Pure inorganic stimuli-responsive sol, preparation method therefor, and use thereof

Abstract

Provided are a pure inorganic stimuli-responsive sol, a preparation method therefor, and a use thereof. The sol comprises an inorganic one-dimensional nanomaterial and a solution for dispersing the inorganic one-dimensional nanomaterial. The inorganic one-dimensional nanomaterial at least comprises a rare earth metal element, and the positive charge of the rare earth metal element causes the inorganic one-dimensional nanomaterials to repel each other to form the sol. The preparation method comprises: step (1). adding an inducer to a metal salt solution while stirring to form a uniform liquid; step (2). adding a liquid to a reaction kettle for reaction; and step (3). controlling the environmental hydroxyl concentration to obtain a sol product. Further provided is a method for the stimuli-responsive conversion of a pure inorganic stimuli-responsive sol into a gel, a method for the conversion of a pure inorganic stimuli-responsive gel into a pure inorganic stimuli-responsive sol, and a use thereof in sterilization, hemostasis, wound recovery, drug carriers, medical auxiliary materials, cosmetic materials, or sunscreen products. The method has low cost, can achieve the adjustment of the interaction between one-dimensional inorganic nanomaterials without the need to replace ligands, and has extremely high advantages in stimuli-responsive sol-gel conversion capacity.

Description

A pure inorganic stimulus-responsive sol, its preparation method and application Technical Field

[0001] This invention relates to the fields of nanomaterials and biomedicine, and in particular to a pure inorganic stimulus-responsive sol, its preparation method, and its application areas. Background Technology

[0002] Products that can transform from a liquid state (sol) to a semi-solid or solid state (gel) under stimulus conditions are called stimulus-responsive sols or stimulus-responsive gels, such as liquid bandages, injectable organic gels, and 3D printing consumables. The stimulus-responsive transformation from a sol state to a gel state can provide great convenience and expand the application range of products.

[0003] Current stimulus-responsive gels are primarily organic hydrogels, and the traditional definition of hydrogel often specifically refers to organic hydrogels formed by a three-dimensional network of hydrophilic polymers. However, the use of organic hydrogels is often limited by their swelling and relatively low mechanical properties. Although the mechanical properties of organic hydrogels have been modified by constructing dual-network structures, their poor thermal stability, high cost, toxicity of crosslinking agents, and complexity of preparation remain issues that need to be considered.

[0004] Currently, inorganic hydrogels with high thermal stability, high strength, and high electrical conductivity are under development. From the perspective of formation mechanism, inorganic hydrogels can be divided into inorganic-based hydrogels formed by direct cross-linking, inorganic-based hydrogels formed by modified ligands, and inorganic hydrogels formed by electrostatic forces. Inorganic-based hydrogels formed by direct cross-linking are often composed of disordered one-dimensional inorganic materials that cannot be untangled, exhibiting poor flexibility and lacking stimulus responsiveness, thus limiting their application range. Inorganic-based hydrogels formed by modified ligands are often composed of zero-dimensional inorganic nanoparticles and relatively expensive ligands, and their gel strength is limited, similarly restricting their practical use and generally not considered for the preparation of organic hydrogels. Inorganic hydrogels formed by electrostatic forces, such as ligand-modified gold nanoparticles, graphene nanosheets, and two-dimensional titanium dioxide nanosheets, possess good gel properties, and their temperature response capabilities have been studied. However, due to their high cost and complex preparation steps, these materials are not yet widely used.

[0005] If inorganic materials are simply incorporated into an organic hydrogel matrix to form an organic-inorganic composite gel, although the preparation cost is saved and the stimulus-responsive gel properties are obtained, the disadvantages of organic hydrogels still exist because the organic materials are the main body.

[0006] Summary of the Invention

[0007] The first objective of this invention is to address the shortcomings of existing stimulus-responsive gels by providing a purely inorganic stimulus-responsive sol. This purely inorganic stimulus-responsive sol not only retains the advantages of inorganic gels in terms of thermal stability, ionic conductivity, strength, and resistance to photodamage, but also possesses the stimulus-responsive properties of organic gels. By selecting the components and adjusting the solution environment, the positive charge on the surface of one-dimensional inorganic nanomaterials can resist particle aggregation, allowing them to be monodispersed in water to form a sol without the need for additional surface modification reagents. By adjusting the forces between nanomaterials through temperature or anions, their dispersion and aggregation states can be switched, thereby selectively forming sols and gels. This ability to disperse nanomaterials through anions is occasionally used for sols and the preparation of precipitated samples. However, the reversible adjustment of one-dimensional sols and gels, and the application of this property, is a first in the application of purely inorganic materials.

[0008] A pure inorganic stimulus-responsive sol, wherein the stimulus response includes at least a transition response from sol to gel; the pure inorganic stimulus-responsive sol comprises inorganic one-dimensional nanomaterials and a solution for dispersing the inorganic one-dimensional nanomaterials; the inorganic one-dimensional nanomaterials contain at least rare earth metal elements, and the positive charge of the rare earth metal elements causes the inorganic one-dimensional nanomaterials to repel each other to form a sol.

[0009] Preferably, the inorganic one-dimensional nanomaterial is at least one of rare earth metal phosphate, rare earth metal borate, rare earth metal oxide, or rare earth metal hydroxide.

[0010] Preferably, the concentration of inorganic one-dimensional nanomaterials in the pure inorganic stimulus-responsive sol is 1-100 mg / mL.

[0011] Preferably, the solution contains anion I, which includes at least one of chloride ion, nitrate ion, borate ion, citrate ion, and acetate ion.

[0012] Preferably, the concentration of anion I in the solution is 0.001-10M.

