Preparation method of natural copper photo-thermal nano-material

Abstract

The application discloses a preparation method of a mineral medicine natural copper photothermal nanometer material, which comprises the following steps: calcining natural copper, quenching treatment in vinegar, grinding into powder, mixing the powder with a surfactant solution, putting the mixture into a ball mill for ball milling, and then performing impurity separation and freeze drying on the ball-milled powder to obtain the required mineral medicine natural copper photothermal nanometer material. The application mainly uses the application of near-infrared inorganic nanometer material as a main line, and prepares a nano-magnetic pyrite photothermal material through the calcination-vinegar quenching and ball milling-magnetic separation method. The phase, particle size, morphology and photothermal performance of the nano-magnetic pyrite are controlled by adjusting the calcination temperature and the ball milling time. The preparation, control and photothermal performance evaluation of the nano-photothermal material are combined in the experiment, the method is low in cost and simple in preparation process, and therefore the mineral medicine nano-photothermal material with good biocompatibility can be widely applied in the biomedical field in the future.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of a photothermal nanomaterial, in particular to a preparation method of a mineral medicine natural copper photothermal nanomaterial. BACKGROUND

[0002] A photothermal material is a material that has strong absorption in the near-infrared region (760-1500 nm) and can convert the absorbed near-infrared light energy into heat, and has potential application prospects in the fields of energy conversion, photothermal imaging, bacterial infection and tumor photothermal treatment. Therefore, in recent years, domestic and foreign researchers have devoted themselves to the research and development of nano photothermal conversion materials. Inorganic nano materials mainly include noble metals (gold, platinum and palladium, etc.), carbon-based materials (carbon nanotubes CNT, carbon quantum dots CQDs, graphene GE, graphene oxide GO, etc.), transition metal-based materials Cu x S y , Cu2-xS, Ag2S, FeS, MoS2, TiS2, WS2, Cu2-xSe, FeSe2 and some oxides such as MoOx, WxOy, TiO2, Ti8O 15 , other inorganic nano materials MXenes materials, black phosphorus (BP) and the like. Organic nano materials include organic small molecules (fluorine, porphyrin) and polymer materials (polyaniline, polypyrrole, polydopamine and the like). Generally speaking, inorganic nano photothermal materials have higher photothermal conversion efficiency and better photothermal stability than organic nano photothermal materials and are more widely used. Fe-based nano photothermal materials are favored due to their good biocompatibility and biosafety, in addition, Fe as an essential element plays an important role in the human body, especially in the manufacture of hemoglobin and the transport of oxygen. PEG-modified FeS (FeS-PEG) nanosheets have very high near-infrared (NIR) absorption, showing higher photothermal conversion efficiency than other known iron oxides. Ultra-small FeS2 nanodots have also been synthesized and proved to be useful for photodynamic therapy, FeS2 nanocrystals utilize near-infrared photothermal therapy to enhance the Fenton reaction to trigger a dual death pathway of apoptosis and ferroptosis in triple-negative breast cancer, and polyvinylpyrrolidone (PVP)-modified iron sulfide nanoparticles (Fe 1-x S-PVP NPs) are successfully synthesized by a one-step hydrothermal method and have very high photothermal conversion efficiency under 808 nm wavelength irradiation, thereby promoting the generation of more -OH in the Fenton reaction, and the in vitro and in vivo experimental results show that Fe 1-x S-PVP NPs realize the high anti-tumor performance of photothermal nano preparations by combining H2S-mediated gas therapy with photothermally enhanced ROS.

[0003] Although the iron-based nanophotothermal materials reported above have good research prospects in the field of biomedicine, they also have some limitations. So far, the iron-based nanophotothermal materials reported have all been synthesized by chemical synthesis, which has the problems of high cost, cumbersome synthesis process, long cycle, biocompatibility and cytotoxicity, which have brought some difficulties to clinical application. Among them, near-infrared inorganic nanomaterials with low cost, simple preparation process, abundant raw material sources and excellent biocompatibility are more popular. In the long and ancient history of traditional Chinese medicine in China, there is a mineral medicine called natural copper, which is a sulfide mineral pyrite family pyrite, mainly containing iron disulfide (FeS2), which has the effects of dispersing blood stasis, relieving pain, and repairing tendons and bones. It is mostly used to treat traumatic injuries, tendon fractures, and bruises and pain. It is one of the commonly used medicines in clinical traumatology of traditional Chinese medicine included in all editions of the "Chinese Pharmacopoeia". It was first recorded in "Leigong Paozhi Lun" during the Southern and Northern Dynasties. Its medicinal use has a history of more than a thousand years. Native copper is one of the most widely distributed minerals on the earth and is also widely distributed in China. However, there are currently no reports on the preparation of nano-photothermal materials using traditional Chinese medicine native copper as raw material. Summary of the Invention

[0004] The present invention aims to provide a method for preparing a mineral-based natural copper photothermal nanomaterial. This method prepares the nano-pyrrhotite photothermal material by calcining the mineral-based natural copper, quenching it in vinegar, and then ball milling and magnetic separation. This method offers low cost, a simple preparation process, and the biocompatibility of this mineral-based nanophotothermal material, which is expected to find widespread application in biomedical research.

