CN116477668B

CN116477668B - Two-dimensional ferric sulfide nano-sheet and preparation method and application thereof

Info

Publication number: CN116477668B
Application number: CN202310727648.8A
Authority: CN
Inventors: 孙晓; 张鑫宇; 许学莉; 王辰宇; 高媛
Original assignee: Shandong First Medical University and Shandong Academy of Medical Sciences
Current assignee: Shandong First Medical University and Shandong Academy of Medical Sciences
Priority date: 2023-06-20
Filing date: 2023-06-20
Publication date: 2023-08-22
Anticipated expiration: 2043-06-20
Also published as: CN116477668A

Abstract

The application discloses a two-dimensional ferric sulfide nano-sheet and a preparation method and application thereof, belonging to the technical field of biological medicine. Dissolving ferrous ammonium sulfate and trisodium citrate in ethylene glycol to obtain a solution A, dissolving polyethyleneimine in ethylene glycol to obtain a solution B, adding the solution B into the solution A, and stirring and reacting at normal temperature to obtain a mixed solution; adding thioacetamide solution into the mixed solution, then dropwise adding triethanolamine, stirring at normal temperature for reaction, performing solvothermal reaction after stirring, centrifuging and washing a product after the reaction is finished, and obtaining the two-dimensional ferric sulfide nano-sheet. And coating the two-dimensional ferric sulfide nano-sheet by mPEG-SH to obtain the degradable photo-thermal preparation. The synthesis method for preparing the two-dimensional ferric sulfide nanosheet photo-thermal preparation is simple and has strong operability; the synthesized product is stable and has repeatability; the iron sulfide nano-sheet synthesized by the application is amorphous, has excellent photo-thermal property and acid response degradability, and is more beneficial to clinical application.

Description

Two-dimensional ferric sulfide nano-sheet and preparation method and application thereof

Technical Field

The application relates to the technical field of biological medicine, in particular to a two-dimensional ferric sulfide nano-sheet and a preparation method and application thereof.

Background

Cancer is one of the main causes of death worldwide, seriously threatens the life safety of human beings, and the treatment means of the cancer still need to be greatly improved. The traditional treatment mode is implemented after the invasive method is used for diagnosis, and surgical excision, radiotherapy and chemotherapy are implemented, but the limitations of more contraindications, serious adverse reactions and the like can not obviously improve the life quality of patients, so the treatment mode with wide application range and small adverse reactions is urgently needed.

Phototherapy (PTT) is a promising and effective cancer treatment with photosensitizers that generate sufficient heat under Near Infrared (NIR) light irradiation to kill tumor cells and induce anti-tumor immunity, with high selectivity and minimal invasiveness. The conventional photothermal treatment materials at present mainly comprise gold nanoparticles, carbon nanotubes, graphene and the like, and the problems that light waves are easy to be absorbed and tissue penetrating power is poor in short-wavelength phototherapy such as ultraviolet light, visible light and the like are solved. However, these photo-thermal materials often cannot achieve both photo-thermal conversion efficiency and biocompatibility.

The two-dimensional nano material has attracted wide attention in the biomedical field by virtue of the advantages of large surface area, large drug loading capacity, good photo-thermal conversion performance and the like. However, the conventional two-dimensional materials are mostly obtained by adopting a stripping method, but the methods still have some problems, and the prepared two-dimensional materials have the defects of more defects, poor universality, low yield and higher required production conditions. Iron sulfide is easy to oxidize and cannot be obtained into two-dimensional nano-sheets by a mechanical stripping method, so that most of the currently prepared iron sulfide is three-dimensional spherical nano-particles. In research on synthesis and new energy application of two-dimensional ferric sulfide nano-sheets (Wu Yang, shuoshi treatises, university of fertilizer combination industry, 2021, 4 months), octoamine and ferric trichloride hexahydrate are utilized to react with sulfur powder to obtain amorphous ferric sulfide nano-sheets, but the thickness of the nano-sheets is 20-30 nm, and the nano-sheets can only be used for electrode materials and cannot be degraded. Therefore, the synthesis of an ultrathin degradable iron sulfide nano-sheet with a photo-thermal effect is very important in the field of biological medicine.

