CN114343651B - Flexible contact with gradient porosity, gel semi-dry electrode containing flexible contact and electroencephalogram cap - Google Patents
Flexible contact with gradient porosity, gel semi-dry electrode containing flexible contact and electroencephalogram cap Download PDFInfo
- Publication number
- CN114343651B CN114343651B CN202111502206.0A CN202111502206A CN114343651B CN 114343651 B CN114343651 B CN 114343651B CN 202111502206 A CN202111502206 A CN 202111502206A CN 114343651 B CN114343651 B CN 114343651B
- Authority
- CN
- China
- Prior art keywords
- hydrogel
- electrode
- semi
- flexible contact
- dry electrode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 239000000017 hydrogel Substances 0.000 claims abstract description 121
- 238000007710 freezing Methods 0.000 claims description 21
- 230000008014 freezing Effects 0.000 claims description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 19
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 17
- 239000003960 organic solvent Substances 0.000 claims description 12
- 239000002184 metal Substances 0.000 claims description 11
- 229910052751 metal Inorganic materials 0.000 claims description 11
- 238000000034 method Methods 0.000 claims description 11
- 235000017166 Bambusa arundinacea Nutrition 0.000 claims description 10
- 235000017491 Bambusa tulda Nutrition 0.000 claims description 10
- 241001330002 Bambuseae Species 0.000 claims description 10
- 235000015334 Phyllostachys viridis Nutrition 0.000 claims description 10
- 239000011425 bamboo Substances 0.000 claims description 10
- 238000007747 plating Methods 0.000 claims description 10
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 9
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 claims description 9
- 229920001971 elastomer Polymers 0.000 claims description 8
- 239000000806 elastomer Substances 0.000 claims description 8
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims description 6
- 238000002360 preparation method Methods 0.000 claims description 6
- 238000002791 soaking Methods 0.000 claims description 6
- 238000010257 thawing Methods 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 5
- 238000012986 modification Methods 0.000 claims description 5
- 239000007864 aqueous solution Substances 0.000 claims description 4
- 230000008961 swelling Effects 0.000 claims description 4
- 229920001661 Chitosan Polymers 0.000 claims description 3
- 229920002307 Dextran Polymers 0.000 claims description 3
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 3
- 229920002401 polyacrylamide Polymers 0.000 claims description 3
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 3
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 claims description 2
- 229920002125 Sokalan® Polymers 0.000 claims description 2
- 239000004584 polyacrylic acid Substances 0.000 claims description 2
- 238000002715 modification method Methods 0.000 claims 1
- 239000000499 gel Substances 0.000 abstract description 13
- 210000004556 brain Anatomy 0.000 abstract description 4
- 239000003792 electrolyte Substances 0.000 description 17
- 239000011148 porous material Substances 0.000 description 8
- 210000004761 scalp Anatomy 0.000 description 6
- 210000003491 skin Anatomy 0.000 description 5
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- 239000000853 adhesive Substances 0.000 description 4
- 230000001070 adhesive effect Effects 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000003990 capacitor Substances 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 206010013786 Dry skin Diseases 0.000 description 2
- 238000005299 abrasion Methods 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 239000000084 colloidal system Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 238000004108 freeze drying Methods 0.000 description 2
- 208000015181 infectious disease Diseases 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 210000000434 stratum corneum Anatomy 0.000 description 2
- 210000001519 tissue Anatomy 0.000 description 2
- 108010010803 Gelatin Proteins 0.000 description 1
- 229920000663 Hydroxyethyl cellulose Polymers 0.000 description 1
- 239000004354 Hydroxyethyl cellulose Substances 0.000 description 1
- 206010020751 Hypersensitivity Diseases 0.000 description 1
- 206010061218 Inflammation Diseases 0.000 description 1
- 229910021607 Silver chloride Inorganic materials 0.000 description 1
- 206010040830 Skin discomfort Diseases 0.000 description 1
- 206010040880 Skin irritation Diseases 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 239000012620 biological material Substances 0.000 description 1
- 229920002678 cellulose Polymers 0.000 description 1
- 239000001913 cellulose Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 201000010099 disease Diseases 0.000 description 1
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000008273 gelatin Substances 0.000 description 1
- 229920000159 gelatin Polymers 0.000 description 1
- 235000019322 gelatine Nutrition 0.000 description 1
- 235000011852 gelatine desserts Nutrition 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 235000019447 hydroxyethyl cellulose Nutrition 0.000 description 1
- 230000004054 inflammatory process Effects 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- JMMWKPVZQRWMSS-UHFFFAOYSA-N isopropanol acetate Natural products CC(C)OC(C)=O JMMWKPVZQRWMSS-UHFFFAOYSA-N 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000001465 metallisation Methods 0.000 description 1
- 125000005395 methacrylic acid group Chemical group 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 description 1
- 230000036556 skin irritation Effects 0.000 description 1
- 231100000475 skin irritation Toxicity 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
Landscapes
- Measurement And Recording Of Electrical Phenomena And Electrical Characteristics Of The Living Body (AREA)
- Electrotherapy Devices (AREA)
Abstract
The invention relates to a flexible contact with gradient porosity, a gel semi-dry electrode and an electroencephalogram cap containing the flexible contact, in particular to a flexible contact for a semi-dry electrode, which is hydrogel with gradient porosity, the hydrogel with gradient porosity is composed of more than two layers of hydrogels with different porosities, wherein the porosity of the hydrogel near the outer layer is lower than that of the hydrogel near the inner layer. The invention also discloses a semi-dry electrode comprising the flexible contact. The semi-dry electrode can be used for acquiring brain electrical signals, is suitable for long-time use, and can effectively prevent contact impedance change and motion signal artifacts caused by motion.
