阅读说明：本技术 一种血管内柔性自供能流速传感器 (Flexible self-powered flow velocity sensor in blood vessel ) 是由 吴俊� 洪剑龙 徐晗 臧傲泽 蒋晓轩 于 2021-09-13 设计创作，主要内容包括：本发明涉及一种血管内柔性自供能流速传感器,其包括流速传感模块、数据采集模块、自供能能源转换模块、无线通信模块；其中,流速传感模块包含柔性基底、电极层、柔性表面层；自供能能源转换模块包含整流桥、能量获取模块、稳压模块。本发明提出的一种血管内柔性自供能流速传感器可在血管内实时监测流速,发送到外部设备,方便患者及其家人、医生查看情况；其成本低、检测过程无辐射、且设备可实现自供能,无需定期取出更换电源。(The invention relates to a flexible self-powered flow velocity sensor in a blood vessel, which comprises a flow velocity sensing module, a data acquisition module, a self-powered energy conversion module and a wireless communication module, wherein the flow velocity sensing module is connected with the data acquisition module; the flow velocity sensing module comprises a flexible substrate, an electrode layer and a flexible surface layer; the self-powered energy conversion module comprises a rectifier bridge, an energy acquisition module and a voltage stabilizing module. The flexible self-powered flow velocity sensor in the blood vessel can monitor the flow velocity in the blood vessel in real time and send the flow velocity to external equipment, so that a patient, family members of the patient and a doctor can conveniently check the conditions; the device has low cost, no radiation in the detection process, self-energy supply of the device and no need of taking out and replacing the power supply regularly.)

1. The flexible self-powered flow velocity sensor in the blood vessel is characterized by comprising a flow velocity sensing module, a data acquisition module, a self-powered energy conversion module and a wireless communication module;

the flow rate sensing module is respectively connected with the data acquisition module and the self-powered energy conversion module, the output end of the self-powered energy conversion module is connected with the data acquisition module and the wireless communication module, and the data acquisition module is connected with the wireless communication module;

when blood flows through the surface of the flow rate sensing module, the flow rate sensing module generates an alternating voltage signal due to the variable flow rate of the blood, the data acquisition module acquires the alternating voltage signal of the flow rate sensing module and sends the acquired voltage signal to the wireless communication module, and the self-powered energy conversion module is used for converting the alternating voltage generated by the flow rate sensing module into constant direct voltage and providing working voltage for the data acquisition module and the wireless communication module; the wireless communication module transmits the received current and voltage data to an external data processing terminal.

2. The intravascular flexible self-powered flow sensor of claim 1, wherein the flow sensing module comprises a flexible substrate, an electrode layer, and a flexible surface layer arranged in sequence.

3. The flexible intravascular self-powered flow rate sensor of claim 2, wherein the flexible surface layer is made of a flexible material having an affinity for negative or positive charges.

4. The intravascular flexible self-powered flow rate sensor according to claim 2, wherein the data acquisition module, the self-powered energy conversion module and the wireless communication module are disposed between the flexible substrate and the flexible surface layer and are wrapped by the flexible substrate and the flexible surface layer.

5. The flexible self-powered intravascular flow rate sensor according to claim 2, wherein the flexible substrate and the flexible surface layer are both made of PDMS, Ecoflex, PVDF, PTFE, PVC or BOPP organic polymer materials.

6. An intravascular flexible self-powered flow rate sensor according to claim 2, wherein the flexible substrate and the flexible surface layer each have a thickness of between 1 μm and 1 mm.

7. The flexible self-powered intravascular flow rate sensor according to claim 2, wherein the electrode layer is made of Ag or Au and has a thickness of 0.1-10 μm.

8. The intravascular flexible self-powered flow rate sensor according to claim 1, wherein the self-powered energy conversion module comprises a rectifier bridge, an energy acquisition module and a voltage stabilization module;

the rectifier bridge, energy acquisition module and voltage stabilizing module connect gradually, the input of rectifier bridge is connected to velocity of flow sensing module output, the alternating current that velocity of flow sensing module produced, behind the rectifier bridge, become the direct current, energy acquisition module is connected to the output of rectifier bridge, energy acquisition module acquires the electric energy from velocity of flow sensing module through the rectifier bridge, voltage stabilizing module is connected to the output of energy acquisition module, voltage stabilizing module is used for obtaining the voltage control of module output at operating voltage Vcc with the energy, provide operating voltage for data acquisition module and wireless communication module.

9. The intravascular flexible self-powered flow sensor of claim 8, wherein the energy harvesting module comprises a power management chip PMIC and an energy storage capacitor; the PMIC is used for storing input electric energy in the energy storage capacitor and controlling the electric energy of the energy storage capacitor to be output to the voltage stabilizing module.

Technical Field

The invention relates to the technical field of medical detection, in particular to an intravascular flexible self-powered flow velocity sensor.

