Copper sulfide nano material, preparation method, photo-thermal material, photo-acoustic probe and application

Abstract

The invention provides a copper sulfide nano material and a preparation method thereof, a photothermal material, a photoacoustic probe and application. The invention relates to a preparation method of a copper sulfide nano material, which comprises the following steps: dissolving protein in deionized water, then adding a soluble copper salt aqueous solution, and stirring to obtain a first solution; adding an alkaline metal salt aqueous solution into the first solution to obtain a second solution; adding a Na2S aqueous solution into the second solution, and stirring to obtain a protein coated CuS nano material; wherein the molar ratio of the soluble copper salt aqueous solution to the alkaline metal salt aqueous solution to the Na2S aqueous solution is (0.2: 1)-(5: 0.4). According to the method, the copper sulfide nano material is synthesized by using the template protein under a relatively mild condition only through simple stirring, so that the requirements on extreme conditions such as high temperature and high pressure are reduced, and the energy consumption and the potential environmental influence are reduced.

Description

Technical Field

[0001] The present disclosure relates to the technical field of the preparation of nanomaterials, and particularly to a copper sulfide nanomaterial and a preparation method thereof, a photothermal material, a photoacoustic probe and applications thereof. Background Art

[0002] Optical diagnosis and treatment has many advantages such as non-invasiveness, remote operation, spatiotemporal controllability and low toxicity and side effects, and has received extensive attention from researchers in recent years. However, due to the high light barrier effect of human tissues, the application of traditional optical diagnosis and treatment modes is limited.

[0003] Biological tissues have weak absorption and scattering of near-infrared light (700 - 1700 nm), enabling near-infrared-based optical diagnosis and treatment methods to achieve higher imaging contrast and deeper tissue penetration depth. This property is particularly important for clinical applications because it can not only improve the visualization of tumors and other diseased tissues, but also enable effective treatment without damaging normal tissues. Currently, materials with near-infrared absorption functions, especially those in the second near-infrared region, are mostly inorganic materials, such as: gold nanoparticles, zinc sulfide, barium titanate, and so on. Copper sulfide (CuS) nanomaterials, as an important transition metal sulfide, have stable properties and strong absorption of near-infrared light, and thus have advantages as photothermal agents in tumor photothermal therapy.

[0004] Currently, the preparation methods of CuS nanomaterials mainly include: chemical precipitation method, hydrothermal method, mechanochemical method, vapor deposition method, sol-gel method, template method, etc. These methods have some problems. First of all, the synthesis process is complex and diverse, and each synthesis method has its specific conditions and steps. The hydrothermal method and solid-phase reaction method usually need to be carried out at a high temperature above 100 °C, which makes the operation process dangerous and complex, and is prone to produce by-products. Subsequent steps require analysis and purification, further increasing the complexity of the operation. Secondly, it is difficult to control the uniformity of particle size and morphology. The inherent synthesis methods are carried out under conditions such as high temperature and high pressure, unstable pH, etc. Coupled with the complexity of the nucleation and growth mechanism, the influence of surfactants, the purity of reactants and the choice of solvents, all of which will lead to inconsistent particle size and morphology. The interaction of these factors makes it difficult to precisely control the morphology and size of CuS nanomaterials. In addition, the poor water solubility, surface pollutants and unreacted precursors that may be introduced during the synthesis process further reduce its water solubility. Compared with other metal sulfides, CuS has lower hydrophilicity, which limits its application in biomedicine, especially in the fields of bioimaging and drug delivery that require good water solubility. The organic solvents (such as ethanol, acetone, etc.) used in the chemical precipitation method or sol-gel method will release volatile organic compounds during the evaporation process, and these substances have a negative impact on the atmospheric environment and human health. Generally speaking, the inherent synthesis conditions are usually relatively harsh, and many methods require high temperature and high pressure or the use of toxic chemical reagents, which not only increases the complexity of the experiment, but also poses a potential threat to the environment and the safety of the operator.

