A magnetoelectric dual-field-driven deformed flexible electrophysiological signal acquisition electrode

Abstract

The present application belongs to the technical field of biological medical devices, and particularly relates to a magnetic and electric dual-field driven deformed flexible electrophysiological signal collection electrode, which comprises, from bottom to top, a magnetic film layer, a first shape memory polymer layer, a first electrode layer, a second shape memory polymer layer and a second electrode layer, which are sequentially arranged and tightly attached to each other; wherein the two shape memory polymer layers, the first electrode layer and the magnetic film layer jointly form a base layer, the first electrode layer receives an externally applied electric field, the magnetic film layer is used for receiving an externally applied magnetic field, and the two shape memory polymer layers are deformed through the shape memory effect caused by the electric field and the magnetic field, so as to drive the deformation of the second electrode layer and realize the collection of electrophysiological signals. The present application solves the problems of complex wired electrode structure and poor thermal field driven deformation effect in the prior art of deformed flexible electrophysiological signal collection electrode.

Description

Technical Field

[0001] This invention belongs to the field of biomedical device technology, specifically relating to a deformable flexible electrophysiological signal acquisition electrode driven by a magnetoelectric dual field. This device is used to acquire bioelectric signals by implantation in a living organism. Background Technology

[0002] The technology of implanting electrodes for monitoring bioelectrical signals in vivo has always attracted widespread attention. Implanting large electrodes in areas with limited space or area presents technical challenges, generally requiring external tools such as conductive strips to assist in deformation. Meanwhile, for implantation sites with complex structures in the body, deformable electrodes offer greater adaptability, reducing tissue irritation and damage, and improving patient comfort. However, current flexible electrodes that utilize shape memory materials for deformation mostly rely solely on thermal field actuation, resulting in unsatisfactory actuation performance. Furthermore, flexible deformable electrodes can closely conform to the surface of the bioelectrical signal measurement site, thus enabling more efficient acquisition of electrophysiological signals, enhancing signal accuracy and stability, and providing more reliable data for medical diagnosis and research. Therefore, developing a flexible electrophysiological acquisition electrode that can deform using a dual-field magnetoelectric actuation mechanism is of great significance. Summary of the Invention

[0003] The purpose of this invention is to provide a deformable flexible electrophysiological signal acquisition electrode driven by a dual magnetoelectric field, so as to solve the problems of complex wired electrode structure and poor thermal field driving effect in the existing flexible electrophysiological acquisition electrode technology.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A deformable flexible electrophysiological signal acquisition electrode driven by a magnetoelectric dual field is characterized by comprising, from bottom to top, a magnetic thin film layer, a first shape memory polymer layer, a first electrode layer, a second shape memory polymer layer, and a second electrode layer, all stacked tightly together. The magnetic thin film layer, the first shape memory polymer layer, the first electrode layer, and the second shape memory polymer layer together constitute a base layer. The magnetic thin film layer receives an externally applied magnetic field, and the first electrode layer receives an externally applied electric field. The combined action of the electric and magnetic fields causes the first and second shape memory polymer layers to deform due to a shape memory effect, thereby inducing deformation of the second electrode layer and achieving electrophysiological signal acquisition.

[0006] Furthermore, the shape memory polymer layer material is a mixture of epoxy resin and polyetheramine.

[0007] Furthermore, a scraping or transfer method is used, in which the shape memory polymer material is coated on the back of the second electrode layer before curing, and then cured as a whole to achieve a tight fit between the layers.

[0008] Furthermore, the second electrode layer is a patterned electrode layer, which includes a wire. One end of the wire has a signal acquisition contact, and the other end has a pad. The physiological electrical signals acquired by the signal acquisition contact are transmitted to an external device via the wire and the pad. This arrangement allows the second electrode layer to better adhere to the substrate layer to achieve better signal acquisition results.

[0009] Furthermore, the material of the first electrode layer is Cu.

[0010] Furthermore, the magnetic thin film layer is made of a mixture of iron oxide and polydimethylsiloxane (PDMS).

