Pt / PEDOT composite modified carbon-based material needle-shaped electrode in-vivo dissolved oxygen electrochemical sensor and construction method and application thereof

Abstract

The invention provides a Pt / PEDOT composite modified carbon-based material needle-shaped electrode in-vivo dissolved oxygen electrochemical sensor as well as a construction method and application thereof, and belongs to the technical field of medical biology. According to the in-vivo dissolved oxygen electrochemical sensor, a carbon-based material microneedle type electrode is modified by electrochemical deposition of platinum nanoparticles by using a chloroplatinic acid hexahydrate solution and depending on a time current method, and poly (3, 4-ethylenedioxythiophene) is generated by direct electro-polymerization on the surface of the Pt-modified microneedle electrode through an electrochemical constant current method. And forming uniform PEDOT (poly (3, 4-ethylenedioxythiophene)) film coated and modified platinum nanoparticles on the microneedle electrode. The composite modified carbon-based material is used for replacing precious metal to reduce cost and improve biocompatibility, low-oxygen sensitivity is optimized by means of composite modification, in-vivo protein adsorption and biological membrane coverage are resisted through anti-pollution surface modification, and therefore the defects are overcome, and monitoring of in-vivo tissue oxygen partial pressure is achieved.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical biotechnology, specifically relating to a Pt / PEDOT composite modified carbon-based material needle electrode in vivo dissolved oxygen electrochemical sensor, its construction method, and its application. Background Technology

[0002] Currently, most methods for detecting partial pressure of oxygen in hospitals use blood gas analyzers for automated single-point analysis, requiring external blood collection and machine testing, and cannot detect blood oxygen levels in real time. There are also no readily implantable electrochemical sensors for this purpose.

[0003] Patent CN201810903984.2 discloses a three-electrode electrochemical dissolved oxygen sensor. It employs a three-electrode structure: a gold electrode as the working electrode (core detection electrode), a double-helix silver electrode as the auxiliary electrode (providing an electron transfer pathway), and a platinum electrode as the protection electrode (applying a protective voltage). All three electrodes are made of traditional precious metals, resulting in high cost. While it mentions suitability for medical scenarios such as "blood dissolved oxygen detection," it does not address invasive implantation applications in in vivo tissues (such as muscle, subcutaneous tissue, and blood vessels). It is more suitable for in vitro detection or short-term blood sampling, and is not applicable to current clinical real-time detection (such as in intensive care units).

[0004] Therefore, current electrochemical detection of dissolved oxygen suffers from problems such as high cost due to reliance on precious metals, defects in biocompatibility, inability to meet the needs of minimally invasive implantation in vivo, and insufficient detection sensitivity in low-oxygen environments. Summary of the Invention

[0005] This invention is made to solve the above-mentioned problems, and aims to provide a Pt / PEDOT composite modified carbon-based material needle electrode in vivo dissolved oxygen electrochemical sensor, its construction method and application.

[0006] This invention provides a method for constructing a Pt / PEDOT composite modified carbon-based needle electrode for an in-situ dissolved oxygen electrochemical sensor, characterized by the use of platinum nanoparticles and poly(3,4-ethylenedioxythiophene) (PEDOT) for construction.

[0007] The method for constructing a Pt / PEDOT composite-modified carbon-based material needle electrode for dissolved oxygen electrochemical sensor provided by the present invention may also have the following feature: wherein, a carbon-based material microneedle electrode is modified by electrochemical deposition of platinum nanoparticles using a chloroplatinic acid hexahydrate solution and by time-current method, thereby obtaining a Pt-modified microneedle electrode.

[0008] The method for constructing a dissolved oxygen electrochemical sensor in a carbon-based needle electrode modified with Pt / PEDOT composite provided by the present invention may also have the following feature: poly(3,4-ethylenedioxythiophene) is directly electropolymerized on the surface of the Pt-modified microneedle electrode by electrochemical galvanostatic method, and a uniform PEDOT film is formed on the microneedle electrode to encapsulate the modified platinum nanoparticles, thereby obtaining the Pt-modified microneedle electrode.

