Optical fiber composite electrode for realizing trace solution delivery and electrochemical luminescence detection, preparation method and application thereof

Abstract

The present invention discloses a fiber composite electrode, a preparation method and an application for realizing trace solution delivery and electrochemiluminescence detection, and relates to the technical field of advanced functional material preparation. The prepared fiber composite electrode can generate electrochemiluminescence in tissues and record optical signals in situ. The fiber composite electrode includes a conductive needle tube and an optical fiber. The surface of the tip of the conductive needle tube is modified with indium tin oxide and reduced graphene oxide in sequence to improve the electrode performance. One end face of the optical fiber is ground and processed into an inclined end face with a certain inclination angle, and a noble metal film is set on the inclined end face as a reflective layer. The inclined end face of the inclined end face optical fiber and the inclined face of the tip of the conductive needle tube are arranged in the same direction, and the inclined end face optical fiber is fixed on the conductive needle tube. The present invention realizes the integration of solution delivery, electrochemiluminescence generation and optical signal acquisition. The fiber composite electrode can be implanted into a specific tissue and applied to the study of tissue function.

Description

Technical Field

[0001] The present invention relates to the technical field of advanced functional material preparation, and in particular to an optical fiber composite electrode for realizing trace solution delivery and electrochemical luminescence detection, a preparation method and application thereof. Background Art

[0002] Implantable detection technology is to measure the concentration of molecules in tissues through implantable devices, and is one of the important means of studying tissue function. At present, the implantable devices that implantable detection technology relies on are usually single electrodes or optical fibers, which measure the changes in electrical signals or fluorescent signals caused by changes in the concentration of molecules in tissues. However, both of the above technologies have their own limitations. The electrode-based detection technology has poor molecular selectivity and high background current, while the optical fiber-based detection technology requires the expression of receptor fluorescent proteins of specific molecules in the body through viral transfection in advance. The experimental cycle is long and the background signal of fluorescent excitation light is high. Therefore, it is necessary to develop new photoelectric molecular detection technologies in tissues.

[0003] Electrochemiluminescence is dark-field light radiation caused by electrochemical reactions. Electrochemiluminescence generally requires luminescent molecules and co-reactants. When electrical excitation is applied, the luminescent molecules and co-reactants react on the electrode surface to produce electrogenerated intermediates. After homogeneous reactions, the excited state of the luminescent molecules is finally generated, which then produces light radiation. The entire process is controlled by electrochemical reactions, which has the advantages of no light excitation, near-zero background, high sensitivity, and time-space controllability, and is expected to break through the limitations of existing implantable detection technologies. However, the biological tissue environment is not conducive to the generation of electrochemiluminescence. First, there are no luminescent molecules required for electrochemiluminescence in the tissue, and additional artificial injection is required. Secondly, the environment in the tissue is special and the molecules diffuse slowly. Even if additional luminescent molecules are injected, it is difficult to quickly diffuse to the electrode surface to react. Finally, brain tissue has strong scattering and absorption effects on light, so it is urgent to develop analytical tools suitable for electrochemiluminescence detection of molecules in tissues.

[0004] One possible strategy is to deposit a noble metal film on the surface of the optical fiber. For example, Paul Pantano prepared a fiber bundle electrode by modifying the end face of one end of the optical fiber bundle with a gold film as a conductive layer, using terpyridine ruthenium and triethylamine as luminescent molecules and co-reactants. The electrochemiluminescent light signal generated after applying electrical excitation can be directly coupled into the optical fiber through the gold film for transmission, and has been successfully used to detect reduced coenzyme I (Electroanalysis, 2001, 13, 1287-1290). However, the device does not have an integrated solution delivery channel and is not suitable for electrochemiluminescence detection of molecules in tissues.

[0005] Therefore, inventing a fiber composite electrode that can realize trace solution delivery and electrochemiluminescence detection has important significance and application prospects. Summary of the invention

[0006] The invention provides a method for preparing an optical fiber composite electrode for realizing trace solution delivery and electrochemical luminescence detection. Firstly, indium tin oxide and reduced graphene oxide are sequentially deposited on the outer surface of a conductive needle tube by magnetron sputtering and electrochemical reduction deposition methods to improve the electrochemical performance of the conductive needle tube. Then, the end face of one end of the optical fiber is ground into an oblique end face, and a noble metal film is deposited as a reflective layer by magnetron sputtering. Finally, the optical fiber and the conductive needle tube are bonded up and down to obtain the optical fiber composite electrode.

