A method for controllably preparing a visible light-induced SiN nanonetwork platform and its applications

Abstract

The present invention discloses a method for controllably preparing a visible light-induced SiN nanonetwork platform and its application. The method is as follows: (1) Use the electron beam of a transmission electron microscope to focus on the SiNx thin film to prepare nanopores with different diameters; (2) Place the SiNx thin film with nanopores obtained in step (1) in solution A, and irradiate it with a highly uniform xenon lamp for different times at room temperature to shrink the pore diameter; (3) Observe the change in the pore diameter of the SiNx nanopores after irradiation under TEM, and determine the variation law of the pore diameter with the irradiation time; (4) Realize the controllable preparation of SiNx nanopores with the desired pore diameter according to the variation law in step (3). The present invention uses the electron beam of a transmission electron microscope to prepare nanopores with different pore diameters, and then uses visible light to induce the shrinkage of SiNx pores. The method is simpler, has lower cost, and the prepared inorganic nanonetwork has good structural stability, adjustable size, easy modification, can be reused, and can be used for the construction of a fully inorganic protein capture platform and protein structure analysis.

Description

Technical Field

[0001] The present invention belongs to the technical field of micro-nano processing, and particularly relates to a method for controllably preparing a visible light-induced SiN nanonetwork platform and its application. Background Art

[0002] In the past two decades, nanopore sensing technology, as a simple and highly sensitive label-free single-molecule analysis method, has received extensive attention, and remarkable achievements have been made in the study of protein molecules using nanopores. The basic principle of nanopore analysis and detection is that when an analyte passes through a nanopore, it will block the ionic open pore current of the nanopore, forming a detectable transient blockage current. When the analyte to be detected completely passes through the nanopore, the ionic current returns to the open pore current level again. Information such as the volume, shape, dipole moment, and concentration of a single protein can be obtained through the amplitude of the current pulse passing through the nanopore, the translocation residence time, and the event interval time. In the past few years, artificially synthesized solid-state nanopores have become a current research hotspot. For example, glass nanopores and silicon nitride nanopores fabricated by laser-assisted capillary pulling have enabled the detection of single proteins that are usually in a folded state, providing the possibility to evaluate the size, shape, charge, dipole, and rotational diffusion coefficient of proteins. However, when using silicon nitride solid-state nanopores to study protein translocation, in addition to the pore-crossing events, the generated current signals also include collision signals with shorter residence times and signals of longer protein-nanopore interactions. Whether these events are caused by the complex three-dimensional structure of the protein and whether they can be used for the characterization of its structure still require a large amount of research. Obtaining more three-dimensional structure information of proteins using nanopores will further enhance the potential of nanopores for describing protein properties. Using negatively charged porous nanospheres formed by DNA origami to capture proteins by electroosmotic flow and block their translocation through the pore, enabling the protein to stay in the cavity for a long time to study the conformational changes of the protein. However, in this strategy, it is also necessary to consider the stability of the DNA assembly and the possibility that it may be compressed in the electric field, causing ionic fluctuations at the pore opening and resulting in a decrease in the signal-to-noise ratio. Whether for pore-crossing or capture research, as the core component of the sensing platform, the applicability of the nanopore restricts the usage scenarios and overall level of this analysis technology. If a stable and rigid all-inorganic protein capture platform based on nanopores can be developed, mimicking the structure of a fishing net, for the study of information such as the morphology and conformational changes of proteins, it will be of great significance. Summary of the Invention

[0003] Aiming at the above technical problems, the present invention provides a method for inducing pore shrinkage of SiNx nanopores under visible light to control the pore diameter, and provides the application of this control method in all-inorganic protein capture and structural analysis.

[0004] The present invention prepares an all-inorganic silicon nitride nanonet structure through a simple two-step method: electron beam lithography to prepare silicon nitride nanopores and subsequent visible light-induced construction of silicon nitride nanonets. Since there is a damaged area around the SiNx pores obtained by electron beam drilling, and this area is mainly composed of Si elements with very little N element content, amorphous Si absorbs visible light. Therefore, light can be used to cause strain in this area, and due to the action of surface tension, the SiNx shrinks the pores. Based on the above characteristics, the method provided by the present invention can determine the law of the pore diameter changing with the illumination time, and further realize the controllable preparation of SiNx nanopores with the required pore diameter.

[0005] The technical solution provided by the present invention is as follows:

[0006] In the first aspect, the present invention provides a method for controllably preparing a visible light-induced SiN nanonet platform, including the following steps:

[0007] (1) Focus the electron beam of a transmission electron microscope on the SiNx film to prepare nanopores with different diameters;

[0008] (2) Place the SiNx film with nanopores obtained in step (1) in solution A, and irradiate it with a xenon lamp at room temperature for different times to shrink the pore diameter;

[0009] (3) Observe the change of the pore diameter of the SiNx nanopores after illumination under TEM, and determine the law of the pore diameter changing with the illumination time;

[0010] (4) Realize the controllable preparation of SiNx nanopores with the required pore diameter through the variation law in step (3).

