Device and method for detecting catalytic activity of single nano-enzyme by using dark field optical imaging

Abstract

The invention discloses a device and a method for detecting the catalytic activity of a single nano-enzyme by using dark-field optical imaging, and relates to the technical field of single-particle dark-field optical imaging. The system comprises: a sample reaction module, which is used for the generation of a nano-enzyme catalytic reaction and comprises a sensing chip and a sample cell; the optical imaging module is used for optical imaging of nano-enzyme catalytic reaction and comprises a laser generator, a light path adjusting assembly, a microscopic imaging objective lens and a dark field condenser; and the image recording module is connected with the optical imaging module and is used for collecting an image signal of the nano enzyme in the reaction solution. According to the device and the method, the catalytic behavior of the nano-enzyme is researched by utilizing dark field scattering optical imaging, the catalytic activity of the single nano-enzyme is measured by directly detecting the dark field scattering optical intensity change of the single nano-enzyme particle, and the device and the method which are free of damage, free of labels and high in sensitivity are provided for researching the catalytic activity of the nano-enzyme.

Description

Technical Field

[0001] The present invention relates to the technical field of single-particle dark-field optical imaging, and particularly to an apparatus and method for detecting the catalytic activity of single nanozymes using dark-field optical imaging. Background Art

[0002] Nanozymes are a class of nanomaterials with enzyme-like catalytic activity, having both the physical and chemical properties of nanomaterials and catalytic functions similar to enzymes, combining the advantages of natural enzymes and artificial enzymes. At the same time, nanozymes have the advantages of good stability, low preparation cost, long storage time, etc., and can effectively avoid the complexity in the preparation and purification of natural enzymes. In recent years, they have shown good application prospects in the fields of biosensing, disease diagnosis and treatment, and environmental governance. The catalytic activity of nanozymes is usually significantly affected by factors such as their size, morphology, and surface chemical properties. Therefore, the development of high-sensitivity and high-selectivity detection devices and methods for the catalytic activity of single-particle nanozymes is of great significance for deeply understanding the structure-activity relationship of nanozymes, optimizing their performance, and expanding their applications.

[0003] Currently, the commonly used methods for detecting the catalytic activity of nanozymes mainly include fluorescence method, colorimetric method, and electrochemical method, etc. Most of these methods are based on the overall or average effect of the system and are difficult to achieve precise measurement of the catalytic activity of single-particle nanozymes. In addition, these methods usually require modification or labeling of nanozymes, and the sample preparation process is cumbersome, which may affect the intrinsic catalytic activity of the nanozymes.

[0004] Optical methods have the advantages of non-contact, non-destructive, and high sensitivity, providing new ideas for the detection of the catalytic activity of single-particle nanozymes. Among them, dark-field optical imaging technology has been widely used in the characterization and dynamic behavior research of single-particle nanomaterials because it can directly observe the optical scattering characteristics of individual nanoparticles. However, the existing dark-field optical imaging technology is mainly used for the morphology and size analysis of nanomaterials and is difficult to directly reflect their catalytic activity. Therefore, the present invention proposes an apparatus and method for detecting the catalytic activity of single nanozymes using dark-field optical imaging. Summary of the Invention

[0005] The purpose of the present invention is to provide an apparatus and method for detecting the catalytic activity of single nanozymes using dark-field optical imaging, so as to solve the problem that it is difficult to achieve precise measurement of the catalytic activity of single-particle nanozymes in the prior art.