Description
Technical Field
The invention belongs to the field of biological materials and detection, and particularly relates to a gel semi-dry electrode for electroencephalogram recording and a preparation method and application thereof.
Background
Electroencephalogram recording can be used for detecting disease states, particularly in the clinical field, such as seizure detection, focal point position estimation and the like, and is widely used in medical and civil attention, relaxation degree, sleep state detection and other devices. Currently, brain electrodes mainly comprise wet electrodes, dry electrodes, capacitive electrodes and quasi-dry electrodes.
The wet electrode used by the traditional electroencephalograph is commonly used as an Ag/AgCl powder electrode, and the purpose of recording can be achieved by combining conductive adhesive. The electrode comprises a wire, a metal contact and a plating layer, and an electrolyte interface which is not easy to polarize can be well established by using conductive gel containing Cl ions, and in addition, the conductive gel can penetrate the scalp surface, conform to the scalp surface and hydrate a high-resistance stratum corneum, so that a stable electrolyte skin interface is ensured. However, the acquisition of such an electroencephalogram signal and the application of the electrode require a large amount of preparation time before use, and the longer the acquisition channel number, the longer the time required. And after a period of use, the conductive adhesive can be gradually dried, so that not only is the bottleneck of long-term electroencephalogram signal recording, but also a great deal of time and effort are required to debug and maintain the recording system. Skin cleansing or abrasion is required during electrode placement, scalp abrasion can present a risk of infection and can present both short and long term pain. In addition, the conductive gel or adhesive may soil the hair and may even cause allergic reactions. At the same time, short circuits often occur between adjacent electrodes due to accidental diffusion of the gel, especially in the case of high density recording. These inconvenient and uncomfortable problems limit the wide application of conductive gel based electroencephalograms.
The use of dry and semi-dry electrodes and capacitive electrodes can avoid the use of conductive paste. The technical principle of dry electrodes is generally to use contact electrodes. The conductive portion is typically comprised of a series of stratum corneum-piercing microneedles or microneedles, typically spike or needle structures on the order of a few times a nanometer micron or even a millimeter, so that the invasive dry electrode can effectively bypass the stratum corneum to access the inner layers of the skin with lower impedance. Although such invasive dry electrodes have advantages such as fast setup, low electrical resistance, good mechanical stability and tolerance to motion artifacts. There are a number of disadvantages to this, for example, the fact that the electrodes are often in motion and other conditions, fragile spikes tend to break off and cause infection or inflammation, and impedance mismatch between the electrodes.
The capacitive electrode solves the bad contact between the electrode and the skin by sacrificing the electrode group, and an insulating layer is usually arranged at the conductive front end of the capacitive electrode, so that a capacitor can be formed between the electrode and the tissue below the skin dry layer, and the conductor of the electrode and the tissue below the skin dry layer serve as two polar plates of the capacitor. However, capacitive electrodes have the major disadvantage of first being too low amplitude to record spontaneous EEG or ERP. Second, the electrode impedance is high, which can lead to reduced signal quality, and ultra-high impedance preamplifiers are integrated with the electrodes in order to alleviate these problems. Finally, the electrodes are very sensitive to motion artifacts due to the variation of the spacing between the two plates of the capacitor.
The semi-dry electrode bridges the gap between the typical dry and wet electrodes, retaining both advantages and addressing most of their respective shortcomings. Typically, the volume of the electrolyte is on the order of a few microliters, which is well below the 1-2mL volume of conductive paste used for each wet electrode. The semi-dry electrode with a small amount of electrolyte can not only avoid polluting hair and preventing short circuit, but also hydrate the scalp locally, so that the impedance of the scalp of the electrode is reduced, the electrode is effectively coupled to the scalp to obtain a relatively stable electrode skin interface, the semi-dry electrode is insensitive to electromagnetic interference and motion artifact, meanwhile, the semi-dry electrode can be arranged conveniently like a dry electrode, and the hair does not need to be cleaned after recording, so that the semi-dry electrode has a wide application prospect in actual electroencephalogram acquisition. However, the existing semi-dry electrode still has the problems of complex preparation process, need of supplementing electrolyte for a period of time, low lamination degree, unsatisfied mechanical strength and the like.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a semi-dry electrode which has simple structure, can self-supplement electrolyte, has good mechanical strength and flexibility and can be used for electroencephalogram recording.