[0009] The method for constructing a dissolved oxygen electrochemical sensor in a carbon-based needle electrode with Pt / PEDOT composite modification provided by the present invention may also include the following steps: Step 1, preparing a PEDOT solution: 1.068 μL of 3,4-ethylenedioxythiophene is added to 1 mL of 0.01 mol / L polystyrene sulfonate aqueous solution, shaken to mix, and the mixed solution is stored at 4°C overnight to obtain a PEDOT solution;

[0010] Step 2, Platinum Nanoparticle Deposition: Hexachloroplatinic acid hexahydrate was dissolved in water to prepare a 0.5-2 wt% stock solution. Then, using this solution and a potentiostatic method, platinum nanoparticles were reduced and deposited onto a carbon-based bare electrode to obtain a Pt-modified microneedle electrode. The constant voltage used in this electrochemical deposition process was -1.5 V, the scan rate was 0.1 V / s, and the deposition time was 80-120 s.

[0011] Step 3, PEDOT modification: A uniform PEDOT film is formed by electrodeposition on the Pt-modified microneedle electrode using a PEDOT solution and a constant current method, thus obtaining an in vivo dissolved oxygen electrochemical sensor.

[0012] The method for constructing a dissolved oxygen electrochemical sensor in a carbon-based needle electrode with Pt / PEDOT composite modification provided by the present invention may also have the following feature: in step 1, the concentrations of 3,4-ethylenedioxythiophene and polystyrene sulfonate aqueous solution are the same and are any values ​​in the range of 0.01-0.02 mol / L.

[0013] The method for constructing a dissolved oxygen electrochemical sensor in a carbon-based needle electrode with Pt / PEDOT composite modification provided by the present invention may also have the following feature: in step 2, the concentration of the stock solution is 1 wt%.

[0014] The method for constructing a dissolved oxygen electrochemical sensor in vivo using a carbon-based needle electrode modified with Pt / PEDOT composite provided by this invention may also have the following features: Step 3 specifically includes: inserting the Pt-modified microneedle electrode into a PEDOT solution, then connecting it to a CHI660E electrochemical workstation for electrodeposition, with a constant current set to 0.1 mA, a scan rate of 0.002 V / s, and a deposition time of 100 s.

[0015] The present invention also provides a Pt / PEDOT composite modified carbon-based material needle electrode in vivo dissolved oxygen electrochemical sensor, which is constructed using any of the above-mentioned methods for constructing a Pt / PEDOT composite modified carbon-based material needle electrode in vivo dissolved oxygen electrochemical sensor.

[0016] The present invention also provides an application of the above-mentioned Pt / PEDOT composite modified carbon-based material needle electrode in vivo dissolved oxygen electrochemical sensor in vivo dissolved oxygen detection products.

[0017] Compared with the prior art, the functions and effects of the present invention include:

[0018] The proposed solution aims to address the aforementioned deficiencies by replacing precious metals with composite-modified carbon-based materials to reduce costs and improve biocompatibility, optimizing hypoxia sensitivity through composite modification, and resisting in vivo protein adsorption and biofilm coverage through anti-fouling surface modification, thereby enabling the monitoring of oxygen partial pressure in in vivo tissues.

[0019] This invention utilizes platinum nanoparticles to increase the amount of catalytic oxygen attached, and then uses poly(3,4-ethylenedioxythiophene) deposition to immobilize the catalytic oxygen and provide good electrode activity. The mechanical and electrical properties of the PEDOT polymer exhibit excellent adhesion and stability, which helps maintain the sensor's sensitivity and reduces the risk of platinum nanoparticle detachment. Simultaneously, this invention obtains the optimal current response value by exploring the platinum nanoparticle deposition potential, platinum nanoparticle deposition time, and electrodeposition times of different concentration ratios of polystyrene sulfonate and 3,4-ethylenedioxythiophene and PEDOT, providing data support for the fabrication of electrochemical sensors.

[0020] This invention utilizes cytotoxicity assays of human umbilical vein endothelial cells (HUVECs) and human aortic smooth muscle cells (HASMCs), animal hemolysis tests, routine blood biochemistry tests, fibrin deposition tests, and hematoxylin and eosin (H&E) staining of major animal organs to demonstrate the good biocompatibility of the Pt / PEDOT composite-modified carbon-based needle electrode in vivo dissolved oxygen electrochemical sensor. In vivo implantation tests were also conducted, and the results showed that the Pt / PEDOT composite-modified carbon-based needle electrode in vivo dissolved oxygen electrochemical sensor can monitor arterial blood oxygen partial pressure in vivo. Attached Figure Description

[0021] Figure 1 These are electrochemical characterization images of the electrodes before and after PEDOT modification in embodiments of the present invention. (a) is a CV comparison image; (b) is an EIS comparison image.