Disclosure of Invention

Aiming at the prior art, the application aims to provide a two-dimensional ferric sulfide nano-sheet and a preparation method and application thereof. The synthesis method for preparing the two-dimensional ferric sulfide nanosheet photo-thermal preparation is simple and has strong operability; the synthesized product is stable and has repeatability; the iron sulfide nano-sheet synthesized by the application is amorphous, has excellent photo-thermal property and acid response degradability, and is more beneficial to clinical application.

In order to achieve the above purpose, the application adopts the following technical scheme:

in a first aspect of the present application, a method for preparing a two-dimensional iron sulfide nanosheet is provided, comprising the steps of:

(1) Dissolving ferrous ammonium sulfate and trisodium citrate in ethylene glycol to obtain a solution A, dissolving polyethyleneimine in ethylene glycol to obtain a solution B, adding the solution B into the solution A, and stirring and reacting at normal temperature to obtain a mixed solution;

(2) Adding thioacetamide solution into the mixed solution, then dropwise adding triethanolamine, stirring at normal temperature for reaction, performing solvothermal reaction after stirring, centrifuging and washing a product after the reaction is finished, and obtaining the two-dimensional ferric sulfide (FeS) nanosheets.

Preferably, in the step (1), the ratio of the addition amount of the ferrous ammonium sulfate, the trisodium citrate and the ethylene glycol in the solution A is 0.6mmol:0.2mmol:15mL; in the solution B, the addition ratio of the polyethyleneimine to the ethylene glycol is 500mg:5mL; the ratio of the volume of the glycol in the solution A to the volume of the glycol in the solution B is 3:1.

preferably, in the step (1), the stirring is magnetic stirring, and the rotating speed is 600-800 rpm; the stirring reaction time is 2h.

Preferably, in step (2), the thioacetamide solution has a concentration of 0.05M; the ratio of the addition amount of the ferrous ammonium sulfate to the thioacetamide solution and the triethanolamine is 0.6mmol:15mL:2mL; the stirring is magnetic stirring, the rotating speed is 600-800 rpm, and the stirring reaction time is 1-10 min.

Preferably, in the step (2), the solvothermal reaction is carried out at a temperature of 200 ℃ for 24 hours; the rotational speed of the centrifugation is 14000rpm and the time is 10min; the washing is 3 times of washing with absolute ethyl alcohol.

In a second aspect of the present application, there is provided a two-dimensional iron sulfide nanoplatelet obtained by the above preparation method, wherein the minimum thickness of the two-dimensional iron sulfide nanoplatelet is 2.5nm.

In a third aspect of the application, there is provided the use of two-dimensional iron sulphide nanoplatelets in the preparation of a degradable photo-thermal formulation.

In a fourth aspect of the present application, a degradable photo-thermal formulation is provided, the degradable photo-thermal formulation being obtained from coating biocompatible materials with two-dimensional iron sulfide nanoplatelets.

Preferably, the biocompatible material is methoxypolyethylene glycol mercapto (mPEG-SH); the degradable photo-thermal preparation is prepared by the following method:

dissolving the two-dimensional ferric sulfide nano-sheet and mPEG-SH in absolute ethyl alcohol, stirring for reaction under the ice bath condition, centrifuging after the reaction is finished, collecting precipitate, and washing to obtain the degradable photo-thermal preparation.

Preferably, the molecular weight of the mPEG-SH is 2000-10000; the ratio of the addition amounts of the two-dimensional ferric sulfide nano-sheet, the mPEG-SH and the absolute ethyl alcohol is 1mg:1mg:1mL; the stirring speed is 350rpm and the stirring time is 6h.