In one aspect, the present invention provides a flexible contact for a semi-dry electrode, the flexible contact being a hydrogel having a gradient porosity, the hydrogel having a gradient porosity being comprised of more than two layers of hydrogels of different porosities, wherein the hydrogel porosity is lower near the outer layer than the hydrogel porosity of the inner layer.
Further, the flexible contact is made by the following method: secondary molding or post-modification; the secondary forming is to adjust the porosity of the material by utilizing a carbon dioxide supercritical process and prepare a double-layer colloid structure through twice forming, and the later modification is to increase the porosity of the inner-layer hydrogel on the premise of protecting the integrity of the inner-layer structure by utilizing an insufficient supercritical technology, quick freezing or freeze drying.
Further, the flexible contact is obtained by: soaking the hydrogel in an aqueous solution for swelling, then soaking the hydrogel in an organic solvent with a freezing point lower than that of water, replacing part of water on the surface of the hydrogel with the organic solvent, then freezing the hydrogel at the temperature lower than 0 ℃, and thawing the hydrogel after the water in the hydrogel is solidified to obtain the hydrogel with gradient porosity. Preferably, the organic solvent is ethanol, acetone, isopropanol, ethyl acetate.
Further, the hydrogel is selected from the group consisting of polyacrylic hydrogels, polyacrylamide hydrogels, methacrylic hydrogels, polyvinyl alcohol hydrogels, chitosan hydrogels, dextran hydrogels, cellulose hydrogels, hydroxyethyl cellulose hydrogels, gelatin hydrogels.
In another aspect, the present invention provides a method for preparing the above flexible contact for semi-dry electrode, comprising the steps of:
s1) soaking the hydrogel in an aqueous solution to swell
S2) soaking the swelled hydrogel obtained in the step S1) in an organic solvent with a freezing point lower than that of water, and replacing part of water on the surface of the hydrogel with the organic solvent;
And S3) freezing the hydrogel obtained in the step S2), wherein the freezing temperature is below 0 ℃, and thawing after the water in the hydrogel is solidified, so as to obtain the hydrogel with gradient porosity.
Further, the organic solvent is ethanol, acetone, isopropanol or ethyl acetate.
Further, the freezing and thawing in step S3) is performed in one cycle or in a plurality of cycles.
In a further aspect, the invention provides the use of a flexible contact as described above for the preparation of a semi-dry electrode for a wearable electroencephalogram device or a medical electroencephalogram.
In a further aspect the present invention provides a hydrogel semi-dry electrode having the flexible contact described above.
Further, the hydrogel semi-dry electrode is made of the flexible contact, the electrode fixing groove, the metal plating cup-shaped electrode, the base and the elastomer;
the electrode fixing groove can fix the flexible contact at the top end and accommodate the metal plating cup-shaped electrode, and simultaneously, the metal plating cup-shaped electrode is in flexible contact with the flexible contact;
The base is fixedly connected with the electrode fixing groove;
The elastic body is arranged in the base and is contacted with the bottom of the electrode fixing groove.
Further, the electrode fixing groove comprises a flexible contact fixing ring and an electrode fixing collet, wherein the top of the flexible contact fixing ring is provided with a cavity for accommodating and fixing the flexible contact, and the inner side of the tail part is provided with threads; the electrode fixing bottom support is cylindrical, and threads matched with the threads on the inner side of the tail part of the flexible contact fixing ring are arranged on the outer side of the top end of the electrode fixing bottom support.
Further, the bottom end of the electrode fixing bottom support is provided with a raised limiting structure; the base is tubular structure, and the top of base is nested with the bottom of electrode fixing collet, and the inside cavity that holds the elastomer that has of base, and base open top diameter is less than the limit structure of the bottom of electrode fixing collet, and the section of thick bamboo wall of base all around comprises 4-6 non-interconnected section of thick bamboo walls, protruding quantity and section of thick bamboo wall quantity on the limit structure are the same.
In still another aspect, the present invention provides a method for manufacturing a wearable electroencephalograph or medical electroencephalograph having the above-described hydrogel semi-dry electrode.
Further, the cap body used for fixing the hydrogel semi-dry electrode is arranged on the wearable electroencephalograph or the medical electroencephalograph, and the cap body is detachably connected with the hydrogel semi-dry electrode.
Further, the cap body is provided with a fixing ring for fixing the hydrogel semi-dry electrode, and the fixing ring is provided with threads which are matched with the threads on the outer side of the hydrogel semi-dry electrode base.
Advantageous effects
Compared with the prior best technology, the semi-dry electrode has the advantages that:
1) The semi-dry electrode has the advantages of simple manufacturing method, low noise and low material cost.
