Self-climbing self-adhesion flexible electrode patch for nerve monitoring

Abstract

The invention discloses a self-climbing and self-adhesion flexible electrode patch for nerve monitoring. The self-climbing and self-adhesion flexible electrode patch comprises a flexible substrate film with an opening interlayer; the memory alloy strip is trained to have the phase change characteristic of bending from a straight line to a circle in a specific temperature interval, and is inserted into the opening interlayer of the flexible substrate film; the temperature control hydrogel film has a temperature control characteristic and is attached to the upper surface of the flexible substrate film; the electrode array comprises an electrode plate wrapped by a temperature control hydrogel film and a corresponding electrode wire, one surface of the electrode plate is exposed outside the temperature control hydrogel film and is used for being in direct contact with human nerves, the electrode wire extends outwards in the temperature control hydrogel film, and an extension part is provided with an electrode switching interface. The electrode patch can be automatically wound to nerves through temperature rise, is easy to operate, can adapt to the nerves of multiple sizes, can perform high-quality electrical stimulation monitoring, can change the adhesion of the interface through temperature rise and fall, and is convenient to take and place.

Description

Technical Field

[0001] The invention belongs to the field of biomedicine, and in particular relates to a self-climbing and self-adhesive flexible electrode patch for nerve monitoring. Background Art

[0002] Neural electrode technology plays an important role in the fields of neuroscience and neuromedicine, especially in neuroregulation and neural signal monitoring. Neural electrodes can capture EEG signals in real time, provide important information about the state of the nervous system, and help doctors make instant decisions during surgery. In thyroid surgery, the application of intraoperative monitoring neural electrodes is mainly focused on protecting the recurrent laryngeal nerve. The recurrent laryngeal nerve is responsible for muscle movement and sound production in the larynx, and is crucial to the success of the operation and postoperative recovery. During surgery, if the recurrent laryngeal nerve is damaged, serious complications such as hoarseness and dysphagia may occur. Therefore, accurate monitoring of the status of the recurrent laryngeal nerve has become an important part of ensuring surgical safety.

[0003] To check the status of the recurrent laryngeal nerve during surgery, the most commonly used and effective method is nerve electrical stimulation-electromyography monitoring, which applies electrical stimulation to the freed vagus nerve to induce muscle vibration on the vocal cords, uses the endotracheal tube as a sensor to obtain signals, and observes the amplitude, duration, and conduction velocity of the electromyographic signal to determine whether the nerve is damaged. Among them, the monitoring electrode / probe that outputs electrical stimulation signals to the nerve is the core of the entire system.

[0004] Traditional intraoperative nerve monitoring electrodes are roughly divided into two types. One is the intermittent electrical stimulation monitoring probe, which has precise stimulation sites and high feedback accuracy. However, since it is necessary to hold the probe at intervals to apply electrical stimulation, it adds extra operations during the operation, reduces surgical efficiency, and cannot judge the state of the nerve in real time. Therefore, there is a probability that abnormalities will be detected only after nerve damage. The other is the continuous electrical stimulation cuff electrode. Compared with the first probe, this electrode can be fixed on the nerve and monitor the nerve state in real time. In theory, it can reduce the injury rate to 0, but this electrode still has some clinical application bottlenecks: ( 1) Difficulty in operating the electrode clip: During surgery, the instrument needs to be operated in a small space. It takes nearly half an hour for an experienced doctor to manually open the electrode clip and accurately clamp the nerve. Its structure is very inconvenient in actual operation. (2) Poor electrode adaptability: The elastic modulus of the current electrode is quite different from that of the nerve, and it cannot adapt to the size and shape of the nerve, which further increases the difficulty of operation. (3) Unstable electrode attachment: There is no adhesion at the electrode-nerve interface, which makes it impossible for the electrode to be tightly fixed on the nerve, resulting in mutual movement, which in turn introduces interference signals such as motion artifacts, resulting in poor signal quality of electrical stimulation. Existing intraoperative nerve monitoring electrodes do not fully consider these issues.

[0005] Therefore, designing an intraoperative nerve monitoring electrode that is easy to operate, adaptable to nerves of different sizes, and has a stable electrode-nerve interface has become an urgent problem to be solved. Summary of the invention

[0006] In view of the above, the purpose of the present invention is to provide a self-climbing and self-adhesive flexible electrode patch for nerve monitoring, which can automatically wrap around the nerve by heating up, is easy to operate, can adapt to nerves of multiple sizes, can perform high-quality electrical stimulation monitoring, and can change the interface adhesion by heating and cooling, making it easy to take and place.