The application has the beneficial effects that:

(1) The synthesis method for preparing the two-dimensional ferric sulfide nanosheet photo-thermal preparation is simple and has strong operability; the synthesized photo-thermal preparation is stable and has repeatability.

(2) The iron sulfide nano-sheet synthesized by the application is amorphous, has excellent photo-thermal performance and acid response degradability, and is more beneficial to clinical application.

(3) The method for synthesizing the two-dimensional ferric sulfide nano-sheet can effectively avoid the oxidization of the ferric sulfide nano-sheet in the synthesis process; the iron sulfide nano-sheet preparation prepared by combining with methoxy polyethylene glycol sulfhydryl has excellent photo-thermal performance, good biocompatibility, safety and no toxicity, and can be used for photo-thermal treatment including tumor.

Drawings

FIG. 1 is a transmission electron microscope image of a two-dimensional FeS nanoplatelet prepared in the examples;

FIG. 2 is an atomic force micrograph of two-dimensional FeS nanoplatelets prepared in the examples: (a) atomic force microscope image thickness test chart of two-dimensional FeS nano-sheets, (b) atomic force microscope electron microscope image of two-dimensional FeS nano-sheets, and (c) height section chart of corresponding lines;

FIG. 3 is an XRD result pattern of two-dimensional FeS nanoplatelets prepared in the examples;

FIG. 4 is a graph of XPS results for two-dimensional FeS nanoplatelets prepared in the examples;

FIG. 5 is a photograph of two-dimensional FeS nanoplatelet aqueous dispersions of different concentrations;

FIG. 6 is an absorption spectrum of two-dimensional FeS nanoplatelet aqueous dispersions of different concentrations;

FIG. 7 is a graph showing the temperature rise profile of two-dimensional FeS nanoplatelet aqueous dispersions of different concentrations;

FIG. 8 is a graph showing the temperature rise profile of two-dimensional FeS nanoplatelet aqueous dispersions of different frequencies;

FIG. 9 is the photo-thermal stability of two-dimensional FeS nanoplatelet aqueous dispersions;

FIG. 10 is a graph of the photothermal conversion efficiency of two-dimensional FeS nanoplatelet aqueous dispersions: (a) A single-period photo-thermal stability test result schematic diagram, (b) a cooling stage temperature change and cooling time negative natural logarithm relation schematic diagram of the single-period photo-thermal stability test;

FIG. 11 is a photograph of two-dimensional FeS nanoplatelets over time in PBS buffer at different pH's;

FIG. 12 shows the detection of cell uptake of MDA-MB-231 cells by flow cytometry after co-incubation with FeS-PEG at different concentrations;

FIG. 13 shows the uptake of MDA-MB-231 cells after co-incubation with FeS-PEG at different concentrations using a laser scanning confocal microscope (CLSM);

FIG. 14 is a graph showing the results of in vitro hemolysis assays for drugs having different concentrations of FeS-PEG: (a) Taking photographs of in vitro hemolysis of medicines with different concentrations of FeS-PEG, (b) carrying out statistical graphs of the hemolysis rate of medicines with different concentrations of FeS-PEG;

FIG. 15 is a graph showing the results of a biocompatibility assay of FeS-PEG on HUVEC cells at various concentrations;

FIG. 16 is a graph showing the effect of FeS-PEG on killing MDA-MB-231 cells at different concentrations;

FIG. 17 is a fluorescent image of live/dead cell staining after detection of FeS-PEG and MDA-MB-231 cells co-incubated at different concentrations with Calcein AM/PI fluorescent probes;

FIG. 18 is a fluorescent image of the presence of OH after detection of FeS-PEG and MDA-MB-231 cells at different concentrations by DCFH-DA fluorescent probe;

Detailed Description

It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the application. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

As described in the background section, two-dimensional iron sulfide nanoplatelets cannot be prepared by mechanical exfoliation due to their susceptibility to oxidation. Therefore, the thickness of the currently prepared iron sulfide nano-sheet is relatively large, two-dimensional iron sulfide nano-sheets with the thickness of a few nanometers cannot be obtained, and degradation is difficult to realize.

