually increase the rotation speed of the magnetic rotating table to 750 - 800 rpm in stages, rotate for 60 - 120 min under the constant temperature condition of 50 - 60 °C, stop rotating and let it stand for 30 - 60 min, then filter, dry and wash to remove the excess silane coupling agent, and dry again to obtain mixed particles, which are used as the flexible composite material containing modified piezoelectric particles;

[0008] S2. Coating the ultra-thin flexible pressure guide wire coating to prepare piezoelectric functional guide wire: Uniformly coat the flexible composite material prepared in step S1 on the surface of the conductive metal wire, and perform thermal curing by gradient temperature rising drying method to form an ultra-thin flexible pressure guide wire coating on the surface of the conductive metal wire, and obtain a piezoelectric functional guide wire with a complete coating structure;

[0009] S3. Preparation of flexible pressure guide wire: Cover the non-electrode area of the piezoelectric functional guide wire with a mask, sputter nano-metal through a magnetron sputtering instrument and then remove the mask. The area covered by the nano-metal is used as the positive electrode, and the area covered by the mask remains as the negative electrode; Then polarize the piezoelectric guide wire in a constant temperature environment; Connect the surface electrodes of the polarized piezoelectric guide wire with wires and fix them with a developing ring, and coat a waterproof layer on the outside for encapsulation to complete the preparation of the flexible pressure guide wire.

[0010] As a further description of the above technical solution, the piezoelectric particles described in step S1 are lead zirconate titanate (PZT); The mass ratio of piezoelectric particles to absolute ethanol is 1:(1.5 - 3).

[0011] As a further description of the above technical solution, the output power of the ultrasonic gradient dispersion described in step S1 is 18%, the working / interval period is 18 s / 9 s, and it is carried out in three stages: Continuously disperse for 3 - 5 min in the first stage and then pause, quickly cool down and let it stand and cool to room temperature; Continuously disperse for 3 - 5 min in the second stage and then pause, quickly cool down and let it stand and cool to room temperature; Continuously disperse for 4 - 10 min in the third stage and then pause, quickly cool down and let it stand and cool to room temperature.

[0012] As a further description of the above technical solution, the silane coupling agent described in step S1 is KBM-503 silane coupling agent, and the mass ratio of piezoelectric particles, silane coupling agent and acetone is 1:(0.03 - 0.05):(3 - 5).

[0013] As a further description of the above technical solution, the conductive metal wire described in step S2 is a medical stainless steel wire.

[0014] As a further description of the above technical solution, the specific operation of uniformly coating the flexible composite material on the surface of the conductive metal wire in step S2 is as follows: Place the flexible composite material obtained in step S1 in a container, and install a matching hollow movable rack in the container; Fix one end of the conductive metal wire on a vertical lifting machine, and immerse the other end in the holes of the hollow movable rack at a depth of 30 - 35 mm; Start the lifting machine, and lift the conductive metal wire upward at a uniform speed of 0.8 - 1.2 mm / s, so that the flexible composite material is uniformly coated on the surface of the conductive metal wire.

[0015] As a further description of the above technical solution, the parameter settings of the magnetron sputtering instrument in step S3 are as follows: current 0.5 - 0.8 mA, air pressure 4 - 6 mmHg; The length of the electrode part is 25 - 30 mm.

[0016] As a further description of the above technical solution, the polarization treatment described in step S3 is specifically as follows: Place the piezoelectric conductive wire in a constant temperature oil bath at 70 - 80 °C, apply a DC electric field with an intensity of 10 kV / mm for continuous polarization for 2 - 2.5 h, stop heating and keep the electric field intensity unchanged, and naturally cool to room temperature, then remove the surface oil stain after taking it out to complete the polarization treatment of the piezoelectric conductive wire.

[0017] As a further description of the above technical solution, the developing ring described in step S3 is made of medical stainless steel; The waterproof layer is made of thermosoluble polyvinyl alcohol.