[0007] In order to achieve the above-mentioned invention object, the present invention provides the following technical solutions:

[0008] A self-climbing and self-adhesive flexible electrode patch for neural monitoring, characterized in that it comprises a flexible substrate film, a memory alloy strip, a temperature-controlled hydrogel film, and an electrode array;

[0009] The flexible substrate film is an insulating flexible polymer, has biocompatibility, and has an open interlayer;

[0010] The memory alloy strip is trained to have a phase change property of bending from a straight line to a circle within a specific temperature range, and is inserted into the open interlayer of the flexible substrate film;

[0011] The temperature-controlled hydrogel film has a temperature-controlled property of changing adhesion based on temperature changes, and is attached to the upper surface of the flexible base film;

[0012] The electrode array includes an electrode sheet wrapped by a temperature-controlled hydrogel film and a corresponding electrode wire, wherein one side of the electrode sheet is exposed outside the temperature-controlled hydrogel film for direct contact with human nerves, the electrode wire extends outward in the temperature-controlled hydrogel film, and the extension portion has an electrode adapter interface;

[0013] The temperature-controlled self-adhesive flexible electrode patch is placed around the nerve at room temperature during surgery. In an environment where the temperature is raised by light or contact with human physiological tissue, the memory alloy strip drives the entire electrode patch to wrap around the nerve based on its phase change properties. The temperature-controlled hydrogel film increases adhesion based on its temperature control properties, allowing the electrode disc to fit tightly to the nerve. After the fitting is completed, the memory alloy strip removes the electrode patch through the open interlayer. After the operation, the electrode patch automatically detaches from the nerve after the temperature is lowered to reduce adhesion, achieving the purpose of convenient operation and continuous monitoring of intraoperative nerve function.

[0014] Preferably, the memory alloy strip is trained to have a phase change characteristic of bending from a straight line to a circle within a specific temperature range, including: a phase change temperature of 30° C. to 40° C., and a bending radius of the memory alloy strip of 0.5 mm to 10 mm.

[0015] Furthermore, the memory alloy strip is a nickel-titanium alloy strip, and the heat treatment process is to bind the alloy strip to a mold for training for 2 to 5 hours under a specific constant temperature state of 100° C. to 450° C., so that it obtains phase change characteristics.

[0016] Preferably, the temperature-controlled hydrogel film has a temperature-controlled characteristic of changing adhesion based on temperature changes, including: the viscosity of the temperature-controlled hydrogel film is less than 3N / m at a surface temperature of 25°C, the viscosity is greater than 90N / m at 37°C, and the adhesion range is 1 to 100N / m in the range of 20°C to 40°C.

[0017] Furthermore, the temperature-control hydrogel film includes a solution of acrylic acid, ammonium persulfate, N,N'-methylenebisacrylamide, acrylamide, and carbon nanofibers, the mass ratio of acrylic acid, ammonium persulfate, N,N'-methylenebisacrylamide, acrylamide, and carbon nanofiber dispersion is 51-357:25:2:357:3600, wherein the carbon nanofiber dispersion includes deionized water and carbon nanofiber dispersion, the corresponding mass ratio is 1:8-8:1, so that the temperature-control hydrogel film has temperature-control adhesion properties.

[0018] Preferably, the flexible base film includes acetate fiber that is strongly bonded to the temperature-control hydrogel film, and also includes at least one of rubber, polyimide, polyester fiber, polydimethylsiloxane, polyurethane, polyethylene terephthalate and polylactic acid as an encapsulation layer to form a composite structure with a thickness of 1 μm to 5 mm. The flexible base film of such a structure is tightly attached to the temperature-control hydrogel film through molecular chain entanglement.

[0019] Preferably, the opening of the open interlayer of the flexible base film is located at an adjacent pair of long sides and short sides of the flexible base film, so as to facilitate the placement of the memory alloy strip in the initial state and the removal of the memory alloy strip in the bent state.

[0020] Preferably, the temperature-controlled self-adhesive flexible electrode patch is in the shape of an elongated strip as a whole, and the overall length including the memory alloy strip is 2 cm to 20 cm, and the entire bendable area of ​​the electrode patch corresponding to the temperature-controlled hydrogel film is 1 cm to 5 cm long, 5 mm to 30 mm wide, and 0.5 mm to 20 mm thick. Among them, the memory alloy strip is in the shape of an elongated strip, with a width of 5 mm to 30 mm and a thickness of 0.05 mm to 0.2 mm.