2) The lower void ratio in the electrode flexible contact can enhance the overall strength of the hydrogel and prevent the hydrogel from losing efficacy due to insufficient mechanical properties. The contact impedance change and the motion signal artifact caused by motion can be effectively prevented.
3) The hydrogel of the inner layer of the flexible contact of the present invention has more pore structure, which allows the flexible contact to store more dielectric. Meanwhile, along with the discharge of the dielectric medium, the dielectric medium in the pores of the inner layer can be released to the surface of the hydrogel too quickly, and when the electrolyte on the surface is exhausted, the electrolyte in the pores can be spontaneously released to the surface of the gel, so that the purpose of rapidly discharging the dielectric medium is realized. The device is safe and simple to use, has the capability of rapidly charging and discharging electrolyte, and can be used for a long time by wearable equipment.
4) The application method does not require professional personnel to perform installation adjustment, and the used materials are safe and have no skin irritation.
Drawings
FIG. 1 is a schematic illustration of a gradient superporous hydrogel sphere;
FIG. 2 is a diagram showing an electrode fixing groove assembly;
FIG. 3 is a split view of an electrode fixing groove;
FIG. 4 is a photograph of a base;
FIG. 5 is a photograph assembled into an electrode;
FIG. 6 is an electroencephalogram cap after an electrode is installed;
Fig. 7 shows an electrode interface that may be used.
Fig. 8 is a state diagram of the use of the electroencephalogram cap.
Fig. 9 is an electroencephalogram signal recorded by the electroencephalogram cap of the present invention.
Detailed Description
The following detailed description of the present invention will be made in detail to make the above objects, features and advantages of the present invention more apparent, but should not be construed to limit the scope of the present invention.
The present invention will be described in detail with reference to the accompanying drawings.
The embodiment of the invention provides a hydrogel semi-dry electrode, which is provided with a flexible contact made of hydrogel, an electrode fixing groove, a metal plating cup-shaped electrode, a base and an elastomer.
As shown in fig. 1, the flexible contact has a gradient hydrogel structure composed of two layers of hydrogels of different porosities, wherein the hydrogel porosity near the outer layer is lower than the hydrogel porosity of the inner layer.
The flexible contact is manufactured by the following method: secondary molding or post-modification; the secondary forming is to adjust the porosity of the material by utilizing a carbon dioxide supercritical process and prepare a double-layer colloid structure through twice forming, and the later modification is to increase the porosity of the outer-layer hydrogel on the premise of protecting the integrity of the inner-layer structure by utilizing an insufficient supercritical technology, quick freezing or freeze drying.
In some specific embodiments, the hydrogel is frozen by placing the uniformly textured hydrogel in an organic solution having a freezing point lower than that of water after absorbing the water, replacing a portion of the water on the surface of the hydrogel with the organic solvent, and then freezing at a temperature of 0 ℃ or less. When the hydrogel is frozen, the water content of the inner layer in the hydrogel can increase the porosity due to freezing, so that a structure that the outer layer pores are smaller than the inner layer pores is obtained.
The hydrogel of the outer layer designed by the invention has a porous structure, so that the hydrogel can store a certain electrolyte, the electroencephalogram acquisition process is simpler, no conductive adhesive is required to be used separately, and a large number of pores of the outer layer of the flexible contact can quickly absorb and discharge the electrolyte like battery charging. Wherein the high porosity of the interior allows for more dielectric storage and replenishment of the outer layer when it is depleted. The outer layer has low porosity, can uniformly release the dielectric medium, and simultaneously endows the flexible contact with better toughness and mechanical properties. Therefore, the flexible contact can gradually discharge electrolyte according to the requirement in the use process, is more suitable for long-time use, and can not cause the problems of low signal acquisition efficiency and skin discomfort due to the fact that the electrolyte is volatilized after a certain time is released simultaneously.
The hydrogel may be selected from any hydrogel which has a certain strength and can form pores, for example, from the group consisting of polyacrylic acid hydrogel, polyacrylamide hydrogel, methacrylic acid hydrogel, polyvinyl alcohol hydrogel, chitosan hydrogel, dextran hydrogel.
The flexible contact can be spherical, ellipsoidal, platform conical or cylindrical.
The electrode fixing groove can fix the flexible contact at the top end and accommodate the metal plating cup-shaped electrode, and simultaneously, the metal plating cup-shaped electrode is in flexible contact with the flexible contact; in some specific embodiments, the metallization of the metallized cup electrode may be any conductive metal, such as a gold plated cup electrode.
