Electrode for deep brain region neurochemical detection and preparation method thereof

Abstract

The invention discloses an electrode for neurochemical detection of a deep brain region and a preparation method thereof, and relates to the technical field of electrochemical analysis, and the key point of the technical scheme is that the electrode comprises carbon fibers, a fused quartz capillary tube and a glass capillary tube; the carbon fiber penetrates into the fused quartz capillary tube, and one end of the fused quartz capillary tube penetrates into the glass capillary tube. The low-damage implantable cranial nerve chemical electrode provided by the invention has the advantages of small implantation cross section, good biocompatibility and the like, greatly reduces the damage of the implanted electrode to brain tissues and possible inflammatory reactions, is beneficial to realizing long-term implantation, supports electrochemical analysis methods such as cyclic voltammetry, oxidation-reduction potential method and the like, and has good application prospects. In-situ high-sensitivity detection of neurochemical substances such as ascorbic acid and dopamine can be realized, and the method has a relatively good application value in the research field of various neurophysiology and pathology processes.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochemical analysis, and more specifically, to an electrode for deep brain region neurochemical detection and a preparation method thereof. Background Art

[0002] The brain is the highest level part of the nervous system. The transmission of information in the brain and the physiological and pathological processes related to brain nerves all involve chemical substances. With the development of brain science and technology, it is very necessary to develop new tools and technologies to record the chemical and electrical signals of neurons. Among all the analysis methods, electrochemical analysis methods can accurately describe the real-time and dynamic changes of neurochemical substances in the brain under physiological or pathological conditions. In the in vivo electrical analysis method, the glass tube carbon fiber microelectrode is more commonly used. In the process of using this electrode for in situ implantation in the brain, it is inevitable to cause damage to the neural tissue and blood vessels along the implantation path, which in turn causes an inflammatory response, changes the microenvironment around the electrode and reduces the sensing performance of the microelectrode.

[0003] In order to minimize the damage and interference caused by the analysis process to the measured object and make the analysis results accurately reflect the true physiological and pathological state of the measured object, brain neurochemistry research at the in vivo level not only needs to consider the compatibility of the analysis method with brain tissue and the research object as a whole, but also needs to reduce the size of the implanted microelectrode as much as possible to protect the research object from damage to the greatest extent.

[0004] Carbon fiber is widely used in in situ electrochemical analysis in vivo due to its excellent conductivity, mechanical strength, chemical stability and electrocatalytic properties. However, the inventors found that the existing microelectrode preparation methods usually use drawn glass tubes, and large-sized rigid electrodes will cause large acute implantation damage during electrode implantation, and will cause inflammatory reactions during long-term implantation, affecting the recording results; through literature research, the inventors found that the main factors causing this problem are that the implanted electrode size is too large and the material modulus is too different from the tissue. The current solution to this problem is mainly to prepare thinner rigid electrodes or flexible electrodes, and the flexible electrode implantation process usually requires the use of rigid guides to assist in implantation into the target brain area, so these methods may still cause additional tissue damage.

[0005] Therefore, the present invention aims to provide a low-damage electrode for deep brain neurochemical detection and a preparation method thereof to solve the above-mentioned problems. Summary of the invention

[0006] The purpose of the present invention is to provide an electrode for neurochemical detection in deep brain regions and a preparation method thereof. The present invention greatly reduces the diameter of the electrode by using a fused silica capillary instead of a glass tube, thereby effectively reducing the damage caused by electrode implantation. At the same time, by controlling the length of the fused silica capillary, implantation in deep brain regions can also be achieved.

[0007] The above technical purpose of the present invention is achieved through the following technical scheme: an electrode for neurochemical detection in deep brain areas, comprising a carbon fiber, a fused silica capillary and a glass capillary; the carbon fiber is inserted into the fused silica capillary, and one end of the fused silica capillary is inserted into the glass capillary.

