A deep brain stimulation electrode capable of detecting blood oxygen levels in deep brain nuclei

Abstract

The present invention relates to the field of biomedical engineering, and specifically to a deep brain stimulation electrode capable of detecting the blood oxygen level of deep brain nuclei, comprising a ring electrode, a core electrode arranged along the axis of the ring electrode, an insulating layer arranged between the ring electrode and the core electrode, a sleeve arranged outside the ring electrode, and an optical fiber arranged between the ring electrode and the sleeve; the output ends of the ring electrode and the optical fiber are arranged flush, and the output end of the core electrode extends out of the output end of the ring electrode. The present invention cleverly integrates the core electrode and the ring electrode pair used for the stimulation electrode, and the optical fiber used for optical signal transmission and collection, and achieves isolation and insulation through the insulating layer, thereby achieving the ability to synchronously observe and record the changes in local blood oxygen saturation of deep brain nuclei when deep brain electrical stimulation is performed on the deep brain nuclei of rodents at the cost of invasiveness, and can be used as a low-cost in vivo research tool for brain tissue metabolic activities, meeting the needs of general research institutions for brain science research such as brain blood oxygen metabolism.

Description

Technical Field

[0001] The invention relates to the field of biomedical engineering, and in particular to a deep brain stimulation electrode capable of detecting blood oxygen levels in deep brain nuclei. Background Art

[0002] The brain is an organ that is highly dependent on blood oxygen levels. There are complex neurovascular regulatory mechanisms in brain tissue to maintain the energy and oxygen required for normal physiological functions of the brain, including electrophysiological activities. Therefore, the study of the distribution law of blood oxygen saturation in deep nuclei and the internal regulatory mechanism under normal physiological conditions and external electrical stimulation has important scientific and clinical significance.

[0003] Currently, the main technical means to study cerebral blood oxygen are nuclear magnetic resonance and near-infrared spectroscopy.

[0004] The nuclear magnetic resonance method uses BOLD sequence imaging with magnetic resonance imaging equipment to non-invasively observe the blood oxygen distribution in the cerebral cortex. It can better observe the overall and local blood oxygen distribution in the cerebral cortex of rodents under anesthesia, and has high research value. However, this method is not compatible with metal electrodes during testing and cannot detect changes in blood oxygen in deep nuclei under external electrical stimulation. Moreover, for small rodents, this method is expensive, and it is difficult for general research institutions to carry out related research.

[0005] Near-infrared spectroscopy utilizes the special absorption spectrum of hemoglobin to visible and near-infrared light, and can also provide non-invasive information on changes in blood oxygen distribution in the cerebral cortex. However, it is limited by the propagation path of reflected light in the skull and the penetration depth is about half the distance between the light source and the detector. It can only provide centimeter-level penetration, which can basically meet the research needs of blood oxygen distribution in the cerebral cortex, but the spatial resolution of blood oxygen distribution research in deep brain nuclei is poor.

[0006] Existing brain blood oxygen detection methods and devices represented by the above methods usually have good detection effects on the blood oxygen distribution in the cerebral cortex, but have low spatial resolution and poor detection effects on deep brain nuclei. It is particularly difficult to simultaneously detect the local blood oxygen level distribution of deep brain nuclei under external electrical stimulation, and it is impossible to conduct in-depth research on the blood oxygen regulation distribution law and internal regulation mechanism of deep nuclei under external electrical stimulation. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention provides a deep brain stimulation electrode that can detect the blood oxygen level in deep brain nuclei. It has a simple structure and is easy to implement. It can be used as a low-cost in vivo research tool for brain tissue metabolic activities, meeting the needs of general research institutions for brain science research such as brain blood oxygen metabolism.

[0008] The present invention is achieved through the following technical solutions:

[0009] A deep brain stimulation electrode capable of detecting the blood oxygen level of deep brain nuclei comprises a ring electrode, a core electrode arranged along the axis of the ring electrode, an insulating layer arranged between the ring electrode and the core electrode, a sleeve arranged outside the ring electrode, and an optical fiber arranged between the ring electrode and the sleeve; the output ends of the ring electrode and the optical fiber are arranged flush with each other, and the output end of the core electrode extends out of the output end of the ring electrode.

[0010] Preferably, the ring electrode and the core electrode are both made of at least one metal material selected from the group consisting of platinum, gold, titanium, iridium and tungsten.