The electrode fixing groove comprises a flexible contact fixing ring and an electrode fixing collet, wherein the top of the flexible contact fixing ring is provided with a cavity for accommodating and fixing the flexible contact, and the inner side of the tail part is provided with threads; the electrode fixing bottom support is cylindrical, and threads matched with the threads on the inner side of the tail part of the flexible contact fixing ring are arranged on the outer side of the top end of the electrode fixing bottom support. The diameter of the cavity at the top of the flexible contact fixing ring is larger than that of the opening at the top, after the flexible contact is placed in the cavity, a part of the flexible contact is exposed outside the flexible contact fixing ring, and the part of the flexible contact placed in the cavity is contacted with the metal plating cup-shaped electrode and is fixed at the position through the cup-shaped electrode and the opening at the top of the flexible contact fixing ring. When the electrode fixing bottom support passes through the outer thread of the top end and is screwed into the inner side of the tail part of the flexible contact fixing ring, the electrode fixing bottom support props against the cup-shaped electrode and is used for fixing the position of the cup-shaped electrode. When the flexible contact needs to be replaced or electrolyte needs to be supplemented for the flexible contact, the flexible contact can be taken out by unscrewing the electrode fixing collet. The structure of the invention is not only convenient for taking out the flexible contact, but also can adapt to flexible contacts with different sizes or different flexibilities by adjusting the size of the cavity at the top of the fixing ring of the flexible contact under the condition of the length of the screw thread.
The bottom end of the electrode fixing bottom support is provided with a raised limiting structure; the limiting structure is an annular structure arranged on the side face of the bottom end of the electrode fixing base, and the annular structure is provided with a plurality of protrusions. The limiting structure is used for connecting the electrode fixing collet and the base.
The metal-plated cup-shaped electrode is provided with a wire for transmitting signals.
As shown in fig. 4 and 5, the base is of a cylindrical structure, the top end of the base is nested with the bottom end of the electrode fixing base, a cavity for accommodating an elastomer is formed in the base, the diameter of an opening at the top of the base is smaller than that of a limiting structure at the bottom end of the electrode fixing base, the walls around the base are composed of 4-6 non-interconnected split type walls, the number of protrusions on the limiting structure is the same as that of the split type walls, and the base is fixedly connected with the electrode fixing groove. The split type section of thick bamboo wall provides certain elasticity, when exerting certain power, makes the limit structure of the fixed collet of electrode can extrude in the split type section of thick bamboo wall gets into the tubular structure of base, and the protruding slip base that passes through split type section of thick bamboo wall on the limit structure to can make protruding and the inboard contact of split type section of thick bamboo wall through the fixed collet of rotatory electrode in the base, increase the stability of being connected to the fixed collet of electrode. The outside of the split cylinder wall can be provided with a plurality of annular structures or thread structures for increasing friction force when the split cylinder wall is fixed with the electroencephalogram cap body.
The elastomer may be a spring. The elastic body is arranged in the base and is contacted with the bottom of the electrode fixing groove. The elastic body applies an outward force to the bottom of the electrode fixing groove and is used for fixing together with the limiting structure.
As shown in fig. 6 and 8, in some embodiments of the present invention, an electroencephalogram cap is provided, on which a cap body for fixing the hydrogel semi-dry electrode is provided, on which a fixing ring for fixing the hydrogel semi-dry electrode is provided, and on which threads matching with threads on the outer side of the base of the hydrogel semi-dry electrode are provided. The cup-shaped electrode lead wire and the electrode interface in the semi-dry electrode are used for connecting wearable electroencephalogram equipment, a high-density electronic connector or a medical electroencephalogram machine.
EXAMPLE 1 preparation of gradient superporous hydrogel spheres
The method comprises the steps of firstly swelling gel by absorbing water, replacing water on the outer layer of the gel by low-melting-point liquid such as ethanol, putting the gel into ethanol solution with the temperature of 80 ℃ below zero for quick freezing, wherein the outer layer contains ethanol and cannot be solidified, the inner layer is an aqueous layer and can be solidified, and the inner layer generates a porous structure after thawing. The freezing point of the outer layer is lower by ethanol, so the outer layer is not frozen, and the porosity of the outer layer is smaller. After the inner layer is frozen, the internal ice crystals will destroy the internal structure of the hydrogel, so that the internal porosity becomes large. The outer hydrogel at this point has a lower porosity than the inner layer because it is not frozen. The freezing may be performed one or more times to achieve different pore sizes and different gradients of porosity.
Example 2 electrode Assembly
As shown in fig. 2-3, the hydrogel ball with multiple gradient holes is placed in a hydrogel ball fixing seat after absorbing water, the fixing seat is of a double-split design, the front end of a light color in the drawing is used for fixing the hydrogel ball, the rear end of a dark color containing threads and the fixing seat is fixed through threads, a gold-plated cup-shaped electrode is arranged in the rear end of the dark color, and after the hydrogel is placed in the front end of the light color and the cup-shaped electrode is fixed at the rear end of the dark color, the connection between the hydrogel ball and the cup-shaped electrode is realized through rotationally linking the two parts. When the gradient superporous hydrogel ball needs to be replaced, the front end of the gradient superporous hydrogel ball can be unscrewed for replacement, so that the hydrogel ball is convenient to replace in the later period, meanwhile, the gradient superporous hydrogel ball can be conveniently taken down and filled with new electrolyte after the electrolyte is consumed, the service life of the electrode is greatly prolonged, and meanwhile, the rear-end gold-plated cup-shaped electrode is protected from being excessively corroded in the electrolyte filling stage.