[0008] The present invention is further configured as follows: the diameter of the carbon fiber is 5-10 μm, the inner diameter of the fused silica capillary is 10-20 μm, and the outer diameter is 50-100 μm, the inner diameter of the glass capillary is 0.86 mm, and the outer diameter is 1.5 mm, and the length of the fused silica capillary is cut according to the target implantation depth in the brain area.

[0009] The present invention also provides a method for preparing an electrode for deep brain region neurochemical detection, comprising the following steps:

[0010] S1, cut the carbon fiber and insert it into the fused silica capillary;

[0011] S2, seal one end of the quartz capillary with insulating glue, and insert the other end into the glass capillary;

[0012] S3, sealing the port where the glass capillary contacts the quartz capillary with insulating glue;

[0013] S4, cutting the ends of the carbon fiber to expose the cross section of the carbon fiber;

[0014] S5. Complete the preparation of electrodes for neurochemical detection in deep brain areas.

[0015] The present invention is further configured such that the brain neurochemical electrode can be reactivated after use to expose a fresh carbon fiber cross section for repeated use.

[0016] The low-damage implantable brain neurochemical electrode of the present invention can be applied to the analysis and detection of ascorbic acid and dopamine.

[0017] In summary, the present invention has the following beneficial effects:

[0018] 1. The present invention uses fused silica capillaries instead of glass tubes to significantly reduce the electrode diameter, which has the advantages of good biocompatibility, greatly reducing the damage to brain tissue caused by implanted electrodes and possible inflammatory reactions, and is conducive to long-term implantation in deep brain regions;

[0019] 2. The brain neurochemical electrode provided by the present invention can realize in situ high-sensitivity detection of neurochemical substances such as ascorbic acid and dopamine, and has good application value in various neurophysiological and pathological process research fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of the structure of an electrode for deep brain region neurochemical detection in Example 1 of the present invention;

[0021] Figure 2 Schematic diagram of carbon fiber and glass capillary of an electrode for deep brain neurochemical detection in Example 1 of the present invention ((a) schematic diagram of carbon fiber structure; (b) schematic diagram of internal connection of glass capillary);

[0022] Figure 3 It is an open circuit potential-time diagram of an electrode for deep brain neurochemical detection in Example 1 of the present invention ((a) open circuit potential-time diagram of the electrode in ascorbic acid solutions of different concentrations; (b) open circuit potential-time diagram of the electrode in solutions of different neurochemical substances; (c) open circuit potential-time diagram of the electrode recorded in the cortical brain area of ​​rats);

[0023] Figure 4 This is an open circuit potential-time diagram of an electrode for deep brain neurochemical detection in Example 1 of the present invention in dopamine solutions of different concentrations. DETAILED DESCRIPTION

[0024] The following is combined with Figure 1-4 The present invention is described in further detail.

[0025] Example 1: A method for preparing an electrode for deep brain neurochemical detection, comprising the following steps:

[0026] S1. Cut a 2 cm long carbon fiber with a diameter of 7 μm, and cut a fused silica capillary (inner diameter: 20 μm, outer diameter: 90 μm) into 1 cm length. Put the carbon fiber and the fused silica capillary into a culture dish and soak them with ethanol.

[0027] S2. Insert the carbon fiber into a fused silica capillary under an optical microscope, expose the same length of carbon fiber at both ends, take it out and dry it, seal one end with epoxy resin, and dry it naturally;

[0028] S3. Take a glass capillary with an inner diameter of 0.86 mm and an outer diameter of 1.5 mm, use a microelectrode pulling instrument to gravity pull it, and cut off the tip of the glass tube for later use; insert the above fused silica capillary (sealed at one end) into the drawn glass capillary, seal the tip with epoxy resin, and dry overnight;

[0029] S4. Use microscissors to cut the carbon fiber at the tip of the electrode to about 200 μm, expose the cross section of the carbon fiber, complete the preparation of the electrode for deep brain neurochemical detection, and place it in a self-priming box for later use.

[0030] The brain neurochemical electrode of this embodiment can be reactivated after use to expose fresh carbon fiber sections for repeated use.