[0005] The technical solution of the present invention is a preparation method of a mineral medicine natural copper photothermal nanomaterial, which comprises the following steps: calcining natural copper, quenching it in a vinegar solution, grinding it into a powder, mixing the powder with a surfactant solution, placing it into a ball mill for ball milling, separating impurities from the ball-milled powder, and freeze-drying it to obtain the desired mineral medicine natural copper photothermal nanomaterial.

[0006] In the aforementioned method for preparing the mineral medicine natural copper photothermal nanomaterial, the specific preparation method is as follows: placing the crushed natural copper in a container and placing it in a box-type muffle furnace, calcining it at a temperature of 800-900°C for at least 1 hour, taking it out and immediately immersing it in vinegar solution for quenching, the vinegar solution should completely submerge the calcined natural copper, pouring out the rice vinegar after quenching, placing it in an oven for drying, and grinding the obtained natural copper in a mortar to obtain calcined natural copper powder;

[0007] F127 was dissolved in distilled water to obtain a 0.5% F127 solution. 5.0 g of calcined natural copper powder quenched in calcined vinegar and 200 ml of the 0.5% F127 solution were added to two ball mill jars respectively. Stainless steel ball milling beads were placed in the ball mill and ball milled for 2 to 6 hours respectively. The natural copper powder liquid after ball milling was collected and magnetically separated from impurities using a magnetic separation rod. The obtained adsorbed powder was poured into a plastic petri dish and freeze-dried to obtain the desired mineral medicine natural copper photothermal nanomaterial.

[0008] In the aforementioned method for preparing the mineral medicine natural copper photothermal nanomaterial, the stainless steel balls placed during the ball milling process are 10 with a diameter of 15 mm; 50 with a diameter of 10 mm; and 307 with a diameter of 5 mm.

[0009] In the aforementioned method for preparing the mineral medicine natural copper photothermal nanomaterial, the natural copper is crushed into pieces of approximately 1 cm in size before calcination; during the vinegar quenching process, the weight ratio of natural copper to vinegar liquid is 100:70; after quenching with vinegar for 20 minutes, the vinegar liquid is poured out, and the product is placed in an oven at 80°C and dried for 2 hours. The resulting natural copper is ground in a mortar and passed through a 100-mesh sieve to obtain a calcined natural copper powder.

[0010] In the aforementioned method for preparing the mineral medicine natural copper photothermal nanomaterial, the obtained adsorption powder is poured into a plastic culture dish and freeze-dried at -60°C.

[0011] Beneficial effects of the present invention: Compared with the existing technology, the present invention takes the application of near-infrared inorganic nanomaterials as the main line, and prepares nano-pyrrhotite photothermal materials through the method of natural copper-fired calcination, vinegar quenching and ball milling magnetic separation of mineral medicines. By regulating the roasting temperature and ball milling time, the physical phase, particle size, morphology and photothermal performance of nano-pyrrhotite can be regulated. This experiment combines the preparation, regulation and photothermal performance evaluation of nano-photothermal materials, involving traditional Chinese medicine processing, chemistry, materials and medical applications. This method is low-cost and has a relatively simple preparation process, so that mineral medicine nano-photothermal materials with good biocompatibility can be widely used in the biomedical field in the future. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 (a) β = 10°C / min -1 TG-DTG-DSC analysis results of thermal decomposition of native copper in air under heating rate conditions;

[0013] Figure 1 (b) Effect of calcination temperature on Fe content of natural copper products 2+ The influence of content;

[0014] Figure 1 (c) The effect of calcination temperature on the physical phases of natural copper artifacts;

[0015] Figure 1(d) UV-vis absorption spectra of natural copper crude products prepared at different calcination temperatures;

[0016] Figure 1 (e) SEM images of natural copper crude;

[0017] Figure 1 (f) SEM images of products prepared by vinegar quenching at 800 °C;

[0018] Figure 2 (a) Representative infrared thermal images of different products under 808 nm laser irradiation;

[0019] Figure 2 (b) Temperature rise curves of crude and products prepared at different calcination temperatures under 0.05 W / cm 2 of 808 nm laser irradiation;

[0020] Figure 2 (c) Temperature rise curves of products prepared at 800 °C under different power conditions;

[0021] Figure 2 (d) Five-cycle curves of products prepared at 800 °C;

[0022] Figure 3 (a) Effect of ball milling time on the phase of natural copper nanoparticles;

[0023] Figure 3 (b-d) Dynamic size distribution of natural copper nanoparticles ball milled for 2 h, 4 h and 6 h. Inset: photograph of natural copper nanoparticles dispersed in water;

[0024] Figure 3 (e) UV-vis absorption spectra of natural copper nanoparticles prepared at different ball milling times;

[0025] Figure 3 (g-h) TEM images of nanoparticles prepared by ball milling for 6 h;

[0026] Figure 4 (a) Representative infrared thermal images of nanoparticles prepared at different ball milling times under 808 nm laser irradiation;

[0027] Figure 4 (b) Temperature rise curves of products prepared from nanoparticles prepared at different ball milling times under 0.05 W / cm 2 of 808 nm laser irradiation;

[0028] Figure 4 (c) Temperature rise curves of nanoparticles prepared by ball milling for 6 h under different power conditions;

[0029] Figure 4(d) Five-cycle curves of nanoparticles prepared with a ball milling time of 6 h. DETAILED DESCRIPTION

[0030] The present invention will be further described below with reference to the accompanying drawings and examples, but they are not intended to limit the present invention.