[0018] The second technical solution adopted by the present invention is to provide a flexible pressure guide wire for real-time blood pressure monitoring in blood vessels, which is prepared by the above preparation method, including a guide wire. A flexible composite material containing modified piezoelectric particles is coated on the surface of one end of the guide wire to form an ultra-thin flexible pressure guide wire coating. A nano-gold electrode layer is sputtered on the ultra-thin flexible pressure guide wire coating. The nano-gold electrode layer is connected to a wire, and a developing ring is used to fix it at the connection. The outside of the guide wire is coated with a waterproof layer for encapsulation.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] 1. By combining the polymer material PZT and the silane coupling agent KBM-503, a stable coupling group is formed between the inorganic material and the organic material, changing the interfacial properties between the materials, making the microstructure of the interface more continuous and smooth. When the guide wire is subjected to external force, it can more effectively transmit stress and strain, avoiding material damage caused by local stress concentration, thereby improving the overall response ability and structural stability of the guide wire.

[0021] 2. By using the ultra-thin flexible pressure wire technology coating technology, an ultra-thin flexible pressure wire with a coating thickness of only 20 - 24 μm was successfully fabricated. It can adapt to extremely narrow and complex vascular spaces. When dealing with narrow or curved vascular segments, the flexible wire can easily pass through, reducing damage to the vascular wall. At the same time, it has a high degree of biocompatibility with blood vessels, improving the safety and effectiveness of the wire in clinical applications.

[0022] 3. By changing the traditional wire structure, without destroying the flexibility of the polymer matrix and being able to exert its own sensing function, the influence of the viscoelasticity of the polymer matrix on the sensing resolution was effectively reduced. In complex vascular operations, the addition of the flexible wire enables the wire to maintain high sensing resolution while having better flexibility and adaptability, improving the safety and precision of surgical operations. In addition, the flexible wire can provide real-time feedback on the contact force between the wire and the vascular wall or other mechanical changes, providing more intuitive navigation information for doctors and helping to improve the surgical efficiency and success rate.

[0023] 4. By using a peristaltic pump and a silicone hose to simulate the real human vascular environment, a blood pressure test simulation system was built and the developed pressure wire was tested in detail. During the test, the simulation system can accurately reproduce the characteristics of the periodic pulsation of human blood pressure. By adjusting the pressure and frequency parameters of the peristaltic pump, different human blood pressure conditions were simulated to test the response speed and signal fidelity of the wire to rapid pressure changes, verifying the stability and reliability of the pressure wire. Brief Description of the Drawings

[0024] Figure 1 is a schematic structural diagram of the flexible pressure wire of the present invention.

[0025] Figure 2 is a schematic cross-sectional structural diagram of the flexible pressure wire of the present invention.

[0026] Figure 3 is a process flow chart of the preparation of the flexible pressure wire of the present invention.

[0027] Figure 4 is a voltage signal output waveform diagram measured when the flexible pressure wire of the present invention is in a simulated human blood vessel with a blood pressure of 130 mmHg and a heart rate of 70 BPM.

[0028] Reference Signs:

[0029] 1 - nano-gold electrode layer; 2 - developing ring; 3 - wire; 4 - guide wire; 5 - waterproof layer; 6 - ultra-thin flexible pressure wire coating. Detailed Description of the Invention

[0030] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the protection scope of the present invention.

[0031] This embodiment provides a flexible pressure guide wire for real-time intravascular blood pressure monitoring, as Figure 1 and Figure 2 shown, including a guide wire 4. A flexible composite material containing modified piezoelectric particles is coated on the surface of one end of the guide wire 4 to form an ultra-thin flexible pressure guide wire coating 6. A nano-gold electrode layer 1 is sputtered on the ultra-thin flexible pressure guide wire coating 6 as the positive electrode. The nano-gold electrode layer 1 is connected to a wire 3 and fixed at the connection with a developing ring 2. The outer side of the guide wire is coated with a waterproof layer 5 for encapsulation.

[0032] Its preparation process is as Figure 3 shown, including the following steps:

[0033] S1. Prepare a flexible composite material containing modified piezoelectric particles: Add lead zirconate titanate with a particle size of 500 nm and absolute ethanol to a reaction vessel in a mass ratio of 1:2 and mix. Place the reaction vessel in an ultrasonic disperser, set the output power of the ultrasonic disperser to 18%, and the working / interval cycle to 18 s / 9 s. Perform ultrasonic gradient dispersion in three stages: Continuously disperse for 3 min in the first stage and then pause. Take out the reaction vessel and uniformly spray the surface with a 95% ethanol solution to achieve rapid heat exchange, and then place it in a constant temperature environment (25 ± 1°C) and let it stand for 90 s to complete cooling. In the second stage, continue to perform periodic dispersion for 3 min. After the end, repeat the above heat management operation and maintain the same standing conditions. In the third stage, extend the treatment time to 4 min to complete the final dispersion. Filter out the piezoelectric particles and place them in an oven to dry at 60°C for 24 h until no moisture remains. Add the dried piezoelectric particles to an acetone solution of silane coupling agent KBM-503 in a mass ratio of lead zirconate titanate, silane coupling agent, and acetone of 1:0.05:3. After ultrasonic gradient dispersion and modification, first stir at a speed of 400 rpm to prevent precipitation. Then quickly transfer the reaction vessel to a magnetic turntable. After the fluid state of the solution is stable, gradually increase the rotation speed of the magnetic turntable to 800 rpm in stages and rotate at a constant temperature of 50°C for 120 min. Stop rotating and let it stand for 60 min, then filter, dry in an oven at 60°C, wash with absolute ethanol and deionized water to remove the excess silane coupling agent, and dry again at 60°C until no moisture remains to obtain mixed particles as the flexible composite material containing modified piezoelectric particles;

[0034] S2. Coating the ultra-thin flexible pressure guide wire coating to prepare a piezoelectric functional guide wire: Place the flexible composite material obtained in step S1 in a special container, and install a matching hollow moving frame in the special container. Fix one end of the medical stainless steel guide wire on a vertical lifting machine, and immerse the other end 35 mm deep into the hole of the hollow moving frame. Start the lifting machine to lift the medical stainless steel guide wire upward at a constant speed of 1.0 mm / s, so that the flexible composite material is evenly coated on the medical stainless steel guide wire. Let the coated medical stainless steel guide wire stand still in a closed environment for 20 min to achieve coating leveling, and then transfer it to an oven. Set the oven heating mode to 25°C / 24 h → 60°C / 72 h, and use the gradient heating drying method for thermal curing to form an ultra-thin flexible pressure guide wire coating with a thickness of 24 μm on the surface of the medical stainless steel guide wire, and obtain a piezoelectric functional guide wire with a complete coating structure.

[0035] S3. Prepare the flexible pressure guide wire: Cover the non-electrode area of the piezoelectric functional guide wire with copper foil tape. Set the current parameter of the magnetron sputtering instrument to 0.5 - 0.8 mA and the air pressure to 4 - 6 mmHg. After sputtering nano-gold by the magnetron sputtering instrument, remove the copper foil tape. The nano-gold covered area is used as the positive electrode, and the original blocked part remains as the negative electrode. The length of the electrode part is 30 mm. Then place the piezoelectric guide wire in an 80°C constant temperature oil bath, apply a DC electric field with an intensity of 10 kV / mm for 2 h of continuous polarization. After stopping heating, maintain the electric field intensity unchanged and naturally cool to 25°C. Take it out and clean the surface oil stain with anhydrous ethanol and lint-free cloth to complete the polarization treatment of the piezoelectric guide wire. Connect the surface electrodes of the polarized piezoelectric guide wire with wires and fix them with a medical stainless steel imaging ring. Coat a thermally soluble polyvinyl alcohol on the outside as a waterproof layer for encapsulation to complete the preparation of the flexible pressure guide wire.

[0036] By using a peristaltic pump and a silicone hose to simulate the real human vascular environment, build a blood pressure test simulation system and conduct detailed tests on the developed pressure guide wire. During the test, the simulation system can accurately reproduce the characteristics of the periodic pulsation of human blood pressure. By adjusting the pressure and frequency parameters of the peristaltic pump, different human blood pressure conditions can be simulated, and the response speed and signal fidelity of the guide wire to rapid pressure changes can be tested. When simulating a human blood pressure of 130 mmHg and a heart rate of 70 BPM, the voltage signal output waveform diagram measured is as Figure 4 shown, which can better reflect blood pressure changes and vascular status. It can be seen that under no external interference, the overall graph is smooth with small perturbations, indicating that the flexible pressure guide wire of the present invention has an excellent signal-to-noise ratio; the graph still maintains a complete waveform at a higher frequency with good repeatability, indicating that the flexible pressure guide wire of the present invention has excellent stability.

[0037] The above is only the best implementation mode of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several modifications or equivalent substitutions can be made to the technical solution of the present invention, and the technical effects of the present invention can also be achieved, which should also be regarded as falling within the protection scope of the present invention.