Background

Atherosclerosis is the leading cause of coronary heart disease, cerebral infarction, peripheral vascular disease. The main reasons are that lipid and complex carbohydrate are accumulated and bleed after the pathological changes in the artery, so that thrombus is formed, fibrous tissues are proliferated and calcified, and the middle layer of the artery is gradually degenerated and calcified, so that the artery wall is thickened and hardened, and the vascular cavity is narrowed. If the lesion develops into a vascular blockage, the tissue or organ supplied by the artery will become ischemic or necrotic.

At present, the problem of blood vessel blockage can be solved by adopting a blood vessel stent intervention mode or a mode of replacing and blocking part of blood vessels by artificial blood vessels, but after operation, the blood vessels need to be checked whether to be blocked again by adopting modes such as ultrasonic waves, arterial angiography and X-ray examination, a patient needs to go to a hospital regularly to use expensive large-scale equipment for examination, a great amount of loss is caused to the family time and money of the patient, and meanwhile, the modes have serious radiation to a human body.

The present invention is intended to solve the above problems by means of a sensor built into a blood vessel, but since an endovascular implant is generally not removed after implantation, the sensor is required to be stably present in the blood vessel for a long period of time. Therefore, in order to realize long-term monitoring and energy supply, the sensor is required to have self-energy supply effect. Within the blood vessel, the most readily available energy is the mechanical energy transmitted by the blood in the vessel, TENG being an efficient method of harnessing such energy. In a tubular form such as a blood vessel, the charge density inside the vessel changes with the magnitude of the flow velocity. The blood transport itself is periodically changed in flow rate, so that the corresponding charge density is also periodically changed, which is very suitable for being designed as TENG.

Therefore, the invention provides the intravascular flexible self-powered flow velocity sensor, which can judge whether the blood vessel is thrombus or even blocked by monitoring the flow velocity change in the blood vessel, can realize the self-powered capability by utilizing the mechanical energy in the blood vessel, can work for a long time, and provides help for solving the problems.

Disclosure of Invention

In order to overcome the problems in the prior art, the invention provides an intravascular flexible self-powered flow velocity sensor which realizes intravascular blood flow velocity sensing based on the electric double-layer principle of a solid-liquid interface and can realize self-powered flow velocity sensing application through electric quantity acquisition.

A flexible self-powered flow velocity sensor in a blood vessel comprises a flow velocity sensing module, a data acquisition module, a self-powered energy conversion module and a wireless communication module;

the flow rate sensing module is respectively connected with the data acquisition module and the self-powered energy conversion module, the output end of the self-powered energy conversion module is connected with the data acquisition module and the wireless communication module, and the data acquisition module is connected with the wireless communication module;

the sensor is arranged in a blood vessel, when blood flows through the surface of a flow velocity sensing module, the flow velocity sensing module generates an alternating voltage signal due to the changing flow velocity of the blood, a data acquisition module acquires the alternating voltage signal of the flow velocity sensing module at enough frequency and sends the acquired alternating voltage signal to a wireless communication module, and a self-powered energy conversion module is used for converting the alternating voltage generated by the flow velocity sensing module into constant direct voltage and providing working voltage for the data acquisition module and the wireless communication module, so that the self-supply of energy is realized, and other energy sources such as additional batteries and the like are not needed; the wireless communication module transmits the received current and voltage data to an external data processing terminal. The external data processing terminal can adopt platforms such as a mobile phone and a computer, data processing is carried out through an upper computer program after voltage data are obtained, the actual blood flow velocity is calculated, and whether thrombus or blockage occurs in the blood vessel at present can be judged through the blood flow velocity.

The flow velocity sensing module comprises a flexible substrate, an electrode layer and a flexible surface layer which are sequentially arranged; the data acquisition module, the self-powered energy conversion module and the wireless communication module are all positioned between the flexible substrate and the flexible surface layer and are wrapped by the flexible substrate and the flexible surface layer.

The flexible surface layer is made of flexible materials with negative charge or positive charge affinity;

the flexible substrate and the flexible surface layer can be made of organic polymer materials such as PDMS, Ecoflex, PVDF, PTFE, PVC or BOPP and the like, and the thickness of the flexible substrate and the thickness of the flexible surface layer are controlled to be between 1 mu m and 1 mm;

the electrode layer is made of Ag or Au, and the thickness is controlled between 0.1 and 10 mu m.

The self-powered energy conversion module comprises a rectifier bridge, an energy acquisition module and a voltage stabilizing module;

the rectifier bridge, energy acquisition module and voltage stabilizing module connect gradually, the input of rectifier bridge is connected to velocity of flow sensing module output, the alternating current that velocity of flow sensing module produced, behind the rectifier bridge, become the direct current, energy acquisition module is connected to the output of rectifier bridge, energy acquisition module acquires the electric energy from velocity of flow sensing module through the rectifier bridge, voltage stabilizing module is connected to the output of energy acquisition module, voltage stabilizing module is used for obtaining the voltage control of module output at operating voltage Vcc with the energy, provide operating voltage for data acquisition module and wireless communication module.