[0006] To achieve the above purpose, the present invention provides the following technical solution: An apparatus for detecting the catalytic activity of single nanozymes using dark-field optical imaging, comprising:

[0007] A sample reaction module, the sample reaction module includes a solution reaction cell and a sensing chip fixed at the bottom of the solution reaction cell, and the sample reaction module is used for the occurrence of nanozyme catalytic reactions;

[0008] An optical imaging module, the optical imaging module includes a laser generator, an optical path adjustment component is arranged downstream of the optical path transmission of the laser generator, a dark field condenser and a microscopic imaging objective are installed downstream of the optical path transmission of the optical path adjustment component, the dark field condenser and the microscopic imaging objective are respectively located above and below the sample reaction module, and the optical imaging module is used for imaging of nanozyme catalytic reactions;

[0009] An image recording module, the image recording module includes a mirror arranged downstream of the optical path transmission of the microscopic imaging objective, and an image sensor is arranged downstream of the optical path transmission of the mirror, the image recording module is connected to the optical imaging module and is used for collecting image signals of nanozymes in the reaction solution.

[0010] Further, the sensing chip is a BK7 cover glass, and the surface contact angle thereof is less than 10°.

[0011] Further, the solution reaction cell is made of polydimethylsiloxane material.

[0012] Further, the dark field condenser is a dry condenser, its numerical aperture is 0.80 - 0.95, the magnification of the microscopic imaging objective is 40, and the numerical aperture is 0.6.

[0013] Further, the dark field condenser, the sensing chip, and the microscopic imaging objective are installed coaxially in the same direction from top to bottom. The laser passes through the dark field condenser, so that the light falls on the sensing chip at an oblique angle. The scattering signal generated by the nanozyme material to be measured passes through the microscopic imaging objective and the image sensor in sequence, so as to form a bright image on a dark background.

[0014] Further, the image sensor is a CCD image sensor or a CMOS image sensor.

[0015] According to the second aspect of the present invention, the present invention provides a method for detecting the catalytic activity of single-particle nanozymes using dark field optical imaging, which is implemented by using the above-mentioned device for detecting the catalytic activity of single-particle nanozymes using dark field optical imaging, and specifically includes the following steps:

[0016] S1. Add a sample into the solution reaction cell, and modify the nanozyme on the surface of the sensing chip by a physical modification method;

[0017] S2. Add a reaction solution into the solution reaction cell, and use the optical imaging module to image the nanozyme catalytic reaction;

[0018] S3. Use the image recording module to collect the dark field scattering images of nanozyme particles, and obtain the change in scattering intensity of nanozymes during the catalytic reaction.

[0019] Further, in step S1, a sample is added to the solution reaction cell, and a nanozyme is modified on the surface of the sensing chip by a physical modification method, specifically as follows:

[0020] (81) Place the solution reaction cell on the surface of the sensing chip, add 50 μL of PBS solution to the solution reaction cell, and let it stand for 5 minutes;

[0021] (82) Subsequently, add 50 μL of manganese dioxide solution to the solution reaction cell and let it stand for 10 minutes;

[0022] (83) Wash the solution reaction cell 5 times with deionized water and place it in a drying oven at 60 °C for 30 minutes to fix the manganese dioxide particles on the surface of the sensing chip.

[0023] Further, in S2, a reaction solution is added to the solution reaction cell, and the nanozyme-catalyzed reaction is imaged using the optical imaging module, specifically as follows:

[0024] (91) Prepare a 0.1 mM hydrogen peroxide solution using deionized water as the solvent. After preparation, add 30 μL of the hydrogen peroxide solution to the sample cell;

[0025] (92) After the reaction is complete, start the laser generator to emit a supercontinuum white laser as the laser for dark-field optical imaging. The laser is reflected by the optical path adjustment component to the dark-field condenser, and the laser is incident on the sensing chip via the dark-field condenser;

[0026] (93) The scattering signal of the nanozyme material to be measured sequentially passes through the microscopic imaging objective lens 24 and the mirror and enters the image sensor.

[0027] Further, in step S3, the image sensor is used to obtain the change in scattering intensity of the manganese dioxide nanozyme after adding the hydrogen peroxide reaction solution. The image recording speed is set to 10 frames per second, and the recording time is 300 seconds.