[0022] Figure 2 These are surface elemental characterization images of the Pt / PEDOT composite material modified on the electrode in the embodiments of the present invention. (a) SEM image of the carbon-based bare electrode; (b) SEM image of the PEDOT-modified electrode; (c) SEM image of the Pt-modified electrode; (d) SEM image of the Pt / PEDOT-modified electrode; (eh) Elemental mapping diagrams of C(e), O(f), S(g), Pt(h) on the Pt / PEDOT-modified electrode; (i) Comprehensive elemental mapping diagram of all target elements.

[0023] Figure 3 These are electrochemical characterization images of different modified electrodes in the embodiments of the present invention. (a) EIS test of carbon-based bare electrodes modified with PEDOT, Pt and Pt / PEDOT; (b) CV test of carbon-based bare electrodes modified with PEDOT, Pt and Pt / PEDOT.

[0024] Figure 4 The parameters for electrocatalytic activity in the embodiments of the present invention are optimized. (a) Electrode potential during current-time (it) testing; (b) Electrochemical deposition time of platinum nanoparticles in chloroplatinic acid solution; (c) Electrochemical deposition time of PEDOT in a mixture of polymer and EDOT monomer; (d) Mixtures of EDOT and PSS in different volume ratios of 2:1, 1:1, 1:2 and 1:4, respectively.

[0025] Figure 5 In this embodiment of the invention, the oxygen concentration response of the constructed Pt / PEDOT modified electrode was tested at -0.65 V. (a) PBS solutions with oxygen concentrations of 0 mM, 0.24 mM and 1.2 mM; (b) blood samples with different oxygen concentrations.

[0026] Figure 6 The figures show the cytotoxicity test results of the Pt / PEDOT modified electrode in the embodiments of the present invention. (a) The cell viability of HAVSMCs is 109.7%; (b) The cell viability of HAVSMCs is 109.7%.

[0027] Figure 7 This is a diagram showing the hemolysis experiment results of the Pt / PEDOT modified electrode in an embodiment of the present invention.

[0028] Figure 8These are blood routine and blood biochemistry images of the Pt / PEDOT modified electrode in an embodiment of the present invention. (a) is the blood routine; (b) is the blood biochemistry.

[0029] Figure 9 The figures show the results of fibrin deposition experiments on the Pt / PEDOT modified electrode in the embodiments of the present invention. (a) Fluorescence microscopy image; (b) Quantitative analysis results of fluorescence intensity.

[0030] Figure 10 These are representative hematoxylin and eosin (H&E) stained sections of rabbit major organs (heart, liver, spleen, lung, and kidney) implanted with Pt / PEDOT modified electrodes in an embodiment of the present invention.

[0031] Figure 11 This is a graph showing the results of real-time monitoring of PO2 changes using IT testing after the Pt / PEDOT modified electrode was implanted into a rabbit in an embodiment of the present invention. Detailed Implementation

[0032] To make the technical means, creative features, objectives and effects of this invention easy to understand, the following embodiments, in conjunction with the accompanying drawings, specifically illustrate a Pt / PEDOT composite modified carbon-based material needle electrode in vivo dissolved oxygen electrochemical sensor, its construction method and application.

[0033] Example

[0034] This embodiment provides a Pt / PEDOT composite modified carbon-based material needle electrode for in vivo dissolved oxygen electrochemical sensor, its construction method, and its application.

[0035] Methods for constructing a Pt / PEDOT composite-modified carbon-based needle electrode in vivo dissolved oxygen electrochemical sensor include:

[0036] Step 1, Prepare PEDOT solution:

[0037] 1.068 μL of 3,4-ethylenedioxythiophene (EDOT) stock solution was added to 1 mL of 0.01 mol / L polystyrene sulfonate (PSS) aqueous solution and mixed thoroughly with a stirrer to ensure that the EDOT monomer was fully dispersed in the PSS solution. The resulting mixed solution was stored at 4°C overnight to obtain a PEDOT solution, which was dark blue or black in color.