[0011] Furthermore, the mixing ratio of iron oxide to polydimethylsiloxane (PDMS) is 3:1.

[0012] This invention provides a deformable flexible electrophysiological signal acquisition electrode driven by a dual magnetoelectric field. On one hand, an externally applied magnetic field influences a magnetocaloric magnetic material, iron(II,III) oxide (Fe3O4), which is doped into polydimethylsiloxane (PDMS) in the form of magnetic particles to form a uniformly distributed magnetic thin film. Under the influence of the external magnetic field, the temperature of the magnetic thin film rises, simultaneously affecting the first shape memory polymer layer to reach its phase transition temperature and deform, thereby controlling the conformal deformation of the tightly bonded second electrode layer. On the other hand, after the first electrode is matched with an external transmitter, the near-field transmission effect during wireless power transmission causes the temperature of the first electrode to rise. This, in turn, affects the shape memory polymer layers located on both sides of the first electrode layer to reach their phase transition temperature and deform, thus controlling the conformal deformation of the tightly bonded second electrode layer. The portions of the electrode deformed using these two principles are respectively matched with shape memory polymers, and the deformation effects of the two shape memory polymer layers can be superimposed, resulting in better deformation of the surface electrode.

[0013] Compared with existing technologies, the deformable flexible electrophysiological acquisition electrode of this invention can achieve autonomous deformation under wireless external fields without the need for external tools such as conductors, thus simplifying the structure and easily adapting to electrodes with different deployment methods and patterns. Furthermore, compared with existing technologies that only drive deformation through thermal fields, the magnetoelectric dual-field driving effect is better and applicable to a wider range of scenarios. Attached Figure Description

[0014] Figure 1 A schematic diagram of the deformable flexible electrophysiological acquisition electrode driven by magnetoelectric dual field provided in Example 1;

[0015] Figure 2 The fabrication process of the deformable flexible electrophysiological acquisition electrode driven by magnetoelectric dual field provided in Example 1 is shown in the flowchart.

[0016] Figure 3 The graph shows the magnetocaloric effect test data of the magnetic thin film and two shape memory polymer layers of the deformable flexible electrophysiological acquisition electrode driven by magnetoelectric dual field provided in Example 1 in Experiment 1; where a is the temperature rise of the magnetic thin film and its adjacent shape memory polymer layer under an external magnetic field strength of 5 mT, and b is the temperature rise of the magnetic thin film and its adjacent shape memory polymer layer under an external magnetic field strength of 10 mT.

[0017] Figure 4 This is a graph showing the test data of the deformation of the deformable flexible electrophysiological acquisition electrode driven by the magnetoelectric dual field provided in Example 1 under heating conditions in Experiment 2.

[0018] Figure label:

[0019] 2-1 is a flowchart of electrode layer preparation, 2-2 is a flowchart of shape memory polymer layer preparation, 2-3 is a flowchart of first electrode layer preparation, and 2-4 is a flowchart of magnetic thin film preparation. Detailed Implementation

[0020] The technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0021] Example 1

[0022] like Figure 1 As shown, the deformable flexible electrophysiological acquisition electrode driven by magnetoelectric dual field provided in this embodiment includes a magnetic thin film layer, a first shape memory polymer layer, a first electrode layer, a second shape memory polymer layer and a second electrode layer stacked sequentially from bottom to top, with each layer tightly bonded together.

[0023] The magnetic thin film layer, the first shape memory polymer layer, the first electrode layer and the first shape memory polymer layer together constitute the base layer. The base layer is used to realize deformation, and the second electrode layer is used to collect electrophysiological signals.

[0024] In this embodiment, the deformation of the second electrode used to acquire electrophysiological signals is achieved by utilizing the temperature change generated under the combined action of the electric field in the deformable substrate layer that matches the first electrode layer and the external magnetic field applied to the magnetic thin film layer, which drives the shape memory polymer layer. Since the deformable substrate layer and the second electrode layer are bonded using a coating or transfer method, uniform and tight adhesion between the two is ensured, thus realizing a wireless electrode capable of conformal deformation under an external magnetic field and a matching electric field.