[0021] Preferably, the thickness of the electrode sheets in the electrode array is 1 μm to 500 μm, the spacing between the electrode sheets is 1 mm to 10 mm, and when the electrode sheets are circular sheets, the radius of each electrode sheet is 1 mm to 10 mm, and each electrode sheet has both collection and stimulation functions.

[0022] Preferably, the material of the electrode array is copper, gold, silver, silver chloride or conductive carbon black, and the number of electrode arrays is 2-128.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) Traditional continuous monitoring electrodes are in a buckle shape and difficult to clamp. The temperature-controlled self-adhesive flexible electrode patch designed by the present invention utilizes the stable physiological parameter of body temperature and the temperature-controlled bendable phase change characteristics of the memory alloy strip after training, so that the electrode patch can automatically curl onto the nerve, avoiding the inconvenience of operation in a small space and greatly improving the efficiency of the operation;

[0025] (2) The conventional continuous monitoring electrode has a fixed shape and cannot adapt to different nerve sizes. The present invention uses low modulus flexible materials to prepare electrodes and substrates, sets the minimum bending radius of the memory alloy strip, and enables the electrode to adapt to the size and shape of the nerve after bending, thus achieving better adaptability.

[0026] (3) Traditional continuous monitoring electrodes have no close contact with the tissue interface, resulting in poor signal quality. The present invention utilizes the temperature control property of the temperature-controlled hydrogel film to change adhesion based on temperature changes. When the temperature is increased, the electrode can be tightly attached to the nerve. After the operation, the electrode can be easily removed by cooling down, ensuring high-quality signal acquisition. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 is a schematic diagram of the overall structure of a temperature-controlled self-adhesive flexible electrode patch provided in an embodiment;

[0029] Figure 2 is a diagram of the wire structure of the extensible portion of the temperature-controlled self-adhesive flexible electrode patch provided in an embodiment;

[0030] Figure 3 Schematic diagram of the adhesion function of the temperature-controlled hydrogel film provided in the embodiment, wherein (a) is a diagram of the adhesion function of the temperature-controlled hydrogel film at 25° C., and (b) is a diagram of the adhesion function change of the temperature-controlled hydrogel film of the electrode patch in a 37° C. environment and in contact with water;

[0031] Figure 4 1 is a state of a memory alloy strip provided in an embodiment, wherein (a) is a schematic diagram of the bending of the memory alloy strip after training, and (b) is a schematic diagram of the application of the memory alloy strip being removed from an open interlayer;

[0032] Figure 5 The temperature-controlled self-adhesive flexible electrode patch of the embodiment is a physical picture;

[0033] Figure 6 This is an application demonstration diagram of a temperature-controlled self-adhesive flexible electrode patch provided in an embodiment being wound around a cylinder with a diameter of 5 mm;

[0034] Figure 7 It is the action potential of a Pana pig recorded at a specific voltage by the temperature-controlled self-adhesive flexible electrode patch provided in the embodiment. DETAILED DESCRIPTION

[0035] To make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific implementation methods described herein are only used to explain the present invention and do not limit the scope of protection of the present invention.

[0036] like Figure 1 and Figure 2 As shown, the self-climbing and self-adhesive flexible electrode patch for neural monitoring provided in the embodiment includes an electrode array 1, a temperature-controlled hydrogel film 2, a memory alloy strip 3, and a flexible substrate film 4. The entire electrode patch, including the length of the memory alloy strip, has an overall length of 100 mm, and the bendable area of ​​the head corresponding to the temperature-controlled hydrogel film is 20 mm long, 10 mm wide, and 0.8 mm thick.

[0037] The electrode array 1 is flexible and includes an electrode sheet wrapped by a temperature-controlled hydrogel film 2 and its corresponding electrode wire, wherein one side of the electrode sheet is exposed outside the temperature-controlled hydrogel film 2 for direct contact with human nerves, the electrode wire extends outward in the temperature-controlled hydrogel film 2, and the extension portion has an electrode adapter interface 5. Specifically, the electrode array 1 includes 2 electrode sheets with a thickness of 0.1 mm. The electrode sheets are round and have a radius of 4 mm, which refers to the radius of the outermost circle. The distance between the electrode sheets is 2 mm.