As shown in fig. 4, the brain electrode needs to maintain the contact stability as much as possible, and the design does not need to additionally introduce conductive gel, and only needs to place a section of elastomer, such as a spring, at the rear end of the hydrogel electrode in the electrode fixing stage, so that stable contact pressure can be provided, and the generation of motion artifacts is reduced. A picture of the combined monolithic electrode is shown in fig. 5. Fig. 6 shows the state of being simultaneously fixed on the electroencephalogram cap after complete installation. The green part is clamped outside the black part and is of a sliding structure, and the rear of the black part is provided with a spring, namely the spring is clamped between the green structure and the black structure.
Example 3 electrode Assembly
As shown in fig. 7, the interface on the recording end of the conductive connection led out by the cup-shaped electrode needs to ensure the stability of contact as much as possible, so that better connection can be realized by soldering tin, but the brain electrical signal amplitude is very sensitive to noise and high impedance connection because of small amplitude and need of amplification. Increasing the conductive area of the interface, i.e. increasing the diameter or increasing the length, if the device allows, can effectively ensure a low impedance contact, such as a medical electroencephalograph interface. However, considering the development volume of the wearable device, the high-density electronic connector can be adopted to realize multi-channel signal transmission, and the impedance is reduced as much as possible on the premise of ensuring conduction.
Example 4 Signal recording
After the electrodes are assembled as described above, the EEG can be recorded by fixing the electrodes to the EEG recording cap as shown in FIG. 8, and the recorded signals are as shown in FIG. 9. Experimental results prove that the semi-dry electrode has low noise.
Claims (14)
1. A flexible contact for a semi-dry electrode, wherein the flexible contact is a hydrogel having a gradient porosity, the hydrogel having a gradient porosity being comprised of more than two layers of hydrogels of different porosities, wherein the hydrogel porosity near the outer layer is lower than the hydrogel porosity near the inner layer;
the flexible contact is spherical, ellipsoidal, conical or cylindrical;
The flexible contact is manufactured by a post-modification method, the post-modification is that hydrogel is soaked in aqueous solution for swelling, then soaked in organic solvent with freezing point lower than that of water, partial water on the surface of the hydrogel is replaced by the organic solvent, then freezing is carried out, the freezing temperature is lower than 0 ℃, and after the water in the hydrogel is solidified, the hydrogel with gradient porosity is obtained.
2. The flexible contact for a semi-dry electrode according to claim 1, wherein the hydrogel is selected from the group consisting of polyacrylic acid hydrogel, polyacrylamide hydrogel, methacrylic acid hydrogel, polyvinyl alcohol hydrogel, chitosan hydrogel, and dextran hydrogel.
3. A method of manufacturing a flexible contact for a semi-dry electrode according to any one of claims 1 to 2, comprising the steps of:
S1) soaking the hydrogel in an aqueous solution for swelling;
s2) soaking the swelled hydrogel obtained in the step S1) in an organic solvent with a freezing point lower than that of water, and replacing part of water on the surface of the hydrogel with the organic solvent;
And S3) freezing the hydrogel obtained in the step S2), wherein the freezing temperature is below 0 ℃, and thawing after the water in the hydrogel is solidified, so as to obtain the hydrogel with gradient porosity.
4. The method for manufacturing a flexible contact for a semi-dry electrode according to claim 3, wherein the organic solvent in step S2) is ethanol, acetone, isopropyl alcohol or ethyl acetate;
Step S3) the freezing and thawing is performed in one cycle or in a plurality of cycles.
5. Use of a flexible contact according to any one of claims 1-2 for the preparation of a semi-dry electrode for a wearable electroencephalogram device.
6. Use of a flexible contact according to any one of claims 1-2 for the manufacture of a semi-dry electrode for a medical electroencephalograph.
7. A hydrogel semi-dry electrode comprising a flexible contact according to any one of claims 1-2.
8. A hydrogel semi-dry electrode according to claim 7, wherein said hydrogel semi-dry electrode is formed from said flexible contacts, electrode mounting slots, metallized cup electrodes, a base and an elastomer; the electrode fixing groove can fix the flexible contact at the top end and accommodate the metal plating cup-shaped electrode, and simultaneously, the metal plating cup-shaped electrode is in flexible contact with the flexible contact; the base is fixedly connected with the electrode fixing groove; the elastic body is arranged in the base and is contacted with the bottom of the electrode fixing groove.
9. The hydrogel semi-dry electrode according to claim 8, wherein the electrode fixing slot comprises a flexible contact fixing ring and an electrode fixing shoe, the flexible contact fixing ring having a cavity for receiving and fixing the flexible contact at the top and a thread at the inner side of the tail; the electrode fixing bottom support is cylindrical, and threads matched with the threads on the inner side of the tail part of the flexible contact fixing ring are arranged on the outer side of the top end of the electrode fixing bottom support.
