Electrochemical dopamine sensor based on manganese monatomic catalyst and construction method and application thereof

Abstract

The application belongs to the field of preparation of functional materials and biomolecule detection, and particularly relates to an electrochemical dopamine sensor based on a manganese monatomic catalyst and a construction method and application thereof. The catalyst is prepared by the following method: firstly, dissolving dopamine hydrochloride in water, then adding manganese chloride tetrahydrate, stirring until completely dissolved to form a clear solution, and performing liquid nitrogen freeze drying; and then carbonizing the dried product. The application firstly proposes introducing manganese salt into a dopamine base carbon material to directly construct an active site, and the construction of the active site improves the catalytic performance of the base on dopamine. The manganese monatomic catalyst is synthesized by a simple preparation method, and an active site capable of high-performance catalysis of dopamine is constructed, which realizes high catalytic performance while saving cost. The sensor prepared by the application has high sensitivity, and realizes direct detection of dopamine in serum, which shows excellent selectivity.

Description

Technical Field

[0001] This invention belongs to the field of functional material preparation and biomolecular detection, specifically relating to an electrochemical dopamine sensor based on a manganese single-atom catalyst, its construction method, and its application. Background Technology

[0002] Dopamine is a biomarker associated with human diseases such as Alzheimer's and Parkinson's. Therefore, achieving highly sensitive and selective detection of dopamine is crucial for human health.

[0003] The paper "Nitrogen-Doped Graphdiyne Quantum-dots as an Optical-Electrochemical sensor for sensitive detection of dopamine" discloses a method for highly sensitive detection of dopamine using an electrode modified with nitrogen-doped graphdiyne quantum dots as the substrate and electrochemical detection technology. The reported detection range is 0.05 to 240 µM, and the limit of detection is 0.02 µM. The detection of dopamine in human serum solution was achieved using a spiked recovery method.

[0004] However, the publicly available detection methods have the following problems: 1) Spike recovery experiments in serum solutions are insufficient to demonstrate the selectivity of the sensing interface for the target analyte; 2) Recovery experiments in serum solutions also indicate that this method is difficult to directly detect dopamine in real, complex physiological media, as these media contain multiple coexisting interfering components at high concentrations. Therefore, the catalytic performance of sensors constructed in the prior art for dopamine needs improvement, especially in sensitivity and selectivity. Furthermore, since human blood contains multiple components, including proteins, DNA, and RNA, these components can severely interfere with the sensor signal, leading to false positive (false negative) results. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention provides an electrochemical dopamine sensor based on a manganese single-atom catalyst.

[0006] The present invention also provides a method for constructing the above-mentioned electrochemical dopamine sensor based on a manganese single-atom catalyst.

[0007] Another object of the present invention is to provide the application of the above-mentioned electrochemical dopamine sensor based on a manganese single-atom catalyst.

[0008] The technical solution adopted by the present invention to achieve the above objectives is as follows: This invention provides a manganese single-atom catalyst, which is prepared by the following method: (1) Dissolve dopamine hydrochloride in water, then add manganese chloride tetrahydrate, stir until completely dissolved to form a clear solution, and freeze dry with liquid nitrogen; (2) The dried product is carbonized once, and then acid-washed after the heat preservation is completed; after acid washing, it is carbonized a second time to finally obtain a black powdery manganese single-atom catalyst.

[0009] Furthermore, in step (1), the ratio of dopamine hydrochloride to water is 3-4 g: 40 mL; the mass ratio of dopamine hydrochloride to manganese chloride tetrahydrate is 3-4: 9.

[0010] Furthermore, in step (2), the first carbonization is: heating to 800°C at a heating rate of 5°C / min, and then holding at that temperature for 2-2.5 hours.

[0011] In the preparation process of the manganese single-atom catalyst provided by the present invention, acid washing can avoid the presence of manganese oxides. Specifically, the acid washing is carried out at 95°C using 2M HCl.

[0012] Furthermore, in step (2), the secondary carbonization is carried out by connecting the air inlet to an ammonia water washing bottle at 800°C for 1 hour.

[0013] This invention also provides a method for constructing an electrochemical dopamine sensor based on the above-mentioned manganese single-atom catalyst, characterized by comprising the following steps: 1) Electrode modification: Glassy carbon electrodes were polished and ground in alumina suspensions of different particle sizes, rinsed with ethanol and water, and sonicated; then placed for later use. 2) Prepare the ink solution: Mix ethanol and water, then add naphthol; 3) Disperse the manganese single-atom catalyst in the ink solution prepared above, and sonicate it to form a homogeneous mixed solution; quickly drop the mixed solution onto the surface of the pretreated glassy carbon electrode and place it to form a uniform electrocatalytic sensing interface.

[0014] Furthermore, in step 1), the diameter of the glassy carbon electrode is 3 mm; the alumina suspensions are 1.0, 0.5, and 0.03 µm, respectively.