Based on the above, the application aims to provide a two-dimensional iron sulfide nano-sheet, and a preparation method and application thereof. The method takes ferrous ammonium sulfate and thioacetamide as raw materials, obtains precursor solution through simple stirring reaction, and then obtains the two-dimensional ferric sulfide nano-sheet through solvothermal reaction. The preparation method is simple, and the synthesized iron sulfide nano-sheet is extremely thin and amorphous, and has good acid response degradability. The photo-thermal preparation prepared by combining with methoxy polyethylene glycol sulfhydryl has excellent photo-thermal performance, good biocompatibility, safety and no toxicity.

In order to enable those skilled in the art to more clearly understand the technical scheme of the present application, the technical scheme of the present application will be described in detail with reference to specific embodiments.

The test materials used in the examples of the present application are all conventional in the art and are commercially available.

Examples

(1) Preparation of two-dimensional ferric sulfide nano-sheet

0.6mmol of ferrous ammonium sulfate and 0.2mmol of trisodium citrate were dissolved in 15mL of ethylene glycol, then 500mg of Polyethylenimine (PEI) was dissolved in 5mL ethylene glycol, PEI was added to the above solution, and reacted under magnetic stirring at 800rpm at room temperature for 120min. Subsequently, 15mL of a 0.05M thioacetamide solution was added to the solution, and then 2mL of triethanolamine was added dropwise to the mixture at 500. Mu.L/min. The reaction was carried out at room temperature under magnetic stirring at 800rpm for 1min. After completion of stirring, the whole of the mixed solution was transferred to an autoclave, and reacted at 200℃for 24 hours with heating. And finally, centrifugally collecting at 14000rpm for 10min, and washing with absolute ethyl alcohol for 3 times to obtain the two-dimensional ferric sulfide nano-sheet.

(2) Preparation of iron sulfide nanosheet photo-thermal preparation

1mg of the iron sulfide nanosheets prepared in the step (1) and 1mg of mPEG ₅₀₀₀ SH was dissolved in 1mL of absolute ethanol and stirred at 350rpm for 6h under ice-bath conditions. And centrifuging the obtained product at 14000rpm for 5min, discarding the supernatant, collecting the precipitate, and washing with absolute ethyl alcohol for 3 times to obtain the final integrated diagnosis and treatment preparation (marked as FeS-PEG) of the iron sulfide nano-sheet.

(3) Performance analysis

As shown in FIG. 1, a proper amount of two-dimensional ferric sulfide nano-sheets are dissolved in absolute ethyl alcohol to prepare a solution with the concentration of 1mg/mL, 20 mu L of the solution is dripped on a copper mesh by using a pipette, a transmission electron microscope detection sample is prepared by drying, and the transmission electron microscope is used for observation, wherein the prepared ferric sulfide has a two-dimensional lamellar shape, and the particle size is about 100-150nm.

As shown in fig. 2, the atomic force microscope of the two-dimensional iron sulfide nanosheets prepared in this example. As shown by atomic force microscopy and thickness quantification results thereof, the iron sulfide is in a two-dimensional lamellar shape, is uniformly dispersed, has a long diameter of 100-150nm, accords with a transmission electron microscopy, and has a thickness of about 2.5nm.

As shown in fig. 3, in XPS measurement spectrum, the two-dimensional iron sulfide nanoplatelets contain Fe, S, C, N, O element, confirming the synthesis of the iron sulfide nanoplatelets.

As shown in fig. 4, the two-dimensional iron sulfide nanoplatelets show typical amorphous structural features in XRD results, indicating that the nanoplatelets may have good biodegradability.

As shown in fig. 5, 10, 20, 40, 80 and 160 μg/mL of aqueous dispersions of iron sulfide nanoplatelets were prepared, respectively.