[0038] Step 2: Electrochemical deposition of platinum nanoparticles on the surface of a carbon-based bare electrode.

[0039] 1 g of hexachloroplatinic acid hexahydrate (H₂PtCl₆·6H₂O) was dissolved in deionized water to prepare a 1 wt% stock solution, which was then subjected to electrochemical deposition. Platinum nanoparticles were reduced and deposited onto a carbon-based bare electrode using a potentiostatic method. The constant voltage used in this electrochemical deposition process was -1.5 V, the scan rate was 0.1 V / s, and the deposition time was 100 s, resulting in a Pt-modified microneedle electrode (also called a Pt-modified electrode).

[0040] In this step, platinum nanoparticles are relatively uniformly distributed on the surface of the carbon electrode, exhibiting a distinct flower-like structure. This morphology is beneficial for increasing the specific surface area and can also increase the number of catalytically active sites, thereby improving the electrochemical properties of the electrode and its oxygen recognition.

[0041] Step 3, perform PEDOT modification:

[0042] A uniform PEDOT thin film was formed by electrodeposition on a Pt-modified microneedle electrode using a PEDOT solution and a constant current method, resulting in an in vivo dissolved oxygen electrochemical sensor. Specifically:

[0043] The PEDOT solution obtained in step 1 was transferred to a beaker, ensuring no bubbles were generated. A Pt-modified microneedle electrode was then inserted into the beaker and connected to a CHI660E electrochemical workstation. The constant current was set to 0.1 mA, the scan rate to 0.002 V / s, and the deposition time to 100 s, resulting in an in vivo dissolved oxygen electrochemical sensor (also called a Pt / PEDOT modified electrode).

[0044] like Figure 1 As shown, the conductivity of the carbon-based bare electrode modified with PEDOT (denoted as Blank in the figure) is significantly improved compared with that of the carbon-based bare electrode (denoted as Blank in the figure).

[0045] 1. Material modification characterization

[0046] To characterize the successful fabrication of the in vivo dissolved oxygen electrochemical sensor, the modified needle electrodes were first characterized using scanning electron microscopy (SEM), including electrodes modified with platinum and PEDOT respectively, as well as an electrode modified first with platinum and then with PEDOT (Pt / PEDOT modified electrode). Experimental results are as follows: Figure 2 As shown in the SEM images, the morphology changed significantly during the electrode modification process. The exposed carbon electrode surface exhibits obvious carbon powder particles and small grooves. Figure 2 a). A transparent film was observed on the electrodeposited PEDOT electrode. Figure 2 b). After platinum electrodeposition, PtNPs cover the electrode surface ( Figure 2c). In the Pt / PEDOT modified electrode, platinum nanoparticles and carbon powder particles were observed to be encapsulated in a uniform and transparent thin film. Figure 2 d).

[0047] Subsequently, elemental mapping was used to illustrate the elemental distribution within the Pt / PEDOT-modified electrode. The electrode exhibited a consistent carbon dominance (…). Figure 2 e), while PtNPs appear in different interface clusters (e), Figure 2 h). After Pt / PEDOT modification, the O element increases and its distribution becomes relatively uniform. Figure 2 f). The thiophene ring structure in PEDOT and the sulfonic acid group in PSS both contain S atoms. They interact with platinum nanoparticles to form Pt-S bonds. This results in a strong elemental S mapping around PtNPs (f). Figure 2 ). Element mapping of a single element ( Figure 2 eh) and the element mapping formed by the four feature element sets ( Figure 2 i) Both SEM imaging and elemental mapping confirmed the successful electrodeposition of the Pt / PEDOT composite material and showed that PEDOT was uniformly coated on PtNPs and carbon substrate.

[0048] 2. Electrochemical performance characterization

[0049] Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to test different modified electrodes. CV was used to evaluate the current response characteristics of the electrodes, while EIS was used to analyze the effect of the modifying material on the electron transfer capability of the electrodes. Experiments were conducted in different electrolyte solutions. The CV test solution was a mixture of 10 mM potassium ferricyanide (K3[Fe(CN)6]) and 0.1 M potassium chloride (KCl), while the EIS test solution was a mixture of 10 mM potassium ferricyanide, 10 mM potassium ferrocyanide (K4[Fe(CN)6]), and 0.1 M potassium chloride. The electrochemical characterization results of the different modified electrodes were then obtained, and the experimental results are shown below. Figure 3 As shown.