[0005] Therefore, organic materials with better biocompatibility and near-infrared absorption have great application potential in the field of photodiagnosis and therapy. For example, a method for synthesizing CuS nanomaterials using protein as a template has been developed. First of all, as a natural material, protein has good biocompatibility and biodegradability, and is suitable for application in the biomedical field. Secondly, the diversity and special three-dimensional structure of proteins can effectively regulate the morphology and particle size of CuS and improve the performance of the material. However, the current synthesis methods usually require high-temperature heating (60-90 °C) during synthesis, and heating will cause the protein to denature or even inactivate, which will affect the biological properties and stability of the template protein. And in the transformation from laboratory scale to industrial production, economy and reproducibility are also problems that need to be solved. Therefore, although synthesizing CuS using protein as a template has advantages, the above challenges still need to be overcome to achieve wide application. Summary of the Invention

[0006] The present disclosure provides a copper sulfide nanomaterial, a preparation method, a photothermal material, a photoacoustic probe and applications thereof, so as to solve at least one of the technical problems existing in the prior art.

[0007] According to a first aspect of the present disclosure, a method for preparing a copper sulfide nanomaterial is provided, and the preparation method includes:

[0008] Dissolve the protein in deionized water, then add a soluble copper salt aqueous solution, and stir to obtain a first solution;

[0009] Add an alkaline metal salt aqueous solution to the first solution to obtain a second solution;

[0010] Add an aqueous Na2S solution to the second solution and stir to obtain a protein@CuS nanomaterial; wherein, the molar ratio of the soluble copper salt aqueous solution, the alkaline metal salt aqueous solution, and the aqueous Na2S solution is 0.2:1 to 5:0.4.

[0011] In one possible embodiment, the concentration of the protein is 10 to 500 mg / ml.

[0012] In one possible embodiment, the protein is one of bovine serum albumin BSA, ovalbumin OVA, green fluorescent protein GFP, or other proteins containing cysteine.

[0013] In one possible embodiment, the soluble copper salt aqueous solution is one of a Cu(NO3)2 aqueous solution and a CuCl2 aqueous solution;

[0014] The alkaline metal salt aqueous solution is one of an NaOH aqueous solution and a KOH aqueous solution.

[0015] In one possible embodiment, the protein can also be replaced with a polypeptide containing cysteine, thereby preparing a polypeptide@CuS nanomaterial;

[0016] Or, the protein can also be replaced with a nuclease, thereby preparing a nuclease@CuS nanomaterial.

[0017] According to a second aspect of the present disclosure, a copper sulfide nanomaterial is provided, which is prepared by the preparation method in any one of the above possible embodiments.

[0018] According to a third aspect of the present disclosure, a photothermal material is provided, which includes a copper sulfide nanomaterial, and the copper sulfide nanomaterial is prepared by the preparation method described above.

[0019] According to a fourth aspect of the present disclosure, a photoacoustic probe is provided, which includes a copper sulfide nanomaterial, and the copper sulfide nanomaterial is prepared by the preparation method described above.

[0020] According to a fifth aspect of the present disclosure, an application of the above-mentioned photothermal material in preparing a photothermal therapy material is provided.

[0021] According to the sixth aspect of the present disclosure, there is provided an application of the described photoacoustic probe in the preparation of photoacoustic imaging materials.

[0022] The nanomaterials of this application also have the following advantages: 1), good biocompatibility and stability: Using proteins, polypeptides, and enzymes as templates can effectively reduce immune responses and toxicity, making them suitable for biomedical applications; it can promote the uniform deposition of CuS nanoparticles, control their shape and size, and ensure the consistency and dispersibility of copper sulfide nanomaterials. Using protein, polypeptide, or enzyme templates can effectively prevent nanoparticle aggregation, maintain the long-term stability of copper sulfide nanomaterials, and at the same time their amino acid composition can provide a good chemical environment, enhancing the interaction with the surrounding medium; the functionalization ability of proteins enables the synthesized CuS nanomaterials to further improve their biological activity and functionality through modification.