[0013] Preferably, the solution also includes hydroxide ions, and the concentration of hydroxide ions is less than 1 mM.

[0014] Preferably, the stimulus response condition is at least one of the concentration or temperature of anions that can have chelation or electrostatic interaction with the metal elements in the inorganic one-dimensional nanomaterial; more preferably, the anions that can have a strong interaction with the metal elements in the inorganic one-dimensional nanomaterial are anions with high polarizability.

[0015] The stimulation response method for the above-mentioned pure inorganic stimulus-responsive sol is as follows: anions are added to the sol to form a gel.

[0016] The anions include, but are not limited to, hydroxide ions and anions that can chelate metals. For example, hydroxide ions are added to the hydrosol of one-dimensional inorganic nanomaterials of phosphate, lysine is added to the hydrosol of one-dimensional inorganic nanomaterials of phosphate (to change the pH and thus increase the hydroxide concentration), and EDTA anions are added to the hydrosol of one-dimensional inorganic nanomaterials of borate.

[0017] The above-mentioned reversible transformation method for pure inorganic stimulus-responsive sols includes: adding an acidic solution (such as hydrochloric acid) to the gel to adjust its pH to below 3, and mixing well to achieve the transformation from gel to sol; or removing anions from the solution by dialysis or ultrafiltration in an acidic solution to achieve the transformation from gel to sol.

[0018] The second objective of this invention is to provide a method for preparing a pure inorganic stimulus-responsive sol, comprising the following steps: Step (1), adding an inducer to a metal salt solution under stirring conditions to form a homogeneous liquid;

[0019] Step (2): Add the liquid to the reaction vessel for reaction;

[0020] Step (3) involves controlling the concentration of hydroxide ions in the environment to obtain the sol product.

[0021] Preferably, the metal salt in step (1) includes salts of rare earth metal elements.

[0022] Preferably, the rare earth metal element is at least one of lanthanum, cerium, arsenic, promethium, samarium, europium, and gadolinium.

[0023] Preferably, the anions in the metal salt in step (1) include at least one of nitrate ions, acetate ions, sulfate ions, chloride ions, bromide ions, and iodide ions.

[0024] Preferably, the concentration of the metal salt in step (1) is 0.1-10M.

[0025] Preferably, the inducing agent in step (1) is an alkaline solution.

[0026] Preferably, the alkaline solution includes at least one of ammonia, sodium hydroxide, and potassium hydroxide.

[0027] Preferably, the inducing agent in step (1) also includes an oxyacid.

[0028] Preferably, the oxyacid includes at least one of concentrated phosphoric acid or boric acid.

[0029] Preferably, the reaction time in step (2) is less than 24 hours and the reaction temperature is 60-300℃.

[0030] Preferably, in step (3), the hydroxide concentration is controlled to be less than 1 mM.

[0031] Preferably, the method for controlling the hydroxide concentration in step (3) is to use an acid.

[0032] Preferably, the acid includes at least one of hydrochloric acid, nitric acid, boric acid, citric acid, or acetic acid.

[0033] Preferably, the oxyacid solution is a metallic oxyacid solution or a non-metallic oxyacid solution, and the pH of the oxyacid solution is less than 5.

[0034] Preferably, the pH of the alkaline solution is greater than 9;

[0035] A third objective of this invention is to provide a method for converting a purely inorganic stimuli-responsive sol into a gel.

[0036] The conditions for the stimulus response include adding anion II, which can have chelating and / or electrostatic interactions with metal elements in inorganic one-dimensional nanomaterials, to the pure inorganic stimulus-response sol, or changing the temperature of the pure inorganic stimulus-response sol.

[0037] Preferably, the anion II that can chelate and / or electrostatically interact with the metal elements in the inorganic one-dimensional nanomaterials includes at least one of hydroxide ions, phosphate ions, carbonate ions, molybdate ions, tungstate ions, titanate ions, sulfate ions, and bismuthate ions.

[0038] Preferably, the anion II is a hydroxide ion.

[0039] Preferably, the anion II is a hydroxide ion, and the anion concentration added is above 0.001M.

[0040] Preferably, changing the temperature of the pure inorganic stimulus-responsive sol involves increasing the temperature of the sol.

[0041] Preferably, when the concentration of added anion is 0.001M, the gel transition temperature is 37 degrees Celsius.

[0042] The fourth objective of this invention is to provide a purely inorganic stimulus-responsive gel.

[0043] The fifth objective of this invention is to provide a method for converting a pure inorganic stimulus-responsive gel into a pure inorganic stimulus-responsive sol.

[0044] The conditions for the stimulus response include removing the anion II or changing the gel temperature.

[0045] Preferably, the specific method for removing the anion II includes adding an acidic solution, dialysis, or ultrafiltration.

[0046] Preferably, the acidic solution includes at least one of hydrochloric acid, nitric acid, boric acid, citric acid, and acetic acid.

[0047] Preferably, the concentration of the acidic solution is 1M;

[0048] Preferably, the acidic solution is added when the hydroxide concentration is below 0.001 M.

[0049] Preferably, the dialysis time is greater than 12 hours and the ultrafiltration time is greater than 10 minutes; the external solution used for dialysis is one or more of hydrochloric acid, nitric acid, boric acid, citric acid, and acetic acid.

[0050] Preferably, changing the gel temperature involves lowering the gel temperature.

[0051] Preferably, when the concentration of added anion is 0.001M, the gelation temperature is lowered to below 37 degrees Celsius.

[0052] The sixth objective of this invention is to provide an application of a pure inorganic stimulus-responsive sol in sterilization, hemostasis, wound healing, drug carrier, medical excipient, cosmetic material or sunscreen product, characterized in that it includes at least the step of converting the sol into a gel and / or the step of converting the gel into a sol.