[0007] The specific technical solutions adopted by the present invention are as follows:

[0008] In the first aspect, the present invention provides a fiber composite electrode for realizing trace solution delivery and electrochemical luminescence detection, comprising a conductive needle tube and an optical fiber with an inclined end face; wherein the conductive needle tube has a pipeline structure for delivering trace solutions and applying electrical excitation; the optical fiber with an inclined end face is used to detect the light signal of electrochemical luminescence generated by power-on; the inclined end face of the optical fiber with an inclined end face is located directly above the solution outlet of the tip of the conductive needle tube to ensure the effective collection of the light signal.

[0009] Preferably, the tail end of the conductive needle tube is connected to a syringe pump for injecting a trace amount of solution and an electrochemical workstation for applying electrical excitation, and the tail end of the oblique end optical fiber is connected to a photomultiplier tube.

[0010] Preferably, the conductive needle tube is made of stainless steel, with an outer diameter of 190 μm to 3 mm and an inner diameter of 130 μm to 2.6 mm; the cladding diameter of the oblique end optical fiber is 125 to 660 μm.

[0011] Preferably, the tip of the conductive needle tube needs to be surface modified to improve the electrochemical performance, as follows:

[0012] (1) depositing an indium tin oxide film on the inner and outer surfaces of the tip of the conductive needle tube by magnetron sputtering; the indium tin oxide film has a thickness of 50 to 150 nm;

[0013] (2) The tip of the conductive needle tube with an indium tin oxide film deposited on the surface is immersed in a graphene oxide solution, wherein the concentration of the graphene oxide solution is 0.1 to 10 mg / mL, and the tail end of the conductive needle tube is connected to an electrochemical workstation and a potential signal is applied to deposit reduced graphene oxide on the tip of the conductive needle tube; in this process, the scanning starting potential of the electrochemical workstation is 0 V, the scanning ending potential is -1 to -1.5 V, the scanning number of circles is 1 to 100 circles, and the scanning speed is 0.01 to 0.1 V / s.

[0014] Preferably, the trace solution includes luminescent molecules and co-reactants required for electrochemiluminescence, and the flow rate range is 50 to 500 nL / min.

[0015] Preferably, the inclination angle of the oblique surface of the oblique end surface optical fiber along the axial direction is 40° to 50°, that is, the angle between the oblique end surface and the axial direction of the optical fiber is 40° to 50°.

[0016] Preferably, a noble metal film with a thickness of 20 to 150 nm is deposited on the oblique end surface of the oblique end optical fiber by magnetron sputtering as a reflective layer; further preferably, the noble metal film is made of gold or silver.

[0017] Preferably, the oblique end face of the oblique end face optical fiber and the oblique face of the tip of the conductive needle tube are arranged in the same direction; the oblique end face optical fiber is located above the conductive needle tube and is adhered and arranged, and the central axes of the two are located in the same vertical plane.

[0018] In a second aspect, the present invention provides a method for preparing a fiber composite electrode for realizing trace solution delivery and electrochemiluminescence detection as described in any one of the first aspects, which is as follows:

[0019] (1) A conductive needle tube with an outer diameter of 190 μm to 3 mm and an inner diameter of 130 μm to 2.6 mm is selected, and an indium tin oxide film is deposited on the tip thereof by magnetron sputtering, wherein the thickness of the indium tin oxide film is 50 to 150 nm;

[0020] (2) immersing the tip of a conductive needle tube with an indium tin oxide film deposited on the surface into a graphene oxide aqueous solution with a concentration of 0.1 to 10 mg / mL, using a platinum electrode and a silver / silver chloride electrode as a counter electrode and a reference electrode respectively, connecting the tail end of the conductive needle tube to an electrochemical workstation and applying a potential signal to deposit reduced graphene oxide on the tip of the conductive needle tube; in this process, the scanning starting potential is 0 V, the scanning ending potential is -1 to -1.5 V, the scanning number of circles is 1 to 100 circles, and the scanning speed is 0.01 to 0.1 V / s;

[0021] (3) selecting an optical fiber with a cladding diameter of 125 to 660 μm, and grinding the end face of one end of the optical fiber into an oblique end face with an axial inclination angle of 40° to 50° to produce an oblique end face optical fiber;

[0022] More preferably, the inclination angle is 45°.