[0011] Preferably, the core electrode used to stimulate the positive electrode is made of 304 medical stainless steel wire with a diameter of 0.15 to 0.22 mm, and is coated with titanium nitride within 2 mm from the output end; the ring electrode used to stimulate the negative electrode is made of 304 medical stainless steel tube with an outer diameter of 0.4 mm, and is coated with titanium nitride within 2 mm from the output end.

[0012] Furthermore, the extension length of the core electrode from the ring electrode is less than 0.1 mm.

[0013] Preferably, the insulating layer is made of Teflon material.

[0014] Preferably, the optical fiber comprises a group of 1 to 3 optical fibers with insulating protective layers, which are arranged in a symmetrical position or a herringbone position on the periphery of the ring electrode and are used for input and output of optical signals.

[0015] Furthermore, the optical fiber includes a group of 1 optical fibers with an insulating protective layer, and a photoelectric detection device for separating incident light from emitted light is provided at the input end of the optical fiber, which serves as both input and output optical fibers.

[0016] Furthermore, the optical fiber includes a group of two optical fibers with insulating protective layers, one of which serves as an input optical fiber to introduce red light and / or infrared light; and the other optical fiber serves as an output optical fiber to export the reflected red light and / or infrared light carrying blood oxygen information to a photoelectric detection device.

[0017] Furthermore, the optical fiber includes a group of three optical fibers with insulating protective layers, one of which imports red light and another imports infrared light, both of which serve as input optical fibers; the third optical fiber exports the reflected red light and infrared light carrying blood oxygen information to the photoelectric detection device, serving as an output optical fiber.

[0018] Preferably, the sleeve is a Teflon heat shrink tube, which shrinks to the outside of the ring electrode and the optical fiber after heating.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects:

[0020] The present invention cleverly integrates the core electrode and ring electrode pair used for stimulation electrodes, and the optical fiber used for light signal transmission and collection, and achieves isolation and insulation through an insulating layer, thereby achieving the ability to synchronously observe and record changes in local blood oxygen saturation in the deep brain nuclei of rodents during deep brain electrical stimulation at the cost of invasiveness. It replaces the existing nuclear magnetic resonance technology that cannot observe and record changes in local blood oxygen saturation in the deep brain nuclei of rodents during electrical stimulation. It can directly synchronously observe and record changes in local blood oxygen saturation in the deep brain nuclei of the target area during deep brain electrical stimulation of rodents in an awake and moving state, providing a low-cost, efficient in vivo metabolic activity research tool that combines electricity and optics for brain science research.

[0021] Furthermore, by limiting the size of the ring electrode, the spatial distance of the optical fiber used to detect the change of local blood oxygen saturation in the deep brain nuclei in the present invention is sub-millimeter, and the spatial resolution of local blood oxygen saturation in the deep brain nuclei that can be provided is also sub-millimeter, which is 1 to 2 orders of magnitude higher than the near-infrared spectroscopy method with centimeter-level resolution. This changes the current situation of low spatial resolution of blood oxygen saturation in the deep brain nuclei in the prior art.

[0022] Furthermore, the metal stimulation electrode in the present invention provides a rigid support for the soft optical fiber, avoiding the defects of easy deformation, bending and poor spatial positioning ability of the optical fiber during the puncture process, and significantly improving the spatial positioning ability of the optical fiber.

[0023] Furthermore, the metal stimulation electrode in the present invention is plated with a titanium nitride protective film on the medical 304 stainless steel material, achieving electrical properties similar to those of precious metal electrodes at the cost of stainless steel electrodes, which not only significantly reduces the electrode manufacturing cost, but also extends the service life of ordinary stainless steel electrodes. Therefore, the medical 304 stainless steel electrode can be used for chronic long-term stimulation, and the changes in local blood oxygen saturation in deep brain nuclei can be simultaneously observed. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the cross-sectional structure of the electrode described in the example of the present invention.

[0025] Figure 2 It is a schematic diagram of the longitudinal section structure of the electrode described in the example of the present invention.

[0026] In the figure: sleeve 1, ring electrode 2, insulation layer 3, optical fiber 4, core electrode 5. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0028] See also Figure 1 and Figure 2 The deep brain stimulation electrode capable of detecting the blood oxygen level of deep brain nuclei of the present invention comprises the following components:

[0029] Component 1, core electrode 5. Located in the center of the deep brain stimulation electrode, it is made of precious metal materials such as platinum, gold, titanium, iridium, tungsten, etc. It serves as the stimulation positive electrode when applying deep brain electrical stimulation. The electrode tip exposed outside component 3 is the output end, that is, the electrode end is used to release the stimulation current to stimulate the surrounding deep brain nuclei.