[0028] The present invention has at least the following beneficial effects:

[0029] The present invention uses dark-field scattering optical imaging to study the catalytic behavior of nanozymes. By directly detecting the change in the dark-field scattering optical intensity of single nanozyme particles, the catalytic activity of single nanozymes is measured, providing a non-destructive, label-free, and highly sensitive device and method for studying the catalytic activity of nanozymes. Moreover, this method has the advantages of high throughput, non-invasiveness, and a wide range of research objects, and can be used for the study of the catalytic activity and structure-activity relationship of nanozymes at the single-particle level, expanding the application of nano-optical imaging analysis.

[0030] Of course, it is not necessary for any product implementing the present invention to achieve all the above-mentioned advantages simultaneously. Brief Description of the Drawings

[0031] Figure 1 is a schematic structural diagram of the device of the present invention;

[0032] Figure 2 In [diagram], A is a dark-field microscopy image of the nanozyme particles in the present invention;

[0033] Figure 2 In [diagram], B is a corresponding in-situ scanning electron microscopy image of the present invention;

[0034] Figure 2 In [diagram], C is Figure 2 an enlarged electron microscopy image corresponding to the framed part in B in [diagram];

[0035] Figure 2 In [diagram], D is an XRD schematic diagram of the nanozyme particles in the present invention;

[0036] Figure 3 In [diagram], A is a graph showing the change of the dark-field optical intensity of the nanoparticles in the present invention with time in hydrogen peroxide solution;

[0037] Figure 3 In [diagram], B is Figure 3 a histogram of the dark-field optical intensity distribution corresponding to A in [diagram];

[0038] Figure 4 In [diagram], A is a graph showing the change of the dark-field optical intensity of the nanozyme particles in the present invention with time in sodium dodecyl sulfate solution;

[0039] Figure 4 In [diagram], B is Figure 4 a histogram of the dark-field optical intensity distribution corresponding to A in [diagram];

[0040] Figure 5 In [diagram], A is a graph showing the change of the dark-field optical intensity of the nanozyme particles in the present invention with time in hydrogen peroxide and ammonium dodecyl sulfate solution;

[0041] Figure 5 In [diagram], B is Figure 5 a histogram of the dark-field optical intensity distribution corresponding to A in [diagram];

[0042] Figure 6 is a mechanism diagram for detecting the catalytic activity of single-particle nanozymes by dark-field microscopy according to the present invention.

[0043] Reference numerals:

[0044] 11. Solution reaction cell; 12. Sensing chip; 21. Laser generator; 22. Optical path adjustment component; 23. Dark-field condenser; 24. Microscopic imaging objective; 31. Mirror; 32. Image sensor. Detailed implementation manners

[0045] Next, the technical solutions in the embodiments of the present disclosure will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present disclosure without creative efforts shall fall within the protection scope of the present disclosure.

[0046] Embodiment 1:

[0047] Please refer to Figures 1 - 6 , the present invention provides a technical solution: a device for detecting the catalytic activity of a single nanozyme using dark-field optical imaging, comprising:

[0048] A sample reaction module, which includes a solution reaction cell 11 and a sensing chip 12 fixed at the bottom of the solution reaction cell 11. The sample reaction module is used for the occurrence of the nanozyme catalytic reaction;

[0049] An optical imaging module, which includes a laser generator 21. Downstream of the optical path transmission of the laser generator 21, there is an optical path adjustment component 22. Downstream of the optical path transmission of the optical path adjustment component 22, a dark-field condenser 23 and a microscopic imaging objective 24 are installed. The dark-field condenser 23 and the microscopic imaging objective 24 are respectively located above and below the sample reaction module. The optical imaging module is used for imaging the nanozyme catalytic reaction;

[0050] An image recording module, which includes a mirror 31 arranged downstream of the optical path transmission of the microscopic imaging objective 24. Downstream of the optical path transmission of the mirror 31, there is an image sensor 32. The image recording module is connected to the optical imaging module and is used for collecting the image signal of the nanozyme in the reaction solution.