[0011] Furthermore, in step (1), the method for preparing nanopores includes focusing the electron beam of the transmission electron microscope in the imaging mode, and obtaining nanopores with different diameters by adjusting the magnification once or multiple times.

[0012] Furthermore, in step (1), the pore diameter range of the nanopores is 5 - 60 nm.

[0013] Furthermore, in step (2), solution A is a KCl solution or water.

[0014] Even further, the concentration of the KCl solution is 0.5 - 3 M. Preferably, the concentration of the KCl solution is 1 M.

[0015] Furthermore, in step (2), the light source used is a 50 W high-uniform xenon lamp, the irradiation height is 20 cm, the output light intensity is measured by a light power meter, and the light intensity is adjusted during the pore shrinking process to make it 2 - 6 mW cm -2 , and the irradiation time is 3 - 60 min. Preferably, the light intensity is 4 mW cm -2 .

[0016] Further, in the step (3), the variation rule is that the pore diameter shrinks with the increase of the illumination time until it completely shrinks to form a reticular platform.

[0017] Furthermore, in the step (3), the thickness of the reticular platform formed by complete shrinkage is smaller than the thickness of the non-shrinking part around it.

[0018] In a second aspect, the present invention provides the application of the method described in the first aspect in the capture and structural analysis of all-inorganic proteins. The SiN nanonet platform with stable rigidity prepared by the method of the present invention can be used for the construction of an all-inorganic protein capture platform and protein structure analysis.

[0019] Advantages of the present invention:

[0020] The present invention uses a transmission electron microscope electron beam to prepare nanopores with different pore diameters, and then uses visible light to induce pore shrinkage of SiNx. Compared with the reported methods of using ion beams and electron beams for pore shrinkage, the method is simpler, has lower cost, and the obtained inorganic nanonet structure has advantages such as better stability, size tunability, easy modification, and reusability. The SiN nanonet platform with stable rigidity prepared by the present invention can be used for the construction of an all-inorganic protein capture platform and protein structure analysis. Description of the drawings

[0021] Figure 1 It is a TEM image of silicon nitride nanopores prepared by TEM electron beam and after being irradiated by a highly uniform xenon lamp. The scale bar is 10 nm; among them, a-c correspond to the pore diameter change diagrams of Example 1 at different irradiation times, d-f correspond to the pore diameter change diagrams of Example 2 at different irradiation times, and g-i correspond to the pore diameter change diagrams of Example 2 at different irradiation times. Detailed implementation manners

[0022] The content of the present invention will be further described below in conjunction with specific embodiments, and the content of the present invention is not limited thereto at all.

[0023] In the following examples, the SiNx thin film was purchased from NANOPORE solutions.

[0024] Example 1

[0025] A preparation method of a visible light-induced SiNx nanonet platform includes the following steps:

[0026] (1) Place the SiNx thin film on the TEM sample rod. After loading the sample, focus the electron beam of the TEM in the imaging mode. At a magnification of 1.2Mⅹ, pores appear in the SiNx thin film under electron beam irradiation, and pores with an initial diameter of 11 nm are obtained;

[0027] (2) Place the above SiNx holes in a 1 M KCl solution and irradiate them under a highly uniform xenon lamp. The power of the xenon lamp is 50 W, the irradiation height is 20 cm, and the light intensity is 4 mW cm -2 , and take them out after 3 minutes, rinse with water, dry, and then observe the change of the holes with TEM. As Figure 1 (b) shows, after 3 minutes, the SiNx holes shrink, and the pore diameter changes from the original 11 nm to 3 nm;

[0028] (3) Place the above SiNx holes that have shrunk partially in a 1 M KCl solution and continue to irradiate them with a highly uniform xenon lamp (the light irradiation conditions remain unchanged). Take them out after 3 minutes, rinse with water, dry, and then observe the change of the holes with TEM. As Figure 1 (c) shows, after 6 minutes of light irradiation, the SiNx holes are completely closed, and a SiNx nano-network platform is obtained. The thickness of the platform part is smaller than that of the surrounding SiNx bulk film.