[0050] Electrochemical characterization of the electrodes using electroimpedance spectroscopy (EIS) and cyclic voltammetry (CV) was performed to verify the conductivity of the modified electrodes. As shown in Figure 3, EIS and CV tests were conducted on the bare electrode, the Pt-modified electrode, the PEDOT-modified electrode, and the PtNPs / PEDOT electrode, respectively. Compared with the unmodified bare electrode, all modified electrodes showed reduced impedance and higher conductivity, with platinum nanoparticles exhibiting the highest conductivity. The PEDOT-modified electrode exhibited a semi-circular characteristic in the mid-frequency impedance band, which may be due to the ion migration resistance within the PEDOT modification layer. Compared with PEDOT, the Pt / PEDOT composite modified electrode showed reduced impedance, increased cyclic voltammetric peak, and enhanced conductivity. These results indicate that platinum nanoparticles promote electron transfer by reducing charge transfer resistance. Although PEDOT introduces ion migration resistance, it forms a stable interfacial bilayer structure after encapsulation, thereby improving the capacitance performance of the composite electrode. This stable interface helps reduce blood flow interference and the interference from other substances in the blood.

[0051] 3. Parameter optimization of electrocatalytic activity

[0052] The electrocatalytic activity and sensing performance of the Pt / pedot modified electrode were maximized by optimizing four key parameters. All optimizations were performed in PBS containing 0.24 mM O2 (pH 7.4, 25°C) and measured using it. Steady-state current was the primary optimization criterion.

[0053] First, optimize the potential (it) during the chronoamperometry process. Figure 4 After testing the peak current at -0.6V, -0.65V, and -0.7V respectively, it was found that the peak current at -0.65V was 11.73% higher than that at -0.60V. Therefore, the timing current was tested at -0.65V.

[0054] Secondly, optimize the platinum electrodeposition time ( Figure 4 (b) Deposition times of 25 seconds, 50 seconds, 100 seconds, 150 seconds, and 200 seconds were selected. Comparison revealed that the maximum current was generated at a deposition time of 100 seconds. Therefore, a deposition time of 100 seconds was chosen.

[0055] Secondly, optimize the volume ratio of EDOT to PSS. Figure 4 d) The volume ratios of the two are 2:1, 1:1, 1:2 and 1:4, respectively. The results show that the maximum current is generated when the volume ratio of EDOT to PSS is 1:1.

[0056] Finally, the optimal electropolymerization time for PEDOT ( Figure 4 c) The highest current was detected when the constant current polymer PEDOT deposition time was 100 seconds.

[0057] Synergistic parameter tuning emphasizes the critical balance between kinetic optimization (voltage), nanostructure control (platinum dispersion), and target substance detection (PEDOT membrane). Through optimization, a high-performance Pt / PEDOT arterial oxygen sensor was constructed. Therefore, enhanced O2 detection sensitivity and stability were achieved within a very small operating region.

[0058] 4. Oxygen Concentration Response and Linear Fitting

[0059] Using phosphate-buffered saline (PBS) solutions with different oxygen concentrations: These solutions were purged with pure nitrogen, air, or pure oxygen for at least 30 minutes to create three different oxygen conditions. Each setup involved purging 20 ml of PBS with nitrogen, air, or pure oxygen for 30 minutes, followed by 15 minutes of static exposure in the corresponding gas environment. The resulting solutions had oxygen concentrations of 0 mM, 0.24 mM, and 1.2 mM, respectively.

[0060] Actual blood sample solution: Oxygen was replaced by passing nitrogen gas through 10 ml of arterial blood for at least 30 minutes, thus lowering the partial pressure of oxygen. Then, pure oxygen was continuously passed through to increase the partial pressure of oxygen. Arterial blood was taken at different time points to achieve different partial pressures of oxygen. The actual partial pressures of oxygen in all blood samples were analyzed using a blood gas analyzer.