[0023] 2), template versatility: There are various types of templates for synthesizing CuS nanomaterials. Fluorescent proteins such as bovine serum albumin (BSA), ovalbumin (OVA), and green fluorescent protein (GFP) can all be used as templates, showing excellent biocompatibility and being particularly suitable for biomedical applications such as bioimaging and drug delivery. These biological macromolecules have diverse structures and can form templates of different shapes, thus effectively regulating the morphology and size of CuS nanoparticles to meet various application requirements. In addition, the template protein can endow CuS with specific functions by binding to other molecules.

[0024] 3), mild conditions, little impact on template proteins, and the activity / fluorescence of template enzymes / proteins is reversible: In this scheme, the synthesis method of CuS nanomaterials has obvious advantages. It is simple to operate, does not require heating, and has a relatively short synthesis cycle. This method is carried out under mild conditions, effectively reducing the impact on template proteins / enzymes and ensuring their biological activity. The template enzymes / proteins can maintain their activity and fluorescence characteristics during the synthesis process, enabling their functions to be retained and reversible. This characteristic provides a good foundation for subsequent biomedical applications such as bioimaging and drug delivery.

[0025] 4), simple synthesis process: Compared with traditional chemical synthesis methods, synthesizing copper sulfide nanomaterials using template proteins usually requires only simple stirring under relatively mild conditions, which reduces the need for extreme conditions such as high temperature and high pressure, thereby reducing energy consumption and potential environmental impacts.

[0026] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present disclosure, nor is it used to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] By reading the following detailed description with reference to the accompanying drawings, the above and other objects, features, and advantages of the exemplary embodiments of the present disclosure will become readily understandable. In the drawings, several embodiments of the present disclosure are shown in an exemplary but non-limiting manner, where:

[0028] In the drawings, the same or corresponding reference numerals denote the same or corresponding parts.

[0029] Figure 1 The test results of the photoacoustic signal intensities of the BSA@CuS nanomaterials and OVA@CuS nanomaterials of the embodiments of the present disclosure are shown;

[0030] Figure 2 The absorption ability of the BSA@CuS nanomaterials of the embodiments of the present disclosure in the wavelength range of 600 - 1100 nm is shown;

[0031] Figure 3 The first fluorescence intensity diagram of the fluorescently labeled polypeptide peptide@CuS nanomaterials of the embodiments of the present disclosure under different pH conditions is shown;

[0032] Figure 4 The second fluorescence intensity diagram of the fluorescently labeled polypeptide peptide@CuS nanomaterials of the embodiments of the present disclosure under different pH conditions is shown;

[0033] Figure 5 The fluorescence intensities of the fluorescently labeled polypeptide peptide@CuS nanomaterials of the embodiments of the present disclosure after adding different concentrations of GSH are shown;

[0034] Figure 6 The photothermal ability of the BSA@CuS nanomaterials of the embodiments of the present disclosure is shown;

[0035] Figure 7 The fluorescence intensities of the RNAse@CuS nanomaterials of the embodiments of the present disclosure before and after adding GSH are shown. Detailed Embodiments

[0036] To make the objectives, features, and advantages of the present disclosure more obvious and understandable, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to 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. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without making creative efforts belong to the scope of protection of the present disclosure.

[0037] The present application proposes a simple, convenient, green and environmentally friendly synthesis method. This synthesis method can be carried out at room temperature, using protein as a template, and CuS nanomaterials with small size, excellent photothermal properties and biocompatibility can be obtained. The synthesis process is simple, the reaction conditions are mild, and the influence on the original properties of the template protein is small. Moreover, the copper sulfide nanomaterials have strong absorption and photothermal conversion efficiency in the infrared and near-infrared regions (600 - 1100 nm). Therefore, the CuS nanomaterials have good photothermal properties and photoacoustic signals, and can be applied to photoacoustic imaging diagnosis and photothermal therapy of diseases. At the same time, different proteins can be used as templates according to different application scenario requirements to obtain protein@copper sulfide nanomaterials with different particle sizes and properties. In addition, enzymes can also be used as templates to obtain enzyme@copper sulfide nanomaterials. The synthesized protein@copper sulfide nanomaterials and enzyme@copper sulfide nanomaterials can inhibit the activities of the template protein and template enzyme, while glutathione (GSH) at a certain concentration can restore the properties of proteins, polypeptides and enzymes, thus constructing multimodal diagnostic and therapeutic probes.