[0051] Regarding the technical solution of this embodiment, the solution reaction cell 11 is fixed on the surface of the sensing chip 12. The reaction solution is placed in the solution reaction cell 11, and the sensing chip 12 is set as a BK7 cover glass. Before use, the sensing chip 12 is rinsed 3 times with ethanol and deionized water respectively, immediately dried with nitrogen, and then treated with a plasma cleaner to make the contact angle of its surface less than 10°;

[0052] Furthermore, the solution reaction cell 11 is made of polydimethylsiloxane (PDMS). Before use, it is rinsed 3 times with ethanol and deionized water respectively, dried with nitrogen, and placed on the surface of the sensing chip 12.

[0053] For the technical solution of this embodiment, the laser generator 21 selects a Japanese KLS halogen lamp (EKE, 21V 150W / AL) to emit super - continuous white laser as the laser for dark - field optical imaging; the optical path adjustment component 22 is used to change the incident laser direction; the dark - field condenser 23 is a dry condenser with a numerical aperture of 0.80 - 0.95, which is used to focus the incident light beam; the microscopic imaging objective lens 24 has a magnification of 40 and a numerical aperture of 0.6, which is used to magnify the optical path signal to meet the requirement of magnifying the imaging of single - particle nanozyme on the surface of the sensing chip 12. It should be noted that the dark - field condenser 23, the sensing chip 12, and the microscopic imaging objective lens 24 are installed in the same direction from top to bottom. The laser passes through the dark - field condenser 23, and the light falls on the sensing chip 12 at an oblique angle. There is a refractive index difference between the nanozyme material to be measured and the surrounding medium, generating sufficient scattering signals, which pass through the microscopic imaging objective lens 24 and the image sensor 32 in sequence, thus forming a bright image on a dark background.

[0054] The image sensor 32 can be set as a CCD image sensor 32 or a CMOS image sensor 32. For the technical solution of this embodiment, the image sensor 32 is set as a CCD image sensor 32, the image recording speed is set to 10 frames per second, and the recording time is 300 seconds.

[0055] Embodiment Two:

[0056] Taking manganese dioxide (MnO₂) nanozyme particles as an example, this embodiment provides a method for detecting the catalytic activity of single - particle nanozyme using dark - field optical imaging, which is implemented by using the device for detecting the catalytic activity of single - particle nanozyme using dark - field optical imaging described in Embodiment One. The specific steps are as follows:

[0057] S1. Add samples to the solution reaction cell 11, and fix MnO₂ nanozyme particles on the surface of the sensing chip 12 by physical modification method, specifically as follows:

[0058] (S11) Place the solution reaction cell 11 on the surface of the sensing chip 12, add 50 μL of PBS solution to the solution reaction cell 11, and let it stand for 5 minutes;

[0059] (S12) Then add 50 μL of manganese dioxide (MnO 2 ) solution to the solution reaction cell 11, and let it stand for 10 minutes;

[0060] (S13) Wash the solution reaction cell 5 times with deionized water, and place it in a drying oven at 60 °C for 30 minutes to fix the manganese dioxide particles on the surface of the sensing chip 12;

[0061] Characterize the MnO 2 nanozyme particles detected in this embodiment, and the results are as Figure 2 shown;

[0062] Figure 2 In it, A and B are MnO respectively 2 Dark-field microscope images and corresponding in-situ scanning electron microscope images of nanozyme particles. It can be seen from the figure that by using dark-field optical imaging technology, high-resolution imaging of MnO nanozyme particles on the sensing chip can be successfully achieved 2 Figure 2 In it, C is MnO 2 High-magnification scanning electron microscope image of nanozyme particles, indicating that the measured MnO nanozyme particles are single particles 2 Figure 2 In it, D is MnO 2 XRD image of nanozyme particles. The characterization results show that the crystal form of the measured MnO nanozyme particles is α-type 2