[0053] The pure inorganic stimulus-responsive sol includes inorganic one-dimensional nanomaterials and a solution for dispersing the inorganic one-dimensional nanomaterials; the inorganic one-dimensional nanomaterials contain at least rare earth metal elements, and the positive charge of the rare earth metal elements causes the inorganic one-dimensional nanomaterials to repel each other to form a sol.

[0054] The seventh objective of this invention is to provide an application of a pure inorganic stimuli-responsive gel in sterilization, hemostasis, wound healing, drug carrier, medical excipient, cosmetic material or sunscreen product, characterized in that it includes at least the step of converting the gel into a sol and / or the step of converting the sol into a gel.

[0055] The sol comprises inorganic one-dimensional nanomaterials and a solution for dispersing the inorganic one-dimensional nanomaterials; the inorganic one-dimensional nanomaterials contain at least rare earth metal elements, and the positive charge of the rare earth metal elements causes the inorganic one-dimensional nanomaterials to repel each other to form a sol.

[0056] The applications include, but are not limited to: applications in bactericides, disinfectants, bacteriostatic agents, liquid wound dressings, hemostatic gels, hemostatic films, wet gauze, hemostatic patches, gel excipients, liquid excipients, gel dressings, liquid dressings, foam dressings, face masks, face creams, serums, body lotions, sunscreens, sunscreen lotions, and sunscreen creams.

[0057] Therefore, the present invention has the following beneficial effects:

[0058] This invention solves the technical problem of the sol-gel transformation of one-dimensional inorganic nanomaterials by utilizing self-positively charged inorganic nanomaterials. First, compared to inorganic nanoparticles of other morphologies, one-dimensional inorganic nanomaterials possess a better foundation for stimulus-responsive sol-gel transformation. Second, the metal ions on the surface of one-dimensional inorganic nanomaterials carry a positive charge sufficient to resist particle aggregation, allowing them to disperse monodisperse in water to form a sol without the need for additional surface modification reagents. One-dimensional inorganic nanomaterials can also crosslink upon the addition of anions, forming a gel in response to stimulation. Compared to methods that provide positive charge to one-dimensional inorganic nanomaterials through modification, this self-positively charged method not only requires inexpensive inorganic materials but also offers a qualitative leap in terms of convenience and cost-effectiveness in further processing and practical applications. It allows for the adjustment of interactions between one-dimensional inorganic nanomaterials without changing ligands, demonstrating a significant advantage in achieving stimulus-responsive sol-gel transformation.

[0059] This invention utilizes rigid, non-stimulating inorganic materials to prepare stimulus-responsive gels, expanding the application fields of inorganic materials. It successfully enables one-dimensional inorganic nanomaterials to form hydrogels through interionic forces and then revert to a sol state. Furthermore, inorganic nanomaterials with strongly positively charged surfaces and their resulting three-dimensional network structures can also possess stimulus-responsive capabilities. Because the inter-material forces within the one-dimensional structure can be adjusted by the environment, a reversible transition from sol to gel can be achieved.

[0060] The method of this invention is low-cost and simple to operate. The prepared hydrogel possesses both good mechanical properties and good stimulus response, making it a material suitable for comprehensive applications. By adjusting its size factor, its gel transformation properties can be modified, making it suitable for various practical needs, such as liquid dressings for wounds and facial gel dressings for cosmetics. Attached Figure Description

[0061] Figure 1 shows transmission electron microscopy images of lanthanum phosphate, cerium phosphate, and praseodymium phosphate nanowires in Example 1 under acidic and alkaline conditions.

[0062] Figure 2 shows a photograph of the transformation between sol and gel in lanthanum phosphate nanowire sol in Test Example 1 via sodium hydroxide and hydrochloric acid.

[0063] Figure 3 shows the mechanical properties of the lanthanum phosphate nanowire sol in Test Example 1 in both sol and gel states using sodium hydroxide and hydrochloric acid, for a total of 4 cycles.

[0064] Figure 4 shows a photograph of the transformation between sol and gel in lanthanum phosphate nanowire sol in Test Example 1 due to temperature changes.

[0065] Figure 5A is an electron microscope image of the iron-doped cerium phosphate nanowire sol in Example 2.

[0066] Figure 5B shows the energy spectrum of the iron-doped cerium phosphate nanowire sol in Example 2.

[0067] Figure 5C is an elemental distribution diagram of the iron-doped cerium phosphate nanowire sol in Example 2.

[0068] Figure 6 shows a photograph of the iron-doped cerium phosphate nanowire sol in Test Example 2, which transitions between sol and gel via sodium hydroxide and hydrochloric acid.

[0069] Figure 7 shows the mechanical properties of iron-doped cerium phosphate nanowire sol in Test Example 2 under both sol and gel states using sodium hydroxide and hydrochloric acid, for a total of 4 cycles.

[0070] Figure 8A shows the elemental distribution of the copper-doped cerium phosphate nanowire sol in Test Example 2.

[0071] Figure 8B shows the elemental distribution of the manganese-doped cerium phosphate nanowire sol in Test Example 2.

[0072] Figure 9 is a transmission electron microscope image of the transformation of lanthanum borate, praseodymium borate, and samarium borate nanorods between sol and gel via sodium hydroxide and hydrochloric acid in Example 4.

[0073] Figure 10 shows a photograph of the transformation of lanthanum borate nanorods between sol and gel via sodium hydroxide and hydrochloric acid in Test Example 4.

[0074] Figure 11 is a transmission electron microscope image of the transformation of lanthanum hydroxide and praseodymium hydroxide nanorods between sol and gel via sodium hydroxide and hydrochloric acid in Example 5.