10. The hydrogel semi-dry electrode according to claim 9, wherein the bottom end of the electrode fixing shoe has a raised spacing structure; the base is tubular structure, and the top of base is nested with the bottom of electrode fixing collet, and the inside cavity that holds the elastomer that has of base, and base open top diameter is less than the limit structure of the bottom of electrode fixing collet, and the section of thick bamboo wall of base all around comprises 4-6 non-interconnected section of thick bamboo walls, protruding quantity and section of thick bamboo wall quantity on the limit structure are the same.
11. A wearable electroencephalogram device, characterized in that it has a hydrogel semi-dry electrode according to any one of claims 7-10; the wearable electroencephalogram device comprises an electroencephalogram cap, wherein the electroencephalogram cap is provided with a cap body used for fixing the hydrogel semi-dry electrode, and the cap body is detachably connected with the hydrogel semi-dry electrode.
12. The wearable electroencephalogram device according to claim 11, wherein the cap body is provided with a fixing ring for fixing the hydrogel semi-dry electrode, and the fixing ring is provided with threads which are matched with threads on the outer side of the hydrogel semi-dry electrode base.
13. A medical electroencephalograph, characterized in that it has the hydrogel semi-dry electrode according to any one of claims 7 to 10; the medical electroencephalograph comprises an electroencephalogram cap, wherein the electroencephalogram cap is provided with a cap body used for fixing the hydrogel semi-dry electrode, and the cap body is detachably connected with the hydrogel semi-dry electrode.
14. The medical electroencephalograph according to claim 13, wherein the cap body is provided with a fixing ring for fixing the hydrogel semi-dry electrode, and the fixing ring is provided with threads which are matched with threads on the outer side of the hydrogel semi-dry electrode base.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111502206.0A CN114343651B (en) | 2021-12-09 | 2021-12-09 | Flexible contact with gradient porosity, gel semi-dry electrode containing flexible contact and electroencephalogram cap |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111502206.0A CN114343651B (en) | 2021-12-09 | 2021-12-09 | Flexible contact with gradient porosity, gel semi-dry electrode containing flexible contact and electroencephalogram cap |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114343651A CN114343651A (en) | 2022-04-15 |
| CN114343651B true CN114343651B (en) | 2024-08-09 |
Family
ID=81099405
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111502206.0A Active CN114343651B (en) | 2021-12-09 | 2021-12-09 | Flexible contact with gradient porosity, gel semi-dry electrode containing flexible contact and electroencephalogram cap |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114343651B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114621497B (en) * | 2022-04-22 | 2023-01-10 | 福州大学 | Preparation method of gradient macroporous conductive composite hydrogel for flexible strain sensor |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103517732A (en) * | 2011-03-10 | 2014-01-15 | 电核有限责任公司 | Devices and methods for non-invasive capacitive electrical stimulation and their use for vagus nerve stimulation on the neck of a patient |
| CN107236146A (en) * | 2017-07-10 | 2017-10-10 | 河南工业大学 | Utilize the method for pinpointing concentration solvent exchange process preparation starch base porous aquagel |
| CN112886304A (en) * | 2021-01-08 | 2021-06-01 | 清华大学 | Flexible non-embedded semi-dry electrode for brain-computer interface, preparation method thereof and brain-computer interface module |
| WO2021210592A1 (en) * | 2020-04-14 | 2021-10-21 | 株式会社アイ・メデックス | Bioelectrode that can be worn for a long period of time |
Family Cites Families (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5038782A (en) * | 1986-12-16 | 1991-08-13 | Sam Technology, Inc. | Electrode system for brain wave detection |
| US5622168A (en) * | 1992-11-18 | 1997-04-22 | John L. Essmyer | Conductive hydrogels and physiological electrodes and electrode assemblies therefrom |
| US5406945A (en) * | 1993-05-24 | 1995-04-18 | Ndm Acquisition Corp. | Biomedical electrode having a secured one-piece conductive terminal |
| US5921925A (en) * | 1997-05-30 | 1999-07-13 | Ndm, Inc. | Biomedical electrode having a disposable electrode and a reusable leadwire adapter that interfaces with a standard leadwire connector |
| JP2004507283A (en) * | 2000-04-22 | 2004-03-11 | エム−バイオテック インコーポレイテッド | Hydrogel biosensor and health alarm system based on biosensor (HYDROGELBIOSENSORANDBIOENSENSOR-BASEDHEALTHALARMSYSTEM) |
| US20070184222A1 (en) * | 2004-04-20 | 2007-08-09 | University Of Rochester | Hydrogel-supported porous semiconductor devices |