The energy acquisition module comprises a power management chip PMIC and an energy storage capacitor; the power management chip PMIC is connected with the energy storage capacitor; the PMIC is used for storing input electric energy in the energy storage capacitor and controlling the electric energy of the energy storage capacitor to be output to the voltage stabilizing module. The voltage stabilizing module comprises a low-dropout voltage stabilizing chip.

The flexible self-powered flow velocity sensor in the blood vessel provided by the invention has the following specific working principle: when blood in the blood vessel flows through the surface of the flow velocity sensing module, the flexible surface layer of the flow velocity sensing module is directly contacted with the blood to form solid-liquid contact; as can be seen from the electrical double layer principle, blood and the flexible surface layer will generate opposite charges. When the flexible surface layer material has negative charge affinity, the inner surface of the flexible surface layer is charged with negative charges, and positive charges are accumulated on the contact part of blood and the flexible surface layer; when the flexible surface layer material has positive charge affinity, the inner surface of the flexible surface layer is positively charged, and negative charges are accumulated on the contact part of blood and the flexible surface layer. For ease of explanation, the following is described by way of example using a flexible surface layer of negative charge affinity: the flow velocity of blood influences the charge density of blood and the flexible surface layer, namely directly influences the quantity of positive charges accumulated on a blood contact surface, when the blood velocity is high, the quantity of the accumulated positive charges is reduced, and the positive charges can be supplemented in the electrode layer for the potential balance of the electrode layer, the flexible surface layer and the contact part of the blood and the flexible surface layer; on the contrary, when the blood flow rate becomes slow, the amount of positive charges accumulated at the portion of the blood in contact with the flexible surface layer becomes large, and also the amount of positive charges in the electrode layer is reduced for potential balance. Thus, in the case where the flow rate of the liquid is changed, the flow of electric charges in the electrode layer is changed, a corresponding current is generated, and the potential difference between the electrode layer and the ground is changed. Meanwhile, the amount of change in the blood flow rate directly affects the amount of current flowing through the electrode layer; since the blood flow change frequency in the blood vessel is considered to be constant and the flow velocity of blood is periodically changed by the heart pulsation, when the blood flow velocity of the blood vessel is increased, the corresponding flow velocity change width is also increased, the current width flowing through the electrode is also increased, and the voltage width between the electrode layer and the ground is also increased. Therefore, the flow velocity change amplitude can be obtained by detecting the peak value of the voltage or current of the flow velocity sensing module, and the flow velocity change amplitude of the blood vessel can be obtained in the blood vessel flow velocity monitoring, namely the flow velocity in the blood vessel can be known. Through the change rule of the blood vessel flow velocity, whether the blood vessel has the problems of thrombus, blockage and the like can be presumed. Meanwhile, the voltage or current flowing through the electrode can be stored as the energy supply of the sensor through the self-energy supply energy conversion module.

Compared with the prior art, the flexible self-powered flow velocity sensor in the blood vessel provided by the invention has the following advantages: the invention can monitor the flow rate in the blood vessel in real time and send the flow rate to external equipment, thereby facilitating the checking of patients, families and doctors; the device has low cost, no radiation in the detection process, self-energy supply of the device and no need of taking out and replacing the power supply regularly.

Drawings

FIG. 1 is a block diagram of an intravascular flexible self-powered flow rate sensing device of the present invention;

FIG. 2 is a schematic diagram of the operation of the flexible self-powered flow sensor of the present invention;

fig. 3 is a graph showing the test results of the friction voltage of the flow rate sensing module of the present invention under different flow rate variations.

Wherein, 1, a flexible substrate; 2. an electrode layer; 3. a flexible surface layer.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

Aiming at the interventional therapy of a vascular stent, the flow velocity sensor provided by the invention is arranged on the inner surface of the vascular stent, aiming at the aneurysm stent, a flexible substrate 1 is fixed in the stent by adopting PVDF, an Ag electrode layer 2 with the thickness of 10 microns is stacked on the flexible substrate 1, a data acquisition module, a self-powered energy conversion module and a wireless communication module are arranged on the surface of the flexible substrate 1, a PDMS flexible surface layer 3 with the thickness of 100 microns is further stacked, the PDMS flexible surface layer 3 covers the Ag electrode layer 2, the data acquisition module, the self-powered energy conversion module and the wireless communication module, and the flexible surface layer 3 faces to the center of the vascular stent. When the stent intervention procedure is completed, the flexible surface layer 3 of the sensor is in direct contact with the blood. After the operation of the patient, blood fluid with the flow velocity changing periodically and in an amplitude mode flows through the stent, and the frequency is the same as the pulse frequency.