[0015] Furthermore, in step 2), the specific composition of the ink is: 0.30 mL of ethanol and 0.15 mL of water with 60.0 µL of naphthol added; the concentration of naphthol is 5.0 wt.%.

[0016] Furthermore, in step 3), the ratio of the manganese single-atom catalyst to the ink is 3 mg: 0.5-1 mL; the placement time is 24 h.

[0017] The present invention also provides an application of the electrochemical dopamine sensor constructed using the above-described method in the detection of dopamine in serum.

[0018] This invention achieves highly sensitive and selective detection of dopamine in serum by preparing a manganese single-atom catalyst and constructing an electrochemical dopamine sensor based on the manganese single-atom catalyst.

[0019] The beneficial effects of this invention are as follows: 1) Novel construction of active sites: This invention is the first to propose the direct construction of active sites by introducing manganese salts on dopamine-based carbon materials. The construction of these active sites improves the catalytic performance of the substrate for dopamine.

[0020] 2) Simple preparation method: A manganese single-atom catalyst was synthesized through a simple preparation method, and active sites capable of high-performance catalysis of dopamine were constructed. This achieved high catalytic performance while saving costs.

[0021] 3) Excellent performance: The sensor exhibits a wide linear detection range for electrocatalyzing dopamine in phosphate buffer solution (0.2 M, pH 7.4): 0.25 - 470.65 µM, with a detection limit as low as 87 nM, which is 1 to 3 orders of magnitude lower than the prior art, indicating that the sensor prepared in this invention has high sensitivity; at the same time, it realizes the direct detection of dopamine in serum, demonstrating excellent selectivity (able to eliminate the influence of other interfering components). Attached Figure Description

[0022] Figure 1 HAADF-STEM image of the manganese single-atom catalyst prepared in Example 1; Figure 2 A manganese single-atom catalyst-modified electrode was used to catalyze dopamine in phosphate buffer solution (pH 7.4, 0.2 M); Figure 3 Linear curves of dopamine catalysis by a manganese single-atom catalyst-modified electrode in phosphate buffer solution (pH 7.4, 0.2 M); Figure 4 Selectivity characterization of dopamine catalysis by manganese single-atom catalyst; Figure 5 A manganese single-atom catalyst that simultaneously catalyzes and distinguishes dopamine and uric acid; Figure 6 This is a graph showing the catalytic performance of direct detection of dopamine in serum. Detailed Implementation

[0023] The technical solution of the present invention will be further explained and described below through specific embodiments.

[0024] Unless otherwise specified, all raw materials used in this invention are commercially available.

[0025] Example 1 1) Preparation of manganese single-atom catalysts and construction of active sites: 3.0002 g of dopamine hydrochloride was dissolved in 40 mL of water, and then 9.0000 g of manganese chloride tetrahydrate was added. The mixture was stirred until completely dissolved to form a clear solution (light yellow). The solution was then freeze-dried with liquid nitrogen. Carbonization was performed by heating to 800 °C at a rate of 5 °C / min and holding at that temperature for 2 h. The solution was then acid-washed with 2M HCl at 95 °C (to avoid the presence of manganese oxides). After acid washing, the solution was carbonized again, and the gas inlet was washed with ammonia water at 800 °C for 1 h. Finally, a black powdery manganese single-atom catalyst in the shape of nanosheets was obtained.

[0026] The presence of atomically dispersed Mn was verified using aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). Figure 1 As shown, the bright spots marked with red circles correspond to the isolated Mn atoms dispersed on the dopamine carbon nanosheets.

[0027] 2) Electrode modification: Glassy carbon electrodes (3 mm in diameter) were polished in alumina suspensions of 1.0, 0.5, and 0.03 µm, respectively, rinsed with ethanol and water, and sonicated; then placed for later use.

[0028] To prepare the ink solution: Add 60.0 µL of naphthol (5.0 wt.%) to 0.30 mL of ethanol and 0.15 mL of water.

[0029] 3.0 mg of manganese single-atom catalyst was dispersed in the ink solution prepared above and ultrasonically treated to form a homogeneous mixed solution.

[0030] Take 7 µL of the above mixed solution and quickly drop it onto the pretreated glassy carbon electrode surface. Let it stand for 24 h to form a uniform electrocatalytic sensing interface.

[0031] Effect verification (I) Performance characterization of electrocatalytic dopamine: high sensitivity Electrochemical catalysis of dopamine was performed in phosphate buffer (0.2 M, pH 7.4) using electrochemical IT testing (electrochemical workstation, 760E, Shanghai Chenhua). The applied voltage was +0.25 V. Dopamine was added every 50 seconds using a 10 µL syringe, with the concentration increasing gradually. (Note: The phosphate buffer solution was kept agitated at a constant speed using a magnetic stirrer). The results of the dopamine catalysis are as follows. Figure 2 As shown.

[0032] The linear catalytic range of manganese single-atom catalysts for dopamine is 0.25 to 470.65 µM, such as... Figure 3 As shown, the detection limit is as low as 87 nM, which is 1 to 3 orders of magnitude lower than that of the prior art. Furthermore, the manganese single-atom catalyst constructed in this invention has a wider detection range for dopamine. All results demonstrate the high sensitivity of the manganese single-atom catalyst for dopamine detection.