[0038] In a first aspect, according to an embodiment of the present disclosure, the present application provides a method for preparing copper sulfide nanomaterials, the preparation method comprising:

[0039] Step 1): Dissolve the protein in deionized water, then add an aqueous solution of soluble copper salt, and stir to obtain a first solution;

[0040] Step 2): Add an aqueous solution of alkaline metal salt to the first solution to obtain a second solution;

[0041] Step 3): Add an aqueous solution of Na2S to the second solution and stir to obtain protein@CuS nanomaterials; wherein, the molar ratio of the aqueous solution of soluble copper salt, the aqueous solution of alkaline metal salt, and the aqueous solution of Na2S is 0.2:1 - 5:0.4.

[0042] The copper sulfide nanomaterials of the present application are synthesized at room temperature, effectively reducing the influence on the template protein, ensuring the biological activity of the protein, and being applicable to large-scale production lines.

[0043] For example, in Step 1), the concentration of the protein is 10 - 500 mg / ml. Exemplarily, the concentration of the protein is 10 mg / mL, 50 mg / mL, 100 mg / mL, 200 mg / mL, 250 mg / mL, 300 mg / mL, 350 mg / mL, 400 mg / mL, 500 mg / mL.

[0044] For example, in step 1), the protein is bovine serum albumin (BSA), ovalbumin (OVA), green fluorescent protein (GFP), or other proteins containing cysteine. Among them, BSA, OVA, and GFP contain cysteine themselves.

[0045] For example, in step 1), the protein can also be replaced by a polypeptide containing cysteine, thereby preparing a polypeptide@CuS nanomaterial.

[0046] Alternatively, in step 1), the protein can also be replaced by a nuclease, thereby preparing a nuclease@CuS nanomaterial. Preferably, the nuclease is ribonuclease (RNAse).

[0047] For example, in step 1), the aqueous solution of soluble copper salt is one of Cu(NO3)2 aqueous solution and CuCl2 aqueous solution.

[0048] For example, in step 2), the aqueous solution of alkaline metal salt is one of NaOH aqueous solution and KOH aqueous solution.

[0049] For example, in step 3), the molar ratio of the aqueous solution of soluble copper salt, the aqueous solution of alkaline metal salt, and the aqueous solution of Na2S is 0.2:1 to 5:0.4. Exemplarily, the molar ratio of these three is 0.2:1:0.4, 0.2:2:0.4, or 0.2:5:0.4.

[0050] The nanomaterial of the present application also has the following advantages: 1), good biocompatibility and stability: Using proteins, polypeptides, or enzymes as templates can effectively reduce immune responses and toxicity, making it suitable for biomedical applications; it can promote the uniform deposition of CuS nanoparticles, control their shape and size, and ensure the consistency and dispersibility of the copper sulfide nanomaterial. Using proteins, polypeptides, or enzyme templates can effectively prevent the aggregation of nanoparticles, maintain the long-term stability of the copper sulfide nanomaterial, and at the same time, their amino acid composition can provide a good chemical environment, enhancing the interaction with the surrounding medium; the functionalization ability of proteins enables the synthesized CuS nanomaterial to further improve its biological activity and functionality through modification.

[0051] 2), template versatility: There are various types of templates for synthesizing CuS nanomaterials. Fluorescent proteins such as BSA, ovalbumin (OVA), and GFP can all be used as templates, showing excellent biocompatibility and being particularly suitable for biomedical applications such as bioimaging and drug delivery. These biological macromolecules have diverse structures and can form templates of different shapes, thereby effectively regulating the morphology and size of CuS nanoparticles to meet various application requirements. In addition, the template protein can endow CuS with specific functions by binding to other molecules.