[0061] The CV test was performed in PBS with oxygen concentrations of 0 mM, 0.24 mM, and 1.2 mM, and in arterial blood with different concentrations at different time points. Results showed that the current increased with increasing oxygen concentration. Based on the CV data, current-time (it) measurements were performed at -0.65 V. Figure 5 As shown, the response indicates the characteristic current of the Pt / PEDOT electrode as oxygen levels gradually change. The electrode current response was recorded, and the relationship between oxygen concentration and response current was experimentally derived. Linear fitting analysis was then performed, and the limit of detection (LOD) of the sensor was calculated. The sensor can detect oxygen partial pressures as low as 10 mmHg, thus evaluating its detection level at different concentrations. The results show that the in vivo dissolved oxygen electrochemical sensor (also called the Pt / PEDOT modified electrode) exhibits good linear response in PBS and blood samples.

[0062] 5. Biocompatibility testing

[0063] Cytotoxicity such as Figure 6As shown: Pt / PEDOT modified electrodes were cut into 1×1 mm pieces, each weighing 0.02 mg, and sterilized in 96-well plates. Human umbilical vein endothelial cells (HUVECs) at a density of 1000-3000 cells / mL and human aortic smooth muscle cells (HASMCs) at the same density were implanted into the wells, respectively. No samples were taken from the control group, and no cells were taken from the blank group. Both groups were cultured at 37°C for 24 hours under a 5% CO2 atmosphere. 10 μL of CCK-8 reagent was added to each well, and cell viability was measured. The cell viability rates were 101.6% and 109%, respectively.

[0064] Hemolysis test, such as Figure 7 As shown: Rabbit arterial blood was extracted and centrifuged to obtain blood cells. A Pt / PEDOT modified electrode sample was placed in 1 ml of PBS solution, another 1 ml of PBS solution without a sample served as a negative control, and 1 ml of ultrapure water served as a positive control. All solutions contained 20 μL of blood cells. After incubation at 37°C for 4 hours, the supernatant was obtained by centrifugation and recorded. 100 μL of the supernatant was placed in a 96-well plate, and the absorbance was measured. The final hemolysis rate was 0.5%.

[0065] Complete blood count and blood biochemistry, such as Figure 8 As shown: Blood samples were collected from healthy rabbits without implanted Pt / PEDOT modified electrodes and rabbits approximately 2 hours after implantation for hematological and chemical analysis. Complete blood count (CBC) measurements included white blood cell (WBC), lymphocytes (LBC), red blood cells (RBC), hemoglobin (HGB), hematocrit (HCT), and neutrophil (Gran) levels. Blood biochemistry measurements included aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (TBIL), albumin (ALB), blood urea nitrogen (UREA), and creatinine (CREA). No significant differences were found between the experimental and control groups.

[0066] fibrin deposition test, such as Figure 9 As shown: Pt / PEDOT modified electrode samples were incubated with fibrinogen (FBG) solution at room temperature. After incubation, the surface was thoroughly rinsed to remove any unbound or loosely adsorbed proteins. Next, the samples were incubated with bovine serum albumin (BSA) solution to block any non-specific binding sites. After this step, the surface was rinsed again. Subsequently, the surface was treated with FITC-conjugated goat anti-human fibrinogen and incubated in the dark. After incubation, excess unbound antibody was removed by washing repeatedly with PBST buffer. After fixation on a 4% paraformaldehyde slide, fluorescence microscopy imaging and fluorescence intensity quantification were performed. The results indicate reduced protein adsorption on the Pt / PEDOT modified electrode surface, which helps alleviate adverse biological reactions such as thrombosis.

[0067] Hematoxylin and eosin (H&E) staining of major organs as follows Figure 10 As shown: Major rabbit organs (heart, liver, spleen, lung, and kidney) were collected approximately 2 hours after implantation of Pt / PEDOT modified electrodes and were fixed overnight in 4% (v / v) paraformaldehyde at 4°C. The fixed tissues were embedded in paraffin and then sliced ​​into sections approximately 4 μm thick using a microtome. The sections were stained with hematoxylin for 10 minutes and then with ethanolic eosin for 30 seconds. Finally, a neutral balsam was applied. Observation was performed under an optical microscope, and digital images of the sections were captured simultaneously. The sensor did not induce systemic toxicity or organ damage.