As shown in fig. 6, 200 μl of each of the iron sulfide nanosheet dispersion solutions of different concentrations was taken, and the absorption curves of the different concentrations were detected using an ultraviolet spectrophotometer. The higher the ultraviolet absorption at 808nm, the more photothermal power can be reflected in the laser irradiation at 808 nm.

As shown in fig. 7, 20, 40, 80 and 160 μg/mL of aqueous dispersions of iron sulfide nanoplatelets were prepared. Irradiation was performed with 808nm laser light, and a temperature profile was recorded at the same time. The results show the temperature rise profile of the temperature of the different concentrations with the laser irradiation time.

As shown in FIG. 8, 80 mug/mL of an aqueous dispersion of iron sulfide nanosheets was prepared using 808nm lasers at 1,1.5 and 2W/cm, respectively ² Is irradiated and the temperature profile is recorded simultaneously. The results show the temperature rise graph of the temperature at different power conditions with the laser irradiation time.

As shown in fig. 9, an 80 μg/mL aqueous dispersion of iron sulfide nanosheets is prepared, and a 808nm laser is adopted, so that a temperature curve under five switching cycles can be seen, and after 5 heating and cooling cycles are performed, the temperature change can be kept approximately consistent, and the good photo-thermal stability of the iron sulfide nanosheets is illustrated.

As shown in fig. 10, the photo-thermal conversion efficiency of the two-dimensional iron sulfide nanoplatelets was calculated to be 25.49%.

As shown in fig. 11, the iron sulfide nano-sheets with the volume of 100 mug/mL are respectively placed in buffer solution environments with different pH values, and the result shows that the solution color of the iron sulfide nano-sheets in the buffer solution with the pH value of 5.5 is gradually transparent, which indicates that the material has the acid-responsive degradation capability, can be degraded in an acidic environment after in-vivo action, is discharged from the body and does not accumulate in the body.

As shown in fig. 12, the FeS-PEG photothermal preparation prepared in step (2) was examined for its ability to be taken up by tumor cells using flow cytometry. First, 1mg of FeS-PEG and 1mg of FITC were mixed in 2mL of PBS, stirred for 6 hours, and then washed 2 times with deionized water to prepare FeS-PEG-FITC. And incubating FeS-PEG-FITC with MDA-MB-231 cells at the concentration of 0 mug/mL (control group), 10 mug/mL and 40 mug/mL, and detecting the uptake condition of the cells on the nano material after 4 hours. As a result, it was found that FITC fluorescence detected by flow cytometry gradually increased with increasing concentration, indicating that FeS-PEG was able to be efficiently taken up by tumor cells in a concentration-dependent manner.

As shown in FIG. 13, the ability of the FeS-PEG photothermal preparation prepared in step (2) to be taken up by tumor cells was examined using a confocal microscope. Preparation method of FeS-PEG-FITC As shown above, feS-PEG-FITC is incubated with MDA-MB-231 cells at concentrations of 0 (control group), 10 and 40 mug/mL, and after 4 hours, the uptake of the nano material by the cells is detected. As a result, it was found that the green fluorescence photographed by confocal microscopy gradually increased with increasing concentration, further demonstrating that FeS-PEG can be efficiently taken up by tumor cells in a concentration-dependent manner.

As shown in FIG. 14, the FeS-PEG photothermal preparation prepared in step (2) was added to the red blood cell suspension to prepare final concentrations of 3, 6, 12.5, 25, 50, 100 and 200. Mu.g/mL. The red blood cell suspension diluted with PBS (represented by (-) in FIG. 14) was used as a negative control, the red blood cell suspension diluted with ultrapure water (represented by (+) in FIG. 14) was used as a positive control, and red blood cells of the above-mentioned different concentrations of materials were added as an experimental group. The solutions of each group were incubated in a constant temperature incubator at 37℃for 4 hours, and then the solutions were centrifuged at 3000rpm for 15 minutes, the hemolysis phenomenon thereof was photographed, absorbance of the sample at 542nm was detected with an enzyme-labeled instrument, and the hemolysis rate was calculated. As a result, it was found that when the erythrocytes were incubated with FeS-PEG at different concentrations, substantially complete sinking of the erythrocytes was observed, and the supernatant was not much changed compared to the negative control group. This indicates that FeS-PEG does not cause hemolysis of erythrocytes and has good compatibility with blood cells.