[0075] Figure 12 shows a photograph of the transformation of lanthanum hydroxide nanorods between sol and gel via sodium hydroxide and hydrochloric acid in Test Example 5.

[0076] Figure 13 is a transmission electron microscope image of cerium oxide, titanium oxide, aluminum oxide and vanadium oxide nanowires in Example 6. From left to right in the figure are: cerium oxide, titanium oxide, aluminum oxide and vanadium oxide.

[0077] Figure 14 shows photographs and transmission electron microscope images of the cerium oxide nanowires in Test Example 6 undergoing transformation between sol and gel via sodium hydroxide and hydrochloric acid.

[0078] Figure 15 shows a photograph of the transformation of cerium phosphate nanowire sol in Example 7 between sol and gel via bacterial growth medium and hydrochloric acid.

[0079] Figure 16 shows the colony status of cerium phosphate nanowires with different degrees of iron doping and Escherichia coli after co-culturing in Example 7.

[0080] Figure 17 shows the colony status and statistical diagram of cerium phosphate nanowires with different degrees of iron doping and Staphylococcus aureus after co-culturing in Example 7.

[0081] Figure 18 shows the colony status and statistical diagram of cerium phosphate nanowires with different degrees of iron doping and Pseudomonas aeruginosa after co-culturing in Example 7.

[0082] Figure 19 shows scanning electron microscope images of cerium phosphate nanowires with different degrees of iron doping and Escherichia coli after co-culturing in Example 7.

[0083] Figure 20 shows the bleeding time after using cerium phosphate and sodium chloride solution in the mouse intravenous hemostasis experiment in Example 8.

[0084] Figure 21 shows the bleeding time after using cerium phosphate and sodium chloride solution in the hemostasis experiments of Dutch rabbit veins, arteries and liver in Example 8.

[0085] Figure 22 is a comparison of the bleeding time of liquid and powdered cerium phosphate in the arterial hemostasis experiment of Dutch rabbits in Comparative Example 1.

[0086] Figure 23 is a comparison of bleeding time using cerium phosphate liquid and chitosan gel in the arterial hemostasis experiment of Dutch rabbits in Comparative Example 2.

[0087] Figure 24 is a transmission electron microscope image of the transformation of cerium phosphate nanowire sol in Example 9 between sol and gel via body fluid and hydrochloric acid.

[0088] Figure 25 shows the antioxidant activity of cerium phosphate nanowires with different degrees of iron doping in Example 9.

[0089] Figure 26 shows the recovery of the mouse full-wound defect model in Example 9 under iron-doped cerium phosphate nanowires at different degrees.

[0090] Figure 27 shows the SOD activity of cerium phosphate nanowires with different degrees of iron doping in Example 10.

[0091] Figure 28 is a transmission electron microscope image of the transformation of lanthanum phosphate nanowires loaded with vitamin C in Example 11 between sol and gel via sodium hydroxide and hydrochloric acid.

[0092] Figure 29 is a photograph of the transformation of lanthanum phosphate nanowires loaded with vitamin C in Example 11 between sol and gel via sodium hydroxide and hydrochloric acid.

[0093] Figure 30 shows the UV-Vis absorption spectrum of the lanthanum phosphate nanowires in Example 12.

[0094] Figure 31 shows the UV-Vis absorption spectrum of praseodymium phosphate nanowires in Example 12.

[0095] Figure 32 shows the UV-Vis absorption spectrum of the lanthanum borate nanorods in Example 12.

[0096] Figure 33 shows transmission electron microscopy images of samarium hydroxide, gadolinium hydroxide, and dysprosium hydroxide nanorods in Comparative Example 3. Detailed Implementation

[0097] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0098] The technical solution of the present invention will be described below with specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0099] Example 1

[0100] Weigh 7.4 g of lanthanum nitrate (molecular weight 324.92, 0.023 mol) and add it to 20 mL of deionized water. Stir magnetically until dissolved. Add 0.6 mL of commercially available concentrated phosphoric acid (85%) to 20 mL of deionized water and mix with 0.4 mL of ammonia (28%). Slowly add the latter to the former while stirring vigorously. After the addition is complete, sonicate for 30 min, then stir vigorously again for 6 h. When the solution becomes clearer and thicker, add the liquid to a reaction vessel and react at 250 °C for 24 h. After the reaction is complete, centrifuge the reactants and redisperse them in water. Repeat this process 5 times. Finally, disperse the product in 10 mL of hydrochloric acid solution at pH 2 to obtain lanthanum phosphate nanowire sol.

[0101] By replacing lanthanum nitrate with equimolar amounts of cerium nitrate, praseodymium nitrate, promethium nitrate, samarium nitrate, europium nitrate, gadolinium nitrate, etc., corresponding metal phosphate nanowires can be prepared, which also possess the aforementioned properties.

[0102] Figure 1 shows transmission electron microscopy images of lanthanum phosphate, cerium phosphate, and praseodymium phosphate nanowires in Example 1 under acidic and alkaline conditions. As can be seen from Figure 1, the prepared material is a one-dimensional nanofiber with a diameter of about 10 nm and a length of about 1000 nm.

[0103] Test Example 1

[0104] Hydroxide ions were added to the lanthanum phosphate nanowire sol prepared in Example 1. The dispersibility of the material could be altered by changing the pH value (hydroxide concentration) of the solution sample. Specifically, 50 μL of pH 14 NaOH was added to 5 mL of 30 mg / mL sol.