[0038] The electrode sheet substrate material is polyimide, and the electrode sheet head material in contact with the human body is metal copper (Cu), conductive carbon material, metal gold (Au), metal silver or silver chloride. The electrode wires corresponding to each electrode sheet and wrapped in the temperature-controlled hydrogel film 2 are arranged in a serpentine shape, and the serpentine line extends to the tail of the bendable part of the electrode. The rear-end extension wires are gathered to the electrode transfer interface and connected to the adapter board through the electrode transfer interface. Specifically, the tail of the extensible flexible electrode array 1 is connected to the external circuit with a zero-plug-in force FPC connector, and after the transfer, the shielded related interface is connected to the signal acquisition part.

[0039] The temperature-controlled hydrogel film 2 has a thickness of 0.5 mm and is composed of acrylic acid (AA), acrylamide (AAm), ammonium persulfate (APS), N,N'-methylenebisacrylamide (MBAA), and carbon nanofibers (CNFs) materials, and the proportions are as follows: 5 g CNFs dispersion (1.768 wt%), 4 g deionized water, 0.4457 g AA, 0.8913 g AAm, 0.005 g MBAA, and 0.0625 g APS are adjusted to mix and synthesize CNF / P (AA-co-AAm) hydrogel, as shown in FIG. Figure 3 As shown in (a), the viscosity of the hydrogel surface is 3N / m at 25°C, 90N / m at 37°C, and 1-100N / m in the range of 20°C to 40°C. The upper surface of the phase-changeable curling region of the electrode patch is made up of a temperature-controlled hydrogel film 2 except for the flexible electrode array 1, accounting for 74.88% of the total area of ​​the adhesive portion.

[0040] like Figure 3 As shown in (b), the adhesion of the temperature-controlled hydrogel film 2 decreases sharply after contacting water. This property is used to add cold water to the surface of the patch after the operation to easily peel off the patch.

[0041] The material of the memory alloy strip 3 is nickel-titanium alloy, in the form of a long sheet, with a width of 10 mm, a length of 20 mm, and a thickness of 0.2 mm. The nickel-titanium ratio is 50.2:49.8, and it is wound and clamped on a 1 mm diameter mold under standard atmospheric pressure. Figure 6 As shown, a heat treatment process is carried out at a constant temperature of 350°C for 120 minutes to train it to curl into a circular shape, the phase transition temperature is between 30°C and 40°C, and the bending radius is 2.5mm. Figure 4 As shown in (a) of FIG. 2 , the memory alloy strip 3 is inserted into the opening interlayer of the flexible substrate film 2, as shown in FIG. Figure 5 shown.

[0042] The material of the flexible base film 4 is polyimide and acetate fiber, with a thickness of 0.2 mm, wherein the acetate fiber is located above the polyimide. Through the entanglement of molecular chains, the flexible base film 4 is tightly connected to the temperature-controlled hydrogel film 2 to form an integrated electrode patch. The flexible base film 4 also has an open interlayer, such as Figure 5 As shown, the opening is located at a pair of adjacent long sides and short sides of the flexible base film, which is convenient for placing the memory alloy strip in the initial state and removing it from the bent state.

[0043] After the nerve is separated, the temperature-controlled self-adhesive flexible electrode patch of the present invention is placed in contact with the nerve with the phase-changeable bendable part of the temporary planar flexible electrode patch. Under the continuous temperature rise driven by body temperature, the memory alloy strip 3 reaches the phase change temperature and begins to automatically curl to match the nerve diameter. After curling is complete, the temperature-controlled hydrogel film 2 reaches the phase change temperature, the adhesion of the electrode-nerve interface increases, the electrode patch is in close contact with the nerve, and the memory alloy strip 3 is taken out from the opening of the temperature-controlled hydrogel film 2 by translation along the axis of the nerve, as shown in FIG. Figure 4 As shown in (b). Figure 7 As shown, the electrical stimulation signal of the back-end system is input into the electrode patch through the electrode connection interface 5 to stimulate the nerve, and the collected model is transmitted through the electrode connection interface 5 for analysis. After the operation, the nerve area is rinsed with cold water to cool down, the adhesion of the temperature-controlled hydrogel film 2 decreases, the electrode patch is separated from the nerve, and the electrode patch is removed.