[0025] In this embodiment, the shape memory polymer layer is prepared by mixing epoxy resin and polyetheramine. The first electrode is obtained by laser cutting copper foil, and the magnetic film is prepared by doping magnetic material iron oxide particles into polydimethylsiloxane (PDMS) at a doping mass ratio of 3:1.

[0026] The fabrication steps of the aforementioned deformable flexible electrophysiological acquisition electrode driven by a dual magnetoelectric field are as follows: Figure 2 As shown, it includes:

[0027] Step 1: Select copper foil as the material of the first electrode layer, and use laser cutting to obtain the first electrode. The first electrode layer is located between the upper surface of the first shape memory polymer layer and the lower surface of the second shape memory polymer layer.

[0028] Step 2: Prepare the first and second shape memory polymer layers separately. The shape memory polymer is a mixture of epoxy resin and polyetheramine in a mass ratio of 1:1.5, which can be adjusted according to the modulus after curing. First, weigh the epoxy resin, then add the polyetheramine dropwise. The resulting mixture is stirred and heated in a water bath at 60°C for 20 minutes, then heated at 100°C for 1 hour, and then at 130°C for 1 hour to complete the curing.

[0029] Step 3: Preparation of the magnetic thin film layer: Mix PDMS solution A and solution B at a mass ratio of 1:10. Weigh out ferric oxide magnetic powder and incorporate it into PDMS at a mass ratio of 3:1 (Fe3O to PDMS). Place the mixture in a mixer and mix thoroughly to obtain a mixed liquid. Then, spin-coat the mixture onto the lower surface of the first shape memory polymer layer using a spin-coating method, ensuring a smooth and uniform surface. Cur the spin-coated sample by heating it at 60°C for 1 hour.

[0030] Step 4: Prepare the second electrode layer for acquiring electrophysiological signals:

[0031] The second electrode layer is disposed on the upper surface of the second shape memory polymer layer and includes a wire. One end of the wire has a contact array for acquiring signals, and the other end has a pad. The contact is 1×1 mm in size and arranged in a 3×3 array. The wire is about 30 mm long, and the pad is 2×2 mm in size. It is obtained by any of the following fabrication methods: laser cutting, photolithography, magnetron sputtering, etc.

[0032] To better illustrate the effect of the deformable flexible electrophysiological acquisition electrode driven by the magnetoelectric dual field in this embodiment, the following experiments 1 and 2 are used for verification. Experiment 1 is used to verify the temperature rise of the shape memory polymer layer in the deformable substrate layer of the electrode provided in Example 1 under the magnetocaloric effect of the magnetic thin film when an external magnetic field is applied. Experiment 2 is used to verify the deformation of the electrode provided in Example 1 under heating conditions.

[0033] Experiment 1

[0034] The magnetocaloric effect of the deformable substrate layer of the electrode in Example 1, namely the magnetic thin film and the shape memory polymer layer, was tested as follows:

[0035] like Figure 3 a and Figure 3 As shown in Figure b, the temperature rise of the magnetic film and shape memory polymer was tested under external magnetic field strengths of 5 mT and 10 mT, respectively, reflecting the magnetocaloric effect of this deformable substrate. The temperature rise of the shape memory polymer was recorded using an infrared thermometer. It can be seen that when the applied external magnetic field strength was 5 mT, the polymer's heating rate was 0.4 °C / s; while when the applied external magnetic field strength increased to 10 mT, the heating rate increased to 0.6 °C / s. This indicates that the magnetocaloric effect is related to the strength of the external magnetic field. The external magnetic fields applied in this experiment at 5 mT and 10 mT are far less than the maximum safe magnetic field strength that most biological organisms can withstand (the maximum safe magnetic field strength that the human body can withstand is 300 mT). Furthermore, the magnetocaloric effect of the magnetic film is the basis for the magnetocaloric-driven deformation of flexible electrophysiological acquisition electrodes, and the heating rate shown in this experiment is feasible for achieving the electrode deformation function.