[0105] As shown in Figure 2, adding 50 μL of NaOH (pH 14) to 5 mL of 30 mg / mL lanthanum phosphate sol forms a lanthanum phosphate gel. Adding 50 μL of hydrochloric acid (pH 0) reverts the sol back to its original state. In an alkaline environment, the hydroxyl concentration is high, and hydroxyl groups act as a "binder" between nanowires, causing them to cross-link and form a gel. In an acidic environment (by adding sodium hydroxide), the hydroxyl concentration decreases sharply, the nanowires lose their "binder," and the sol redisperses.

[0106] Take 1 mL of lanthanum phosphate sol with a concentration of 30 mg / mL and test its rheological properties. After adding 10 μL of NaOH solution with pH 14, test its rheological properties again. Then add 10 μL of HCl solution with pH 0 and test its rheological properties again. Repeat 4 times.

[0107] As shown in Figure 3, G' is the storage modulus, G” is the loss modulus, and 1G'-8G' and 1G”-8G” are the modulus changes during the four sol and gel cycles, respectively. This indicates that the material has good reversible transformation properties.

[0108] The lanthanum phosphate nanowire sol prepared in Example 1 was heated; as shown in Figure 4, the sol and gel can also be transformed by changing the temperature.

[0109] The conversion from sol to gel can also be achieved by adding other anions, but because they are difficult to remove, it is not easy to reverse the process from gel to sol. Specific dosages are shown in Table 1.

[0110] Table 1. Minimum concentrations of different reagents required for the transformation of lanthanum phosphate nanowire sol into gel.

[0111] Table 2. Substances requiring high concentrations for the transformation of lanthanum phosphate nanowire sol into gel.

[0112] It is evident that the substances listed in Table 2 are difficult to convert from sol to gel.

[0113] Example 2

[0114] Weigh 7.4 g of cerium nitrate and 1.3 g of ferric nitrate and add them to 20 mL of deionized water. Stir magnetically until dissolved. Add 0.6 mL of commercially available concentrated phosphoric acid (85%) to 20 mL of deionized water and mix with 0.3 mL of ammonia water (25%-28%). Slowly add the latter to the former while stirring vigorously. After the addition is complete, sonicate for 30 min, then stir vigorously again for 6 h. When the solution becomes clearer and thicker, add the liquid to a reaction vessel and react at 250 °C for 24 h. After the reaction is complete, centrifuge the reactants and redisperse them in water. Repeat this process 5 times. Finally, disperse the product in 10 mL of hydrochloric acid solution at pH 2 to obtain iron-doped cerium phosphate nanowire sol.

[0115] As shown in Figure 5, the prepared material is a one-dimensional nanowire; the energy spectrum and elemental distribution diagram confirm that iron was successfully incorporated into the nanowire.

[0116] Test Example 2

[0117] Adding hydroxide ions to the sol prepared in Example 2, as shown in Figure 6, allows the material to undergo reversible transformation between the sol and gel states by adjusting the pH environment of the solution with hydrochloric acid and sodium hydroxide.

[0118] 1 mL of a sol with a concentration of 30 mg / mL was taken and its rheological properties were tested. After adding 10 μL of NaOH solution with pH 14, its rheological properties were tested again. Then, 10 μL of NaOH solution with pH 0 was added, and the rheological properties were tested again, repeating this process four times. As shown in Figure 7, G' is the storage modulus, G” is the loss modulus, and 1G'-8G' and 1G”-8G” are the modulus changes during the four cycles, indicating that the material possesses good reversible transformation properties.

[0119] By replacing cerium nitrate with equal molar amounts of other raw materials such as lanthanum nitrate, praseodymium nitrate, promethium nitrate, samarium nitrate, europium nitrate, and gadolinium nitrate, corresponding iron-doped metal phosphate nanowires can be prepared, which also possess the aforementioned properties.

[0120] By replacing ferric nitrate with other raw materials such as cobalt nitrate, copper nitrate, nickel nitrate, and manganese nitrate, other metal-doped cerium phosphate nanowires with the same properties can be prepared. The elemental distribution diagrams of copper-doped cerium phosphate and manganese-doped cerium phosphate are shown in Figure 8.

[0121] Similar to Example 1, the transformation from sol to gel can also be achieved by changing the temperature and adding other anions.

[0122] Example 3

[0123] Weigh 7.4 g of lanthanum nitrate and add it to 20 mL of deionized water, stirring magnetically until dissolved. Dissolve 0.84 g of boric acid (99.99%) in 20 mL of deionized water, and mix with 0.8 mL of ammonia (25%-28%). Under vigorous stirring, slowly add the latter to the former, sonicate for 5 min after addition, and then stir vigorously again for 1 h. When the solution becomes clearer and thicker, add the liquid to a reaction vessel and react at 250 °C for 24 h. After the reaction, centrifuge the reactants and redisperse them in water, repeating this process 5 times. Finally, disperse the product in 10 mL of deionized water to obtain lanthanum borate nanorods.

[0124] Test Example 3

[0125] Hydroxide ions were added to the sol prepared in Example 4. As shown in Figure 9, the prepared material is a one-dimensional nanorod with a diameter of about 10 nm and a length of about 400 nm. The dispersibility of the material can be changed by changing the pH value (hydride concentration) of the solution sample.

[0126] As shown in Figure 10, adding 50 μL of pH 14 NaOH to 5 mL of 30 mg / mL sol forms a gel. Adding 50 μL of pH 0 hydrochloric acid solution again reverts the gel back to a sol.

[0127] Similar to Example 1, the transformation from sol to gel can also be achieved by changing the temperature and adding other anions.