[0052] 3), Mild conditions, little impact on the template protein, and reversible activity / fluorescence of the template enzyme / protein: In this protocol, the synthesis method of CuS nanomaterials has obvious advantages, such as simple operation, no need for heating, and relatively short synthesis cycle. This method is carried out under mild conditions, effectively reducing the impact on the template protein / enzyme and ensuring its biological activity. The template enzyme / protein can maintain its activity and fluorescence characteristics during the synthesis process, enabling its function to be retained and reversible. This property provides a good foundation for subsequent biomedical applications, such as bioimaging and drug delivery.

[0053] 4), Simple synthesis process: Compared with traditional chemical synthesis methods, the synthesis of copper sulfide nanomaterials using template proteins is usually carried out under milder conditions and only requires simple stirring, which reduces the need for extreme conditions such as high temperature and high pressure, thereby reducing energy consumption and potential environmental impacts.

[0054] According to the second aspect of the present disclosure, the present application also provides a photothermal material, which includes copper sulfide nanomaterials prepared by the above preparation method.

[0055] According to the third aspect of the present disclosure, the present application also provides a photoacoustic probe, which includes copper sulfide nanomaterials prepared by the above preparation method, wherein in this method, the protein used is a fluorescent protein, or the protein can also be replaced by a fluorescently labeled polypeptide.

[0056] In addition, the present application also provides the applications of the photothermal material and the photoacoustic probe. Specifically, the application of the photothermal material in the preparation of photothermal therapy materials. The application of the photoacoustic probe in the preparation of photoacoustic imaging materials.

[0057] The following further describes the present application in detail with specific examples:

[0058] Example 1

[0059] A preparation method of copper sulfide nanomaterials using protein as a template, the preparation method includes:

[0060] Step 1), Weigh 2.5 mL of bovine serum albumin BSA with a concentration of 100 mg / mL and dissolve it in 4.25 mL of deionized water, then add 1 mL of an aqueous solution of Cu(NO3)2 with a concentration of 0.2 mol / L, and stir to mix evenly to obtain a first solution, and the solution is bluish-green.

[0061] Step 2), After 3 minutes, add 1 mL of an aqueous solution of NaOH with a concentration of 1 mol / L to the first solution to obtain a second solution, and the solution turns purple;

[0062] Step 3): Add 2 mL of an aqueous solution of Na2S with a concentration of 0.2 mol / L to the second solution. The solution turns dark brown. After continuing to stir for 4 h, the reaction ends. After ultrafiltration with a 30K ultrafiltration tube for 15 min, the product is recovered to obtain the BSA@CuS nanomaterial.

[0063] Example 2

[0064] A preparation method of a copper sulfide nanomaterial, the preparation method comprising:

[0065] Step 1): Weigh 2.5 mL of a fluorescently labeled polypeptide peptide with a concentration of 100 mg / mL and dissolve it in 4.25 mL of deionized water. Then add 1 mL of an aqueous solution of Cu(NO3)2 with a concentration of 0.2 mol / L and stir to mix evenly to obtain a first solution; wherein, the polypeptide is a polypeptide containing cysteine, and the polypeptide sequence is: RDHCVLHECVNCAGIRVRCSVK-FAM, and FAM is a fluorescent modification; FAM (carboxyfluorescein) modifies the lysine (K) at the end of this sequence and is covalently linked through the ε-amino group of its side chain.

[0066] Step 2): After 3 min, add 1 mL of an aqueous solution of NaOH with a concentration of 1 mol / L to the first solution to obtain a second solution;

[0067] Step 3): Add 2 mL of an aqueous solution of Na2S with a concentration of 0.2 mol / L to the second solution. After continuing to stir for 4 h, the reaction ends. After ultrafiltration with a 30K ultrafiltration tube for 15 min, the product is recovered to obtain the fluorescently labeled polypeptide peptide@CuS nanomaterial.