[0033] (II) Performance characterization of electrocatalytic dopamine: high selectivity The effects of various interfering components at different concentrations on dopamine catalysis were tested using IT technology, such as... Figure 4 As shown: A voltage of 0.25 V was applied. After adding 10 µM dopamine, 50 s later, 20 µM of interfering components (A) L-tyrosine, (B) L-tryptophan, and (C) KCl were added. No significant current response was observed for the interfering components. Then, after adding 100 µM dopamine, 50 s later, 200 µM of interfering components (A) L-tyrosine, (B) L-tryptophan, and (C) KCl were added, again without a significant current response. Finally, after adding 200 µM dopamine, 500 µM glucose and artificial sweat (containing various interfering components such as sodium chloride, a small amount of urea, lactic acid, and fatty acids) were added, 50 s later, and the current response still did not increase significantly. These results all indicate that the sensor based on a manganese single-atom catalyst exhibits excellent selectivity for dopamine catalysis.

[0034] Because uric acid and dopamine have similar structures and redox properties, we further tested the performance of manganese single-atom catalysts in simultaneously catalyzing dopamine and uric acid using differential pulse voltammetry. Figure 5 As shown. First, differential pulse voltammetry produced a significant current signal for 100 µM dopamine, with the oxidation peak appearing at approximately 0.155 V. Then, with the addition of uric acid (200 µM), which had a higher concentration than dopamine, differential pulse voltammetry exhibited a small current response, with a peak potential appearing at approximately 0.268 V. However, the difference between the peak potential of uric acid and that of dopamine (ΔV) was not as large. E At 113 mV, this result indicates that even in the presence of uric acid, the manganese single-atom catalyst can still effectively distinguish the signal responses of uric acid and dopamine. All the above results further demonstrate that the manganese single-atom catalyst exhibits significant catalytic selectivity for dopamine.

[0035] (III) Detection of dopamine in serum: Based on the excellent sensitivity and selectivity of manganese single-atom catalysts for dopamine catalysis, we directly performed catalytic detection of dopamine in serum samples (containing multiple interfering components), such as... Figure 6As shown, the electrochemical sensor based on a manganese single-atom catalyst remained sensitive to the catalytic response of dopamine in serum, indicating its potential for practical application.

Claims

1. The application of a manganese single-atom catalyst in the detection of dopamine in serum, characterized in that, The manganese single-atom catalyst was prepared by the following method: (1) Dissolve dopamine hydrochloride in water, then add manganese chloride tetrahydrate, stir until completely dissolved to form a clear solution, and freeze dry with liquid nitrogen; (2) The dried product is carbonized once, and then acid-washed after the heat preservation is completed; after acid washing, it is carbonized a second time to finally obtain a black powdery manganese single-atom catalyst. In step (2), the first carbonization is: heating to 800℃ at a heating rate of 5℃ / min, and then holding at that temperature for 2-2.5h; In step (2), the secondary carbonization is carried out by connecting the inlet of the gas inlet to an ammonia water washing bottle at 800°C for 1 hour.

2. The application according to claim 1, characterized in that, In step (1), the ratio of dopamine hydrochloride to water is 3-4 g: 40 mL; the mass ratio of dopamine hydrochloride to manganese chloride tetrahydrate is 3-4:

9.

3. The application according to claim 1, characterized in that, In step (2), the pickling is performed at 95°C using 2M HCl.

4. A method for constructing an electrochemical dopamine sensor based on the application of the manganese single-atom catalyst according to any one of claims 1-3 in the detection of dopamine in serum, characterized in that, Includes the following steps: 1) Electrode modification: Glassy carbon electrodes were polished and ground in alumina suspensions of different particle sizes, rinsed with ethanol and water, and sonicated; then placed for later use. 2) Prepare the ink solution: Mix ethanol and water, then add naphthol; 3) Disperse the manganese single-atom catalyst in the ink solution prepared above, and sonicate it to form a homogeneous mixed solution; quickly drop the mixed solution onto the surface of the pretreated glassy carbon electrode and place it to form a uniform electrocatalytic sensing interface.

5. The method according to claim 4, characterized in that, In step 1), the diameter of the glassy carbon electrode is 3 mm; the alumina suspensions are 1.0, 0.5, and 0.03 µm, respectively.

6. The method according to claim 5, characterized in that, In step 2), the ink solution is composed of 0.30 mL of ethanol and 0.15 mL of water with 60.0 µL of naphthol added; the concentration of naphthol is 5.0 wt.%.

7. The method according to claim 4, characterized in that, In step 3), the ratio of the manganese single-atom catalyst to the ink is 3 mg: 0.5-1 mL; the placement time is 24 h.

8. The use of an electrochemical dopamine sensor constructed according to any one of claims 4-7 in the detection of dopamine in serum.

Images