[0063] S2. Add the reaction solution to the solution reaction pool, and use the optical imaging module to image the nanozyme catalytic reaction. Taking hydrogen peroxide (H 2 O 2 ) reaction solution as an example:

[0064] (S21) Use deionized water as the solvent to prepare a hydrogen peroxide solution with a concentration of 0.1 mM. After preparation, add 30 μL of the hydrogen peroxide solution to the solution reaction pool 11

[0065] (S22) After the reaction is complete, start the laser generator 21 to emit a supercontinuum white laser as the laser for dark-field optical imaging. The laser is reflected by the optical path adjustment component 22 to the dark-field condenser 23, and the laser is incident on the sensing chip 12 through the dark-field condenser 23

[0066] (S23) The scattering signals of the nanozyme material to be measured sequentially pass through the microscopic imaging objective lens 24 and the mirror 31 and enter the image sensor 32

[0067] S3. Use the image recording module to collect the dark-field scattering images of nanozyme particles and obtain the change in scattering intensity of nanozymes during the catalytic reaction

[0068] Use the above CCD sensor to obtain the change in scattering intensity of the above MnO nanozyme after adding the above reaction solution. Set the image recording speed to 10 frames per second and the recording time to 300 seconds 2

[0069] S4. Data processing: Use the Plot Z-axis Profile command of Image J software to draw the change graph of the time-brightness curve of MnO nanoparticles, and further statistically analyze the histogram of brightness distribution 2 ​​​​​

[0070] Detect the catalytic behavior of MnO 2 nanozyme particles in this example. The results are as Figure 3 shown. After adding 0.1 mM H 2 O 2 solution to the reaction solution, no obvious change in the optical intensity signal was observed using a dark-field microscope, indicating that no nanobubbles were generated under this condition.

[0071] Example 3:

[0072] (S11) Place the solution reaction cell 11 on the surface of the sensing chip 12, and add 50 μL of PBS solution to the solution reaction cell 11, and let it stand for 5 minutes;

[0073] (S12) Then add 50 μL of manganese dioxide (MnO2) solution to the solution reaction cell 11, and let it stand for 10 minutes;

[0074] (S13) Wash the solution reaction cell 5 times with deionized water, and place it in a drying oven at 60 °C for 30 minutes to fix the manganese dioxide particles on the surface of the sensing chip 12;

[0075] S2. Add the reaction solution to the solution reaction cell, and use the optical imaging module to image the nanozyme-catalyzed reaction, specifically as follows:

[0076] (S21) Prepare a sodium dodecyl sulfate (SDS) solution with a concentration of 107.7 mM using deionized water as the solvent. After preparation, add 30 μL of the above SDS solution to the solution reaction cell 11;

[0077] (S22) After the reaction is complete, start the laser generator 21 to emit a supercontinuum white laser as the laser for dark-field optical imaging. The laser is reflected by the optical path adjustment component 22 to the dark-field condenser 23, and the laser is incident on the sensing chip 12 through the dark-field condenser 23;

[0078] (S23) The scattering signal of the nanozyme material to be measured sequentially passes through the microscopic imaging objective lens 24 and the mirror 31 and enters the image sensor 32;

[0079] S3. Use the image recording module to collect the dark-field scattering images of the nanozyme particles and obtain the change in the scattering intensity of the nanozyme during the catalytic reaction.

[0080] Detect the catalytic behavior of MnO 2 nanozyme particles in this example. The results are as Figure 4 shown. After adding 107.7 mM SDS solution, no obvious change in the optical intensity signal was observed using a dark-field microscope, indicating that no nanobubbles were generated under this condition.

