Implantable miniature optical fiber photoelectric sensor and preparation method and application thereof

Abstract

The invention discloses an implantable miniature optical fiber photoelectric sensor and a preparation method and application thereof, and relates to an interface design, system building and measurement method of an implantable miniature optical fiber photoelectric microelectrode, and a sensing system comprises an electrochemical workstation, an optical fiber photoelectrode and a laser. The microelectrode provides excellent sensitivity, quick response and multifunctionality, so that the microelectrode becomes an ideal choice for real-time detection and monitoring application.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical fiber sensing, and relates to an implantable micro-optical fiber photoelectric sensor and a preparation method and application thereof, and specifically relates to an implantable micro-optical fiber photoelectric microelectrode and a preparation method and application thereof. Background Art

[0002] With the breakthroughs in new materials, microelectronics technology and electrochemical understanding, biosensors are developing in the direction of miniaturization, digitization, intelligence and systematization. Microelectrode biosensors developed based on micro / nano arrays, carbon fibers, platinum electrodes, nanoneedles, optical fibers, etc. have been widely used in the detection of various targets, but these sensors are mainly electrochemical sensors or optical sensors, and there are still few designs for photoelectrochemical microsensors. Compared with electrochemical sensors and optical sensors, photoelectrochemical sensors have higher sensitivity, fast response and high resolution. Their diverse detection capabilities and high-precision measurement results have made them widely used in many fields. At present, the working electrodes used in most photoelectrochemical sensors are relatively large in size, and external light sources are required for spatial illumination. These factors hinder the development of photoelectrochemical sensors towards miniaturization and integration, and it is also difficult to perform real-time online monitoring in vivo. Therefore, the development of photoelectrochemical sensors based on microelectrodes can have far-reaching significance and help expand their scope of application.

[0003] Fiber optic microelectrodes have become a new hot spot in the development of biosensors due to their wide adaptability to sensing environments, extremely high cost-effectiveness, and excellent long-distance, low-loss information transmission capabilities. At present, the development of sensors based on optical fibers is mainly concentrated in the fields of surface plasmon resonance, electrochemiluminescence, and electron microscopy, which often require expensive optical instruments, increasing the complexity and cost of the system. The development of micro-photoelectric microelectrodes using optical fibers as photoelectrodes can not only achieve the miniaturization of photoelectric sensors, but also give full play to the unique in-situ photoconductive function of optical fibers and realize the integration of photoelectric sensors. At the same time, the cost of optical fibers is very low, which effectively reduces the cost of sensing systems, making them promising for use in areas with limited medical resources to maximize the advantages of photoelectric sensing. Reasonable interface design can give fiber optic microelectrodes higher sensitivity, excellent selectivity, and better biocompatibility. In addition, the rich and diverse customizable micro-sizes of optical fibers also enable them to easily obtain physiological signals in various deep tissue environments without causing excessive damage to the organism. This provides new options for building integrated, implantable detection devices and long-term monitoring systems, and can also provide possibilities for real-time online monitoring of pathological signals, providing more valuable support for early diagnosis and prognosis monitoring of diseases.

[0004] At present, there are relatively few studies on fiber-optic photoelectric microelectrodes, and there are still many shortcomings, such as low sensitivity, low selectivity, time-consuming, poor biocompatibility, etc. Therefore, it is urgent to develop implantable miniature fiber-optic photoelectric microelectrodes with high selectivity, strong specificity, and excellent biocompatibility. Summary of the invention

[0005] In view of the problems of low sensitivity, low selectivity, time consumption, poor biocompatibility and the like of optical fiber photoelectric sensors in the prior art, the present invention provides an implantable miniature optical fiber photoelectric sensor and a preparation method and application thereof, an implantable miniature optical fiber photoelectric microelectrode and a preparation method and application thereof, and also an interface design, system construction and biological application of an implantable miniature optical fiber photoelectric sensor, so as to solve the deficiencies in the prior art research on the field of optical fiber photoelectric sensing and develop an implantable miniature optical fiber photoelectric sensor with high selectivity, strong specificity and excellent biocompatibility.

[0006] The technical solution of the present invention is as follows: An implantable micro-fiber optoelectronic microelectrode, comprising an optical fiber sensing region, an optoelectronically active material layer, and a biomolecule recognition layer; The composite optoelectronic sensing interface includes an optoelectronically active material layer and a biomolecule recognition layer; The optical fiber sensing area is made of multimode optical fiber after being corroded by hydrofluoric acid and activated by piranha solution, with a length of 2-3 cm and a diameter of 30-100 μm; The photoelectric active material layer is evenly coated on the surface of the optical fiber sensing area (referring to the surface of the optical fiber after corrosion), with a length of 2-3 cm; the photoelectric active material layer is a titanium dioxide / cadmium sulfide composite material; The biomolecule recognition layer is uniformly loaded on the surface of the photoelectric active material layer, and the biomolecule recognition layer is assembled layer by layer. The number of modified layers of the biomolecule recognition layer is 1 to 6 layers, the modification time is 15 to 60 minutes, and the length is 2 to 3 cm. The biomolecule recognition layer is [Ru(bpy)2dppz] 2+ @dsDNA / Au@EGCG nanoparticles.

[0007] Furthermore, the geometric parameters of the optical fiber sensing area, such as the length and diameter of the sensing detection area, are mainly determined by the hydrofluoric acid immersion depth and immersion time. The length of the optical fiber sensing area is 2-3 cm, and the diameter of the optical fiber sensing area is 30-100 μm, preferably 40 μm. The optical fiber sensing area after activation treatment is used to continue to modify the photoelectric active material layer and the biological molecule recognition layer.

[0008] Furthermore, the photoelectric active material layer is also a titanium dioxide-based semiconductor interface layer, including a cadmium sulfide quantum dot / titanium dioxide interface layer and a selenium sulfide quantum dot / titanium dioxide interface layer.

[0009] Furthermore, the composite photoelectric sensing interface refers to the photoelectrically active material layer and the biomolecule recognition layer modified in the photoelectric sensing region, including a titanium dioxide-based semiconductor interface layer.

[0010] Furthermore, the [Ru(bpy)2dppz] 2+ @dsDNA / Au@EGCG nanoparticles, composed of [Ru(bpy)2dppz] 2+ / dsDNA complex, wherein the dsDNA includes an adapter sequence of a target molecule and its corresponding complementary chain.

[0011] The present invention also provides a method for preparing the above-mentioned implantable micro-optical optical fiber photoelectric microelectrode, comprising the following steps: 1) Preparation of corrosion-activated optical fiber sensing area: remove the outer cladding of the optical fiber, cut the optical fiber after the outer cladding is removed into small segments of 5-6 cm, soak it in a 40wt% hydrofluoric acid solution (hydrofluoric acid concentration is about 23.8 M) for 10-30 minutes, and then soak it in a mixed solution of hydrogen peroxide and concentrated sulfuric acid in a volume ratio of 3:7 for 30-60 minutes to activate its surface and obtain the optical fiber sensing area; 2) preparing a photoelectric active material layer: dispersing a titanium dioxide / cadmium sulfide composite material in water to obtain a 5 mM titanium dioxide / cadmium sulfide solution 1; Dispersing polydiallyldimethylammonium chloride in water to obtain a 2 wt % dispersion 2; The optical fiber sensing area after corrosion activation is alternately immersed in solution 1 and solution 2 for 5 minutes each, to obtain a layer of titanium dioxide / cadmium sulfide composite material layer, and the obtained optical fiber microelectrode with photoelectric active material layer; 3) Modifying the biomolecule recognition layer: Soak the optical fiber microelectrode with the photoelectric active material layer obtained in the previous step in a 5-10 mM biorecognition molecule solution with an aptamer for 15-60 minutes to combine it with the photoelectric active material layer through amide condensation to obtain an optical fiber microelectrode in an implantable micro-optical optical sensor; The biorecognition molecule solution with aptamer is [Ru(bpy)2dppz] 2+ @dsDNA / Au@EGCG nanoparticles, composed of [Ru(bpy)2dppz] 2+ / dsDNA complex, wherein the dsDNA includes an adapter sequence of a target molecule and its corresponding complementary chain.

[0012] Furthermore, in step 3), the immersion time of the optical fiber microelectrode (incubation time of the biomolecule recognition layer) is 30-60 min.

[0013] Furthermore, the optical fiber photoelectric microelectrode is used in conjunction with a micro laser and an electrochemical workstation to construct a micro optical fiber photoelectric detection system.

[0014] The present invention also provides a method for detecting a target object using an implantable micro-optical fiber photoelectric microelectrode, the method comprising the following steps: 1) Coupling the optical fiber photoelectric microelectrode incubated with the target with the multimode optical fiber to obtain a sensing device; 2) placing the sensing device in phosphate buffer with an electron donor; 3) Input a laser of a specific wavelength into the sensor device and use an electrochemical workstation to capture the resulting photogenerated current changes.

[0015] Furthermore, in step 1), coupling the optical fiber photoelectric microelectrode incubated with the target object with the multimode optical fiber to obtain the sensing device is performed by incubating the obtained optical fiber photoelectric microelectrode with the target object for 15 to 60 minutes, then cleaning it, fusing it with the multimode optical fiber, coupling a laser light source with a wavelength of 400 to 650 nm into the sensing device, connecting it to an electrochemical workstation, and outputting the photoelectric changes of the sensing interface.

[0016] The laser of specific wavelength described in step 2) is a laser light source used to excite the photoelectric active material layer to generate a photoelectric signal.

[0017] The sensing device described in step 1) further comprises a biomolecule detection pool for detecting changes in the concentration of the target; the biomolecule detection pool comprises a phosphate buffer with a pH value of 7.4 and an electron donor of a certain concentration.

[0018] Compared with the prior art, the present invention has the following advantages: 1. The preparation method of the implantable micro-fiber optoelectronic microelectrode described in the present invention is simple and rapid, the material synthesis is green and convenient, and the biorecognition mode of the aptamer used to recognize the target molecule also has strong universality and more development potential.

[0019] 2. The implantable micro-fiber photoelectric microelectrode of the present invention realizes the integration and integration of the sensing system. The micro-fiber photoelectrode also gives the sensor the possibility of being an implantable device, providing a new idea for the construction of portable devices. The target detection method provided by the present invention can be applied to the detection of a variety of targets, has wide universality, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of a micro-fiber photoelectric microelectrode detection system according to Embodiment 1 and Embodiment 4 of the present invention; Figure 2 This is a schematic diagram of interface modification of a micro-fiber optoelectronic microelectrode according to Example 2 of the present invention; Figure 3 This is a graph showing the effect of different numbers of titanium dioxide / cadmium sulfide deposition layers on the photoelectric performance of micro-optical fiber microelectrodes in Example 3 of the present invention; Figure 4 This is a graph showing the effect of the incubation time of the biometric material on the photoelectric performance of the micro-fiber photoelectric microelectrode according to Example 4 of the present invention; Figure 5 This is a diagram showing the detection of targets of different concentrations by the micro-fiber photoelectric microelectrode of Example 4 of the present invention. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0022] Embodiment 1: A method for constructing an implantable micro-fiber photoelectric microelectrode uses fiber photoelectric sensing technology, which is a new sensing mode that uses multimode optical fiber as a sensing element and the electrical signal generated by light excitation as an information transmission medium. This method has the advantages of strong anti-interference ability, wide application range, high cost-effectiveness, low transmission loss and large transmission capacity. Compared with traditional photoelectric technology, micro-fiber photoelectric sensors are more conducive to the integration and miniaturization of sensing systems, providing new manufacturing ideas for portable sensor devices, greatly improving their detection capabilities, and are suitable for more detection scenarios.

[0023] Figure 1 The diagram shows the construction of the micro-fiber photoelectric microelectrode detection system of Example 1, including a fiber microelectrode pretreated with surface activation, including a sensing detection area at the tip of the fiber microelectrode; and a nanomaterial layer with photoelectric effect and a further modified biomolecule recognition layer uniformly wrapped in the sensing detection area of ​​the optical fiber. In a specific implementation example, the photoelectric nanomaterial layer is a titanium dioxide / cadmium sulfide composite interface layer, which is used to convert electrical signals under light excitation. After the target is introduced, the biomolecule layer modified on the surface of the fiber microelectrode will capture the target, and the fiber microelectrode responds to the change in the electrical signal to generate a change in the intensity of the photocurrent. The change in the intensity of the photocurrent generated in this process is captured by the electrochemical workstation and transmitted to the computer, thereby realizing the detection of the target.

[0024] Embodiment 2: An implantable micro-fiber optoelectronic microelectrode, comprising an optical fiber sensing region, an optoelectronically active material layer, and a biomolecule recognition layer; The composite optoelectronic sensing interface includes an optoelectronically active material layer and a biomolecule recognition layer; The optical fiber sensing area is made of multimode optical fiber after being corroded by hydrofluoric acid and activated by piranha solution, and has a length of 2-3 cm; The photoelectric active material layer is evenly coated on the surface of the optical fiber sensing area (referring to the surface of the optical fiber after corrosion), with a length of 2-3 cm; the photoelectric active material layer is a titanium dioxide / cadmium sulfide composite material; The biomolecule recognition layer is uniformly loaded on the surface of the photoelectric active material layer, and the biomolecule recognition layer is assembled layer by layer. The number of modified layers of the biomolecule recognition layer is 1 to 6 layers, the modification time is 15 to 60 minutes, and the length is 2 to 3 cm. The biomolecule recognition layer is [Ru(bpy)2dppz] 2+ @dsDNA / Au@EGCG nanoparticles.

[0025] In this embodiment, the optical fiber microelectrode with surface activation pretreatment is prepared by hydrofluoric acid corrosion treatment and immersion in piranha solution; the geometric parameters of the optical fiber microelectrode, such as the length and diameter of the sensing detection area, are mainly determined by the hydrofluoric acid immersion depth and immersion time. In this embodiment, the diameter of the sensing area is 40μm. The optical fiber microelectrode after activation treatment is used to continue to modify optoelectronic active nanomaterials and biorecognition molecules.

[0026] Figure 2 This is a schematic diagram of the interface modification of the micro-optical fiber optoelectronic microelectrode of Example 2; first, the optical fiber is subjected to corrosion treatment to obtain the optical fiber sensing area, and then the photoelectric active material layer is modified on the surface of the optical fiber sensing area, and then the biomolecule recognition layer is further modified to obtain the optical fiber optoelectronic microelectrode for detecting specific targets.

[0027] Embodiment 3: A method for preparing an implantable micro-optical optical fiber photoelectric microelectrode comprises the following steps: 1) Preparation of corrosion-activated optical fiber sensing area: remove the outer cladding of the optical fiber, cut the optical fiber after the outer cladding is removed into small segments of 5-6 cm, soak it in a 40wt% hydrofluoric acid solution (hydrofluoric acid concentration is about 23.8 M) for 30 minutes, and then soak it in a mixed solution of hydrogen peroxide and concentrated sulfuric acid in a volume ratio of 3:7 for 30 minutes to activate its surface, thereby obtaining the optical fiber sensing area; 2) preparing a photoelectric active material layer: dispersing a titanium dioxide / cadmium sulfide composite material in water to obtain a 5 mM titanium dioxide / cadmium sulfide solution 1; Dispersing polydiallyldimethylammonium chloride in water to obtain a 2 wt % dispersion 2; The optical fiber sensing area after corrosion activation is alternately immersed in solution 1 and solution 2 for 5 minutes each, to obtain a layer of titanium dioxide / cadmium sulfide composite material layer, and the obtained optical fiber microelectrode with photoelectric active material layer; 3) Modifying the biomolecule recognition layer: Immerse the optical fiber microelectrode with the photoelectric active material layer obtained in the previous step in a 10 mM biorecognition molecule solution with an aptamer for 30 minutes to combine it with the photoelectric active material layer through amide condensation to obtain an optical fiber microelectrode in an implantable micro-optical optical sensor; The biorecognition molecule solution with aptamer is [Ru(bpy)2dppz] 2+ @dsDNA / Au@EGCG nanoparticles, composed of [Ru(bpy)2dppz] 2+ / dsDNA complex, wherein the dsDNA includes an adapter sequence of a target molecule and its corresponding complementary chain.

[0028] The number of the coated titanium dioxide / cadmium sulfide composite material layers can be 1 to 6 layers; the method for preparing each titanium dioxide / cadmium sulfide composite material layer is as follows: dispersing the titanium dioxide / cadmium sulfide composite material in water to obtain a 5 mM titanium dioxide / cadmium sulfide solution 1; dispersing polydiallyldimethylammonium chloride in water to obtain a 2% dispersion 2; and immersing the corrosion-activated optical fiber microelectrode in solutions 1 and 2 for 5 minutes each in turn to obtain a titanium dioxide / cadmium sulfide composite material layer.

[0029] Figure 3 This is a graph showing the effect of different numbers of deposited titanium dioxide / cadmium sulfide layers on the photoelectric performance of the micro-fiber microelectrode of Example 3; different numbers of photoelectrically active material layers are deposited on the sensing area of ​​the optical fiber microelectrode after activation treatment. As the number of deposited photoelectrically active material layers increases, the photocurrent signal first increases and then gradually stabilizes and slightly decreases. When the number of deposited layers is 2, the current signal is the largest.

[0030] The activated optical fiber microelectrode is immersed in a titanium dioxide / cadmium sulfide composite material dispersion liquid with a concentration of 5 mM, for example, to form a uniformly coated titanium dioxide / cadmium sulfide composite material layer in the optical fiber microelectrode sensing area to obtain a micro-optical fiber photoelectric sensing device. The titanium dioxide / cadmium sulfide composite material layer is a photoelectric nanomaterial layer that can generate photoelectric signals under the action of laser. The optical fiber microelectrode is fused with a multimode optical fiber, and a laser light source with a wavelength of 400 to 650 nm is coupled into the sensing device to excite the titanium dioxide / cadmium sulfide composite material to generate photogenerated electrons, thereby converting the optical signal into an electrical signal and outputting the photoelectric change of the sensing interface. The biorecognition layer can capture the target molecule, causing the resistance change on the optical fiber microelectrode interface, thereby changing the photocurrent signal, thereby realizing the recognition and detection of the target molecule. The micro-optical fiber photoelectric sensor of the present invention can be customized to modify different photoelectric active material layers to adapt to different excitation wavelengths, and the directional design of the biorecognition layer can also easily realize the recognition and detection of different target molecules, which has a wide range of application value and provides an important reference for the construction of integrated and portable sensing devices.

[0031] Embodiment 4: A method for detecting a target object using an implantable micro-optical fiber photoelectric microelectrode, the method comprising: 1) Coupling the optical fiber photoelectric microelectrode incubated with the target with the multimode optical fiber to obtain a sensing device; 2) placing the sensing device in phosphate buffer with an electron donor; 3) Input a laser of a specific wavelength into the sensor device and use an electrochemical workstation to capture the resulting photocurrent changes; In step 1), the optical fiber photoelectric microelectrode incubated with the target object is coupled with a multimode optical fiber to obtain a sensing device, which is to incubate the obtained optical fiber photoelectric microelectrode with the target object for 60 minutes, then wash it, fuse it with the multimode optical fiber, couple a laser light source with a wavelength of 400 to 650 nm into the sensing device, connect it to an electrochemical workstation, and output the photoelectric changes of the sensing interface; The laser of specific wavelength described in step 2) is a laser light source used to excite the photoelectric active material layer to generate a photoelectric signal; The sensing device described in step 1) further comprises a biomolecule detection pool for detecting changes in the concentration of the target; the biomolecule detection pool comprises a phosphate buffer with a pH value of 7.4 and an electron donor of a certain concentration.

[0032] Figure 1 Schematic diagram of a micro-fiber photoelectric microelectrode detection system of Example 4; Figure 4 A graph showing the effect of the incubation time of the biorecognition material on the photoelectric performance of the micro-fiber photoelectric microelectrode of Example 4; The optical fiber microelectrode constructed above was incubated with the target for different lengths of time and then the photocurrent was detected. As the incubation time increased from 15 min to 30 min, the photocurrent gradually increased. When the incubation time was further increased, the photocurrent did not increase much, indicating that the biomolecule recognition process had reached saturation at 30 min.

[0033] Figure 5 The micro-optical fiber photoelectric microelectrode of Example 4 detects targets of different concentrations. The optical fiber photoelectric microelectrode is incubated with targets of different concentrations and then subjected to photoelectric testing. The signals obtained are as follows: Figure 5 As shown in the figure, as the concentration of the target increases, the photocurrent decreases and the relationship is linear. This shows that the optical fiber photoelectric microelectrode proposed in the present invention can be applied to the detection of actual targets.

[0034] Results and Discussion: The present invention discloses an interface design, system construction and measurement method of an implantable miniature optical fiber photoelectric microelectrode, wherein the sensing system includes an electrochemical workstation, an optical fiber photoelectrode and a laser. The microelectrode provides excellent sensitivity, rapid response and versatility, making it an ideal choice for real-time detection and monitoring applications. Photoelectrochemical (PEC) sensors have the advantages of high sensitivity, fast response and convenient operation, and show great application value in many fields. However, traditional PEC sensing relies on bulky external light sources and bulky electrodes, which hinders its miniaturization and implantation, thereby limiting its application in real-time disease monitoring.

[0035] To overcome these limitations, the inventors developed a nanoencapsulated optical fiber (OF)-based PEC microelectrode with TiO2 / CdS nanocrystals and bis(2,2'-bipyridyl)(10-methylphenanthroline[3,2-a:2'3'-c]pyridineruthenium(II)dichloride ([Ru(bpy)2dppz] 2+ ) @dsDNA / Au@epigallocatechin gallate catechin nanoparticles (EGCGNPs). And its application in the detection of N-terminal pro-brain natriuretic peptide (NT-proBNP) as a biomarker for cardiovascular disease (CVD) was discussed. -1 Within a wide linear range, 0.36 pg mL -1A low detection limit of 100 μg / cm2 was achieved. This range not only covers the recommended thresholds for excluding cardiovascular disease in clinical diagnosis for individuals of all age groups, but also includes prognostic target values. The sensor showed good selectivity, stability and significant label recovery in serum tests. Crucially, the sensor successfully identified changes in NT-proBNP secretion levels in human smooth muscle cells by comparing before and after platelet-derived growth factor-bb stimulation. More importantly, skin puncture experiments on mice showed that OF-PEC microelectrodes have significant portability and biocompatibility. This solves the key challenges that microelectrodes usually face when used as implantable devices, such as minimizing invasive trauma, reducing inflammation and preventing biofouling, thereby firmly establishing its applicability in the development of advanced implantable sensing devices. Therefore, the current microelectrode PEC biosensor is not only cost-effective, easy to operate and miniaturized, but also has great potential in achieving more accurate, minimally invasive and continuous monitoring of biomarkers without causing inflammation. This capability is crucial for early disease detection, tracking disease progression and promoting personalized treatment strategies, greatly expanding the practical application of PEC sensors. The present invention has high universality and integration, can realize sensitive and efficient detection, and has the advantages of implantability and good biocompatibility. The miniature size of the photoelectrode also improves the portability of the detection device, making it more convenient to use and less expensive. The material usage requirement is very low, and it has important application value in new type evaluation.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An implantable micro-fiber optoelectronic microelectrode, characterized in that: It consists of a fiber optic sensing region, a photoelectrically active material layer, and a biomolecule recognition layer; The composite optoelectronic sensing interface includes an optoelectronically active material layer and a biomolecule recognition layer; The optical fiber sensing area is made of multimode optical fiber after being corroded by hydrofluoric acid and activated by piranha solution, with a length of 2-3 cm and a diameter of 30-100 μm; The photoelectric active material layer is evenly coated on the surface of the optical fiber sensing area, with a length of 2-3 cm; the photoelectric active material layer is a titanium dioxide / cadmium sulfide composite material; The biomolecule recognition layer is uniformly loaded on the surface of the photoelectric active material layer, and the biomolecule recognition layer is assembled layer by layer. The number of modified layers of the biomolecule recognition layer is 1 to 6 layers, the modification time is 15 to 60 minutes, and the length is 2 to 3 cm. The biomolecule recognition layer is [Ru(bpy)2dppz] 2+ @dsDNA / Au@EGCG nanoparticles.

2. The implantable micro-fiber optoelectronic microelectrode according to claim 1, characterized in that: The diameter of the optical fiber sensing area is 40 μm.

3. The implantable micro-optical optical microelectrode according to claim 1, characterized in that: The photoelectric active material layer is also a titanium dioxide-based semiconductor interface layer, including a cadmium sulfide quantum dot / titanium dioxide interface layer and a selenium sulfide quantum dot / titanium dioxide interface layer.

4. The implantable micro-fiber optoelectronic microelectrode according to claim 1, characterized in that: The composite photoelectric sensing interface refers to the photoelectric active material layer and the biomolecule recognition layer modified in the photoelectric sensing region, including a titanium dioxide-based semiconductor interface layer.

5. The implantable micro-fiber optoelectronic microelectrode according to claim 1, characterized in that: The biomolecule recognition layer [Ru(bpy)2dppz] 2+ @dsDNA / Au@EGCG nanoparticles, composed of [Ru(bpy)2dppz] 2+ / dsDNA complex, wherein the dsDNA includes an adapter sequence of a target molecule and its corresponding complementary chain.

6. A method for preparing an implantable micro-fiber optoelectronic microelectrode according to any one of claims 1 to 5, characterized in that: The following steps are involved: 1) Preparation of corrosion-activated optical fiber sensing area: remove the outer cladding of the optical fiber, cut the optical fiber after the outer cladding is removed into small segments of 5-6 cm, soak it in a 40wt% hydrofluoric acid solution for 10-30 minutes, and then soak it in a mixed solution of hydrogen peroxide and concentrated sulfuric acid in a volume ratio of 3:7 for 30-60 minutes to activate its surface, thereby obtaining the optical fiber sensing area; 2) preparing a photoelectric active material layer: dispersing a titanium dioxide / cadmium sulfide composite material in water to obtain a 5 mM titanium dioxide / cadmium sulfide solution 1; Dispersing polydiallyldimethylammonium chloride in water to obtain a 2 wt % dispersion 2; The optical fiber sensing area after corrosion activation is alternately immersed in solution 1 and solution 2 for 5 minutes each, to obtain a layer of titanium dioxide / cadmium sulfide composite material layer, and the obtained optical fiber microelectrode with photoelectric active material layer; 3) Modifying the biomolecule recognition layer: soaking the optical fiber microelectrode with the photoelectric active material layer obtained in the previous step in a 5-10 mM biorecognition molecule solution with an aptamer for 15-60 min, so that it is combined with the photoelectric active material layer through amide condensation, thereby obtaining an optical fiber microelectrode in an implantable micro-optical optical sensor; The biorecognition molecule solution with aptamer is [Ru(bpy)2dppz] 2+ @dsDNA / Au@EGCG nanoparticles, composed of [Ru(bpy)2dppz] 2+ / dsDNA complex, wherein the dsDNA includes an adapter sequence of a target molecule and its corresponding complementary chain.

7. The method for preparing an implantable micro-optical optical fiber microelectrode according to claim 6, characterized in that: The optical fiber microelectrode is immersed for 30-60 minutes.

8. The method for detecting a target object using an implantable micro-fiber photoelectric microelectrode according to claim 1, characterized in that: The following steps are involved: 1) Coupling the optical fiber photoelectric microelectrode incubated with the target with the multimode optical fiber to obtain a sensing device; 2) placing the sensing device in phosphate buffer with an electron donor; 3) Input a laser of a specific wavelength into the sensor device and use an electrochemical workstation to capture the resulting photogenerated current changes.

9. The method for detecting a target object using an implantable micro-fiber photoelectric microelectrode according to claim 8, characterized in that: In step 1), the optical fiber photoelectric microelectrode incubated with the target object is coupled with the multimode optical fiber to obtain the sensing device, which is to incubate the obtained optical fiber photoelectric microelectrode with the target object for 15 to 60 minutes, then wash it, fuse it with the multimode optical fiber, couple a laser light source with a wavelength of 400 to 650 nm into the sensing device, connect it to the electrochemical workstation, and output the photoelectric changes of the sensing interface.

10. The method for detecting a target object using an implantable micro-fiber photoelectric microelectrode according to claim 8, characterized in that: The sensing device described in step 1) further includes a biomolecule detection pool for detecting changes in the concentration of the target; the biomolecule detection pool includes a phosphate buffer with a pH value of 7.4 and an electron donor with a set concentration.

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