[0031] Example 1 of the present invention: A method for preparing a mineral medicine natural copper photothermal nanomaterial, wherein a natural copper of about 1 cm in size is placed in a porcelain ark and placed in a box-type muffle furnace (YTH-2.5-12 type 1200°C) and calcined at 800°C for 1 hour. After being taken out, it is immediately immersed in vinegar solution for quenching, and the weight ratio of natural copper to vinegar solution is 100:70. At least 70 parts of vinegar solution are required to completely submerge 100 parts by weight of natural copper to ensure that the natural copper is completely quenched. After quenching with vinegar for 20 minutes, the rice vinegar is poured out, and the natural copper is placed in an oven and dried at 80°C for 2 hours. The obtained natural copper is ground into powder with a mortar and passed through a 100-mesh sieve to obtain a calcined natural copper powder.

[0032] Dissolve 2.5g of F127 in 500ml of distilled water to prepare a 0.5% F127 solution. Add 5.0g of calcined natural copper powder quenched by fire-calcined vinegar and 200ml of 0.5% F127 solution to two ball mill jars respectively, and add 10 stainless steel ball milling beads with a diameter of 15mm; 50 with a diameter of 10mm; and 307 with a diameter of 5mm to ensure rapid and thorough earth milling. Mill them separately in a ball mill for 2 hours. Collect the natural copper powder liquid after ball milling and use a 19mm×200mm magnetic separation rod to separate impurities by magnetic separation. Pour the obtained adsorbed powder into a plastic culture dish and freeze-dry at -60°C to obtain the required mineral medicine natural copper photothermal nanomaterial.

[0033] Example 2 of the present invention: A method for preparing a mineral medicine natural copper photothermal nanomaterial, wherein a natural copper of about 1 cm in size is placed in a porcelain ark and placed in a box-type muffle furnace (YTH-2.5-12 type 1200°C) and calcined at 800°C for 1 hour. After being taken out, it is immediately immersed in vinegar solution for quenching. The weight ratio of natural copper: vinegar solution is 100:70. At least 70 parts of vinegar solution are required to completely submerge 100 parts by weight of natural copper to ensure that the natural copper is completely quenched. After quenching with vinegar for 20 minutes, the rice vinegar is poured out, and the natural copper is placed in an oven and dried at 80°C for 2 hours. The obtained natural copper is ground into powder with a mortar and passed through a 100-mesh sieve to obtain a calcined natural copper powder.

[0034] Dissolve 2.5g of F127 in 500ml of distilled water to prepare a 0.5% F127 solution. Add 5.0g of calcined natural copper powder quenched by fire-calcined vinegar and 200ml of 0.5% F127 solution to two ball mill jars respectively, and add 10 stainless steel ball milling beads with a diameter of 15mm; 50 with a diameter of 10mm; and 307 with a diameter of 5mm to ensure rapid and thorough earth milling. Ball milling is carried out in a ball mill for 4 hours respectively. The natural copper powder liquid after ball milling is collected and magnetically separated from impurities using a 19mm×200mm magnetic separation rod. The obtained adsorbed powder is poured into a plastic culture dish and freeze-dried at -60°C to obtain the required mineral medicine natural copper photothermal nanomaterial.

[0035] Example 3 of the present invention: A method for preparing a mineral medicine natural copper photothermal nanomaterial, wherein a natural copper of about 1 cm in size is placed in a porcelain ark and placed in a box-type muffle furnace (YTH-2.5-12 type 1200°C) and calcined at 800°C for 1 hour. After being taken out, it is immediately immersed in vinegar solution for quenching. The weight ratio of natural copper: vinegar solution is 100:70. At least 70 parts of vinegar solution are required to completely submerge 100 parts by weight of natural copper to ensure that the natural copper is completely quenched. After quenching with vinegar for 20 minutes, the rice vinegar is poured out, and the natural copper is placed in an oven and dried at 80°C for 2 hours. The obtained natural copper is ground into powder with a mortar and passed through a 100-mesh sieve to obtain a calcined natural copper powder.