[0068] Example 3

[0069] A preparation method of a copper sulfide nanomaterial using a protein as a template, the preparation method comprising:

[0070] Step 1): Weigh 2.5 mL of ovalbumin OVA with a concentration of 100 mg / mL and dissolve it in 4.25 mL of deionized water. Then add 1 mL of an aqueous solution of Cu(NO3)2 with a concentration of 0.2 mol / L and stir to mix evenly to obtain a first solution.

[0071] Step 2): After 3 min, add 1 mL of an aqueous solution of NaOH with a concentration of 1 mol / L to the first solution to obtain a second solution;

[0072] Step 3): Add 2 mL of an aqueous solution of Na2S with a concentration of 0.2 mol / L to the second solution. After continuing to stir for 4 h, the reaction ends. After ultrafiltration with a 30K ultrafiltration tube for 15 min, the product is recovered to obtain the OVA@CuS nanomaterial.

[0073] Example 4

[0074] A preparation method of copper sulfide nanomaterials uses protein as a template. The preparation method includes:

[0075] Step 1), weigh 2.5 mL of ribonuclease RNase with a concentration of 100 mg / mL and dissolve it in 4.25 mL of deionized water, then add 1 mL of an aqueous solution of Cu(NO3)2 with a concentration of 0.2 mol / L, and stir to mix them evenly to obtain a first solution.

[0076] Step 2), after 3 min, add 1 mL of an aqueous solution of NaOH with a concentration of 1 mol / L to the first solution to obtain a second solution;

[0077] Step 3), add 2 mL of an aqueous solution of Na2S with a concentration of 0.2 mol / L to the second solution, continue to stir for 4 h, then the reaction ends. After ultrafiltration with a 30K ultrafiltration tube for 15 min and recovery, RNase@CuS nanomaterials are obtained.

[0078] Performance test

[0079] I): Measure the photoacoustic signal intensity of the BSA@CuS nanomaterials prepared in Example 1 and the OVA@CuS nanomaterials prepared in Example 3 under a photoacoustic device. The results are as Figure 1 shown. The results show that the BSA@CuS nanomaterials and OVA@CuS nanomaterials have strong photoacoustic signals at 1064 nm, while the photoacoustic signals at 532 nm are very weak, which reduces the interference of blood vessels on the photoacoustic imaging of nanomaterials in practical applications. This indicates that the protein@CuS nanomaterials prepared with protein as a template can be used to prepare photoacoustic probes, and further, the photoacoustic probes can be used for photoacoustic imaging.

[0080] II): Measure the absorption ability of the BSA@CuS nanomaterials prepared in Example 1 under an ultraviolet-visible spectrophotometer. The results are as Figure 2 shown. It can be obtained from Figure 2 that the BSA@CuS nanomaterials have strong absorption in the wavelength range of 600 - 1100 nm.

[0081] III): Measure the stability of the fluorescently labeled polypeptide peptide@CuS nanomaterials prepared in Example 2 under different pH conditions. The results are as Figure 3 shown. And measure the fluorescence intensity of the fluorescently labeled polypeptide peptide@CuS nanomaterials under different pH conditions. The results are as Figure 4 shown.

[0082] It can be obtained from Figure 3-4We can find that when the pH changes from 5 to 8, the fluorescence intensity of the nanomaterial does not change significantly, which proves the stability of the nanomaterial under different physiological conditions.

[0083] IV): Take the fluorescently labeled peptide@CuS nanomaterial prepared in Example 2, and after adding GSH aqueous solution (glutathione) of different concentrations (5mM, 10mM, 15mM, 20mM, 25mM, 30mM, 35mM), the fluorescence intensity of the nanomaterial recovers, as shown in FIG. Figure 5 shown. Figure 5 In the experiment, I is the template fluorescently labeled peptide (abbreviated as "P"), II is the fluorescently labeled peptide@CuS nanomaterial (abbreviated as "P-CuS"), and III to IX are the fluorescently labeled peptide@CuS nanomaterials with 5-35 mM GSH added. The results show that the synthesized fluorescently labeled peptide@CuS nanomaterial can quench the original fluorescence of the peptide, while a certain concentration of GSH (5-35 mM) can restore its fluorescence properties.