[0030] In this preferred embodiment, the core electrode 5 is made of 304 medical stainless steel wire with a diameter of 0.15-0.22 mm, the output end is ground flat, and a titanium nitride coating is plated within 2 mm from the output end. When assembled, the core electrode 5 extends out of the ring electrode 2, and the extension length is less than 0.1 mm. The grinding is to grind the surface of the rod-shaped stainless steel wire and the stainless steel sleeve smooth and flat without burrs.

[0031] Component 2, ring electrode 2. The metal electrode surrounding the outer periphery of the core electrode 5 is made of precious metal materials such as platinum, gold, titanium, iridium, tungsten, etc., and serves as the stimulation negative electrode when deep brain electrical stimulation is applied. The ring electrode 2 and the core electrode 5 are insulated by component 3 and no electrical connection occurs.

[0032] In this preferred embodiment, the ring electrode 2 is made of a 304 medical stainless steel tube with an outer diameter of 0.4 mm, the output end is ground flat, and a titanium nitride coating is plated within 2 mm from the output end.

[0033] Component 3, insulating layer 3. Located between the core electrode 5 and the ring electrode 2, isolating the direct electrical connection between the two electrodes.

[0034] In this preferred embodiment, the insulating layer 3 is made of Teflon material.

[0035] Component 4, optical fiber 4. A group of 1 to 3 optical fibers with insulating protective layers, located on the periphery of the ring electrode 2, arranged in a symmetrical position or in a herringbone shape, for input and output of optical signals.

[0036] When the in vitro photoelectric detection device includes a spectroscope that can separate the incident light from the emitted light, only one optical fiber 4 is needed to be used as both the input and output optical fiber.

[0037] In this preferred embodiment, three optical fibers 4 are selected and arranged in a herringbone pattern outside the ring electrode 2. One optical fiber 4 introduces 660nm red light into the deep brain nucleus tissue, and another optical fiber 4 introduces 940nm infrared light into the deep brain tissue, both of which serve as input optical fibers; the third optical fiber 4 guides the red light and infrared light carrying blood oxygen information reflected by the tissue to the external photoelectric detection device, serving as an output optical fiber.

[0038] Preferably, the local blood oxygen saturation of the deep brain nuclei is detected by a dual-wavelength photoelectric capacitance wave sensor with red light of wavelength λ1 and infrared light of wavelength λ2, which is described by formulas (1), (2) and (3):

[0039] S p O2=α-βR(I)

[0040] S p O2=α-βR-γR 2 (2)

[0041]

[0042] in, are the AC components of the red light and infrared light intensity detected by brain tissue, They are the DC components of the red light and infrared light intensity detected by brain tissue reflection. Therefore, when the DC and AC components of the red light and infrared light intensity are obtained within a cardiac interval, the R value can be calculated, and then the local blood oxygen saturation of the deep brain nuclei within the cardiac cycle can be calculated; in this preferred embodiment, λ1 and λ2 are 660nm and 940nm respectively.

[0043] α, β and γ are empirical values, which are determined by calibration. Formula (1) is the first-order linear relationship between blood oxygen saturation and R value. When the first-order relationship cannot meet the linearity requirement, the second-order formula (2) can be used to describe it.

[0044] Component 5, sleeve 1. Located on the outer periphery of the optical fiber, it insulates and protects the ring electrode from being corroded by body fluid.

[0045] Preferably, the sleeve 1 is made of a Teflon heat shrink tube, which is heated by an external heat source during assembly and shrinks to the outside of the ring electrode 2 and the optical fiber 4 .