[0023] (4) depositing a noble metal film on the oblique end surface of the oblique end surface optical fiber by magnetron sputtering; the noble metal film has a thickness of 20 to 150 nm;

[0024] The optical fiber with the inclined end face can collect light from the side. The optical signal enters the optical fiber from the side and is coupled into the optical fiber core for transmission after being reflected by the noble metal film.

[0025] (5) On the premise that the beveled end face of the beveled end face of the optical fiber and the beveled end face of the conductive needle tube tip are arranged in the same direction, the beveled end face of the optical fiber and the conductive needle tube are bonded together, with their central axes located in the same vertical plane, and the beveled end face of the optical fiber located directly above the outlet of the solution at the conductive needle tube tip, to obtain a fiber composite electrode.

[0026] In a third aspect, the present invention provides an application of the optical fiber composite electrode for realizing trace solution delivery and electrochemiluminescence detection as described in any one of the first aspects in the field of life science and tissue function. For example, the optical fiber composite electrode of the present invention is used for the detection of molecules in the brain.

[0027] The optical fiber composite electrode of the present invention has the functions of conveying solution, applying electrical excitation and collecting and transmitting optical signals, and can realize in-situ generation of electrochemical luminescence in tissues and detection of optical signals.

[0028] The present invention integrates the functions of delivering solution, applying electrical excitation and collecting and transmitting optical signals, and can generate electrochemical luminescence at a fixed point in the tissue and detect the optical signal. The principle is that the optical fiber composite electrode is implanted into the tissue, and the reactant solution required for electrochemical luminescence is injected from the tail end of the conductive needle tube, and is delivered to the solution outlet at the tip of the conductive needle tube through the pipeline structure of the conductive needle tube. When electrical excitation is applied, electrochemical luminescence is generated at the tip, and the optical signal enters from the side of the optical fiber with an inclined end face, and after being reflected by the precious metal film, the transmission direction is changed and coupled to the core of the optical fiber with an inclined end face for transmission, so that the optical signal generated by the electrochemical luminescence can be detected.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The optical fiber composite electrode of the present invention solves the difficulty of generating and collecting electrochemical luminescence in tissues, can simultaneously carry out solution delivery and signal collection, avoids the dissipation of exogenously injected solution in tissues, and the luminescent molecules and co-reactants contained in the solution can effectively participate in the reaction on the electrode surface, and also overcomes the scattering and absorption of light signals by tissues; 2. The optical fiber composite electrode of the present invention realizes the integration of solution delivery, electrical excitation and transmission of light signals, and can generate and collect electrochemical luminescence in situ in tissues; 3. The optical fiber composite electrode of the present invention adopts electrochemical luminescence, has the advantages of no light excitation and high sensitivity, and the generated signal quality is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a micrograph of the optical fiber composite electrode prepared in Example 1;

[0032] Figure 2 is a schematic diagram of the structure of the optical fiber composite electrode prepared in Example 1;

[0033] Figure 3is a schematic diagram of the cross-sectional structure of the optical fiber composite electrode prepared in Example 1;

[0034] Figure 4 This is a schematic diagram of the optical path of the optical fiber composite electrode prepared in Example 1. DETAILED DESCRIPTION

[0035] The present invention is further described and illustrated below in conjunction with the accompanying drawings and specific embodiments. The technical features of each embodiment of the present invention can be combined accordingly without conflicting with each other.