[0128] By replacing lanthanum nitrate with other raw materials such as cerium nitrate, praseodymium nitrate, promethium nitrate, samarium nitrate, europium nitrate, and gadolinium nitrate in equal molar amounts, corresponding metal borate nanorods can be prepared, which also possess the aforementioned properties.

[0129] Example 4

[0130] Weigh 8.68 g of lanthanum nitrate (99.99%) and add it to 20 mL of deionized water, stirring magnetically until dissolved. Dissolve 14.4 g of sodium hydroxide (99.99%) in 20 mL of deionized water. Under vigorous stirring, slowly add the sodium hydroxide to the sodium hydroxide solution, sonicate for 5 min after addition, and then stir vigorously again for 1 h. Add the liquid to a reaction vessel and react at 80 °C for 24 h. After the reaction, centrifuge the reactants and redisperse them in water, repeating this process 8 times. Finally, disperse the product in 10 mL of pH 4 hydrochloric acid solution to obtain lanthanum hydroxide nanowires.

[0131] Test Example 4

[0132] Hydroxide ions were added to the sol prepared in Example 5. As shown in Figure 11, the prepared material is a one-dimensional nanowire with a diameter of about 15 nm and a length of about 600 nm. The dispersibility of the material can be changed by changing the pH value (hydride concentration) of the solution sample.

[0133] As shown in Figure 12, adding 50 μL of pH 14 NaOH to 5 mL of 30 mg / mL sol forms a gel. Adding 50 μL of pH 0 hydrochloric acid solution again reverts the gel back to a sol.

[0134] Similar to Example 1, the transformation from sol to gel can also be achieved by changing the temperature and adding other anions.

[0135] By replacing lanthanum nitrate with other raw materials such as praseodymium nitrate, promethium nitrate, samarium nitrate, europium nitrate, and gadolinium nitrate in equal molar amounts, corresponding metal hydroxide nanowires can be prepared, which also possess the aforementioned properties.

[0136] Example 5

[0137] Weigh 8.68 g of cerium nitrate (99.99%) and add it to 20 mL of deionized water, stirring magnetically until dissolved. Dissolve 14.4 g of sodium hydroxide (99.99%) in 20 mL of deionized water. Under vigorous stirring, slowly add the latter to the former, sonicate for 5 min after addition, and then stir vigorously again for 1 h. Add the liquid to a reaction vessel and react at 80 °C for 24 h. After the reaction, centrifuge and redisperse the reactants in water, repeating this process 8 times. Finally, disperse the product in 10 mL of hydrochloric acid solution (pH = 4) to obtain a one-dimensional cerium oxide material.

[0138] By replacing cerium nitrate with aluminum nitrate, vanadium nitrate, or titanium oxide, corresponding one-dimensional oxide nanomaterials can be prepared, as shown in Figure 13.

[0139] Test Example 5

[0140] Adding hydroxide ions to the sol prepared in Example 6, as shown in Figure 14, resulted in the formation of a gel after adding 50 μL of pH 14 NaOH to 5 mL of 30 mg / mL cerium oxide one-dimensional material sol. This gel could be restored to a sol by adding another 50 μL of pH 0 hydrochloric acid solution.

[0141] Similar to Example 1, the transformation from sol to gel can also be achieved by changing the temperature and adding other anions.

[0142] Example 6

[0143] Cerium phosphate nanowires with different iron doping ratios were prepared using the preparation method in Example 2 for the purpose of investigating their bactericidal properties.

[0144] As shown in Figure 15, the material can undergo reversible transformation between sol and gel states by contacting the bacterial growth environment and adding hydrochloric acid. Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa were cultured in the presence of cerium iron phosphate, and their bactericidal properties were tested by counting colonies on a plate.

[0145] As shown in Figures 16, 17, and 18, the nanowires themselves possess bactericidal properties, which are further enhanced by iron doping. Scanning electron microscopy, as shown in Figure 23, demonstrates that this material can contact bacteria and kill them.

[0146] Example 7

[0147] The cerium phosphate nanowires from Example 1 were used to investigate hemostatic properties.

[0148] To investigate the hemostatic properties of the material, a mouse tail amputation model was established, and the hemostatic ability of the material was evaluated by recording the hemostasis time of the mice.

[0149] As shown in Figure 20, the hemostasis time in mice was greatly shortened under the conditions of sol-gel reversible variable materials.

[0150] To further investigate, arterial bleeding and liver bleeding models were established in Dutch rabbits, and the hemostatic ability of the materials was evaluated by recording the hemostasis time.

[0151] As shown in Figure 21, the bleeding time of both models was significantly shortened under the influence of this material.

[0152] Comparative Example 1

[0153] Cerium phosphate nanowire solid powder was used for research on arterial hemostatic properties.

[0154] As shown in Figure 22, compared with the results in Example 7, the hemostatic effect of solid powder with the same solid content is not good. The reason is that the dry powder has agglomerated and cannot be dispersed in the blood and cross-linked. It cannot fully contact and coagulate with the blood, making it difficult to produce a sol effect.

[0155] Comparative Example 2

[0156] Compared with common organic gels, chitosan hydrogels were synthesized in acetic acid solution using chitosan as the raw material and glutaraldehyde as the cross-linking agent. The chitosan hydrogel was prepared at 45 degrees Celsius with a chitosan concentration of 2.5% and a glutaraldehyde concentration of 1%, and used for hemostasis testing. As shown in Figure 23, the hemostasis time was slightly longer than that in Example 7. This indicates that due to the sol-gel transition effect, the hemostatic effect of cerium phosphate sol is slightly higher than that of ordinary gels.

[0157] In terms of the price of the main raw materials, chitosan is priced at 100-200 yuan / kg, while cerium nitrate is only around 20 yuan / kg, giving chitosan a significant cost advantage.