As shown in fig. 2, when the PDMS flexible surface layer 3 flows through blood, the PDMS flexible surface layer 3 acts as a material with negative charge affinity, negative charges are accumulated in the surface of the PDMS flexible surface layer 3, and positive charges are accumulated on the corresponding contact surface of the PDMS flexible surface layer 3 in the blood; when the blood flow speed is fast, the amount of positive charges accumulated on the contact surface of the blood and the PDMS flexible surface layer 3 is reduced, and the Ag electrode layer 2 can supplement positive charges for the potential balance among the Ag electrode layer 2, the PDMS flexible surface layer 3 and the blood contact surface; when the blood flow rate becomes slow, the amount of positive charges accumulated on the contact surface of blood and PDMS becomes large, and also the amount of positive charges is reduced in the Ag electrode layer 2 for potential balance. Since the blood flow rate in the blood vessel changes periodically, the Ag electrode layer 2 is supplied with a periodically changing voltage or current.

As shown in fig. 1: after blood flows through the flow velocity sensing module, the flow velocity sensing module generates an alternating voltage signal, the data acquisition module acquires the alternating voltage of the flow velocity sensing module, sends the alternating voltage signal to the wireless communication module, and sends the alternating voltage signal to the external data processing terminal through the wireless communication module. The self-powered energy conversion module is used for storing electric energy generated by the flow rate sensing module, controlling the electric energy under constant direct current voltage and providing working voltage for the data acquisition module and the wireless communication module, so that self-supply of energy is realized, and other energy sources such as an additional battery are not needed.

When the blood vessel of the patient implanted in the stent is normal, the flow velocity of the blood can be kept within a certain amplitude range.

When a patient is implanted into a blood vessel in the stent and thrombus occurs, because the blood flow volume of the blood vessel is kept unchanged and the radius of the blood vessel is reduced, the flow rate obtained by the sensor is increased and exceeds a normal amplitude value, the amplitude value of current or voltage generated by the flow rate sensing module is also changed, and the flow rate can be found to exceed the normal amplitude value; when the sensor finds that the flow rate exceeds the normal amplitude, the thrombus generated when the patient is implanted into the stent can be judged.

When the blood vessel of the patient implanted in the stent is blocked, the blood flow of the blood vessel is blocked, and the flow rate measured by the sensor is 0; therefore, when the flow rate is 0, the sensor can judge that the implanted stent of the patient is blocked. The information can be sent to the patient and his family, the doctor to look up the situation.

Example 2

Aiming at the open type medical operation of the artificial blood vessel, the sensor can be attached to the inner surface of the artificial blood vessel, the flexible substrate 1 of the sensor can be the surface of the artificial blood vessel, the Ag electrode layer 2 and the flexible surface layer 3 are sequentially stacked on the inner surface of the artificial blood vessel, the flexible surface layer 3 faces the center in the artificial blood vessel, and the flexible surface layer 3 covers the Ag electrode layer 2, the data acquisition module, the self-powered energy conversion module and the wireless communication module. The procedure was similar to example 1.

Example 3

In order to test the relationship between the voltage amplitude and the flow rate of the flow rate sensing module under different flow rate changes, the flow rate sensing module is separately prepared in the embodiment, and the amplitude value of the alternating voltage signal generated by the flow rate sensing module under different flow rate changes is measured. The flow rate sensing module in this embodiment employs a PVC film with a thickness of 1mm as the flexible surface layer 3, Ag with a thickness of 10 μm as the electrode layer 2, and PDMS material with a thickness of 100 μm as the flexible substrate 1. The flow sensing module is bent into a tube shape with the flexible surface layer 3 facing inwards and the flexible substrate 1 facing outwards; the flow rate sensing module after being bent into a tubular shape has a length of 20mm and a diameter of 6 mm. The peristaltic pump is adopted to provide liquid with different flow rates for the flow rate sensing module, the liquid flows through the tubular flow rate sensing module, and the flow rate changes are as follows: 0 to 100ml/min, 0 to 200ml/min, 0 to 500ml/min, 0 to 1000ml/min, 0 to 1500 ml/min; the change voltage is measured by a DMM7510 digital multimeter, and as can be seen from FIG. 3, the maximum amplitude of the voltage generated by the DMM7510 digital multimeter is respectively: 10mV, 20mV, 35mV, 45mV, 60 mV. The measurement result shows that the sensing module has different voltage amplitude expressions under the condition of different flow rate changes, and the corresponding relation is formed for the same liquid flow rate and the same voltage amplitude, so that the flow rate passing through the sensing module can be estimated from the voltage amplitude. The experimental result proves the feasibility of the flow velocity sensing module.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.