[0046] The present invention provides a deep brain stimulation electrode capable of detecting the blood oxygen level of deep brain nuclei. The metal stimulation electrode is combined with an optical fiber, and penetrated into the deep brain nuclei tissue through the skull of a small rodent. While the metal stimulation electrode applies an electrical stimulation pulse, red light and infrared light with wavelengths of 660nm and 940nm are respectively introduced into the deep brain nuclei tissue through two optical fibers. After being reflected by the local deep brain nuclei tissue and carrying the blood oxygen information in the state of electrical stimulation activation, the light is picked up by a third optical fiber and sent to an in vitro detection device to detect the local blood oxygen level. Thus, the changes in the local cerebral blood oxygen level of the deep brain nuclei can be detected while the deep brain nuclei of the small rodent are electrically stimulated under a conventional environment. The present invention not only saves the expensive small animal magnetic resonance imaging equipment, but also avoids the thermal damage of the metal electrode to the brain tissue under the condition of the magnetic resonance radio frequency field. It can be directly applied to rodents in a conscious and moving state, and improves the spatial resolution of the local blood oxygen level distribution of the deep brain nuclei. It can provide a low-cost and efficient metabolic activity research tool in the active body that combines electricity and optics for brain science research.

Claims

1. A deep brain stimulation electrode capable of detecting blood oxygen levels in deep brain nuclei, characterized in that: It comprises a ring electrode (2), a core electrode (5) arranged along the axis of the ring electrode (2), an insulating layer (3) arranged between the ring electrode (2) and the core electrode (5), a sleeve (1) arranged outside the ring electrode (2), and an optical fiber (4) arranged between the ring electrode (2) and the sleeve (1); the output ends of the ring electrode (2) and the optical fiber (4) are arranged flush with each other, and the output end of the core electrode (5) extends out of the output end of the ring electrode (2); The ring electrode (2) and the core electrode (5) are both made of metal materials; The optical fiber (4) comprises a group of 1 to 3 optical fibers with insulating protective layers, which are arranged symmetrically or in a herringbone shape on the periphery of the ring electrode (2) and are used for input and output of optical signals; The core electrode (5) for stimulating the positive electrode is made of a 304 medical stainless steel wire with a diameter of 0.15 to 0.22 mm, and is coated with a titanium nitride coating within 2 mm from the output end; the ring electrode (2) for stimulating the negative electrode is made of a 304 medical stainless steel tube, and is coated with a titanium nitride coating within 2 mm from the output end; By limiting the size of the ring electrode (2), the spatial distance of the optical fiber used by the deep brain stimulation electrode to detect changes in local blood oxygen saturation in deep brain nuclei is at the sub-millimeter level; The spatial resolution of local blood oxygen saturation in deep brain nuclei is also sub-millimeter.

2. A deep brain stimulation electrode capable of detecting blood oxygen levels in deep brain nuclei according to claim 1, characterized in that: The ring electrode (2) used for stimulating the negative electrode is made of a 304 medical stainless steel tube with an outer diameter of 0.4 mm.

3. A deep brain stimulation electrode capable of detecting blood oxygen levels in deep brain nuclei according to claim 1, characterized in that: The extension length of the core electrode (5) extending from the ring electrode (2) is less than 0.1 mm.

4. A deep brain stimulation electrode capable of detecting blood oxygen levels in deep brain nuclei according to claim 1, characterized in that: The insulating layer (3) is made of Teflon material.

5. The deep brain stimulation electrode capable of detecting blood oxygen level in deep brain nuclei according to claim 1, characterized in that: The optical fiber (4) comprises a group of optical fibers with an insulating protective layer, and a photoelectric detection device for separating incident light from emitted light is provided at the input end of the optical fiber, which serves as both an input and an output optical fiber.

6. The deep brain stimulation electrode capable of detecting blood oxygen level in deep brain nuclei according to claim 1, characterized in that: The optical fiber (4) comprises a group of two optical fibers with insulating protective layers, wherein one optical fiber serves as an input optical fiber to introduce red light and / or infrared light; and the other optical fiber serves as an output optical fiber to output the reflected red light and / or infrared light carrying blood oxygen information to a photoelectric detection device.

7. A deep brain stimulation electrode capable of detecting blood oxygen levels in deep brain nuclei according to claim 1, characterized in that: The optical fiber (4) comprises a group of three optical fibers with insulating protective layers, one of which is used to introduce red light, and the other is used to introduce infrared light, both of which serve as input optical fibers; The third optical fiber guides the reflected red light and infrared light carrying blood oxygen information to the photoelectric detection device as the output optical fiber.

8. The deep brain stimulation electrode capable of detecting blood oxygen level in deep brain nuclei according to claim 1, characterized in that: The sleeve (1) is a Teflon heat shrink tube, which shrinks around the outside of the ring electrode (2) and the optical fiber (4) after being heated.

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