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CN-117305804-B - Boron-doped diamond microelectrode and preparation method and electroencephalogram application thereof

CN117305804BCN 117305804 BCN117305804 BCN 117305804BCN-117305804-B

Abstract

The invention discloses a boron-doped diamond microelectrode and a preparation method and application thereof, wherein the preparation method comprises the following steps: and (3) ultrasonically cleaning and drying the substrate in the diamond micro-nano powder suspension to obtain a nucleated substrate, growing a boron-doped diamond film on the nucleated substrate by adopting an electronic auxiliary hot wire chemical vapor deposition method, and obtaining the boron-doped diamond microelectrode by adopting the electronic auxiliary hot wire chemical vapor deposition method, wherein the quality is better, the preparation is simple, and the process is mature. The boron-doped diamond microelectrode does not need to be added with conductive paste media to help signal acquisition. The boron-doped diamond film originally belongs to an intrinsic semiconductor, is not conductive, and changes the internal structure of atoms by introducing boron through substitutional doping, so that the boron-doped diamond film has good conductive performance.

Inventors

  • LI HONGJI
  • YAO YUKUN
  • LI MINGJI
  • ZHOU BAOZENG
  • XUAN XIUWEI
  • CHEN ZHENG
  • ZHANG RUIYUAN
  • WANG YONG

Assignees

  • 天津理工大学

Dates

Publication Date
20260508
Application Date
20220622

Claims (12)

  1. 1. The application of the boron-doped diamond microelectrode in scalp electroencephalogram acquisition is characterized in that the boron-doped diamond microelectrode is fixed at a target position, a small amount of physiological saline is added, and then the electroencephalogram is directly acquired by opening, and the preparation method of the boron-doped diamond microelectrode comprises the following steps: 1) Ultrasonic treatment is carried out on a substrate in a diamond micro-nano powder suspension for 60-80 min, cleaning and drying are carried out, and a nucleated substrate is obtained, wherein the diamond micro-nano powder suspension is a mixture of diamond micro-nano powder and a solvent, the concentration of the diamond micro-nano powder in the diamond micro-nano powder suspension is 1-3 mg/mL, the substrate is a planar spiral tantalum strip, and the width of the tantalum strip is 0.65-1.8 mm; 2) And growing a boron-doped diamond film on the nucleated substrate, wherein the boron-doped diamond film consists of 96-97% of carbon, 1.3-1.7% of boron and the balance of oxygen according to mass percent.
  2. 2. The use according to claim 1, wherein in step 1), the width of the planar spiral is 10-12 mm and the thickness of the tantalum strip is 0.08-0.17 mm.
  3. 3. The use according to claim 1, wherein in step 1) the solvent is a mixture of acetone and absolute ethanol, and the ratio of acetone to absolute ethanol in the solvent is 1 (1-1.2) in parts by volume.
  4. 4. The use according to claim 1, wherein in step 1), the washing is sequentially carried out with each ultrasonic wave in absolute ethanol and ultra-pure water for 5-8 min.
  5. 5. The use according to claim 1, wherein in step 1) the drying is baking with a baking lamp.
  6. 6. The use according to claim 1, wherein in step 1) the substrate is polished and cleaned prior to use, said cleaning being sequentially followed by at least 5min of each of ultrapure water, absolute ethanol and ultrapure water.
  7. 7. The use according to claim 1, wherein in step 2), the thickness of the boron doped diamond film is 15-17 μm.
  8. 8. The method according to claim 1, wherein in the step 2), an electron-assisted hot wire chemical vapor deposition method is used to grow a boron doped diamond film on the nucleated substrate, the electron-assisted hot wire chemical vapor deposition method comprises the steps of placing the nucleated substrate in a reaction chamber, continuously introducing hydrogen and methane into the reaction chamber, continuously inputting a boron source into the reaction chamber, applying a bias voltage to the nucleated substrate while keeping the reaction chamber at 800-900 ℃ for 6-8 hours, wherein the current applied by the bias voltage power supply is 8-9A, and the voltage applied by the bias voltage power supply is 185-190V.
  9. 9. The use according to claim 8, wherein the flow ratio of hydrogen to methane into the reaction chamber is 325 (6-8).
  10. 10. The application of claim 8, wherein the boron source is trimethyl borate and is carried into the reaction chamber by a carrier gas, and the specific method is that the boron source and absolute ethyl alcohol are mixed to obtain mixed liquid, the carrier gas is input into the mixed liquid and then is bubbled and discharged from the mixed liquid, the gas discharged by bubbling is input into the reaction chamber, and the ratio of the boron source to the absolute ethyl alcohol in the mixed liquid is 1 (3-3.2).
  11. 11. The method according to claim 10, wherein the hydrogen is divided into two parts, wherein the flow ratio of the hydrogen directly introduced into the reaction chamber to the hydrogen used as the carrier gas is 300 (20-30).
  12. 12. The use of claim 10, wherein the gas pressure in the reaction chamber is 4.9-5.1 kPa.

Description

Boron-doped diamond microelectrode and preparation method and electroencephalogram application thereof Technical Field The invention belongs to the technical field of electroencephalogram (EEG) electrodes, and particularly relates to a Boron Doped Diamond (BDD) microelectrode, a preparation method and application thereof. Background Scalp electroencephalogram is a typical noninvasive brain wave measurement method, and records the electrophysiological activity of brain nerve cells on the surface of cerebral cortex or scalp. Hans Berger in 1924 recorded human electroencephalograms for the first time and Jasper in 1958 used EEG as the basis for clinical diagnosis and brain research. EEG as a noninvasive electroencephalogram monitoring means can detect brain diseases such as migraine, epilepsy, brain tumor and the like, and can assist diagnosis and research of functional diseases of a nervous system. The traditional scalp brain electrode is an Ag-AgCl electrode coated with conductive paste, and is called a wet electrode, and the Ag-AgCl wet electrode has the advantages of low impedance, good stability, high signal to noise ratio and the like. However, the wet electrode has obvious disadvantages in that the experimental preparation process is complicated and time-consuming due to the need of applying the conductive paste. For example, the electrode has low spatial resolution, a tested person has uncomfortable feeling, and the conductive paste collected for a long time can be dried to influence the accuracy of signal collection, and the like, so that the wet electrode is inconvenient to use and difficult to popularize and develop. Compared with a wet electrode using conductive adhesive, the scalp electroencephalogram electrode using the physiological saline as the electrolyte has obvious advantages, such as no pollution of the electrode, no phenomenon of colloid adhesion to hair, and the like. BDD brain electrical electrode has advantages of corrosion resistance, stability, low impedance and the like, and has few applications in brain electrical acquisition in skull. BDD is among the hardest semiconductor materials, however, which makes it of limited application in brain or intra-cranial electroencephalogram acquisition. Disclosure of Invention Aiming at the defects of the prior art, the invention aims to provide a preparation method of a boron-doped diamond microelectrode. Another object of the present invention is to provide a boron doped diamond microelectrode obtained by the above preparation method. The aim of the invention is achieved by the following technical scheme. The preparation method of the boron-doped diamond microelectrode comprises the following steps: 1) Ultrasonic treatment is carried out on a substrate in a diamond micro-nano powder suspension for 60-80 min, cleaning and drying are carried out, and a nucleated substrate is obtained, wherein the diamond micro-nano powder suspension is a mixture of diamond micro-nano powder and a solvent, the concentration of the diamond micro-nano powder in the diamond micro-nano powder suspension is 1-3 mg/mL, the substrate is tantalum wire or tantalum strip, the diameter of the tantalum wire is 0.2-0.6 mm, the width of the tantalum strip is 0.65-1.8 mm, and the length of the tantalum strip or tantalum wire is 40-50 mm; in the step 1), the substrate is in a linear structure or a plane spiral shape, and the width of the plane spiral shape is 10-12 mm. In the step 1), the thickness of the tantalum strip is 0.08-0.17 mm. In the step 1), the solvent is a mixture of acetone and absolute ethyl alcohol, and the ratio of the acetone to the absolute ethyl alcohol in the solvent is 1 (1-1.2) in parts by volume. In the step 1), the cleaning is sequentially carried out on anhydrous ethanol and ultrapure water for 5-8 min. In the step 1), the drying is baking by a baking lamp. In the step 1), the substrate is polished and cleaned before use, and the cleaning is sequentially carried out on ultrapure water, absolute ethanol and ultrapure water for at least 5min. 2) And growing a boron-doped diamond film on the nucleated substrate. In the step 2), the thickness of the boron-doped diamond film is 15-17 μm. In the step 2), the boron-doped diamond film consists of 96-97% of carbon, 1.3-1.7% of boron and the balance of oxygen in percentage by mass. In the step 2), a boron doped diamond film is grown on the nucleated substrate by adopting an electron-assisted hot wire chemical vapor deposition method, wherein the electron-assisted hot wire chemical vapor deposition method comprises the steps of placing the nucleated substrate in a reaction chamber, continuously introducing hydrogen and methane into the reaction chamber, continuously inputting a boron source into the reaction chamber, applying a bias voltage to the nucleated substrate, and simultaneously keeping the reaction chamber at 800-900 ℃ for 6-8 hours, wherein the current of the applied bias voltage power supply is 8-9A, an