[0036] Experiment 2

[0037] The deformation of the electrode in Example 1 under heating conditions was tested, as follows:

[0038] The time required for the deformable flexible electrophysiological acquisition electrode to deform to a specified shape was tested under heating conditions of 40℃, 60℃, and 80℃, respectively. Figure 4 As shown, the required deformation time is approximately 4 minutes at a heating temperature of 40℃; approximately 30 seconds at a heating temperature of 60℃; and approximately 10 seconds at a heating temperature of 80℃. This indicates that the deformation rate of the deformable flexible electrophysiological acquisition electrode is temperature-dependent, specifically related to the near-field transmission effect of the first electrode layer and the magnetocaloric effect of the magnetic thin film.

[0039] In summary, the deformable flexible electrophysiological acquisition electrode provided in this embodiment can fit tightly and seamlessly onto the surface of biological tissue, ensuring efficient and stable acquisition of electrophysiological signals and greatly improving signal accuracy and acquisition quality.

[0040] The above description is merely a specific embodiment of the present invention for acquiring electroencephalogram (EEG) signals. For the acquisition of other electrophysiological signals, adjustments can be made according to specific circumstances. Any feature disclosed in this specification, unless specifically stated otherwise, may be replaced by other equivalent or similarly purposed alternative features; all disclosed features, or steps in all methods or processes, may be combined in any manner, except for mutually exclusive features and / or steps.

Claims

1. A magnetoelectric dual-field-driven morphing flexible electrophysiological signal acquisition electrode, characterized in that: The magnetic film layer, the first shape memory polymer layer, the first electrode layer and the second shape memory polymer layer jointly constitute a base layer, the magnetic film layer is used for receiving an externally applied magnetic field, the first electrode layer receives an externally applied electric field, and the first and second shape memory polymer layers are deformed due to the shape memory effect under the joint action of the electric field and the magnetic field, so as to drive the deformation of the second electrode layer and realize the collection of the electrophysiological signal. The second electrode layer is used for collecting the electrophysiological signal. Under the action of the external magnetic field, the temperature of the magnetic film rises, the first shape memory polymer layer is heated to its phase transition temperature and deformed, so that the second electrode layer is coformally deformed; the temperature of the first electrode rises under the near-field transmission effect, so that the first and second shape memory polymer layers in contact with the upper and lower sides of the first electrode layer reach the phase transition temperature and are deformed, so that the second electrode layer in contact with the second shape memory polymer is coformally deformed. The material of the first and second shape memory polymer layers is a mixture obtained by mixing epoxy resin and polyether amine at a mass ratio of 1:1.

5.

2. The piezoelectric dual-field-driven deformable flexible electrophysiological signal acquisition electrode according to claim 1, characterized in that: The base layer and the second electrode layer are combined by using a doctor blade method or a transfer method.

3. The dual magnetic and electric field driven flexible electro-physiological signal acquisition electrode of claim 1, wherein: The second electrode layer is an electrode layer after patterning, and the electrode layer includes a wire, one end of the wire is provided with a signal collection contact, and the other end of the wire is provided with a solder pad.

4. The flexible and deformable electro-physiological signal acquisition electrode driven by magnetic and electric dual fields according to claim 1, characterized in that: The material of the first electrode layer is Cu.

5. The dual magnetic and electric field driven flexible electro-physiological signal acquisition electrode of claim 1, wherein: The material of the magnetic film layer is a mixture of ferroferric oxide and polydimethylsiloxane (PDMS) at a mass ratio of 3:

1.

6. The dual magnetic and electric field driven flexible electro-physiological signal acquisition electrode of claim 1, wherein: The material of the magnetic film layer is a mixture of ferroferric oxide and polydimethylsiloxane (PDMS) at a mass ratio of 3:1.

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