[0158] Example 8

[0159] The iron-doped cerium phosphate nanowires from Example 2 were used to investigate wound healing.

[0160] As shown in Figure 24, the material can undergo reversible transformation in both sol and gel states by contacting the body fluid environment and adding hydrochloric acid.

[0161] To investigate the material's effect on wound healing, its ability to scavenge reactive oxygen species was tested using PTIO. As shown in Figure 25, cerium phosphate itself possesses a certain ability to scavenge reactive oxygen species, while the incorporation of iron greatly enhances this property, thereby promoting wound healing.

[0162] To investigate the effect of materials on wound healing, a mouse model of full-thickness epidermal resection was established. A reversible inorganic nanomaterial, cerium iron phosphate sol-gel, was used to form a coating layer with body fluid at the wound site. The wound healing was observed and its ability to promote wound healing was evaluated.

[0163] As shown in Figure 26, the reversible transformation inorganic nanomaterials of cerium iron phosphate sol-gel promote wound healing.

[0164] Example 9

[0165] The iron-doped cerium phosphate nanowires from Example 2 were used to investigate their cosmetic effects.

[0166] As shown in Figure 27, the SOD enzyme performance of the material was detected by pyrogallol, revealing that materials with a specific doping level exhibit optimal biocatalytic performance. This indicates that in addition to the antioxidant activity shown in Example 9, the material also possesses a certain degree of SOD activity, making it suitable for use as a cosmetic material.

[0167] Example 10

[0168] Weigh 7.4 g of lanthanum nitrate and add it to 20 mL of deionized water, stirring magnetically until dissolved. Add 0.6 mL of commercially available concentrated phosphoric acid to 20 mL of deionized water, and mix with 0.4 mL of ammonia. Slowly add the latter to the former while stirring vigorously. After the addition is complete, sonicate for 30 min, then stir vigorously again for 6 h. When the solution becomes clearer and thicker, add the liquid to a reaction vessel and react at 250 °C for 24 h. After the reaction is complete, centrifuge the reactants and redisperse them in water, repeating this process 5 times. Finally, disperse the product in 10 mL of pH 2 hydrochloric acid solution to obtain lanthanum phosphate nanowire sol. Add 0.1 g of vitamin C to the liquid and disperse by sonication.

[0169] As shown in Figure 28, the prepared material is a one-dimensional nanofiber; the dispersibility of the material can be changed by altering the hydroxide concentration in the solution sample, and vitamin C does not interfere with its sol-gel reversible properties.

[0170] As shown in Figure 29, adding 50 μL of NaOH (pH=14) to 5 mL of 30 mg / mL sol forms a gel. Adding 50 μL of hydrochloric acid (pH=0) solution reverts the gel back to a sol. Vitamin C does not interfere with its sol-gel reversibility.

[0171] Example 11

[0172] The ultraviolet absorption capacity of a material is detected by ultraviolet-visible light absorption testing.

[0173] As shown in Figure 30, the lanthanum phosphate in Example 1 has high absorption capacity in both the UVA and UVB ultraviolet bands and can be used as an ultraviolet absorber.

[0174] As shown in Figure 31, the praseodymium phosphate in Example 1 has a similar ultraviolet absorption capacity.

[0175] As shown in Figure 32, lanthanum borate in Example 4 also has similar ultraviolet absorption capabilities.

[0176] Comparative Example 3

[0177] Weigh 7.4 g of samarium nitrate and add it to 20 mL of deionized water, stirring magnetically until dissolved. Add 0.6 mL of commercially available concentrated phosphoric acid to 20 mL of deionized water, and mix with 0.4 mL of ammonia. Slowly add the latter to the former while stirring vigorously. After the addition is complete, sonicate for 30 min, then stir vigorously again for 6 h. When the solution becomes clearer and thicker, add the liquid to a reaction vessel and react at 250 °C for 24 h. After the reaction is complete, centrifuge the reactants and redisperse them in water, repeating this process 5 times. Finally, disperse the product in 10 mL of pH 2 hydrochloric acid solution to obtain a one-dimensional samarium hydroxide sol. Replacing nitric acid with gadolinium nitrate and dysprosium nitrate will yield gadolinium hydroxide and dysprosium hydroxide.

[0178] As shown in Figure 33, the prepared samarium hydroxide, gadolinium hydroxide and dysprosium hydroxide are all nanorods with a size greater than 50 nm, and none of them have gel transition characteristics.

Claims

1. A purely inorganic stimulus-responsive sol, wherein the stimulus response includes at least a transition response from sol to gel; characterized in that, The pure inorganic stimulus-responsive sol comprises inorganic one-dimensional nanomaterials and a solution for dispersing the inorganic one-dimensional nanomaterials; the inorganic one-dimensional nanomaterials contain at least rare earth metal elements, and the positive charge of the rare earth metal elements causes the inorganic one-dimensional nanomaterials to repel each other to form a sol.

2. The pure inorganic stimulus-responsive sol according to claim 1, characterized in that: The inorganic one-dimensional nanomaterials include at least one of rare earth metal phosphates, rare earth metal borates, rare earth metal oxides, or rare earth metal hydroxides.

3. The pure inorganic stimulus-responsive sol according to claim 2, characterized in that: The concentration of the inorganic one-dimensional nanomaterial is 1-100 mg / mL.

4. The pure inorganic stimulus-responsive sol according to claim 1, characterized in that: The solution contains anion I, which includes at least one of chloride ion, nitrate ion, borate ion, citrate ion, and acetate ion.

5. The pure inorganic stimulus-responsive sol according to claim 4, characterized in that: The concentration of anion I in the solution is 0.001-10M.