Claims

1. A preparation method of a flexible pressure guide wire for intravascular real-time blood pressure monitoring, characterized in that, It includes the following steps: S1. Prepare a flexible composite material containing modified piezoelectric particles: Mix piezoelectric particle powder and absolute ethanol in a certain proportion, filter out the piezoelectric particles after ultrasonic gradient dispersion and dry them until no moisture remains; Add the dried piezoelectric particles into the acetone solution of silane coupling agent, disperse and modify them by ultrasonic gradient, then transfer them to a magnetic rotating table. After the fluid state of the solution is stable, gradually increase the rotation speed of the magnetic rotating table to 750 - 800 rpm in stages, rotate for 60 - 120 min under the constant temperature condition of 50 - 60 °C, stop rotating and let it stand for 30 - 60 min, then filter, dry and wash to remove the excess silane coupling agent, and dry again to obtain mixed particles, which are used as the flexible composite material containing modified piezoelectric particles; The silane coupling agent is KBM-503 silane coupling agent; S2. Coat an ultra-thin flexible pressure guide wire coating to prepare a piezoelectric functional guide wire: Uniformly coat the flexible composite material prepared in step S1 on the surface of the conductive metal wire, and perform thermal curing by gradient heating drying method to form an ultra-thin flexible pressure guide wire coating on the surface of the conductive metal wire, and obtain a piezoelectric functional guide wire with a complete coating structure; S3. Prepare a flexible pressure guide wire: Cover the non-electrode area of the piezoelectric functional guide wire with a mask, sputter a nano-metal layer by a magnetron sputtering instrument and then remove the mask, and the nano-metal serves as the positive electrode; Then perform polarization treatment in a constant temperature environment; Connect the surface electrodes of the polarized piezoelectric functional guide wire with wires and fix them with a developing ring, and coat a waterproof layer on the outside for encapsulation to complete the preparation of the flexible pressure guide wire; The conductive metal wire described in step S2 is a medical stainless steel wire; The specific operation of uniformly coating the flexible composite material on the surface of the conductive metal wire in step S2 is: Place the flexible composite material obtained in step S1 in a container, and install a matching hollow moving rack in the container; Fix one end of the conductive metal wire on a vertical lifting machine, and immerse the other end 30 - 35 mm deep into the hole of the hollow moving rack; Start the lifting machine to lift the conductive metal wire upward at a constant speed of 0.8 - 1.2 mm / s, so that the flexible composite material is uniformly coated on the surface of the conductive metal wire.

2. The preparation method according to claim 1, characterized in that: The piezoelectric particles described in step S1 are lead zirconate titanate; The mass ratio of piezoelectric particles to absolute ethanol is 1:(1.5 - 3).

3. The preparation method according to claim 2, characterized in that: The output power of the ultrasonic gradient dispersion described in step S1 is 18%, and the working / interval period is 18 s / 9 s, which is divided into three stages: Continuously disperse for 3 - 5 min in the first stage and then pause, quickly cool down and let it stand and cool to room temperature; Continue to continuously disperse for 3 - 5 min in the second stage and then pause, quickly cool down and let it stand and cool to room temperature; Continuously disperse for 4 - 10 min in the third stage and then pause, quickly cool down and let it stand and cool to room temperature.

4. The preparation method according to claim 3, characterized in that: The mass ratio of piezoelectric particles, silane coupling agent and acetone in step S1 is 1:(0.03 - 0.05):(3 - 5).

5. The preparation method according to claim 1, characterized in that: The parameter settings of the magnetron sputtering instrument in step S3 are: current 0.5 - 0.8 mA, air pressure 4 - 6 mmHg; The length of the electrode part is 25 - 30 mm.

6. The preparation method according to claim 5, wherein: The polarization treatment described in step S3 is specifically as follows: Place the piezoelectric conductive wire in a constant temperature oil bath at 70-80°C, apply a DC electric field with an intensity of 10 kV / mm for continuous polarization for 2-2.5 h, maintain the electric field intensity unchanged after stopping heating and naturally cool to room temperature, remove it and clean the surface oil stain to complete the polarization treatment of the piezoelectric conductive wire.

7. The preparation method according to claim 6, characterized in that: The developing ring described in step S3 is made of medical stainless steel; the waterproof layer is thermosoluble polyvinyl alcohol.

8. A flexible pressure guide wire for real-time intravascular blood pressure monitoring, characterized in that: It is prepared by using the preparation method described in any one of claims 1-7.

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