[0036] Example 1

[0037] (1) First, a stainless steel needle tube with an outer diameter of about 190 μm and an inner diameter of about 130 μm is selected, and an indium tin oxide film is deposited on the tip of the stainless steel needle tube by magnetron sputtering. The thickness of the indium tin oxide film is 100 nm;

[0038] (2) The tip of a stainless steel needle tube with indium tin oxide deposited on the surface was immersed in a graphene oxide aqueous solution with a concentration of 1 mg / mL, and a platinum electrode and a silver / silver chloride electrode were used as the counter electrode and the reference electrode, respectively. The tail end of the stainless steel needle tube was connected to an electrochemical workstation and a potential signal was applied. The scanning start potential was 0 V, the scanning end potential was -1 V, and the scanning number of circles was 10 circles;

[0039] (3) Select an optical fiber with a cladding diameter of 125 μm, grind the end face of one end of the optical fiber into an inclined end face with an inclination angle of 45°, and make an inclined end face optical fiber;

[0040] (4) depositing a noble metal film on the oblique end face of the oblique end face optical fiber by magnetron sputtering, wherein the thickness of the noble metal film is 100 nm;

[0041] (5) Under the premise that the beveled end surface of the beveled end surface optical fiber and the beveled surface of the stainless steel needle tube tip are arranged in the same direction, the beveled end surface optical fiber and the stainless steel needle tube are bonded together, the beveled end surface optical fiber is located above the stainless steel needle tube, the central axes of the two are aligned, and the beveled end surface of the beveled end surface optical fiber is located directly above the solution outlet of the stainless steel needle tube tip, thereby obtaining a fiber composite electrode;

[0042] The optical fiber composite electrode was implanted into the tissue and the reaction solution required for electrochemiluminescence was delivered at a flow rate of 200nL / min. In the solution, the luminescent molecule was luminol and the co-reactant was hydrogen peroxide. The light signal generated by the electrochemiluminescence was generated and collected in the tissue.

[0043] Figure 1 is a micrograph of the prepared optical fiber composite electrode.

[0044] The structural schematic diagram of the optical fiber composite electrode of the present invention is as follows Figure 2 As shown, its cross-section is as follows Figure 3As shown, the stainless steel needle tube is conductive and has a pipeline structure, which can simultaneously apply electrical excitation and transport solution. The oblique end optical fiber can collect the electrochemical luminescence signal generated by the tip of the stainless steel needle tube. The optical path diagram is shown in Figure 4 shown.

[0045] Example 2

[0046] (1) preparing a stainless steel needle tube with an outer diameter of about 190 μm and an inner diameter of about 130 μm, and depositing an indium tin oxide film on the tip of the stainless steel needle tube by magnetron sputtering, wherein the indium tin oxide film has a thickness of 50 nm;

[0047] (2) The tip of the stainless steel needle tube with indium tin oxide deposited on the surface was immersed in an aqueous solution containing graphene oxide at a concentration of 0.1 mg / mL, and a platinum electrode and a silver / silver chloride electrode were used as the counter electrode and the reference electrode, respectively. The tail end of the stainless steel needle tube was connected to an electrochemical workstation and a potential signal was applied. The scanning start potential was 0 V, the scanning end potential was -1.5 V, and the scanning number was 1 circle;

[0048] (3) preparing an optical fiber with a cladding diameter of 125 μm, and grinding the end face of one end of the optical fiber into an inclined end face with an inclination angle of 40° to produce an inclined end face optical fiber;

[0049] (4) depositing a noble metal film on the oblique end face of the oblique end face optical fiber by magnetron sputtering, wherein the thickness of the noble metal film is 20 nm;

[0050] (5) On the premise that the beveled end surface of the beveled end surface optical fiber and the beveled surface of the stainless steel needle tube tip are arranged in the same direction, the beveled end surface optical fiber and the stainless steel needle tube are bonded together, the beveled end surface optical fiber is located above the stainless steel needle tube, the central axes of the two are aligned, and the beveled end surface of the beveled end surface optical fiber is located directly above the solution outlet of the stainless steel needle tube tip, thereby obtaining a fiber composite electrode similar to Example 1;

[0051] The optical fiber composite electrode is implanted into tissue, and the reaction solution required for electrochemiluminescence is delivered at a flow rate of 50 nL / min. In the solution, the luminescent molecule is terpyridine ruthenium, and the co-reactant is tri-n-propylamine, which can generate and collect electrochemiluminescence in situ in the tissue.