| US8005526B2 (en) * | 2005-08-31 | 2011-08-23 | The Regents Of The University Of Michigan | Biologically integrated electrode devices |
| BRPI0720148B8 (en) * | 2006-12-07 | 2021-06-22 | Koninklijke Philips Electronics Nv | EKG monitoring device, and, method of obtaining ecg data from an individual |
| US20090105576A1 (en) * | 2007-10-22 | 2009-04-23 | Nam Hoai Do | Electrode conductive element |
| EP2052677A1 (en) * | 2007-10-23 | 2009-04-29 | Sensile Pat AG | Medical device for glucose monitoring or regulation |
| CN206612788U (en) * | 2016-10-31 | 2017-11-07 | 江南大学 | A kind of novel human-body physiologic signal monitoring electrode |
| KR101970696B1 (en) * | 2017-08-30 | 2019-04-19 | 고려대학교 산학협력단 | Electroencephalogram electrode and apparatus comprising the same |
| CN108309307A (en) * | 2018-02-05 | 2018-07-24 | 中科知岸（北京）科技有限公司 | It prints three-dimensional grapheme elastomer various dimensions and moves wearable sensors |
| WO2019188818A1 (en) * | 2018-03-30 | 2019-10-03 | 積水化成品工業株式会社 | Hydrogel |
| KR102123065B1 (en) * | 2018-07-20 | 2020-06-15 | 고려대학교 산학협력단 | Membrane based semi-dry electrode for recording electroencephalogram |
| CN211609774U (en) * | 2018-10-24 | 2020-10-02 | 波尓瑟兰尼提公司 | Electrode for electrochemical cell |
| CN110327041B (en) * | 2019-06-27 | 2021-08-13 | 天津大学 | Reflection type optical brain electrical signal sensor with sandwich structure |
-
2021
- 2021-12-09 CN CN202111502206.0A patent/CN114343651B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103517732A (en) * | 2011-03-10 | 2014-01-15 | 电核有限责任公司 | Devices and methods for non-invasive capacitive electrical stimulation and their use for vagus nerve stimulation on the neck of a patient |
| CN107236146A (en) * | 2017-07-10 | 2017-10-10 | 河南工业大学 | Utilize the method for pinpointing concentration solvent exchange process preparation starch base porous aquagel |
| WO2021210592A1 (en) * | 2020-04-14 | 2021-10-21 | 株式会社アイ・メデックス | Bioelectrode that can be worn for a long period of time |
| CN112886304A (en) * | 2021-01-08 | 2021-06-01 | 清华大学 | Flexible non-embedded semi-dry electrode for brain-computer interface, preparation method thereof and brain-computer interface module |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114343651A (en) | 2022-04-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN114343651B (en) | Flexible contact with gradient porosity, gel semi-dry electrode containing flexible contact and electroencephalogram cap | |
| CN105748065A (en) | Moisture-retention microneedle matrix array surface bioelectric electrode | |
| DK2608839T3 (en) | SHIFT RESISTANT MICROELECTRODE, MICROELECTRODE BOND AND MICROELECTRODE GROUP | |
| CN106419913A (en) | Half-dry electrode, system and method for bioelectrical signal sensing | |
| CN104688223A (en) | Bioelectrical signal sensor and acquisition device | |
| JP6062460B2 (en) | Equipment for electrode assembly | |
| US3865099A (en) | Medical electrode and method of making | |
| CN112886304B (en) | Flexible non-embedded semi-dry electrode for brain-computer interface, preparation method thereof and brain-computer interface module | |
| CN103932704A (en) | Skin contact device for wet electrode, wet electrode liquid storage box and brain wave collecting electrode with wet electrode liquid storage box | |
| KR102123065B1 (en) | Membrane based semi-dry electrode for recording electroencephalogram | |
| CN103767704B (en) | Dry electrode of a kind of standard for EEG measuring and preparation method thereof | |
| CN106963376B (en) | A kind of Low ESR brain fax sense electrode device based on independent point of circle buffer structure | |
| WO2022088500A1 (en) | A patch-type drug infusion device | |
| CN105232035A (en) | Bioelectric signal sensor | |
| CN113855033A (en) | Saline electrode electroencephalogram cap easy to assemble and disassemble and capable of flexibly positioning and supplementing liquid | |
| CN103932695B (en) | Wet electrode liquid reserve tank and the acquiring biological electric signals wet electrode with this liquid reserve tank | |
| CN114343650B (en) | Flexible contact modified by electropolymerization and semi-dry electrode and electroencephalogram cap containing flexible contact | |
| CN209574689U (en) | Hydrogel reservoirs electrode for encephalograms | |
| EP1151720A1 (en) | Electrophysiology catheter with enhanced sensing | |
| CN113261978A (en) | Self-supporting graphene wall electrode and preparation method and application thereof | |
| CN208511023U (en) | A kind of multifunctional human surface biological electrical signal collection electrode | |
| CN207384257U (en) | New ultra micro scalp electrode array | |
| CN211749603U (en) | Elastic test electrode for electroencephalogram signal acquisition | |
| CN111281381A (en) | Electrode and equipment for keeping long-term wetting of contact part | |
| CN114617561A (en) | Needle type dry electrode structure and wireless brain electric cap capable of disassembling electrode and adjusting lead |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |