A fiber sensor and its preparation method

Abstract

The present invention discloses a fiber sensor and a preparation method thereof, belonging to the technical field of wearable devices, including: separately preparing a sensing fiber, a silver / silver chloride reference fiber, and a repair gel; coating polydimethylsiloxane on the sensing fiber and the silver / silver chloride reference fiber as an insulating layer; arranging the sensing fiber and the silver / silver chloride reference fiber coated with polydimethylsiloxane in parallel, so that there is an axial displacement difference at the sensing part, and the sensing part is the area on the fiber for detecting the target substance; fixing one end of the parallel arrangement in a limited way, and fixing the other end with tape to form a spiral structure; coating polydimethylsiloxane again on the spiral structure for curing; coating the repair gel on the cured spiral structure to form a fiber sensor. Aiming at the problem that the prior art cannot realize real-time in-vivo monitoring of amniotic fluid during pregnancy, the present invention realizes real-time in-vivo monitoring of amniotic fluid during pregnancy by coating the repair gel on the surface of the sensor.

Description

Technical Field

[0001] The present invention relates to the field of wearable sensors, and more particularly, to a fiber sensor and a preparation method thereof. Background Art

[0002] The incidence and prevalence of pregnancy diseases are a concern globally, threatening the health of the fetus. More than 20,000,000 high-risk pregnancies and 2,600,000 fetal deaths occur worldwide each year. Among them, the incidences of intrauterine hypoxia, intrauterine infection, and maternal-fetal blood group incompatibility are 38.5%, 10%, and 25% respectively, which can be early warned by abnormalities of biochemical substances in amniotic fluid. For example, the upregulation of lactate and the accumulation of protons in amniotic fluid are closely related to intrauterine hypoxia, while a decrease in glucose is found in intrauterine infection. Other biochemical substances in amniotic fluid, including nitric oxide, uric acid, and bilirubin, can evaluate fetal development. Therefore, if the biochemical substances in amniotic fluid can be monitored in real time during pregnancy, it is feasible to intervene in a timely manner and prevent adverse outcomes after sudden adverse situations.

[0003] Currently, B-ultrasound and amniocentesis are used clinically for amniotic fluid assessment. B-ultrasound imaging provides information related to the amount of amniotic fluid and fetal morphology, but cannot directly detect biochemical substances. Amniocentesis analyzes biochemical substances by extracting amniotic fluid with a puncture needle. However, the biochemical information obtained by amniocentesis is non-real-time and discontinuous. Repeated amniocentesis can lead to amniotic membrane rupture, amniotic fluid hemorrhage, and fetal malformations, increasing the risk of miscarriage. To our knowledge, there is currently no technology available for real-time monitoring of biochemical substances in amniotic fluid during pregnancy.

[0004] The particularity of the amniotic membrane is an important obstacle to real-time monitoring of amniotic fluid. During fetal growth, the amniotic membrane acts as a protective barrier with anti-microbial, anti-fibrotic, and anti-inflammatory properties. However, the amniotic membrane consists of fewer cells and has a thickness of 20 - 50 microns. When continuously penetrated by a detection device, deformation can cause amniotic membrane rupture, leading to intrauterine infection, maternal hemorrhage, and miscarriage, endangering the health of the mother and fetus. In addition, compared with other tissues, the amniotic membrane contains fewer immune cells and stress repair factors, resulting in poor regenerative ability after acute trauma. Moreover, the stress concentration generated by the dynamic deformation of the amniotic membrane leads to an increase in matrix metalloproteinase expression and extracellular matrix degradation, further aggravating amniotic membrane rupture. Therefore, to achieve real-time monitoring of amniotic fluid, it is crucial to stabilize the device-amniotic membrane interface and maintain amniotic fluid homeostasis.

[0005] In the related art, sensing fibers are woven into electrochemical fabrics for real-time health monitoring. "Advanced Functional Materials", 2018, 28(42): 1804456, Wang Lie et al. reported that by depositing different active materials on the surface of carbon nanotube fibers, glucose fiber sensors, sodium ion fiber sensors, potassium ion fiber sensors, and PH fiber sensors were prepared. They were respectively woven with silver / silver chloride reference electrodes into electrochemical sensing fabrics, which were then woven into clothing and connected to wireless chips to construct intelligent sensing clothing for real-time monitoring of biochemical components in body surface sweat. However, since the fiber sensors in this project did not verify their biocompatibility, they could not be implanted into the in-vivo environment, and thus could not detect biochemical substances in amniotic fluid; moreover, this project was not used for amniotic fluid detection.

[0006] In the related art, the functionalization of carbon nanotube helical fiber bundles as electrochemical sensors for long-term in-vivo monitoring of multiple disease biomarkers. "Nature Biomedical Engineering", 2020, 4(2): 159-171, Wang Lie et al. reported a flexible fibrous implantable electrochemical sensor. The response principle of the sensor was the same as that reported by Wang Lie et al., but it simulated the hierarchical and helical assembly of natural soft tissues. The sensor provided a flexible and stable fiber-tissue interface through mechanical matching with human tissues, showing good biocompatibility. Further injecting and implanting it into the venous blood vessels of cats could achieve real-time monitoring of calcium ions and glucose in the blood. However, the fiber sensors in this project only matched the mechanical properties of tissues and could not repair the amniotic membrane, which would cause the rupture of the amniotic membrane under dynamic conditions, and thus could not detect biochemical substances in amniotic fluid; moreover, this project was not used for amniotic fluid detection.

[0007] In the related art, flexible dopamine-sensing fibers based on potentiometry for long-term in-vivo detection. "Science China Chemistry", 2021, 64(10): 1763-1769, Wang Liyuan et al. deposited Pt nanoparticles on the surface of carbon nanotube fibers by multi-potentiometry and then coated them with Nafion solution to prepare dopamine fiber sensors. The sensor had a low detection limit of 5 nM, a wide linear range of 5 to 185 nM, which was very compatible with the in-vivo dopamine concentration (26-40 nM). After being implanted into the mouse brain, through potential testing, the sensing fiber had no effect on the firing rate of neurons, indicating high neuron compatibility and could stably monitor the changes of dopamine in the body for 8 weeks. However, the fiber sensors in this project only had high compatibility with neurons and could not be compatible with the amniotic membrane, and thus could not detect biochemical substances in amniotic fluid; moreover, this project was not used for amniotic fluid detection.

[0008] In summary, the prior art cannot achieve real-time in-vivo monitoring of amniotic fluid during pregnancy. Summary of the Invention

[0009] 1. Technical problems to be solved

[0010] In view of the problem that the prior art cannot achieve real-time in-vivo monitoring of amniotic fluid during pregnancy, the present invention provides an interfacially stable fiber sensor containing a repair gel and a preparation method thereof. By coating the repair gel on the surface of the sensor, seamless fusion of the sensor with the amniotic membrane is achieved, thereby realizing real-time in-vivo monitoring of amniotic fluid during pregnancy.

[0011] 2. Technical solution

[0012] The object of the present invention is achieved by the following technical solutions.

[0013] Based on the above problems, it is necessary to study a preparation method of a fiber sensor for preparing a fiber sensor for real-time monitoring of amniotic fluid during pregnancy.

[0014] One aspect of the embodiments of the present specification provides a preparation method of a fiber sensor, including: separately preparing a sensing fiber, a silver / silver chloride reference fiber, and a repair gel; coating polydimethylsiloxane on the sensing fiber and the silver / silver chloride reference fiber as an insulating layer; arranging the sensing fiber and the silver / silver chloride reference fiber coated with polydimethylsiloxane in parallel, so that there is an axial displacement difference in the sensing part, and the sensing part is the area on the fiber for detecting the target substance; fixing one end of the parallel arrangement in a limited way, and fixing the other end with tape to form a spiral structure; coating polydimethylsiloxane on the spiral structure again for curing; coating the repair gel on the cured spiral structure to form a fiber sensor.

[0015] Further, the steps of preparing the silver / silver chloride reference fiber include: placing a carbon nanotube fiber in a 1 mM to 5 mM silver nitrate or 1 M to 10 M potassium nitrate solution, and depositing silver nanoparticles by cyclic voltammetry; immersing the carbon nanotube fiber deposited with silver nanoparticles in a 0.1 M to 1 M potassium chloride or 0.01 M to 0.1 M hydrochloric acid solution, and performing chlorination treatment by cyclic voltammetry; dissolving 50 mg to 100 mg of polyvinyl butyral, 50 mg to 70 mg of sodium chloride, and 0.1 mg to 0.2 mg of multi-walled carbon nanotubes in 0.1 mL to 1 mL of methanol to obtain a polyvinyl butyral solution; dropping 1 μL to 4 μL of the polyvinyl butyral solution onto the carbon nanotube fiber subjected to chlorination treatment to obtain the silver / silver chloride reference fiber.

[0016] Further, the steps for preparing the repair gel include: dissolving 10 wt% to 30 wt% of sericin in 10 mM to 100 mM of tris(2-carboxyethyl)phosphine or 1 mM to 10 mM of 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid to generate a reduced sericin solution; adding 0.3 g / mL to 1 g / mL of tannic acid to an equal volume of the reduced sericin solution to generate a gel-like precipitate of rSer-TA; dissolving type I collagen into rSer-TA to obtain the repair gel; wherein, the volume ratio of type I collagen to rSer-TA is 1:2.

[0017] Further, the steps for preparing the sensing fiber include: electrodepositing platinum nanoparticles and electrochemically polymerizing polyaniline on a carbon nanotube fiber to obtain a pH sensing fiber; modifying polyaniline and platinum nanoparticles on a carbon nanotube fiber, and coating single-walled carbon nanotubes, chitosan, and glucose oxidase to obtain a glucose sensing fiber; coating nickel-cobalt bimetallic hydroxide on a carbon nanotube fiber to obtain a lactic acid sensing fiber; depositing a gold nanomembrane and electrochemically depositing a polyeugenol membrane on a carbon nanotube fiber to obtain a nitric oxide sensing fiber.

[0018] Further, the steps for preparing the pH sensing fiber include: electrodepositing platinum nanoparticles on the surface of a carbon nanotube fiber, using a 0.01 M to 1 M potassium chloride or 0.1 mM to 5 mM potassium chloroplatinate solution, and performing electrodeposition by the arbitrary constant potential staircase wave method; electrochemically polymerizing polyaniline on the surface of the electrodeposited platinum nanoparticles, using a 0.01 M to 1 M aniline or 0.01 M to 1 M sulfuric acid solution, and performing electro-polymerization by cyclic voltammetry to obtain the pH sensing fiber.

[0019] Further, the steps for preparing the glucose fiber include: electrochemically polymerizing polyaniline on the surface of a carbon nanotube fiber, using a 0.1 M to 1 M aniline or 0.1 M to 1 M sulfuric acid solution, and performing electrodeposition by the constant potential staircase wave method to generate a B1 fiber; electrodepositing platinum nanoparticles on the surface of the B1 fiber, using a 0.01 M to 1 M potassium chloride or 0.1 mM to 5 mM potassium chloroplatinate solution, and performing electrodeposition by the arbitrary constant potential staircase wave method to generate a B2 fiber; dissolving chitosan in an acetic acid solution to generate a chitosan solution A1 with a concentration of 100 mg / mL to 800 mg / mL; dispersing 10 mg / mL to 40 mg / mL of glucose oxidase and 1 mg / mL to 2 mg / mL of single-walled carbon nanotubes in the chitosan solution A1 to generate an A2 solution; dropping 1 μL to 4 μL of the A2 solution onto the B2 fiber to generate a B3 fiber; dropping 1 μL to 2 μL of a 0.5 wt% perfluorosulfonic acid separator solution onto the surface of the B3 fiber to generate a B4 fiber; soaking the B4 fiber in a 1 wt% to 2 wt% glutaraldehyde solution to obtain the glucose fiber.

[0020] Further, the steps for preparing the lactic acid sensing fiber include: injecting cobalt nitrate hexahydrate at 20 mg / mL to 29 mg / mL and cetyltrimethylammonium bromide at 0.1 mg / mL to 0.5 mg / mL into 2-methylimidazole at 50 mg / mL to 100 mg / mL, and performing centrifugal drying to generate cobalt dimethylimidazole powder; dispersing cobalt dimethylimidazole powder at 0.1 mg / mL to 1.2 mg / mL in a nickel nitrate hexahydrate ethanol solution at 1 mg / mL to 2.4 mg / mL, and performing centrifugal drying to generate nickel / cobalt layered double hydroxide; dispersing nickel / cobalt layered double hydroxide at 10 mg / mL to 74 mg / mL in a mixed solution of isopropanol, deionized water, and 5% Nafion to generate a NiCo-LDH dispersion; dropping 5 μL to 15 μL of the NiCo-LDH dispersion onto the surface of a carbon nanotube fiber to obtain the lactic acid sensing fiber; wherein the volume ratio of isopropanol, deionized water, and Nafion is 14:5:1.

[0021] Further, the steps for preparing the nitric oxide sensing fiber include: dropping 1 μL to 2 μL of an Au nanoparticle solution at 0.1 mg / mL to 1 mg / mL onto the carbon nanotube fiber to generate an Au nanomembrane; placing the carbon nanotube fiber with the Au nanomembrane in an eugenol solution at 1 mM to 10 mM or a NaOH solution at 0.1 M to 1 M, and depositing a polyeugenol membrane by cyclic voltammetry; dropping 1 μL to 2 μL of a 5 wt% Nafion solution onto the surface of the carbon nanotube fiber with the deposited polyeugenol membrane to obtain the nitric oxide sensing fiber.

[0022] Further, the polydimethylsiloxane is prepared by formulating an organosilicon elastomer matrix and its crosslinking agent in a weight ratio of 10:1.

[0023] Another aspect of the embodiments of this specification also provides a fiber sensor, including: a sensing fiber and a silver / silver chloride reference fiber, with polydimethylsiloxane coated on both the sensing fiber and the silver / silver chloride reference fiber as an insulating layer; a sensing unit formed by arranging the sensing fiber and the silver / silver chloride reference fiber in parallel is in a spiral structure in the sensing area, and both ends of the sensing area are fixed by fixing devices; the spiral structure is coated with polydimethylsiloxane and a repair gel is applied; wherein, the sensing fiber is prepared by a preparation method of a fiber sensor.

[0024] 3. Beneficial effects

[0025] Compared with the prior art, the advantages of the present invention are as follows:

[0026] (1) The PH sensing uses polyaniline, which can change the degree of protonation according to the change of solution PH to achieve PH detection. Glucose sensing utilizes glucose oxidase to catalyze the oxidation of glucose to generate hydrogen peroxide and detects the change of current. Lactate sensing is based on the redox reaction of Ni and Co ions in the NiCo-LDH material to detect lactate. Nitric oxide sensing relies on the specific permeation of poly(eugenol). The repair gel enables the sensor to be stably implanted into the amniotic membrane and continuously work to achieve continuous monitoring;

[0027] (2) Sericin and tannic acid can form a gel, and collagen further enhances cell adhesion. The repair gel can promote the healing of the ruptured amniotic membrane and prevent amniotic fluid leakage;

[0028] (3) The multi-sensor with high sensitivity and selectivity can detect the subtle changes in amniotic fluid. Continuous monitoring can early diagnose the abnormal amniotic fluid indicators, achieve early warning of diseases, and integrate with the chip to obtain an automated closed-loop system. Description of the Drawings

[0029] Figure 1 It is a schematic diagram of the structure of the fiber sensor;

[0030] Figure 2 It is the characterization of the flexible fiber sensor;

[0031] Figure 3 It is a schematic diagram for implanting into the uterus to continuously monitor biochemical signals during pregnancy;

[0032] Figure 4 It is the characterization diagram, structure schematic diagram and scanning electron microscope (SEM) image of the pH sensing fiber;

[0033] Figure 5 It is the characterization diagram, structure schematic diagram and scanning electron microscope (SEM) image of the glucose sensing fiber;

[0034] Figure 6 It is the characterization diagram, structure schematic diagram and scanning electron microscope (SEM) image of the lactate sensing fiber;

[0035] Figure 7 It is the characterization diagram, structure schematic diagram and scanning electron microscope (SEM) image of the nitric oxide sensing fiber;

[0036] Figure 8 It is the characterization diagram, structure schematic diagram and scanning electron microscope (SEM) image of the silver / silver chloride reference fiber;

[0037] Figure 9 It is the SEM image of the repair gel;

[0038] Figure 10 It is the biocompatibility of the flexible fiber sensor to cells;

[0039] Figure 11 For implanting a fiber sensor by a minimally invasive injection method assisted by B-ultrasound

[0040] Figure 12 Immunofluorescence staining photographs in the amniotic membrane 3 days after implanting amniotic membrane with or without repair gel on the surface of carbon nanotube fibers

[0041] Figure 13 Levels of interleukin 6 (IL-6) and interleukin 1β (IL-1β) in amniotic fluid 3 days after implanting the control group, the IEFS implantation group, and carbon nanotube fibers without repair gel into amniotic fluid

[0042] Figure 14 Chronoamperometric responses of IEFS to lactic acid (a), glucose (b), and nitric oxide (c) in various analyte solutions, and open-circuit potential response to pH (d)

[0043] Figure 15 Block diagram of the amniotic fluid warning system

[0044] Figure 16 Comparison of ex vivo analysis (including lactate, glucose, NO, and pH) of amniotic fluid samples collected from pregnant rats using clinical gold standards (blood gas analyzer and biochemical analyzer) with in vivo real-time analysis using IEFS Specific implementation manners

[0045] The present invention will be described in detail below in conjunction with the accompanying drawings of the specification and specific embodiments

[0046] Example 1

[0047] The present invention discloses a preparation method of a fiber sensor for preparing a fiber sensor that can be minimally invasively implanted into the amniotic membrane to realize real-time in vivo monitoring of amniotic fluid during pregnancy. By adopting a repair gel, the problem that the amniotic membrane is easily ruptured during continuous puncture of the sensing device is solved, thereby ensuring the safety of the mother and fetus

[0048] The present invention uses carbon nanotube fibers as the base material, and modifies different sensing materials on its surface according to different detection targets to realize the detection of amniotic fluid pH value, glucose, lactic acid, and nitric oxide. Among them, the pH sensing fiber is realized by electrodepositing platinum nanoparticles and electrochemically polymerizing polyaniline; the glucose sensing fiber is realized by modifying polyaniline, platinum nanoparticles, and coating single-walled carbon nanotubes and chitosan containing glucose oxidase; the lactic acid sensing fiber is realized by coating NiCo-LDH; the nitric oxide sensing fiber is realized by coating gold nanoparticles and electrochemically polymerizing eugenol. At the same time, an Ag / AgCl reference electrode fiber is also prepared

[0049] Figure 1Schematic diagram of the fiber sensor structure, as shown in Figure 1 As shown, the fiber sensor consists of multiple layers of sensing fiber cores (composed of corresponding sensing fibers and reference electrodes) and a repair gel sheath. The sensing fiber core is composed of different sensing fibers and reference electrodes. The sensing fiber for the target analyte (such as the glucose oxidase fiber for detecting glucose) and the reference electrode are coated into a single fiber core to form a sensing unit. Multiple such sensing units are integrally arranged side by side to form a sensing fiber core. The repair gel sheath completely coats the sensing fiber core, protecting the sensing fiber core and also promoting the regeneration of the amniotic membrane.

[0050] Among them, the steps for preparing the flexible fiber sensor are as follows:

[0051] Coat the surfaces of the sensing fiber and the reference fiber with polydimethylsiloxane (PDMS) (PDMS is prepared by mixing an organosilicon elastomer matrix and its cross-linking agent in a weight ratio of 10:1) as the insulating layer and cure at 80 °C for 1 hour. Arrange the sensing fiber and the reference fiber in parallel with a certain axial displacement difference at the sensing part. Fix one end on the rotating motor shaft and fix the other end with tape, and the motor rotates at a speed of 200 rad / min to form a spiral structure. Coat PDMS again to fix the spiral structure, and drop the repair gel to wrap the sensor to form a single-functional flexible fiber sensor. For a multi-functional sensor, different sensing fiber units can be twisted in advance and then integrated, and integrated with a flexible chip with a wireless transmitter to obtain an amniotic fluid monitoring and warning system.

[0052] Through the above steps, a flexible fiber sensor and a warning system for monitoring amniotic fluid biochemical indicators can be prepared.

[0053] Specifically, PDMS has good insulation performance and flexibility and can be used as the insulating layer of an electrochemical sensor to protect the sensing element. Adopting a spiral winding structure can significantly improve the mechanical flexibility and tensile resistance of the sensor. The repair gel has biocompatibility and can promote the regeneration of the amniotic membrane. Different sensing optical fibers use different sensing materials, enabling the detection of multiple target analytes. Integrating a wireless communication chip enables remote real-time monitoring.

[0054] In summary, the sensor structure design takes into account both flexibility and biocompatibility and can be applied to the monitoring of biological fluids such as amniotic fluid.

[0055] Figure 2 Characterization of the flexible fiber sensor, as shown in Figure 2As shown, SEM images of the flexible fiber sensor, the sensing site (a) and the repair gel site (b). The sensor consists of two key parts, the sensing site (a) and the repair gel site (b). The sensing site (a) is the functional area for target detection, and the SEM image shows a complex nanostructure. The repair gel site (b) is the area for repair and regeneration functions, and the SEM image shows a relatively flat surface. The integration of the two functional areas enables the highly biosafe use of the sensor. The scale bar shows the size of each part of the sensor in the micrometer range. The micrometer-scale design enables smaller implantation trauma.

[0056] Figure 3 Schematic diagram for implantation into the uterus for real-time monitoring of biochemical signals during pregnancy, as Figure 3 shown. By modifying the repair gel onto the surface of the fiber electrochemical sensor, this application designs a method for continuously, real-time, and selectively monitoring multiple biomarkers in amniotic fluid during pregnancy. It successfully overcomes the problem of easy rupture of the amniotic membrane during continuous puncture of the sensing device, thus maintaining the amniotic fluid homeostasis and ensuring maternal and fetal safety. It can real-time monitor multiple biomarkers related to the fetal health status, such as glucose and lactate in amniotic fluid, which is of great value for the early diagnosis of pregnancy diseases and understanding the biochemical dynamics of amniotic fluid. After integrating it with a flexible chip, a closed-loop fetal status diagnosis system can be obtained to achieve real-time monitoring of amniotic fluid and early warning of sudden abnormalities.

[0057] Specifically, the preparation principle of each independent sensing fiber is as follows:

[0058] PH sensing fiber: Platinum nanoparticles can improve the conductivity of the substrate. Polyaniline changes its degree of protonation according to the solution pH, thereby changing the conductivity of polyaniline to achieve the detection of solution pH.

[0059] Glucose sensing fiber: Glucose oxidase can catalyze the oxidation reaction of glucose to generate hydrogen peroxide, and detect the change in hydrogen peroxide concentration to detect glucose concentration.

[0060] Lactic acid sensing fiber: The Ni and Co ions in NiCo—LDH undergo redox reactions, and its current signal is proportional to the lactic acid concentration.

[0061] Nitric oxide sensing fiber: The poly(eugenol) membrane can specifically permeate nitric oxide, and then contact the electrode to undergo a reversible redox reaction, and detect the change in its current signal to detect NO.

[0062] The chemical principle for preparing the repair gel is: Tannic acid reacts with the reduced sericin to form a gel, and then collagen is added to enhance the mechanical strength and cell adhesion of the gel. This gel is modified on the surface of the sensor, can tightly adhere to the amniotic membrane, repair the damage of the amniotic membrane, prevent the loss of amniotic fluid, and ensure the safety of the mother and baby.

[0063] The present invention prepares an integrated flexible fiber sensor using multiple carbon nanotube fibers with different sensing principles, which can be implanted into the amniotic membrane to realize real-time in-vivo monitoring of various biomarkers in amniotic fluid during pregnancy, and has the advantages of maintaining the homeostasis of amniotic fluid and ensuring the safety of the mother and fetus. The preparation method of this sensor can realize the real-time assessment of pregnancy health and the early warning of diseases.

[0064] Figure 4 It is the characterization diagram, structural schematic diagram and scanning electron microscope (SEM) image of the pH sensing fiber, as Figure 4 shown. The pH sensing fiber uses carbon nanotubes (CNTs) as the base material, and is wrapped with polyaniline (PANI) as the functional material. The SEM picture clearly shows the PANI layer covering the surface of the CNTs. As a conductive polymer, PANI is sensitive to pH and can realize the electrochemical detection of pH. The CNTs provide a good conductive scaffold, and the PANI layer realizes the pH-sensitive function. The combination of the two realizes a high-performance pH sensing fiber.

[0065] Among them, in this embodiment, the steps for preparing the pH sensing fiber are as follows: Immerse the carbon nanotube fiber in a mixed solution of 0.1 M potassium chloride or 1 mM potassium chloroplatinate. Use any potentiostatic staircase wave method to electro-deposit platinum nanoparticles on the fiber surface: initial potential 0.5 V, duration 10 s; final potential -0.7 V, duration 10 s; operate for 10 cycles. Transfer the treated fiber to a mixed solution of 0.1 M aniline or 0.1 M sulfuric acid. Use cyclic voltammetry to electro-polymerize polyaniline on the fiber surface: scan rate 100 mV / s; initial potential -0.2 V; final potential 1 V; number of cycles 25. Take out the sample and dry it. Through the above steps, a composite coating of platinum nanoparticles and polyaniline can be obtained on the surface of the carbon nanotube fiber for making the pH sensing fiber.

[0066] In this embodiment, the concentration of potassium chloride is selected as 0.1 M, and the concentration of potassium chloroplatinate is selected as 1 mM. However, those skilled in the art can understand that as long as it does not affect the function of the prepared pH sensing fiber, other concentrations of potassium chloride solution, potassium chloroplatinate solution and sulfuric acid solution can also be selected. Specifically, the molar concentration of the potassium chloride solution can be selected in the range of 0.01 M to 1 M; the molar concentration of the potassium chloroplatinate solution can be selected in the range of 0.1 mM to 5 mM; the molar concentration of aniline can be selected in the range of 0.01 M to 1 M; the molar concentration of the sulfuric acid solution can be selected in the range of 0.01 M to 1 M. Where M represents moles per liter and mM represents millimoles per liter, the same below and will not be repeated.

[0067] Specifically, in a potassium chloride and potassium chloroplatinate solution, through an electrochemical reduction reaction, platinum metal nanoparticles can be deposited on the electrode surface from potassium chloroplatinate. Platinum nanoparticles have good electron conductivity and a high specific surface area, which can improve the electrochemical activity of the electrode. In an aniline and sulfuric acid solution, through an oxidative coupling reaction, aniline monomers can undergo radical polymerization to form a conductive polyaniline film on the electrode surface. Polyaniline has unique protonation and deprotonation behaviors and can sensitively respond to changes in the solution pH. Platinum nanoparticles improve the electrode conductivity, while polyaniline responds to pH changes through protonation and deprotonation. The combination of the two can achieve sensitive and stable pH response characteristics. Carbon nanotube fibers have excellent conductivity and a high specific surface area and can serve as an ideal electrochemical sensing platform, providing a basis for the preparation of pH electrodes.

[0068] In summary, by electrochemically depositing platinum nanoparticles and polyaniline composite films on carbon nanotube fibers, each component plays a synergistic role, thus preparing a sensitive and stable pH sensing fiber.

[0069] Figure 5 Figures, structural schematic diagrams, and scanning electron microscope (SEM) images of the glucose sensing fiber are shown as Figure 5 shown. The glucose sensing fiber is a glucose sensing fiber with CNT as the core and NiCo-LDH wrapped around it as the sensing functional material. NiCo-LDH represents nickel-cobalt double metal layered double hydroxide (Nickel Cobalt Layered Double Hydroxide). It is a layered compound with good sensing performance. The SEM image shows that the surface of the sensing fiber is coated with a large number of flaky NiCo-LDH.

[0070] Among them, the steps for preparing the glucose sensing fiber electrode are as follows: Immerse the carbon nanotube fiber in a mixed solution of 0.5 M aniline or 0.1 M sulfuric acid, polarize it at a constant potential of 0.75 V for 20 seconds to modify polyaniline. Continue to modify platinum nanoparticles through an arbitrary constant potential staircase wave (initial potential 0.5 V, final potential -0.7 V, each potential is maintained for 10 seconds, and the cycle is 50 times). Dissolve chitosan in an acetic acid solution to obtain a 1 wt% chitosan solution. Disperse the glucose oxidase (40 mg / mL) solution and single-walled carbon nanotube (2 mg / mL) suspension in the chitosan solution and sonicate for 30 minutes. Take 4 μL of the mixed solution of single-walled carbon nanotubes, chitosan, and glucose oxidase and drop-coat it on the modified fiber. Drop-coat 1 μL to 2 μL of a 0.5 wt% perfluorosulfonic acid membrane (Nafion) solution and soak it in a 2 wt% glutaraldehyde solution for 30 minutes. Dry it at 4°C.

[0071] In this embodiment, the concentration of aniline is 0.5 M, and that of glucose oxidase is 40 mg / mL. However, those skilled in the art can understand that as long as the function of the prepared glucose sensing fiber electrode is not affected, other concentrations of aniline and glucose oxidase can also be selected. Specifically, the molar concentration of aniline can be selected in the range of 0.1 M to 1 M; the molar concentration of sulfuric acid can be selected in the range of 0.1 M to 1 M; the mass concentration of glucose oxidase can be selected in the range of 10 mg / mL to 40 mg / mL; the mass concentration of single-walled carbon nanotubes can be selected in the range of 1 mg / mL to 2 mg / mL; the solute concentration of glutaraldehyde can be selected in the range of 1 wt% to 2 wt%.

[0072] Specifically, for the electrochemical polymerization of aniline, in the aniline / sulfuric acid solution, aniline undergoes oxidative coupling radical polymerization to form conductive polyaniline, improving the conductivity of the electrode. For the electrodeposition of platinum nanoparticles, the stepped potential method can be used to reductively deposit platinum nanoparticles on the electrode surface, further enhancing the conductivity and providing catalytically active sites with a high specific surface area. For the chitosan / glucose oxidase mixture, chitosan has good biocompatibility and can immobilize the enzyme; glucose oxidase can catalyze the oxidation reaction of glucose. For single-walled carbon nanotubes, they can improve the electrode conductivity and connect the electron transfer between the electrode and the enzyme. The Nafion membrane can prevent possible interfering substances from approaching the electrode surface; the cross-linking effect of glutaraldehyde can further stabilize the structure of the enzyme and improve its stability.

[0073] In summary, a sensitive and stable glucose sensing fiber electrode is prepared by means of electrochemical polymerization, modification of catalytically active components, enzyme immobilization, etc.

[0074] Figure 6 Figures, structural diagrams, and scanning electron microscope (SEM) images are provided for the lactate sensing fiber, as Figure 6 shown. The lactate sensing fiber is one with CNT as the core, and the CNT surface is coated with NiCo-LDH and Nafion materials. NiCo-LDH can specifically catalyze lactate to undergo oxidation-reduction reactions, providing the biological recognition function of lactate. The SEM image shows that these coating layers form a relatively uniform film layer.

[0075] Among them, the steps for preparing the lactate sensing fiber are as follows: A mixed aqueous solution of cobalt nitrate hexahydrate (29 mg / mL) and cetyltrimethylammonium bromide (0.5 mg / mL) is rapidly injected into an aqueous solution of cobalt dimethylimidazole (64.8 mg / mL), and stirred at 25 °C for 20 minutes to synthesize cobalt dimethylimidazole (ZIF-67). After the solution turns purple, the above mixed solution is centrifuged (10000 rad·min -1, 5 min), washing (washed with ethanol at least 6 times), drying (70 °C, 24 h) to obtain cobalt dimethylimidazole (ZIF-67) powder. Disperse cobalt dimethylimidazole (ZIF-67) (1.2 mg / mL) in an ethanol solution of nickel nitrate hexahydrate (2.4 mg / mL), stir at 25 °C for 90 min until the solution turns green, and centrifuge (10,000 rad·min -1 , 5 min), washing (washed with ethanol at least 6 times), drying (70 °C, 24 h) to obtain green NiCo-LDH powder. Disperse NiCo-LDH (74 mg / mL) in a mixed solution of isopropanol, deionized water and Nafion, where the volume ratio of isopropanol, deionized water and Nafion is 14:5:1. Drop 5 μL to 15 μL of the above dispersion onto the surface of the carbon nanotube fiber. Natural drying can obtain the lactate sensing fiber. Through the above steps, using cobalt dimethylimidazole (ZIF-67) as a template, a NiCo-LDH sensing film can be prepared on the surface of the carbon nanotube fiber for making the lactate sensing fiber.

[0076] In this example, cobalt dimethylimidazole is 64.8 mg / mL, but those skilled in the art can understand that as long as the function of the prepared lactate sensing fiber is not affected, other concentrations of cobalt dimethylimidazole can also be selected. Specifically, the mass concentration of cobalt dimethylimidazole can be selected in the range of 50 mg / mL to 100 mg / mL; similarly, the mass concentration of nickel nitrate hexahydrate can be selected in the range of 20 mg / mL to 29 mg / mL; the mass concentration of cetyltrimethylammonium bromide can be selected in the range of 0.1 mg / mL to 0.5 mg / mL; the mass concentration of nickel nitrate hexahydrate ethanol can be selected in the range of 1 mg / mL to 2.4 mg / mL; the mass concentration of nickel / cobalt layered double metal hydroxide can be selected in the range of 10 mg / mL to 74 mg / mL; the mass concentration of cobalt dimethylimidazole powder can be selected in the range of 0.1 mg / mL to 1.2 mg / mL.

[0077] Specifically, cobalt dimethylimidazole (ZIF-67) has a pore structure and can control the morphology of NiCo-LDH. Nickel nitrate grows on the cobalt dimethylimidazole (ZIF-67) template by an in-situ precipitation method to obtain NiCo-LDH with a pore structure imitating the template. NiCo-LDH belongs to layered double metal hydroxide and has a typical layered structure. Among them, Ni2+ can chemically react with lactate and produce a measurable oxidation current signal in electrochemical tests. Carbon nanotube fibers have excellent electrical conductivity and high specific surface area, which can improve the sensing sensitivity of NiCo-LDH; the fiber structure is convenient for making flexible sensors. Nafion has an ion exchange function, which can reduce interference and improve sensing selectivity.

[0078] In summary, by controlling the microstructure of NiCo-LDH, a lactic acid sensing film was prepared on the carbon nanotube fiber to achieve the purpose of sensitive detection of lactic acid.

[0079] Figure 7 Figures 4(a)-(c) are the characterization diagram, structure schematic diagram and scanning electron microscope (SEM) image of the nitric oxide sensing fiber, as Figure 7 shown. For the nitric oxide sensing fiber, two layers of functional materials, gold nanoparticles (Au) and poly(eugenol), are sequentially coated on the surface of CNT; the Au nanoparticle layer is used to provide good conductivity and electrocatalytic activity, and poly(eugenol) is used as the outermost layer, which has selectivity for detecting nitric oxide. The SEM image clearly shows the two layers of Au and poly(eugenol) coated on the surface of CNT.

[0080] Among them, the steps for preparing the nitric oxide sensing fiber are as follows: At 25 °C, an appropriate amount of carbon nanotube fiber is taken, and 1 μL to 2 μL of 0.1 mg / mL Au nanoparticle solution is added dropwise, and left standing for 30 minutes to form an Au nanomembrane. The fiber with the formed Au nanomembrane is immersed in a mixed solution of 10 mM eugenol or 0.1 M NaOH. Electrochemical polymerization is carried out by cyclic voltammetry: the initial potential is 0 V, the final potential is 0.7 V, the scanning rate is 50 mV / s, and it is cycled 10 times to deposit a poly(eugenol) film on the fiber. The fiber is taken out, and 1 μL to 2 μL of 5 wt% Nafion solution is added dropwise. After natural drying, the fiber electrode for nitric oxide sensing can be obtained. Through the above steps, Au nanoparticles and poly(eugenol) are modified on the carbon nanotube fiber substrate, and Nafion is used for modification, and a fiber electrode for detecting nitric oxide can be prepared.

[0081] In this embodiment, 10 mM eugenol is used, but those skilled in the art can understand that as long as it does not affect the function of the prepared nitric oxide sensing fiber, other concentrations of eugenol can also be selected. Specifically, the molar concentration of eugenol can be selected in the range of 1 mM to 10 mM; similarly, the mass concentration of Au nanoparticles can be selected from 0.1 mg / mL to 1 mg / mL; the molar concentration of NaOH can be selected from 0.1 M to 1 M.

[0082] Specifically, Au nanoparticles can improve the conductivity of the electrode and can also catalyze the electrochemical polymerization process of eugenol. Through cyclic voltammetry, eugenol undergoes electrochemical oxidative coupling polymerization to generate a poly(eugenol) conductive polymer. The poly(eugenol) film only allows nitric oxide to selectively penetrate, and redox reactions can occur on the carbon nanotube fiber / Au, generating measurable current signals in electrochemical tests. The carbon nanotube fiber has excellent conductivity and a high specific surface area, which improves the conductivity of the electrode.

[0083] In summary, a fiber electrode capable of sensitively detecting nitric oxide was prepared by modifying the carbon nanotube fiber with an Au catalyst and a poly(eugenol) sensing film.

[0084] Figure 8 Figures, structural schematic diagrams, and scanning electron microscope (SEM) images of the silver / silver chloride reference fiber are shown as Figure 8 shown. For the silver / silver chloride reference fiber, two layers of materials, silver / silver chloride (Ag / AgCl) and polyvinyl butyral (PVB), are sequentially coated on the surface of the CNT. Ag / AgCl serves as the active component of the reference electrode, and PVB is used as the bonding / coating layer. The SEM image clearly shows the Ag / AgCl particles adhered to the surface of the CNT and the PVB coating layer. The CNT provides conductive support, Ag / AgCl generates a stable reference potential, and PVB plays a role in bonding and wrapping.

[0085] Among them, the steps for preparing the silver / silver chloride reference fiber are as follows: Immerse the carbon nanotube fiber in a mixed solution of 5 mM silver nitrate or 1 M potassium nitrate, and deposit silver nanoparticles on its surface by cyclic voltammetry (scan rate: 100 mV·s-1, initial potential: -0.9 V, final potential: 0.9 V, number of cycles: 14). Transfer the fiber with deposited silver nanoparticles to a mixed solution of 0.1 M potassium chloride and 0.01 M hydrochloric acid, and carry out a chlorination process by cyclic voltammetry (scan rate: 50 mV·s-1, initial potential: -0.15 V, final potential: 1.05 V, number of cycles: 4) to chlorinate the silver nanoparticles. Take polyvinyl butyral (79.1 mg), sodium chloride (50 mg), and multi-walled carbon nanotubes (0.2 mg), dissolve them in 1 mL of methanol to prepare a polyvinyl butyral solution. Take 1 μL to 4 μL of the above polyvinyl butyral solution and drop-coat it on the surface of the fiber after chlorination treatment. After natural drying, the silver / silver chloride reference fiber can be obtained.

[0086] In this embodiment, the molar concentration of silver nitrate is 5 mM. However, those skilled in the art can understand that as long as the function of the prepared silver / silver chloride reference fiber is not affected, other concentrations can also be selected. Specifically, the molar concentration of silver nitrate can be selected from 1 mM to 5 mM; similarly, the molar concentration of potassium nitrate can be selected from 1 M to 10 M; the molar concentration of potassium chloride can be selected from 0.1 M to 1 M; the molar concentration of hydrochloric acid can be selected from 0.01 M to 0.1 M; the mass of polyvinyl butyral can be selected from 50 mg to 100 mg; the mass of sodium chloride can be selected from 50 mg to 70 mg; the mass of multi-walled carbon nanotubes can be selected from 0.1 mg to 0.2 mg; and the volume of methanol can be selected from 0.1 mL to 1 mL.

[0087] Silver nanoparticles are deposited on the carbon nanotube fiber by an electrochemical method, chlorinated, and then modified with polyvinyl butyral to prepare the silver / silver chloride reference fiber.

[0088] Specifically, cyclic voltammetry is used to reduce and deposit silver nanoparticles during anodic oxidation to enhance the electrode conductivity. The silver nanoparticles are immersed in a potassium chloride solution, and a displacement reaction occurs on the surface of the silver nanoparticles to form silver chloride. The stable potential of silver chloride can be used as a reference electrode. Polyvinyl butyral can enhance the mechanical stability of the silver chloride structure. Carbon nanotube fibers improve the electrode conductivity and connect the electrode substrate.

[0089] In summary, a reliable silver / silver chloride reference electrode is prepared on carbon nanotube fibers by electro-depositing silver nanoparticles, chlorinating, and modifying the polymer.

[0090] Figure 9 For the SEM image of the repair gel, as Figure 9 shown, the image shows the scanning electron microscope (SEM) image of the repair gel. Judging from the marked scale, the size of the repair gel is in the micron order of magnitude.

[0091] Among them, the steps for preparing the repair gel are as follows:

[0092] Dissolve sericin (10 wt%) in a buffer solution containing 100 mM of tris(2-carboxyethyl)phosphine (TCEP) or 10 mM of 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid (HEPES) to prepare a reduced sericin (rSer) solution. Add a tannic acid (0.3 g / mL) solution to the rSer solution, mix and react to form an rSer-TA gel precipitate. Dissolve type I collagen in rSer-TA at a volume ratio of 1:2 and mix evenly. The repair gel can be obtained.

[0093] In this embodiment, the solute concentration of sericin is 10 wt%, but those skilled in the art can understand that other concentrations can also be selected as long as the function of the prepared repair gel is not affected. Specifically, the solute concentration of sericin can be selected from 10 wt% to 30 wt%; similarly, the molar concentration of tris(2-carboxyethyl)phosphine can be selected from 10 mM to 100 mM; the molar concentration of 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid can be selected from 1 mM to 10 mM; the mass concentration of tannic acid can be selected from 0.3 g / mL to 1 g / mL.

[0094] Through the above steps, a gel material for tissue repair can be prepared by using the self-assembly reaction of reduced sericin and tannic acid and adding type I collagen.

[0095] Specifically, the reducing agent TCEP is used to break the disulfide bonds in sericin, exposing more free reactive groups. The phenolic hydroxyl groups in tannic acid undergo self-assembly with the amino groups in reduced sericin to form a gel network structure. Type I collagen can improve the biocompatibility of the gel, promote cell adhesion and extracellular matrix deposition. The gel state can better contact the pores of damaged tissues and gradually release active ingredients to participate in repair. The ratios of sericin, tannic acid, and collagen are optimized to endow the gel with appropriate mechanical properties and biological activities.

[0096] In summary, by selecting bioactive components and accurately constructing a gel network through chemical reactions, a gel material for tissue repair with both mechanical strength and biological repair functions is obtained.

[0097] Figure 10 For the biocompatibility of the flexible fiber sensor with cells, as Figure 10 shown, the biocompatibility of the flexible fiber sensor with two types of cells (HACAT, HUVEC) was investigated in experiments. The cells were co-cultured with the sensor for 24, 48, and 72 hours, and the cell viability was evaluated by CCK-8 analysis. The results showed that there was no significant difference in the cell survival rate between the cells co-cultured with the flexible fiber sensor and the blank group. In summary, the experiments clearly demonstrated the good biocompatibility of the sensor, providing support for its biological detection applications.

[0098] Figure 11 For implanting the fiber sensor through a minimally invasive injection method assisted by B-ultrasound, as Figure 11 shown, under B-ultrasound guidance, the fiber sensor was injected into the amniotic fluid. B-ultrasound was used for real-time imaging to observe the fetal position and injection path. Utilizing the ultrasound positioning function of B-ultrasound, the fetal part was accurately located. Under B-ultrasound guidance, the fiber sensor was injected into the amniotic fluid through a minimally invasive syringe. The schematic diagram shows the process of the B-ultrasound probe positioning the fetus and the syringe inserting into the uterus to inject the fiber sensor. This B-ultrasound-guided minimally invasive injection method can accurately implant the fiber sensor into the target position, with a minimally invasive process, avoiding trauma to the mother and fetus. The implanted fiber sensor can monitor fetal physiological parameters.

[0099] Figure 12 For the immunofluorescence staining of the amniotic membrane 3 days after implanting the repair gel on the surface of carbon nanotube fibers. As Figure 12 shown, in the group without the repair gel, the holes in the ruptured amniotic membrane were larger, while in the group with the repair gel, there were almost no ruptured holes in the amniotic membrane. The repair gel improved the biocompatibility of the fiber sensor. The scale bar shows that the size of the tissue structure is in the order of hundreds of micrometers. In summary, the experiments proved that the repair gel can reduce amniotic membrane rupture and improve the biocompatibility of the fiber sensor.

[0100] Figure 13Three days after the implantation of carbon nanotube fibers without repair gel into the amniotic fluid in the control group and the IEFS implantation group, the levels of interleukin 6 (IL-6) and interleukin 1β (IL-1β) in the amniotic fluid were as follows Figure 13 As shown, the levels of IL-6 and IL-1β in the IEFS implantation group were close to those in the control group, while the levels of IL-6 and IL-1β in the group without repair gel were significantly increased. This indicates that the implantation of IEFS does not cause obvious inflammatory reactions, while the fibers without repair gel can cause inflammation and cytokine release. The repair gel significantly reduces the inflammatory reaction. In summary, this experiment proves that the repair gel improves the biocompatibility of the fiber sensor and reduces the inflammatory reaction.

[0101] Figure 14 The amperometric responses of IEFS to lactate (a), glucose (b), and nitric oxide (c) in various analyte solutions, and the open-circuit potential response to pH (d) were as follows Figure 14 As shown, IEFS responded to lactate, glucose, and nitric oxide solutions at different concentrations. As the concentration increased, the response currents of lactate, glucose, and nitric oxide gradually increased. The results indicate that IEFS can detect lactate, glucose, and nitric oxide at different concentrations. IEFS also has a good response to different pH solutions. In summary, IEFS can sensitively detect changes in the concentrations of lactate, glucose, and nitric oxide, and can measure the pH value, achieving the detection of multiple analytes.

[0102] Figure 15 The block diagram of the amniotic fluid warning system was as follows Figure 15 As shown, in the amniotic fluid warning system, the pH signal is amplified by an open-circuit potential difference amplifier and then enters the ADC for conversion, and then is sent to the microcontroller. The signals of lactate, glucose, and NO are first amplified by a steady-state potential measurement amplifier, then amplified by a transimpedance amplifier, then enter the ADC for conversion, and finally are sent to the microcontroller. The output signal of the microcontroller is filtered by a low-pass filter and then enters the Bluetooth transmitter, and finally is transmitted to the mobile phone. The reference electrode Ag / AgCl of the open-circuit potential difference amplifier is grounded. The reference electrode Ag / AgCl of the steady-state potential measurement is also grounded.

[0103] Among them, using an open-circuit potential difference amplifier to measure pH can avoid errors caused by directly measuring pH through a glass electrode. The open-circuit potential difference amplifier acts as a buffer, which can reduce the load effect of the glass electrode and improve the measurement accuracy. Using the potentiostatic method to measure lactic acid, glucose, and iodide can accurately measure the concentration of target analytes in complex media. The potentiostatic method can effectively suppress the interference of other electroactive substances. Using a low-pass filter to filter out high-frequency noise can improve the signal quality and reduce transmission errors. Using Bluetooth to transmit the signal to a mobile phone realizes the remote monitoring and warning function, which is convenient for doctors to remotely judge the fetal status. The Ag / AgCl reference electrode is grounded, which can provide a stable reference potential and improve the accuracy and stability of the measurement. The microcontroller collects and processes various signals, realizes the monitoring and warning of multiple parameters, and can comprehensively judge the fetal status.

[0104] In summary, generally speaking, this system combines multiple sensing technologies, solves the problem of safe monitoring of biochemical signals in amniotic fluid, and realizes the reliable evaluation and warning of fetal status.

[0105] Figure 16 For the comparison between in vitro analysis (including lactic acid, glucose, NO, and pH) of amniotic fluid samples collected from pregnant rats using clinical gold standards (blood gas analyzer and biochemical analyzer) and in vivo real-time analysis using IEFS, as Figure 16 shown, the arrows indicate the saline solutions of lactic acid, glucose, nitric oxide, and citric acid injected into the amniotic fluid of pregnant rats respectively. According to Figure 16 it can be seen that the in vivo real-time monitoring results using IEFS have a good correlation with the in vitro analysis results using a blood gas analyzer and a biochemical analyzer. After injecting different solutions into the amniotic fluid, IEFS can monitor the change trends of lactic acid, glucose, NO, and pH in real time, and the change curves are very consistent with the results obtained from in vitro analysis. The real-time monitoring curves of lactic acid, glucose, and pH basically coincide with the in vitro analysis curves, showing a good correlation. The real-time monitoring results of NO are slightly lower than the in vitro analysis results, but the change trends are the same, showing a good correlation. In summary, the IEFS system can perform high-precision in vivo real-time monitoring, and its results have a good correlation with the clinical gold standard.

[0106] The present invention and its implementation manners are schematically described above. This description is not restrictive. Without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. What is shown in the drawings is only one of the implementation manners of the present invention, and the actual structure is not limited thereto. Any reference signs in the claims should not limit the claims involved. Therefore, if those of ordinary skill in the art are inspired by it and, without departing from the purpose of this creation, design similar structural manners and embodiments to this technical solution without creative efforts, they shall fall within the protection scope of this patent. In addition, the term "comprising" does not exclude other elements or steps, and the word "a" before an element does not exclude including "a plurality of" such elements. The multiple elements stated in the product claims can also be implemented by one element through software or hardware. The words such as "first" and "second" are used to represent names and do not represent any specific order.

Claims

1. A preparation method of a fiber sensor, comprising: Preparing a sensing fiber, a silver / silver chloride reference fiber, and a repair gel respectively; Coating polydimethylsiloxane on the sensing fiber and the silver / silver chloride reference fiber as an insulating layer; Arranging the polydimethylsiloxane-coated sensing fiber and silver / silver chloride reference fiber in parallel, so that there is an axial displacement difference at the sensing part, and the sensing part is the area on the fiber for detecting the target substance; Fixing one end of the parallel arrangement, and fixing the other end with tape to form a spiral structure; Coating polydimethylsiloxane on the spiral structure again for curing; Coating the repair gel on the cured spiral structure to form a fiber sensor; The steps of preparing the repair gel include: Dissolving 10wt% to 30wt% of sericin in 10mM to 100mM of tris(2-carboxyethyl)phosphine or 1mM to 10mM of 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid to generate a reduced sericin solution; Adding 0.3g / mL to 1g / mL of tannic acid to the same volume of the reduced sericin solution to generate a gel-like precipitate of rSer-TA; Dissolving type I collagen into rSer-TA to obtain a repair gel; Wherein, the volume ratio of type I collagen to rSer-TA is 1:2; The steps of preparing the sensing fiber include: Electrodepositing platinum nanoparticles and electrochemically polymerizing polyaniline on a carbon nanotube fiber to obtain a pH sensing fiber; Modifying polyaniline and platinum nanoparticles on a carbon nanotube fiber, and coating single-walled carbon nanotubes, chitosan, and glucose oxidase to obtain a glucose sensing fiber; Coating nickel-cobalt bimetallic hydroxide on a carbon nanotube fiber to obtain a lactic acid sensing fiber; Depositing a gold nanomembrane and electrochemically depositing a polyeugenol film on a carbon nanotube fiber to obtain a nitric oxide sensing fiber.

2. The preparation method of the fiber sensor according to claim 1, characterized in that: The steps of preparing the silver / silver chloride reference fiber include: Placing the carbon nanotube fiber in a 1mM to 5mM silver nitrate or 1M to 10M potassium nitrate solution, and depositing silver nanoparticles by cyclic voltammetry; Immersing the carbon nanotube fiber deposited with silver nanoparticles in a 0.1M to 1M potassium chloride or 0.01M to 0.1M hydrochloric acid solution, and performing chlorination treatment by cyclic voltammetry; Dissolving 50mg to 100mg of polyvinyl butyral, 50mg to 70mg of sodium chloride, and 0.1mg to 0.2mg of multi-walled carbon nanotubes in 0.1mL to 1mL of methanol to obtain a polyvinyl butyral solution; Dropping 1μL to 4μL of the polyvinyl butyral solution onto the carbon nanotube fiber subjected to chlorination treatment to obtain a silver / silver chloride reference fiber.

3. The preparation method of the fiber sensor according to claim 1, characterized in that: The steps of preparing the pH sensing fiber include: Electrodepositing platinum nanoparticles on the surface of the carbon nanotube fiber, using a 0.01M to 1M potassium chloride or 0.1mM to 5mM potassium chloroplatinate solution, and performing electrodeposition by any constant potential staircase wave method; Electropolymerize polyaniline on the surface of electrodeposited platinum nanoparticles using aniline with a concentration of 0.01 M to 1 M or a sulfuric acid solution with a concentration of 0.01 M to 1 M, and perform electropolymerization by cyclic voltammetry to obtain pH sensing fibers.

4. The method for preparing a fiber sensor according to claim 1, characterized in that: The steps for preparing glucose fibers include: Electropolymerize polyaniline on the surface of carbon nanotube fibers using aniline with a concentration of 0.1 M to 1 M or a sulfuric acid solution with a concentration of 0.1 M to 1 M, and perform electrodeposition by the potentiostatic step wave method to generate B1 fibers; Electrodeposit platinum nanoparticles on the surface of B1 fibers using potassium chloride with a concentration of 0.01 M to 1 M or potassium chloroplatinate solution with a concentration of 0.1 mM to 5 mM, and perform electrodeposition by any potentiostatic step wave method to generate B2 fibers; Dissolve chitosan in an acetic acid solution to generate a chitosan solution A1 with a concentration of 100 mg / mL to 800 mg / mL; Disperse glucose oxidase with a concentration of 10 mg / mL to 40 mg / mL and single-walled carbon nanotubes with a concentration of 1 mg / mL to 2 mg / mL in the chitosan solution A1 to generate solution A2; Drop 1 μL to 4 μL of solution A2 onto B2 fibers to generate B3 fibers; Drop 1 μL to 2 μL of a 0.5 wt% perfluorosulfonic acid membrane solution onto the surface of B3 fibers to generate B4 fibers; Soak B4 fibers in a 1 wt% to 2 wt% glutaraldehyde solution to obtain glucose fibers.

5. The method for preparing a fiber sensor according to claim 1, characterized in that: The steps for preparing lactic acid sensing fibers include: Inject cobalt nitrate hexahydrate with a concentration of 20 mg / mL to 29 mg / mL and cetyltrimethylammonium bromide with a concentration of 0.1 mg / mL to 0.5 mg / mL into 2-methylimidazole with a concentration of 50 mg / mL to 100 mg / mL, and perform centrifugation and drying to generate cobalt dimethylimidazole powder; Disperse cobalt dimethylimidazole powder with a concentration of 0.1 mg / mL to 1.2 mg / mL in a nickel nitrate hexahydrate ethanol solution with a concentration of 1 mg / mL to 2.4 mg / mL, and perform centrifugation and drying to generate nickel / cobalt layered double metal hydroxide; Disperse nickel / cobalt layered double metal hydroxide with a concentration of 10 mg / mL to 74 mg / mL in a mixed solution of isopropanol, deionized water, and 5% Nafion to generate a NiCo-LDH dispersion; Drop 5 μL to 15 μL of the NiCo-LDH dispersion onto the surface of carbon nanotube fibers to obtain lactic acid sensing fibers; Among them, the volume ratio of isopropanol, deionized water, and Nafion is 14:5:

1.

6. The method for preparing a fiber sensor according to claim 1, characterized in that: The steps for preparing nitric oxide sensing fibers include: Drop 1 μL to 2 μL of an Au nanoparticle solution with a concentration of 0.1 mg / mL to 1 mg / mL onto carbon nanotube fibers to generate an Au nanomembrane; Place the carbon nanotube fibers containing the Au nanomembrane in a solution of eugenol with a concentration of 1 mM to 10 mM or a NaOH solution with a concentration of 0.1 M to 1 M, and deposit a polyeugenol membrane by cyclic voltammetry; Drop 1 μL to 2 μL of 5 wt% Nafion solution on the surface of the carbon nanotube fiber coated with polyeugenol film to obtain a nitric oxide sensing fiber.

7. The method for preparing a fiber sensor according to claim 1, wherein: The polydimethylsiloxane is prepared by mixing an organosilicon elastomer matrix and its crosslinking agent in a weight ratio of 10:

1.

8. A fiber sensor, comprising: A sensing fiber and a silver / silver chloride reference fiber, both of which are coated with polydimethylsiloxane as an insulating layer; A sensing unit formed by arranging the sensing fiber and the silver / silver chloride reference fiber in parallel is in a spiral structure in the sensing area, and both ends of the sensing area are fixed by fixing devices respectively; The spiral structure is coated with polydimethylsiloxane and a repair gel is applied; Among them, the sensing fiber is obtained by the method described in any one of claims 1 to 7.

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