[0031] Example 2: Ascorbic acid analysis and detection experiment of an electrode for deep brain neurochemical detection

[0032] The tip of the low-damage implantable neurochemical electrode prepared according to the method described in Example 1 was modified with multi-walled carbon nanotubes and immersed in artificial cerebrospinal fluid containing 20 μmol / L ascorbic acid. The carbon fiber was used as the working electrode and the Ag / AgCl electrode was used as the counter electrode to form a two-electrode system. The change of the open circuit voltage over time was recorded. When 20, 30, 40, 50, 100, and 200 μmol / L ascorbic acid were added in sequence, the potential-time graph obtained was as shown in FIG. Figure 3 (a) When 40 μmol / L UA, 10 μmol / L DA, 10 μmol / L DOPAC, 1 mmol / L glucose, 1 mmol / L L-lactate and other neurochemical interfering substances were added, and finally 150 μmol / L LAA was added, the potential-time diagram was as follows Figure 3 (b) As shown; the above electrodes were implanted into the cortical brain area of ​​rats, high potassium stimulation was given to induce spreading inhibition, and the process of ascorbic acid release was recorded. The potential-time diagram obtained is shown in Figure 3 (c) as shown.

[0033] This example shows that by coating the carbon fiber surface with multi-walled carbon nanotubes, the overpotential of ascorbic acid can be reduced, and selective analysis and detection of ascorbic acid can be achieved. The low-damage implantable brain neurochemical electrode of the present invention has good selectivity and sensitivity, and successfully achieves in situ detection of ascorbic acid release at the living body level.

[0034] Example 3: Dopamine analysis and detection experiment using an electrode for deep brain neurochemical detection

[0035] The low-damage implantable neurochemical electrode prepared according to the method described in Example 1 was immersed in artificial cerebrospinal fluid containing 0.5 μM dopamine, and a bare carbon fiber was used as a working electrode and an Ag / AgCl electrode was used as a counter electrode to form a two-electrode system. The change of the open circuit voltage over time was recorded. When 1, 2, 4, 5, 10, and 20 μmol / L dopamine was added in sequence, the potential-time graph obtained was as shown in FIG. Figure 4 shown.

[0036] This example shows that the low-damage implantable brain neurochemical electrode of the present invention can realize the analysis and detection of dopamine.

[0037] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. An electrode for deep brain neurochemical detection, characterized by: The invention comprises a carbon fiber, a fused silica capillary and a glass capillary; the carbon fiber penetrates into the fused silica capillary, and one end of the fused silica capillary penetrates into the glass capillary.

2. The electrode for deep brain neurochemical detection according to claim 1, characterized in that: The diameter of the carbon fiber is 5-10 μm, the inner diameter of the fused silica capillary is 10-20 μm and the outer diameter is 50-100 μm, the inner diameter of the glass capillary is 0.86 mm and the outer diameter is 1.5 mm, and the length of the fused silica capillary is cut according to the target implantation depth in the brain area.

3. The method for preparing an electrode for deep brain neurochemical detection according to claim 1, characterized in that: The following steps are involved: S1, cut the carbon fiber and insert it into the fused silica capillary; S2, seal one end of the quartz capillary with insulating glue, and insert the other end into the glass capillary; S3, sealing the port where the glass capillary contacts the quartz capillary with insulating glue; S4, cutting the ends of the carbon fiber to expose the cross section of the carbon fiber; S5. Complete the preparation of electrodes for neurochemical detection in deep brain areas.

4. The method for preparing an electrode for deep brain neurochemical detection according to claim 3, characterized in that: The brain neurochemical electrode can be reactivated after use to expose fresh carbon fiber sections for repeated use.

5. The electrode for deep brain neurochemical detection according to claim 1 can be applied to the analysis and detection of ascorbic acid.

6. The electrode for deep brain neurochemical detection according to claim 1 can be applied to the analysis and detection of dopamine.

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