[0068] 6. In vivo implantation test

[0069] A sensor (Pt / PEDOT modified electrode) was surgically inserted into the left femoral artery of a rabbit and secured with a hemostatic clip. This allowed for continuous real-time monitoring of PO2 using a time-amperometry method for approximately 1-2 hours. Results were as follows... Figure 11 As shown, the real-time it curve indicates that the current signal is relatively stable during acute implantation, suggesting that it can be used as an indicator for monitoring arterial blood oxygen partial pressure.

[0070] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for constructing a Pt / PEDOT composite-modified carbon-based needle electrode for a bulk dissolved oxygen electrochemical sensor, characterized in that, It was constructed using platinum nanoparticles and poly(3,4-ethylenedioxythiophene) (PEDOT).

2. The method for constructing a Pt / PEDOT composite-modified carbon-based needle electrode for bulk dissolved oxygen electrochemical sensor according to claim 1, characterized in that: in, A carbon-based microneedle electrode was modified by electrochemical deposition of platinum nanoparticles using a chloroplatinic acid hexahydrate solution and a time-current method, resulting in a Pt-modified microneedle electrode.

3. The method for constructing a Pt / PEDOT composite-modified carbon-based needle electrode for an in-situ dissolved oxygen electrochemical sensor according to claim 2, characterized in that: in, Poly(3,4-ethylenedioxythiophene) is generated directly by electropolymerization on the surface of the Pt-modified microneedle electrode using an electrochemical galvanostatic method. A uniform PEDOT film is then formed on the microneedle electrode to encapsulate the modified platinum nanoparticles, thus obtaining the Pt-modified microneedle electrode.

4. The method for constructing a Pt / PEDOT composite-modified carbon-based needle electrode for bulk dissolved oxygen electrochemical sensing according to any one of claims 1-3. Its features are, Includes the following steps: Step 1, Preparation of PEDOT solution: Add 1.068 μL of 3,4-ethylenedioxythiophene to 1 mL of 0.01 mol / L polystyrene sulfonate aqueous solution, shake to mix, and store the mixed solution at 4°C overnight to obtain the PEDOT solution; Step 2, deposition of platinum nanoparticles: Hexachloroplatinic acid hexahydrate is dissolved in water to prepare a stock solution with a concentration of 0.5-2 wt%. Then, using the prepared solution and relying on a potentiostatic method, platinum nanoparticles are reduced and deposited onto a carbon-based bare electrode to obtain a Pt-modified microneedle electrode. The constant voltage used in this electrochemical deposition process is -1.5V, the scan rate is 0.1V / s, and the deposition time is 80-120s. as well as Step 3, PEDOT modification: Using the PEDOT solution, a uniform PEDOT film is formed on the Pt-modified microneedle electrode by electrodeposition using a constant current method, thus obtaining an in vivo dissolved oxygen electrochemical sensor.

5. The method for constructing a bulk dissolved oxygen electrochemical sensor using a Pt / PEDOT composite-modified carbon-based needle electrode according to claim 4, characterized in that: in, In step 1, the concentrations of the 3,4-ethylenedioxythiophene and the aqueous solution of the polystyrene sulfonate are the same and are any values ​​between 0.01 and 0.02 mol / L.

6. The method for constructing a Pt / PEDOT composite-modified carbon-based needle electrode for bulk dissolved oxygen electrochemical sensor according to claim 4, characterized in that: in, In step 2, the concentration of the stock solution is 1 wt%.

7. The method for constructing a Pt / PEDOT composite-modified carbon-based needle electrode for bulk dissolved oxygen electrochemical sensor according to claim 4, characterized in that: in, Step 3 specifically includes: inserting the Pt-modified microneedle electrode into the PEDOT solution, then connecting it to a CHI660E electrochemical workstation for electrodeposition, with a constant current set to 0.1 mA, a scan rate of 0.002 V / s, and a deposition time of 100 s.

8. A Pt / PEDOT composite-modified carbon-based needle electrode for bulk dissolved oxygen electrochemical sensing, characterized in that, The dissolved oxygen electrochemical sensor in vivo was constructed using the method described in any one of claims 1-7 for constructing a carbon-based needle electrode with Pt / PEDOT composite modification.

9. The application of the Pt / PEDOT composite modified carbon-based material needle electrode in vivo dissolved oxygen electrochemical sensor as described in claim 8 in an in vivo dissolved oxygen detection product.

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