As shown in FIG. 15, 1X 10 portions of each of the well plates were individually added to each of the well plates ⁴ Human umbilical vein endothelial cells HUVEC in the presence of 5% CO ₂ After 24 hours of culture in a constant temperature incubator at 37 ℃, the FeS-PEG prepared in the step (2) and the culture medium are prepared into mixed solutions with final concentrations of 0, 5, 10, 20, 40 and 80 mug/mL, and the mixed solutions are incubated with cells for 24h. After that, the culture solution was aspirated, MTT medium was added to each well for 3h, the culture solution was aspirated, 150 μl DMSO was added to each well, shaking was performed for 10min to completely dissolve the purple solid, absorbance values at each concentration were read with an microplate reader, and the relationship between the cell viability calculated from absorbance values and nanomaterial concentration was plotted. The results showed that the viability of HUVEC cells was about 80% at nanomaterial concentrations below 80. Mu.g/mL, indicating that FeS-PEG formulations were normalThe cells have good biocompatibility.

As shown in FIG. 16, 2 96-well plates were prepared in total, and 1X 10 wells were added to each well ⁴ MDA-MB-231 in human breast cancer cells containing 5% CO ₂ After incubation of FeS-PEG preparation prepared in step (2) with cells at various final concentrations of 0, 10, 20, 40 and 80. Mu.g/mL for 24h in a constant temperature incubator at 37℃one of the groups was subjected to 808nm laser light for further incubation for 24h. After that, the culture solution was aspirated, MTT medium was added to each well for 3h, the culture solution was aspirated, 150 μl DMSO was added to each well, shaking was performed for 10min to completely dissolve the purple solid, absorbance values at each concentration were read with an microplate reader, and the relationship between the cell viability calculated from absorbance values and nanomaterial concentration was plotted. The results showed that with increasing concentration of the FeS-PEG formulation, the cell viability of MDA-MB-231 was progressively lower, with lower cell viability in the experimental group irradiated with near infrared laser, indicating that the photothermal effect of the FeS-PEG formulation had significant cytotoxic effects on tumor cells.

As shown in fig. 17, living cells and dead cells were labeled with Calcein-AM and PI two fluorescent dyes, respectively, 4T1 cells were plated in 6-well plates, and the cells were treated in six groups: control group (FeS concentration 0. Mu.g/mL, without laser), NIR group (1.5W/cm ² 5 min), feS-20 group (FeS concentration 20. Mu.g/mL), feS-20 (FeS concentration 20. Mu.g/mL) +NIR group, feS-40 group (FeS concentration 40. Mu.g/mL), feS-40 (FeS concentration 40. Mu.g/mL) +NIR group. After 24h, the broth was aspirated, 1mL of Calcein AM/PI assay working solution was added and incubated at 37℃for 30min in the absence of light. After 30min, the distribution of red fluorescence (PI: ex/em=535/617 nm) and green fluorescence (Calcein AM: ex/em=494/517 nm) was observed under a fluorescence microscope. The results show that as the concentration of the FeS-PEG preparation increases, the red fluorescence gradually increases, the green fluorescence gradually decreases, and the experimental group irradiated by the near infrared laser has fewer living cells (green fluorescence) and more dead cells (red fluorescence), which further indicates that the photo-thermal effect of the FeS-PEG preparation has obvious cytotoxicity effect on tumor cells.