6. The pure inorganic stimulus-responsive sol according to claim 4, characterized in that: The solution also contains hydroxide ions, with a concentration of less than 1 mM.

7. A method for preparing a pure inorganic stimulus-responsive sol, characterized in that, Includes the following steps: Step (1): Add an inducing agent to the metal salt solution under stirring conditions to form a homogeneous liquid; Step (2): Add the liquid to the reaction vessel for reaction; Step (3): Control the concentration of hydroxide ions in the environment to obtain the sol product.

8. The method for preparing a pure inorganic stimulus-responsive sol according to claim 7, characterized in that: In step (1), the metal salts include salts of rare earth metal elements.

9. The method for preparing a pure inorganic stimulus-responsive sol according to claim 8, characterized in that: The rare earth metal element is at least one selected from lanthanum, cerium, arsenic, promethium, samarium, europium, and gadolinium.

10. The method for preparing a pure inorganic stimulus-responsive sol according to claim 7, characterized in that: In step (1), the anions in the metal salt include at least one of nitrate ions, acetate, sulfate, hydrochloride, bromide, and iodide.

11. The method for preparing a pure inorganic stimulus-responsive sol according to claim 7, characterized in that: The concentration of the metal salt in step (1) is 0.1-10M.

12. The method for preparing a pure inorganic stimulus-responsive sol according to claim 7, characterized in that: The inducing agent in step (1) includes an alkaline solution.

13. The method for preparing a pure inorganic stimulus-responsive sol according to claim 12, characterized in that: The alkaline solution includes at least one of ammonia, sodium hydroxide, and potassium hydroxide.

14. The method for preparing a pure inorganic stimulus-responsive sol according to claim 12, characterized in that: The inducing agent in step (1) also includes oxyacids.

15. The method for preparing a pure inorganic stimulus-responsive sol according to claim 14, characterized in that: The oxyacid includes at least one of concentrated phosphoric acid or boric acid.

16. The method for preparing a pure inorganic stimulus-responsive sol according to claim 7, characterized in that: Step (2) The reaction time is less than 24 hours and the reaction temperature is 60-300℃.

17. The method for preparing a pure inorganic stimulus-responsive sol according to claim 7, characterized in that: In step (3), the hydroxide concentration is controlled to be less than 1 mM.

18. The method for preparing a pure inorganic stimulus-responsive sol according to claim 7, characterized in that: The method for controlling the hydroxide concentration in step (3) is to use acid.

19. The method for preparing a pure inorganic stimulus-responsive sol according to claim 18, characterized in that: The acid mentioned includes at least one of hydrochloric acid, nitric acid, boric acid, citric acid, or acetic acid.

20. A method for converting a purely inorganic stimuli-responsive sol into a gel according to any one of claims 1-6, characterized in that, The conditions for the stimulus response include adding anion II, which can have chelating and / or electrostatic interactions with metal elements in inorganic one-dimensional nanomaterials, to the pure inorganic stimulus-response sol, or changing the temperature of the pure inorganic stimulus-response sol.

21. The method according to claim 20, characterized in that: The anion II that can chelate and / or electrostatically interact with the metal elements in inorganic one-dimensional nanomaterials includes at least one of hydroxide ions, phosphate ions, carbonate ions, molybdate ions, tungstate ions, titanate ions, sulfate ions, and bismuthate ions.

22. The method according to claim 20, characterized in that: The anion II is a hydroxide ion.

23. The method according to claim 20, characterized in that: The temperature of the purely inorganic stimulus-responsive sol was changed by increasing the temperature of the sol.

24. A pure inorganic stimulus-responsive gel, prepared by the method described in any one of claims 20-23.

25. A method for converting the pure inorganic stimulus-responsive gel of claim 24 into a pure inorganic stimulus-responsive sol, characterized in that, The conditions for the stimulus response include removing the anion II or changing the gel temperature.

26. The method according to claim 25, characterized in that: The method for removing the anion II includes adding an acidic solution, dialysis, or ultrafiltration.

27. The method according to claim 26, characterized in that: The acidic solution includes at least one of hydrochloric acid, nitric acid, boric acid, citric acid, and acetic acid.

28. The method according to claim 26, characterized in that: The dialysis time is greater than 12 hours and the ultrafiltration time is greater than 10 minutes; the external solution used for dialysis includes at least one of hydrochloric acid, nitric acid, boric acid, citric acid, and acetic acid.

29. The method according to claim 25, characterized in that: Change the gel temperature to lower the gel temperature.

30. The application of a pure inorganic stimulus-responsive sol in bactericidal, hemostatic, wound healing, drug carrier, medical excipient, cosmetic material, or sunscreen product, characterized in that, It includes at least the step of converting a sol into a gel and / or the step of converting a gel into a sol; The pure inorganic stimulus-responsive sol comprises inorganic one-dimensional nanomaterials and a solution for dispersing the inorganic one-dimensional nanomaterials; The inorganic one-dimensional nanomaterials contain at least rare earth metal elements, and the positive charge of the rare earth metal elements causes the inorganic one-dimensional nanomaterials to repel each other to form a sol.

31. The application of a purely inorganic stimuli-responsive gel in bactericidal, hemostatic, wound healing, drug carrier, medical excipient, cosmetic material, or sunscreen product, characterized in that, It includes at least the steps of converting a gel into a sol and / or converting a sol into a gel; the sol comprises an inorganic one-dimensional nanomaterial and a solution for dispersing the inorganic one-dimensional nanomaterial; The inorganic one-dimensional nanomaterials contain at least rare earth metal elements, and the positive charge of the rare earth metal elements causes the inorganic one-dimensional nanomaterials to repel each other to form a sol.

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