[0084] Five): Take the BSA@CuS nanomaterial prepared in Example 1 and test its photothermal properties. Place it under 808nm laser irradiation (2W / cm 2 ), and measure its heating curve, such as Figure 6 The results show that the BSA@CuS nanomaterial exhibits good photothermal conversion ability. Figure 6 In the experiment, H2O was used as the control group. Therefore, the protein@CuS nanomaterials prepared using protein as a template can be used as photothermal materials, and further the photothermal materials can be used in photothermal therapy.

[0085] VI): Take the RNase@CuS nanomaterial prepared in Example 4 and measure the RNase as a template, RNase@CuS nanomaterial (corresponding to Figure 7 "CuS-RNase" in the ), and after adding 10 mM GSH (glutathione) (corresponding to Figure 7 The digestion ability of the "CuS-RNase+GSH" in the above table is the same as that of the RNA substrate labeled with a fluorescent group and a quenching group at both ends, such as Figure 7 As shown, Figure 7 The fluorescence intensity of the RNase@CuS nanomaterial before and after the addition of GSH is shown. The results show that the RNase@CuS nanomaterial can inhibit the digestion of RNA substrates by RNase, while the addition of GSH can reversibly restore the enzymatic activity of RNase.

[0086] It should be understood that the various forms of processes shown above can be used, with steps reordered, added or deleted. For example, the steps described in this disclosure can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solutions disclosed in this disclosure can be achieved, and this is not limited herein.

[0087] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of this disclosure, "a plurality" means two or more, unless otherwise specifically defined.

[0088] As described above, the above are only specific embodiments of this disclosure, but the protection scope of this disclosure is not limited thereto. Any person skilled in the art within the technical scope disclosed in this disclosure can easily think of changes or substitutions, which should all be covered within the protection scope of this disclosure. Therefore, the protection scope of this disclosure should be subject to the protection scope of the claims.

Claims

1. A preparation method of copper sulfide nanomaterials, characterized in that: The preparation method includes the following steps: Dissolve the protein in deionized water, then add an aqueous solution of soluble copper salt, and stir to obtain a first solution; Add an aqueous solution of alkaline metal salt to the first solution to obtain a second solution; Add an aqueous solution of Na2S to the second solution and stir to obtain the protein@CuS nanomaterial; wherein, the molar ratio of the aqueous solution of soluble copper salt, the aqueous solution of alkaline metal salt, and the aqueous solution of Na2S is 0.2:1 to 5:0.

4.

2. The preparation method according to claim 1, characterized in that: The concentration of the protein is 10 - 500 mg / ml.

3. The preparation method according to claim 1, characterized in that: The protein is one of bovine serum albumin BSA, ovalbumin OVA, green fluorescent protein GFP, or other proteins containing cysteine.

4. The preparation method according to claim 1, characterized in that: The aqueous solution of soluble copper salt is one of an aqueous solution of Cu(NO3)2 and an aqueous solution of CuCl2; The aqueous solution of alkaline metal salt is one of an aqueous solution of NaOH and an aqueous solution of KOH.

5. The preparation method according to any one of claims 1-4, characterized in that: The protein can also be replaced by a polypeptide containing cysteine, so as to prepare a polypeptide@CuS nanomaterial; Or, the protein can also be replaced by a nuclease, so as to prepare a nuclease@CuS nanomaterial.

6. A copper sulfide nanomaterial, characterized in that: It is prepared by the preparation method described in any one of claims 1 - 5.

7. A photothermal material, which comprises the copper sulfide nanomaterial described in claim 6.

8. A photoacoustic probe, which comprises the copper sulfide nanomaterial described in claim 6.

9. Use of the photothermal material described in claim 7 in the preparation of a photothermal therapy material.

10. Use of the photoacoustic probe described in claim 8 in the preparation of a photoacoustic imaging material.

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