[0036] Dissolve 2.5g of F127 in 500ml of distilled water to prepare a 0.5% F127 solution. Add 5.0g of calcined natural copper powder quenched by fire-calcined vinegar and 200ml of 0.5% F127 solution to two ball mill jars respectively, and add 10 stainless steel ball milling beads with a diameter of 15mm; 50 with a diameter of 10mm; and 307 with a diameter of 5mm to ensure rapid and thorough earth milling. Ball milling is carried out in a ball mill for 6 hours respectively. The natural copper powder liquid after ball milling is collected and magnetically separated from impurities using a 19mm×200mm magnetic separation rod. The obtained adsorbed powder is poured into a plastic culture dish and freeze-dried at -60°C to obtain the required mineral medicine natural copper photothermal nanomaterial.

[0037] Example 4 of the present invention: A method for preparing a mineral medicine natural copper photothermal nanomaterial, wherein a natural copper of about 1 cm in size is placed in a porcelain ark and placed in a box-type muffle furnace (YTH-2.5-12 type 1200°C) and calcined at 900°C for 1 hour. After being taken out, it is immediately immersed in vinegar solution for quenching, and the weight ratio of natural copper to vinegar solution is 100:70. At least 70 parts of vinegar solution are required to completely submerge 100 parts by weight of natural copper to ensure that the natural copper is completely quenched. After quenching with vinegar for 20 minutes, the rice vinegar is poured out, and the natural copper is placed in an oven and dried at 80°C for 2 hours. The obtained natural copper is ground into powder with a mortar and passed through a 100-mesh sieve to obtain a calcined natural copper powder.

[0038] Dissolve 2.5g of F127 in 500ml of distilled water to prepare a 0.5% F127 solution. Add 5.0g of calcined natural copper powder quenched by fire-calcined vinegar and 200ml of 0.5% F127 solution to two ball mill jars respectively, and add 10 stainless steel ball milling beads with a diameter of 15mm; 50 with a diameter of 10mm; and 307 with a diameter of 5mm to ensure rapid and thorough earth milling. Mill them separately in a ball mill for 2 hours. Collect the natural copper powder liquid after ball milling and use a 19mm×200mm magnetic separation rod to separate impurities by magnetic separation. Pour the obtained adsorbed powder into a plastic culture dish and freeze-dry at -60°C to obtain the required mineral medicine natural copper photothermal nanomaterial.

[0039] Example 5 of the present invention: A method for preparing a mineral medicine natural copper photothermal nanomaterial, wherein a natural copper of about 1 cm in size is placed in a porcelain ark and placed in a box-type muffle furnace (YTH-2.5-12 type 1200°C) and calcined at 900°C for 1 hour. After being taken out, it is immediately immersed in vinegar solution for quenching, and the weight ratio of natural copper to vinegar solution is 100:70. At least 70 parts of vinegar solution are required to completely submerge 100 parts by weight of natural copper to ensure that the natural copper is completely quenched. After quenching with vinegar for 20 minutes, the rice vinegar is poured out, and the natural copper is placed in an oven and dried at 80°C for 2 hours. The obtained natural copper is ground with a mortar and passed through a 100-mesh sieve to obtain a calcined natural copper powder.

[0040] Dissolve 2.5g of F127 in 500ml of distilled water to prepare a 0.5% F127 solution. Add 5.0g of calcined natural copper powder quenched by fire-calcined vinegar and 200ml of 0.5% F127 solution to two ball mill jars respectively, and add 10 stainless steel ball milling beads with a diameter of 15mm; 50 with a diameter of 10mm; and 307 with a diameter of 5mm to ensure rapid and thorough earth milling. Ball milling is carried out in a ball mill for 4 hours respectively. The natural copper powder liquid after ball milling is collected and magnetically separated from impurities using a 19mm×200mm magnetic separation rod. The obtained adsorbed powder is poured into a plastic culture dish and freeze-dried at -60°C to obtain the required mineral medicine natural copper photothermal nanomaterial.

[0041] Example 6 of the present invention: A method for preparing a mineral medicine natural copper photothermal nanomaterial, wherein a natural copper of about 1 cm in size is placed in a porcelain ark and placed in a box-type muffle furnace (YTH-2.5-12 type 1200°C) and calcined at 900°C for 1 hour. After being taken out, it is immediately immersed in vinegar solution for quenching, and the weight ratio of natural copper to vinegar solution is 100:70. At least 70 parts of vinegar solution are required to completely submerge 100 parts by weight of natural copper to ensure that the natural copper is completely quenched. After quenching with vinegar for 20 minutes, the rice vinegar is poured out, and the natural copper is placed in an oven and dried at 80°C for 2 hours. The obtained natural copper is ground into powder with a mortar and passed through a 100-mesh sieve to obtain a calcined natural copper powder.

[0042] 2.5 g of F127 was dissolved in 500 ml of distilled water to prepare a 0.5% F127 solution. 5.0 g of calcined natural copper powder and 200 ml of the 0.5% F127 solution were added to two ball milling tanks, respectively, and 10 stainless steel milling beads with a diameter of 15 mm, 50 with a diameter of 10 mm, and 307 with a diameter of 5 mm were added to ensure rapid and sufficient ball milling. The ball milling was carried out in a ball milling instrument for 6 hours, respectively. After ball milling, the natural copper powder liquid was collected and the impurities were separated by magnetic separation with a 19 mm x 200 mm magnetic separator. The obtained adsorbed powder was poured into a plastic culture dish and freeze-dried at -60°C to obtain the desired mineral medicine natural copper photothermal nanomaterial.