[0044] The specific implementation methods described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above is only the most preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, supplements and equivalent substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A self-climbing and self-adhesive flexible electrode patch for neural monitoring, characterized in that: It includes a flexible substrate film, a memory alloy strip, a temperature-controlled hydrogel film, and an electrode array; The flexible substrate film is an insulating flexible polymer, has biocompatibility, and has an open interlayer; The memory alloy strip is trained to have a phase change property of bending from a straight line to a circle within a specific temperature range, and is inserted into the open interlayer of the flexible substrate film; The temperature-control hydrogel film has temperature-control properties and is attached to the upper surface of the flexible base film; The electrode array includes an electrode sheet wrapped by a temperature-controlled hydrogel film and a corresponding electrode wire, wherein one side of the electrode sheet is exposed outside the temperature-controlled hydrogel film for direct contact with human nerves, the electrode wire extends outward in the temperature-controlled hydrogel film, and the extension portion has an electrode adapter interface; The temperature-controlled self-adhesive flexible electrode patch is placed around the nerve at room temperature during surgery. In an elevated temperature environment, the memory alloy strip drives the entire electrode patch to wrap around the nerve based on its phase change properties. The temperature-controlled hydrogel film increases adhesion based on its temperature control properties, allowing the electrode disc to fit tightly to the nerve. After the fitting is completed, the memory alloy strip removes the electrode patch through the open interlayer. After the operation, the electrode patch automatically detaches from the nerve after the temperature is lowered to reduce adhesion.

2. The self-climbing and self-adhesive flexible electrode patch for neural monitoring according to claim 1, characterized in that: The memory alloy strip has a phase change characteristic of bending from a straight line to a circle within a specific temperature range after training, including: the phase change temperature is between 30° C. and 40° C., and the bending radius of the memory alloy strip is between 0.5 mm and 10 mm.

3. The self-climbing and self-adhesive flexible electrode patch for neural monitoring according to claim 2, characterized in that: The memory alloy strip is a nickel-titanium alloy strip, and the heat treatment process is to bind the alloy strip to a mold for training for 2 to 5 hours under a specific constant temperature state of 100° C. to 450° C., so that it obtains phase change characteristics.

4. The self-climbing and self-adhesive flexible electrode patch for neural monitoring according to claim 1, characterized in that: The temperature-controlled hydrogel film has a temperature-controlled characteristic of changing adhesion based on temperature changes, including: the viscosity of the temperature-controlled hydrogel film is less than 3N / m at a surface temperature of 25°C, the viscosity is greater than 90N / m at 37°C, and the adhesion range is 1 to 100N / m in the range of 20°C to 40°C.

5. The self-climbing and self-adhesive flexible electrode patch for neural monitoring according to claim 4, characterized in that: The temperature-control hydrogel film includes a solution of acrylic acid, ammonium persulfate, N,N'-methylenebisacrylamide, acrylamide, and carbon nanofibers, wherein the mass ratio of acrylic acid, ammonium persulfate, N,N'-methylenebisacrylamide, acrylamide, and carbon nanofiber dispersion is 51-357:25:2:357:3600, wherein the carbon nanofiber dispersion includes deionized water and carbon nanofiber dispersion, and the corresponding mass ratio is 1:8-8:1, so that the temperature-control hydrogel film has temperature-control adhesion characteristics.

6. The self-climbing and self-adhesive flexible electrode patch for neural monitoring according to claim 1, characterized in that: The flexible base film includes acetate fiber that is strongly bonded to the temperature-controlled hydrogel film, and also includes at least one of rubber, polyimide, polyester fiber, polydimethylsiloxane, polyurethane, polyethylene terephthalate and polylactic acid as an encapsulation layer to form a composite structure with a thickness of 1 μm to 5 mm.

7. The self-climbing and self-adhesive flexible electrode patch for neural monitoring according to claim 1, characterized in that: The opening of the open interlayer of the flexible base film is located at a pair of adjacent long sides and short sides of the flexible base film, which is convenient for placing the memory alloy strip in an initial state and removing it from a bent state.

8. The self-climbing and self-adhesive flexible electrode patch for neural monitoring according to claim 1, characterized in that: The entire bendable region of the electrode patch corresponding to the temperature-controlled hydrogel film has a length of 1 cm to 5 cm, a width of 5 mm to 30 mm, and a thickness of 0.5 mm to 20 mm.

9. The self-climbing and self-adhesive flexible electrode patch for neural monitoring according to claim 1, characterized in that: The thickness of the electrode sheets in the electrode array is 1 μm to 500 μm, the spacing between the electrode sheets is 1 mm to 10 mm, and when the electrode sheets are circular sheets, the radius of each electrode sheet is 1 mm to 10 mm.

10. The self-climbing and self-adhesive flexible electrode patch for neural monitoring according to claim 1, characterized in that: The material of the electrode array is copper, gold, silver, silver chloride or conductive carbon black, and the number of electrode arrays is 2-128.

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