[0052] Example 3

[0053] (1) First, a stainless steel needle tube with an outer diameter of about 3 mm and an inner diameter of about 2.6 mm is selected, and an indium tin oxide film is deposited on the tip of the stainless steel needle tube by magnetron sputtering. The thickness of the indium tin oxide film is 150 nm;

[0054] (2) The tip of a stainless steel needle tube with indium tin oxide deposited on the surface was immersed in a graphene oxide aqueous solution with a concentration of 10 mg / mL, and a platinum electrode and a silver / silver chloride electrode were used as the counter electrode and the reference electrode, respectively. The tail end of the stainless steel needle tube was connected to an electrochemical workstation and a potential signal was applied. The scanning start potential was 0 V, the scanning end potential was -1 V, and the scanning number of circles was 100 circles;

[0055] (3) preparing an optical fiber with a cladding diameter of 660 μm, and polishing one end of the optical fiber into an inclined end face with an inclination angle of 50° to produce an inclined end face optical fiber;

[0056] (4) depositing a noble metal film on the oblique end face of the oblique end face optical fiber by magnetron sputtering, wherein the thickness of the noble metal film is 150 nm;

[0057] (5) On the premise that the beveled end surface of the beveled end surface optical fiber and the beveled surface of the stainless steel needle tube tip are arranged in the same direction, the beveled end surface optical fiber is located on the stainless steel needle tube and bonded together, the beveled end surface optical fiber is located above the stainless steel needle tube, the central axes of the two are aligned, and the beveled end surface of the beveled end surface optical fiber is located directly above the solution outlet of the stainless steel needle tube tip, thereby obtaining a fiber composite electrode similar to Example 1;

[0058] The optical fiber composite electrode is implanted into tissue, and the reaction solution required for electrochemiluminescence is delivered at a flow rate of 500nL / min. In the solution, the luminescent molecule is luminol and the co-reactant is hydrogen peroxide, thereby achieving the effect of generating and collecting electrochemiluminescence in the tissue.

[0059] Example 4

[0060] First, the fiber composite electrode is implanted into the brain tissue of a mouse, the stainless steel needle in the fiber composite electrode is connected to a syringe pump and an electrochemical workstation, the oblique end optical fiber in the fiber composite electrode is connected to a photomultiplier tube, and the reaction solution required for electrochemiluminescence is transported at a flow rate of 50 nL / min. In the solution, the luminescent molecule is terpyridine ruthenium, and the co-reactant is tri-n-propylamine. Under the stimulation of a high concentration of potassium ion solution, the quenching of the electrochemiluminescence light signal caused by dopamine secreted in the mouse brain is detected, that is, the light intensity of the electrochemiluminescence decreases.

[0061] Example 5

[0062] First, the fiber-optic composite electrode was implanted into the brain tissue of a pig. The stainless steel needle in the fiber-optic composite electrode was connected to the injection pump and the electrochemical workstation. The oblique-end optical fiber in the fiber-optic composite electrode was connected to the photomultiplier tube. The reaction solution required for electrochemiluminescence was transported at a flow rate of 500nL / min. In the solution, the luminescent molecule was terpyridine ruthenium. The pyruvate produced during energy metabolism in the pig brain was detected by electrochemiluminescence, and the intensity of the electrochemiluminescence increased.