[0043] To verify the performance of the natural copper photothermal nanomaterial prepared by the above method, the following experiments were conducted:

[0044] 1. Experimental section

[0045] 1.1 Materials

[0046] The natural copper raw material was purchased from Guizhou Tongjitang Drink Pieces Co., Ltd. (Guiyang, China), and the production place was Zunyi, Guizhou. Rice vinegar (Jiangsu Hengshun Vinegar Co., Ltd.) and Pluronic F127 (Sigma Aldrich) are a kind of triblock copolymer with a molecular formula of (PEO) 106 (PPO) 70 (PEO) 106. The experimental water is deionized water.

[0047] 1.2 Experimental instruments

[0048] YTH-2.5-12 type 1200°C box muffle furnace (Super Co., Ltd.) was used for calcination experiment of mineral medicine natural copper; ball mill (YXQM-2L, Changsha Miqi Co., Ltd.) was used for preparation of nano-calcined natural copper particles; simultaneous thermal analyzer (STA449-F3, NETZSCH, Germany) was used to analyze the thermal reaction process of natural copper at different temperatures in air; scanning electron microscope (SEM, ZEISS-Sigma500, Germany) was used to observe the morphology of natural raw product, processed product and nano-particles; transmission electron microscope (TEM, JEM-2100F, Japan) was used to observe the morphology of nano-particles; D8 ADANCE type X-ray diffractometer (Bruker, Germany) was used to study the phase of natural copper raw product, processed product and nano-particles; (UV-vis) ultraviolet-visible spectrophotometer (UV-2700i, Shimadzu, Japan) was used to test the light absorption performance of natural copper powder; nano-particle size analyzer (BECKMAN DelsaMax PRO) was used to test the dynamic particle size of nano-particles; 808 near-infrared conductor laser (Beijing Honglan Optoelectronics Technology Co., Ltd., VCL-808nmM0-2W) and infrared thermal imager (FLIR ONE PRO IOS) were used to test the photothermal performance of natural copper and processed products.

[0049] 1.3 Preparation of nano-photothermal materials by natural copper calcination-ball milling and magnetic separation

[0050] A natural copper of about 1 cm in size was placed in a porcelain ark and placed in a box-type muffle furnace (YTH-2.5-12 type 1200℃) and calcined at intervals of 100℃ in the range of 600-900℃ (calcination temperatures were 600, 700, 800 and 900℃ respectively) for 1 hour. After being taken out, it was immediately immersed in vinegar solution (weight ratio of natural copper: vinegar = 100:70) for quenching. After quenching in vinegar for 20 minutes, the vinegar was poured out, and the copper was placed in an oven at 80℃ for drying for 2 hours. The obtained natural copper was ground into powder with a mortar and passed through a 100-mesh sieve to obtain calcined natural copper powder.

[0051] 2.5 g of F127 was dissolved in 500 ml of distilled water to prepare a 0.5% F127 solution. 5.0 g of calcined natural copper powder quenched in vinegar at 800°C and 200 ml of the 0.5% F127 solution were added to two ball mills, respectively. Stainless steel ball milling beads (10 beads with a diameter of 15 mm; 50 beads with a diameter of 10 mm; and 307 beads with a diameter of 5 mm) were placed in the ball mill and milled for 2, 4, and 6 hours, respectively. The milled natural copper powder liquid was collected and magnetically separated for impurities using a 19 mm × 200 mm magnetic separation rod. The resulting adsorbed powder was poured into a plastic petri dish and freeze-dried at -60°C.

[0052] 1.4 Determination of the content of active ingredients in natural copper

[0053] Determination of Fe in natural copper medicinal materials and processed products according to the potassium dichromate titration method in Part I of the 2020 edition of the Chinese Pharmacopoeia 2+ Content method: Take about 0.25g of fine powder of this product, weigh it accurately, put it in a porcelain crucible, burn it at 650℃ for about 30 minutes, take it out, let it cool, transfer the burned material to a conical flask, add 15ml of hydrochloric acid and 3ml of 25% potassium fluoride solution, cover it with a watch glass, heat to a slight boil, add 6% stannous chloride solution dropwise, shake it continuously, wait until the decomposition is complete and only white residue is left at the bottom of the bottle, wash the watch glass and the inner wall of the bottle with a small amount of water, add 6% stannous chloride solution dropwise while it is hot until it turns light yellow (such as stannous chloride If the solution is excessive, add potassium permanganate solution dropwise until it develops a light yellow color. Add 100ml of water and 15 drops of 25% sodium tungstate solution. Add 1% titanium trichloride solution dropwise until a blue color develops. Carefully add potassium dichromate solution (0.01667 mol / L) dropwise until the blue color just fades. Immediately add 10ml of sulfuric acid-phosphoric acid-water (2:3:5) and 10 drops of 0.5% sodium diphenylamine sulfonate solution. Titrate with potassium dichromate solution (0.01667 mol / L) until the solution develops a stable blue-purple color. Each 1ml of potassium dichromate solution (0.01667 mol / L) is equivalent to 5.585mg of iron (Fe).