As shown in FIG. 18, detection of FeS-PEG preparation post-treatment fines using DCFH-DA fluorescent probeIntracellular ROS production. 4T1 cells were grown at 2X 10 ⁵ Density of wells/density of wells was seeded in 6-well plates and divided into four groups: control group (FeS concentration 0. Mu.g/mL, without laser), NIR group (1.5W/cm ² 5 min), feS group (FeS concentration 40. Mu.g/mL), feS+NIR group. After 6h of culture, the DCFH-DA fluorescent probe is diluted to 10 mu mol/L by a serum-free culture medium. The culture medium of the supernatant of the 6-well plate was aspirated, DCFH-DA working solution (1 mL/well) was added, and the mixture was incubated in a cell incubator at 37℃for 30min in the dark. The cells were washed 3 times to remove extracellular DCFH-DA. Intracellular DCF fluorescence was observed using CLSM using 488nm excitation wavelength, 525nm emission wavelength. The results show that the green fluorescence of DCF in FeS+NIR group is strongest, which indicates that the photo-thermal effect of FeS-PEG preparation prepared in step (2) increases the active oxygen content in tumor cells.

The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. The two-dimensional ferric sulfide nano sheet is characterized by being prepared by the following steps:

(1) Dissolving ferrous ammonium sulfate and trisodium citrate in ethylene glycol to obtain a solution A, dissolving polyethyleneimine in ethylene glycol to obtain a solution B, adding the solution B into the solution A, and stirring and reacting at normal temperature to obtain a mixed solution; in the solution A, the addition amount ratio of the ferrous ammonium sulfate, the trisodium citrate and the ethylene glycol is 0.6mmol:0.2mmol:15mL; in the solution B, the addition amount ratio of the polyethyleneimine to the ethylene glycol is 500mg:5mL; the ratio of the volume of the glycol in the solution A to the volume of the glycol in the solution B is 3:1, a step of; the stirring is magnetic stirring, and the rotating speed is 600-800 rpm; the stirring reaction time is 2 hours;

(2) Adding thioacetamide solution into the mixed solution, then dropwise adding triethanolamine, stirring at normal temperature for reaction, performing solvothermal reaction after stirring, and centrifuging and washing a product after the reaction is finished to obtain a two-dimensional ferric sulfide nano-sheet; the concentration of the thioacetamide solution is 0.05M; the ratio of the addition amount of the ferrous ammonium sulfate to the thioacetamide solution and the triethanolamine is 0.6mmol:15mL:2mL; the stirring is magnetic stirring, the rotating speed is 600-800 rpm, and the stirring reaction time is 1-10 min; the temperature of the solvothermal reaction is 200 ℃ and the time is 24 hours; the rotational speed of the centrifugation is 14000rpm and the time is 10min; the washing is carried out by using absolute ethyl alcohol for 3 times;

the minimum thickness of the two-dimensional ferric sulfide nano-sheet is 2.5nm.

2. Use of the two-dimensional iron sulfide nanoplatelets of claim 1 for the preparation of a degradable photo-thermal formulation.

3. A degradable photo-thermal preparation, characterized in that the degradable photo-thermal preparation is obtained by coating the biocompatible material with the two-dimensional ferric sulfide nano-sheet according to claim 1;

the biocompatible material is methoxy polyethylene glycol sulfhydryl; the degradable photo-thermal preparation is prepared by the following method:

dissolving the two-dimensional ferric sulfide nano-sheet and methoxy polyethylene glycol mercapto in absolute ethyl alcohol, stirring for reaction under ice bath condition, centrifuging after the reaction is finished, collecting precipitate, and washing to obtain a degradable photo-thermal preparation;

the molecular weight of methoxy polyethylene glycol mercapto is 2000-10000; the addition ratio of the two-dimensional ferric sulfide nano-sheet, methoxy polyethylene glycol mercapto and absolute ethyl alcohol is 1mg:1mg:1mL; the stirring speed is 350rpm and the stirring time is 6h.