[0081] Example 4:

[0082] (S11) Place the solution reaction cell 11 on the surface of the sensing chip 12, add 50 μL of PBS solution to the solution reaction cell 11, and let it stand for 5 minutes;

[0083] (S12) Then add 50 μL of manganese dioxide (MnO 2 ) solution to the solution reaction cell 11 and let it stand for 10 minutes;

[0084] (S13) Wash the solution reaction cell 5 times with deionized water and place it in a drying oven at 60 °C for 30 minutes to fix the manganese dioxide particles on the surface of the sensing chip 12;

[0085] S2. Add the reaction solution to the solution reaction cell 11 and image the nanozyme-catalyzed reaction using the optical imaging module, specifically as follows:

[0086] Prepare a 0.1 mM hydrogen peroxide (H 2 O 2 ) solution and a 107.7 mM sodium dodecyl sulfate (SDS) solution using deionized water as the solvent. After preparation, add 15 μL of each of the above H 2 O 2 solution and SDS solution to the solution reaction cell 11;

[0087] S3. Use the image recording module to collect the dark-field scattering images of the nanozyme particles and obtain the change in scattering intensity during the catalytic reaction of the nanozyme;

[0088] S4. Data processing: Use the Plot Z-axis Profile command of Image J software to plot the change graph of the time-brightness curve of the MnO 2 nanoparticles, and further statistically analyze the histogram of the brightness distribution.

[0089] Detect the catalytic behavior of the MnO 2 nanozyme particles in this example. The results are as shown in Figure 5 A. After adding 0.1 mM H 2 O 2 solution and 107.7 mM SDS solution, obvious changes in the optical intensity signal were observed using a dark-field microscope; the scattering light intensity-time curve of the MnO 2 nanozyme particles has two stable catalytic states, high state and low state. The high state is that MnO 2 nanozyme catalyzes H 2 O 2 , generating nano-bubbles, causing an increase in the dark-field scattering intensity ( Figure 6) That is, in the scattered light intensity-time curve, the low state corresponds to the "stopped" state of the catalytic reaction, and the high state corresponds to the "occurring" state of the catalytic reaction; the above results indicate that the device and method involved in the present invention can detect the catalytic activity of single-particle nanozymes through dark-field optical imaging technology, providing a novel and important means for studying the catalytic activity of nanozymes.

[0090] In summary, the present invention uses dark-field scattered optical imaging to study the catalytic behavior of nanozymes. By directly detecting the change in the dark-field scattered optical intensity of single nanozyme particles, the catalytic activity of single nanozymes is determined, providing a non-destructive, label-free, and highly sensitive device and method for studying the catalytic activity of nanozymes. Moreover, this method has the advantages of high throughput, non-invasiveness, and a wide range of research objects, and can be used to study the catalytic activity and structure-activity relationship of nanozymes at the single-particle level, expanding the application of nano-optical imaging analysis.

[0091] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device.

[0092] For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. When an element is referred to as "assembled on", "mounted on", "fixed to" or "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation.

[0093] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

[0094] In the description of this specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

Claims

1. A device for detecting the catalytic activity of a single nanozyme using dark-field optical imaging, characterized in that: include: A sample reaction module, the sample reaction module comprising a solution reaction pool (11) and a sensor chip (12) fixed at the bottom of the solution reaction pool (11), the sample reaction module being used for the occurrence of a nanozyme catalytic reaction; An optical imaging module, the optical imaging module comprising a laser generator (21), an optical path adjustment component (22) being arranged downstream of the optical path transmission of the laser generator (21), a dark field condenser (23) and a microscopic imaging objective lens (24) being installed downstream of the optical path transmission of the optical path adjustment component (22), the dark field condenser (23) and the microscopic imaging objective lens (24) being respectively located above and below the sample reaction module, the optical imaging module being used for imaging of nanozyme catalytic reactions; An image recording module, the image recording module comprising a reflector (31) arranged downstream of the optical path transmission of the microscopic imaging objective lens (24), an image sensor (32) being arranged downstream of the optical path transmission of the reflector (31), the image recording module being connected to the optical imaging module and being used to collect image signals of the nanozyme in the reaction solution.

2. The device for detecting the catalytic activity of a single nanozyme using dark-field optical imaging according to claim 1, characterized in that: The sensor chip (12) is a BK7 cover glass, and its surface contact angle is less than 10°.