[0054] 2. Results and Discussion

[0055] 2.1 Effect of calcination temperature on the phase, morphology and photothermal properties of processed products

[0056] In order to understand the calcination of native copper under air conditions, the thermal reaction process of native copper under air conditions was analyzed by thermogravimetry (TG), differential thermal analysis (DTG) and differential scanning calorimetry (DSC). The weight of the sample was about 10 mg. In an air environment, the sample was heated from 25°C to 1000°C at a flow rate of 50 mL / min and a heating rate of 10°C / min until the thermal analysis curve reached a stable state. The obtained curve is shown in Figure 2. Figure 1 As shown in Figure a, the TG curves can be observed to follow three stages as the furnace temperature increases. From room temperature to 400°C, the TG curves show a 1.99% weight loss of native copper, attributed to the volatilization of moisture and volatile impurities in the native copper. These results indicate that native copper is difficult to thermally decompose at low temperatures (below 400°C). Between 400°C and 660°C, the mass loss reaches 26.33%, attributed to the reaction of native copper to form pyrrhotite (primarily Fe7S8). This is confirmed by DSC analysis, as a distinct endothermic peak is observed within this temperature range. The DSC curves reach a minimum of -14.33% / min at 572.2°C. From 660°C to 1000°C, the TG curves show a 1.61% weight loss, for a total weight loss of 29.93% over the entire reaction process. The DTG curves reveal a peak temperature of 536.4°C for the thermal decomposition of native copper, with a weight loss rate of -3.70% / min. The above TG-DTG-DSC analysis is consistent with the results reported in previous literature.

[0057] During the calcination process of natural copper, the calcination temperature has an effect on Fe 2+ The content of Fe in the processed products obtained by calcining natural copper at different temperatures was determined according to the potassium dichromate titration method in the 2020 edition of the Chinese Pharmacopoeia. 2+ The content of each group was repeated three times and the percentage content, standard deviation and mean value were calculated (each 1ml of potassium dichromate titrant 0.01667mol / L is equivalent to 5.585mg of iron Fe). The deviation of the three parallel measurements was less than 1. The pharmacopoeia stipulates that the iron (Fe) content of natural copper should be 40.0%-55.0%. The Fe content of processed products at different calcination temperatures was 2.3477 W / m2. 2+ The content measurement results of Figure 1 As shown in b, when calcined in air, at 600-700℃, the iron content increases sharply with increasing temperature. 2+The content increased from 42.09% to 59.96%, reached a maximum of 60.62% at 800℃, decreased to 59.20% at 900℃, and was 61.66% when calcined at 1000℃. However, the calcination temperature of 1000℃ was too high and the sample turned into a molten state.

[0058] During the calcination process of natural copper, the calcination temperature has a significant effect on the physical phase of the processed product. In order to find out the relationship between the calcination temperature, physical phase and light absorption performance, the absorption is regulated by changing the calcination temperature. In order to understand the phase change mechanism of the mineral phase reconstruction during the calcination process of natural copper, XRD was used to characterize the natural copper calcined products at different temperatures. The results are shown in Figure 2. Figure 1 c. The main phase composition of natural copper raw product is FeS2 (JCPDF card number: 71-1680). In addition, it also contains a small amount of other phases SiO2 (JCPDF card number: 99-0088. The reaction atmosphere during the calcination of natural copper has a significant effect on the formation of reaction products. In the presence of O2, the pyrite FeS2 in natural copper is first partially desulfurized to form pyrrhotite (Fe7S8) and S2, and then S2 is easily oxidized to form SO2. Natural copper and its pyrolysis products (FeS or Fe7S 8) It is easily oxidized by O2 to form iron oxide. When large pieces of natural copper are roasted, O2 diffuses into the interior of the copper due to the resistance of the outer layer. Therefore, in an inert or weakly oxygenated atmosphere, the particle core tends to decompose into pyrrhotite Fe7S8. To prevent oxidation during annealing, rice vinegar is used for quenching. Therefore, the roasting temperature of natural copper is raised to above 600°C-800°C to form a phase dominated by pyrrhotite Fe7S8. The processed copper product roasted at 900°C forms a composite phase of Fe7S8 and Fe2O3.

[0059] The UV-vis absorption spectra of the processed products of natural copper raw products calcined at different temperatures are shown in Figure 1 It can be found that the raw copper and the processed copper calcined at 600-900℃ have no light absorption at 200nm-300nm wavelength, but have excellent light absorption performance at 300nm-800nm ​​wavelength. Moreover, with the increase of calcination temperature, the Fe7S8 content at 800nm ​​near infrared light increases, and the Fe 2 + The higher the content, the stronger the absorption peak of the processed product.