[0063] The above-described embodiment is only a preferred solution of the present invention, but it is not intended to limit the present invention. A person skilled in the relevant technical field may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. An optical fiber composite electrode for realizing trace solution delivery and electrochemical luminescence detection, characterized in that: It includes a conductive needle tube for conveying a trace solution and applying electrical excitation, and an optical fiber with an oblique end face for detecting an electrochemical luminescent light signal generated after the trace solution is energized, wherein the oblique end face of the optical fiber with an oblique end face is located directly above the solution outlet at the tip of the conductive needle tube; The surface of the conductive needle tube tip is modified with a material for improving electrochemical performance, specifically as follows: (1) depositing an indium tin oxide film on the inner and outer surfaces of the tip of the conductive needle tube by magnetron sputtering; the indium tin oxide film has a thickness of 50 to 150 nm; (2) immersing the tip of the conductive needle tube with an indium tin oxide film deposited on the surface into a graphene oxide solution, wherein the concentration of the graphene oxide solution is 0.1 to 10 mg / mL, and applying a potential signal to deposit reduced graphene oxide on the tip of the conductive needle tube; In this process, the scanning start potential is 0 V, the scanning end potential is -1 to -1.5 V, the scanning number is 1 to 100, and the scanning speed is 0.01 to 0.1 V / s; The trace solution includes luminescent molecules and co-reactants required for electrochemiluminescence, and the flow rate range is 50 to 500 nL / min; By magnetron sputtering, a noble metal film with a thickness of 20 to 150 nm is deposited on the oblique end surface of the oblique end optical fiber as a reflective layer; The oblique end face of the oblique end face optical fiber and the oblique face of the tip of the conductive needle tube are arranged in the same direction; the oblique end face optical fiber is located above the conductive needle tube and is adhered and arranged, and the central axes of the two are located in the same vertical plane.

2. The optical fiber composite electrode for realizing trace solution delivery and electrochemical luminescence detection according to claim 1, characterized in that: The tail end of the conductive needle tube is connected to an injection pump for injecting a trace solution and an electrochemical workstation for applying electrical excitation, and the tail end of the oblique end optical fiber is connected to a photomultiplier tube.

3. The optical fiber composite electrode for realizing trace solution delivery and electrochemical luminescence detection according to claim 1, characterized in that: The conductive needle tube is made of stainless steel, with an outer diameter of 190 μm to 3 mm and an inner diameter of 130 μm to 2.6 mm; the cladding diameter of the oblique end optical fiber is 125 to 660 μm.

4. The optical fiber composite electrode for realizing trace solution delivery and electrochemical luminescence detection according to claim 1, characterized in that: The inclination angle of the oblique end surface optical fiber along the axial direction is 40° to 50°.

5. The optical fiber composite electrode for realizing trace solution delivery and electrochemical luminescence detection according to claim 1, characterized in that: The noble metal film is gold or silver.

6. A method for preparing a fiber composite electrode for realizing trace solution delivery and electrochemiluminescence detection as claimed in any one of claims 1 to 5, characterized in that: The details are as follows: (1) A conductive needle tube with an outer diameter of 190 μm to 3 mm and an inner diameter of 130 μm to 2.6 mm is selected, and an indium tin oxide film is deposited on the tip thereof by magnetron sputtering, wherein the thickness of the indium tin oxide film is 50 to 150 nm; (2) immersing the tip of the conductive needle tube with an indium tin oxide film deposited on the surface into a graphene oxide aqueous solution with a concentration of 0.1 to 10 mg / mL, using a platinum electrode and a silver / silver chloride electrode as a counter electrode and a reference electrode, respectively, and connecting the tail end of the conductive needle tube to an electrochemical workstation and applying a potential signal to deposit reduced graphene oxide on the tip of the conductive needle tube; In this process, the scanning start potential is 0 V, the scanning end potential is -1 to -1.5 V, the scanning number is 1 to 100, and the scanning speed is 0.01 to 0.1 V / s; (3) selecting an optical fiber with a cladding diameter of 125 to 660 μm, and grinding the end face of one end of the optical fiber into an oblique end face with an axial inclination angle of 40° to 50° to produce an oblique end face optical fiber; (4) depositing a noble metal film on the oblique end surface of the oblique end surface optical fiber by magnetron sputtering; the noble metal film has a thickness of 20 to 150 nm; (5) On the premise that the beveled end face of the beveled end face of the optical fiber and the beveled end face of the conductive needle tube tip are arranged in the same direction, the beveled end face of the optical fiber and the conductive needle tube are bonded together, with their central axes located in the same vertical plane, and the beveled end face of the optical fiber located directly above the outlet of the solution at the conductive needle tube tip, to obtain a fiber composite electrode.

7. Application of the optical fiber composite electrode for realizing trace solution delivery and electrochemiluminescence detection as claimed in any one of claims 1 to 5 in the field of life sciences.

Images