[0029] Example 2

[0030] A method for preparing a visible light-induced SiNx nano-network platform, comprising the following steps:

[0031] (1) Place the SiNx film on the TEM sample rod. After loading the sample, focus the electron beam of the TEM in the imaging mode. At a magnification of 1.2 Mⅹ, holes appear in the SiNx film under electron beam irradiation, obtaining holes with an initial diameter of about 10 nm. Then slightly disperse the electron beam and expand the holes at a magnification of 1.0 Mⅹ to obtain holes with a diameter of 21 nm;

[0032] (2) Place the above SiNx holes in a 1 M KCl solution and irradiate them under a highly uniform xenon lamp. The power of the xenon lamp is 50 W, the irradiation height is 20 cm, and the light intensity is 4 mW cm -2 , and take them out after 3 minutes, rinse with water, dry, and then observe the change of the holes with TEM. As Figure 1 (e) shows, after 3 minutes of light irradiation, the SiNx holes shrink, and the pore diameter changes from the original 21 nm to 17 nm;

[0033] (3) Place the above SiNx holes that have shrunk partially in a 1 M KCl solution and continue to irradiate them with a highly uniform xenon lamp (the light irradiation conditions remain unchanged). Take them out after 7 minutes, rinse with water, dry, and then observe the change of the holes with TEM. As Figure 1 (f) shows, after 10 minutes of light irradiation, the SiNx holes are completely closed, and a SiNx nano-network platform is obtained. The thickness of the platform part is smaller than that of the surrounding SiNx bulk film.

[0034] Example 3

[0035] A method for preparing a visible light-induced SiNx nano-network platform, comprising the following steps:

[0036] (1) Place the SiNx thin film on the TEM sample holder. After loading the sample, focus the electron beam of the TEM in the imaging mode. Under a magnification of 1.2Mⅹ, pores are formed in the SiNx thin film under electron beam irradiation, obtaining pores with an initial diameter of approximately 10 nm. Then, slightly disperse the electron beam and expand the pores under a magnification of 1.0Mⅹ to obtain pores with a diameter of 33 nm;

[0037] (2) Place the above SiNx pores in a 1M KCl solution and irradiate them under a highly uniform xenon lamp. The power of the xenon lamp is 50 W, the irradiation height is 20 cm, and the light intensity is 4 mW cm -2 . After 25 minutes, take it out, rinse it with water, dry it, and then observe the change of the pores with TEM. As Figure 1 (h) shows, after 25 minutes of light irradiation, the SiNx pores shrink, and the pore diameter changes from the original 33 nm to 4 nm;

[0038] (3) Place the partially shrunk SiNx pores in a 1M KCl solution and continue to irradiate them with a highly uniform xenon lamp (the light irradiation conditions remain unchanged). After 20 minutes, take it out, rinse it with water, dry it, and then observe the change of the pores with TEM. As Figure 1 (i) shows, after 45 minutes of light irradiation, the SiNx pores are completely closed, obtaining a SiNx nano-network platform, and the thickness of the platform part is smaller than that of the surrounding SiNx bulk thin film.

[0039] As described above, it is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any modification, equivalent replacement, and improvement made by those skilled in the art within the technical scope disclosed by the present invention shall be included within the protection scope of the invention.

Claims

1. A method for controllably preparing a visible light-induced SiN nanonetwork platform, characterized in that, it comprises the following steps: (1) Using the electron beam of a transmission electron microscope to focus on the SiNx film to prepare nanopores with different diameters; (2) Placing the SiNx film with nanopores in step (1) in solution A, and irradiating with a xenon lamp at room temperature for different times to shrink the pore diameter; the solution A is a KCl solution or water; (3) Observing the change in the pore diameter of the SiNx nanopores after irradiation under TEM, and determining the variation law of the pore diameter with the irradiation time; (4) Realizing the controllable preparation of SiNx nanopores with the required pore diameter through the variation law in step (3).

2. The method according to claim 1, characterized in that, in step (1), the method for preparing nanopores includes focusing the electron beam of the transmission electron microscope in the imaging mode, and obtaining nanopores with different diameters by adjusting the magnification once or multiple times.

3. The method according to claim 1, characterized in that: in step (1), the pore diameter range of the nanopores is 5 - 60 nm.

4. The method according to claim 1, characterized in that: the concentration of the KCl solution is 0.5 - 3M.

5. The method according to claim 1, characterized in that: In step (2), the light source is a 50 W high-uniform xenon lamp, the irradiation height is 20 cm, the output light intensity is measured by a optical power meter, and the light intensity is adjusted to be 2 - 6 mW cm -2 , and the irradiation time is 3 - 60 min.

6. The method according to claim 1, characterized in that: in step (3), the variation law is that the pore diameter shrinks with the increase of the irradiation time until it completely shrinks to form a network platform.

7. The method according to claim 6, characterized in that: in step (3), the thickness of the network platform formed by complete shrinkage is smaller than the thickness of the non-shrinking part around it.

8. Application of the method according to any one of claims 1 - 7 in all-inorganic protein capture and structural analysis.

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