[0060] The surface morphology of raw and processed natural copper was observed by scanning electron microscopy. Figure 1 e shows that the native copper product has a compact interior and is covered with powdery pyrite. Figure 1 Figure f shows that acetic acid corrosion on natural copper artifacts reveals numerous honeycomb-like and bubble-like protrusions and faults, which are caused by 800°C high-temperature roasting and vinegar quenching. Therefore, natural copper artifacts are clearly more fragile and more easily shattered than raw natural copper.

[0061] Since the photon energy of 808nm laser is higher than the band gap of pyrrhotite, it absorbs light energy under the irradiation of 808nm laser and produces a thermal effect. Figure 2 a shows representative infrared thermal images of different preparations irradiated with near-infrared light. Figure 2 b is the raw product and the processed products prepared at different calcination temperatures at 0.05W / cm 2 From the temperature rise curve under 808nm laser irradiation, it can be seen that the temperature of the natural copper product increased by 43.2℃ after 30s of near-infrared 808nm light irradiation, and gradually increased to 47.25±0.47℃ after 120s. The temperatures of the processed products prepared at 600-900℃ increased by 47.64±0.33℃, 48.19±0.35℃, 48.92±0.29℃, and 49.18±0.42℃, respectively. This shows that the processed products prepared by natural copper fire calcination and vinegar quenching have good photothermal properties. The photothermal properties and light absorption spectra of the processed products prepared at 800℃ and 900℃ are not much different. In order to save energy, the processed products calcined at 800℃ were selected for temperature rise curve study under different power conditions. The obtained temperature rise curve is shown in 2c. It can be clearly seen that the temperature rise is positively correlated with the laser power density. The surface temperature fluctuates slightly within 100s. When the laser power density is 0.07W / cm 2 The temperature of the powder surface can be raised to 49.1℃ in 5min. What is exciting is that when the laser power density is 0.39W / cm 2 The temperature of the powder surface can rise to 96.3℃ in 5 minutes. The photothermal stability study was conducted by repeatedly turning on / off the 808 laser. The photothermal stability of the processed product calcined at 800℃ and quenched with vinegar was evaluated using an infrared thermal imager. Figure 2 d is the temperature change curve of the natural copper product recorded by 5 times of laser on / off. It can be seen that the temperature of the powder increased from 34.2℃ to 49.2℃ 5 minutes after the first laser irradiation; the temperature of the powder can be increased to about 49℃ after the second to fifth laser irradiation for 5 minutes, indicating that the product prepared by natural copper calcination and vinegar quenching has good photothermal stability.

[0062] 2.2 Effect of ball milling time on the phase, particle size, morphology and photothermal properties of the processed product

[0063] Combined with native copper TG-DTG-DSC analysis, XRD, Fe 2+ Content analysis and UV-vis absorption spectrum analysis determined that the raw material of natural copper was roasted at 800℃ for 1h and then quenched in vinegar to obtain the processed natural copper for subsequent research on nano-photothermal particles.

[0064] Figure 3a shows the XRD spectra of nanoparticles prepared from the fire-calcined and vinegar-quenched products under different ball milling conditions. The results show that the cubic block of natural copper after high-temperature calcination at 800℃ and vinegar-quenching and crushing is mainly of the structure of Fe7S8. The nano-calcined natural copper after F127 surfactant-assisted mechanical ball milling for 2h, 4h and 6h is still the phase of Fe7S8. The results show that mechanical milling does not cause changes in the phase structure. Figure 3 bd shows that due to the use of surfactant F127 during ball milling, the average hydrodynamic diameters of the nanoparticles prepared by ball milling calcined natural copper for 2h, 4h and 6h are 460.00nm, 425.00nm and 374.99nm, and the nano-calcined natural copper is well distributed in water ( Figure 3 d), which confirms that the natural copper calcined and vinegar-quenched products can be successfully converted into nanoparticles by using high-energy planetary ball milling process assisted by F127 surfactant. When the ball milling time exceeds 6 hours, the average hydrodynamic diameter of the nanoparticles does not continue to decrease, but increases. Based on the ball milling quality and time cost, it is more appropriate to choose a ball milling time of 2 to 6 hours. Transmission electron microscopy (TEM) shows that the nano-calcined natural copper prepared by calcined and vinegar-quenched ball milling has an irregular spherical structure and the particle size is in the range of 50-200nm ( Figure 3 g and 3h), such nanomaterials can provide special physical and chemical properties, and photothermal therapy (PTT) of nanomaterials can be used to generate heat to kill bacteria or tumor cells to achieve the purpose of promoting the healing of infected wounds and killing tumor cells.