3. The device for detecting the catalytic activity of a single nanozyme using dark-field optical imaging according to claim 2, characterized in that: The solution reaction tank (11) is made of polydimethylsiloxane.

4. The device for detecting the catalytic activity of a single nanozyme using dark-field optical imaging according to claim 3, characterized in that: The dark field condenser (23) is a dry condenser with a numerical aperture of 0.80-0.95, and the magnification of the microscopic imaging objective lens (24) is 40 and the numerical aperture is 0.

6.

5. The device for detecting the catalytic activity of a single nanozyme using dark-field optical imaging according to claim 4, characterized in that: The dark field condenser (23), the sensor chip (12), and the microscopic imaging objective lens (24) are installed in the same direction and on the same axis from top to bottom. The laser passes through the dark field condenser (23) so that the light falls on the sensor chip (12) at an inclined angle. The scattered signal generated by the nano-enzyme material to be tested passes through the microscopic imaging objective lens (24) and the image sensor (32) in turn, thereby forming a bright image on a dark background.

6. The device for detecting the catalytic activity of a single nanozyme using dark-field optical imaging according to claim 5, characterized in that: The image sensor (32) is a CCD image sensor or a CMOS image sensor.

7. A method for detecting the catalytic activity of a single-particle nanozyme using dark-field optical imaging, characterized in that: The method is implemented by using a device for detecting the catalytic activity of a single nanozyme using dark-field optical imaging as described in any one of claims 1 to 6, and specifically comprises the following steps: S1. Add the sample to the solution reaction pool and modify the nanozyme on the surface of the sensor chip by physical modification method; S2. adding a reaction solution to the solution reaction pool, and imaging the nanozyme catalytic reaction using an optical imaging module; S3. Use the image recording module to collect the dark field scattering image of the nanozyme particles and obtain the change in the scattering intensity of the nanozyme during the catalytic reaction.

8. The method for detecting the catalytic activity of a single-particle nanozyme using dark-field optical imaging according to claim 7, characterized in that: In step S1, a sample is added to the solution reaction pool, and the nanozyme is modified on the surface of the sensor chip by a physical modification method, as follows: (81) placing the solution reaction pool (11) on the surface of the sensor chip (12), adding 50 μL of PBS solution into the solution reaction pool, and letting it stand for 5 minutes; (82) Then, 50 μL of manganese dioxide solution was added to the solution reaction cell (11) and allowed to stand for 10 min; (83) The solution reaction pool (11) was washed 5 times with deionized water and placed in a drying oven at 60°C for 30 minutes to fix the manganese dioxide particles on the surface of the sensor chip (12).

9. The method for detecting the catalytic activity of a single-particle nanozyme using dark-field optical imaging according to claim 8, characterized in that: S2. Add the reaction solution to the solution reaction pool (11), and use the optical imaging module to image the nanozyme catalytic reaction, as follows: (91) Deionized water was used as the solvent to prepare a 0.1 mM hydrogen peroxide solution. After the preparation was completed, 30 μL of the hydrogen peroxide solution was added to the sample cell; (92) After the reaction is complete, the laser generator (21) is started to emit supercontinuum white laser as the laser for dark field optical imaging, and the laser is reflected to the dark field condenser (23) through the optical path adjustment component (22), and the laser is incident on the sensor chip (12) through the dark field condenser (23); (93) The scattered signal of the nanozyme material to be tested passes through the microscope imaging objective lens 24 and the reflector (31) in turn and enters the image sensor (32).

10. The method for detecting the catalytic activity of a single-particle nanozyme using dark-field optical imaging according to claim 9, characterized in that: In step S3, an image sensor (32) is used to obtain the change in scattering intensity of the manganese dioxide nanozyme after the hydrogen peroxide reaction solution is added, and the image recording speed is set to 10 frames per second and the recording time is 300 seconds.

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