[0065] Figure 4 a shows representative infrared thermal images of nanoparticles prepared with different ball milling times under near-infrared light irradiation. Figure 4 b is the nanoparticles prepared without ball milling and with different ball milling times at a power density of 0.05 W / cm 2 From the temperature rise curve under 808nm laser irradiation, it can be seen that after 30s of near-infrared 808nm light irradiation, the temperature of the natural copper sample at 800℃ without ball milling increased by 43.2℃, and gradually increased to 48.92±0.29℃ after 120s. The temperature of the nanoparticles prepared by ball milling for 2h, 4h and 6h increased by 49.34±0.25℃, 50.39±0.43℃ and 50.72±0.34℃ respectively. The nanoparticles with smaller nanoparticle size obtained by longer ball milling time have larger surface area, and more particles transition when irradiated with laser, so the temperature rises higher. This shows that the nanoparticles prepared by natural copper calcination, vinegar quenching, ball milling and magnetic separation have good photothermal properties. The temperature rise curve of the nanoparticles prepared with a ball milling time of 6h was studied under different power conditions. The obtained temperature rise curve is shown in 4c. It can be clearly seen that the temperature rise is positively correlated with the laser power density. When the laser power density is 0.07W / cm 2The temperature of the powder surface can be raised to 52.3°C in 5 min, and excitingly, when the laser power density is 0.39 W / cm 2 , the temperature of the powder surface can be raised to 130.0°C in 5 min. In order to determine the thermal conversion behavior of the nano-photothermal material repeatedly exposed to near-infrared environment, the nanoparticles after ball milling for 6 h were exposed to near-infrared irradiation for five cycles, Figure 4 d is the temperature change curve of natural copper processed products recorded by laser on / off 5 times. It can be seen that after 5 min of laser irradiation, the temperature of the powder increased from 33.5°C to 51.4°C; after 5 min of laser irradiation for the 2nd to 5th time, the temperature of the powder can all be raised to about 51°C, indicating that the nano-particles prepared by fire calcination and vinegar quenching-ball milling-magnetic separation of natural copper have stable photothermal properties.

[0066] 3. Conclusion

[0067] (1) The pyrite Fe7S8 nano-photothermal material was prepared by fire calcination and vinegar quenching-ball milling-magnetic separation method using mineral medicine natural copper as raw material. The XRD spectrum, SEM image, TEM image and thermogravimetric analysis results show the formation mechanism of natural copper nano-photothermal material.

[0068] (2) The photothermal experiment results show that natural copper raw products, processed products and nanoparticles all have good near-infrared photothermal conversion capacity, which is due to the fact that the photon energy of 808 nm laser is higher than the band gap of pyrite, so that the absorption of near-infrared light can be realized. The research results of this experiment prove that the nano-photothermal material can be prepared by using mineral medicine natural copper through fire calcination and vinegar quenching-ball milling-magnetic separation method.

Claims

1. A method for preparing mineral medicine natural copper photothermal nanomaterials, characterized by: The method comprises the following steps: calcining natural copper, quenching it in a vinegar solution, grinding it into a powder, mixing the powder with a surfactant solution, and putting it into a ball mill for ball milling. The powder after ball milling is subjected to impurity separation and freeze drying to obtain the desired mineral medicine natural copper photothermal nanomaterial; The specific preparation method is as follows: crushed natural copper is placed in a container and placed in a box-type muffle furnace, calcined at 800-900°C for at least 1 hour, taken out and immediately immersed in vinegar solution for quenching, the vinegar solution should completely cover the calcined natural copper, after quenching with vinegar, the rice vinegar is poured out, and the copper is placed in an oven for drying, and the obtained natural copper is ground in a mortar to obtain calcined natural copper powder; Dissolve F127 in distilled water to obtain a 0.5% F127 solution. Add 5.0 g of calcined natural copper powder quenched in calcined vinegar and 200 ml of the 0.5% F127 solution to two ball mills, respectively. Place stainless steel ball mill beads in the mill and mill for 2 to 6 hours. Before calcining, the native copper was crushed into pieces of 1 cm in size. During the vinegar quenching process, the weight ratio of native copper to vinegar was 100:

70. After quenching for 20 minutes, the vinegar was discarded, and the copper was dried in an oven at 80°C for 2 hours. The resulting native copper was ground in a mortar and passed through a 100-mesh sieve to obtain a calcined native copper powder.

2. The method for preparing the mineral medicine natural copper photothermal nanomaterial according to claim 1, characterized in that: After ball milling, the natural copper powder liquid after ball milling is collected and magnetically separated for impurities using a magnetic separation rod. The obtained adsorbed powder is poured into a plastic culture dish and freeze-dried to obtain the required mineral medicine natural copper photothermal nanomaterial.

3. The method for preparing the mineral medicine natural copper photothermal nanomaterial according to claim 2, characterized in that: During the ball milling process, 10 stainless steel balls with a diameter of 15 mm, 50 stainless steel balls with a diameter of 10 mm, and 307 stainless steel balls with a diameter of 5 mm were placed.

4. The method for preparing the mineral medicine natural copper photothermal nanomaterial according to claim 2, characterized in that: The obtained adsorption powder was poured into a plastic petri dish and freeze-dried at -60°C.

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