Histidine-loaded iron-sodium hexametaphosphate nanomaterial, and preparation method and application thereof

Abstract

This invention discloses a histidine-loaded iron-hexametaphosphate nanomaterial, its preparation method, and its applications, belonging to the field of nanoenzyme technology. The histidine-loaded iron-hexametaphosphate nanomaterial is prepared by loading histidine onto iron-hexametaphosphate nanomaterials, which are obtained through the reaction of ferric chloride hexahydrate and sodium hexametaphosphate. The histidine-loaded iron-hexametaphosphate nanomaterial exhibits peroxidase-like activity and can be applied to uric acid detection. Furthermore, it is also used in the preparation of antibacterial products. The sodium nanomaterial of this invention provides high accuracy and sensitivity in detecting uric acid concentration and can also provide antibacterial protection against gout wounds.

Description

Technical Field

[0001] This invention belongs to the field of nanoenzyme technology, specifically relating to an iron-sodium hexametaphosphate nanomaterial loaded with histidine, its preparation method, and its application. Background Technology

[0002] Blood biochemical indicators are closely related to human health. The normal reference range for serum uric acid is 2.5-7.0 mg / dL for men and 1.5-6.0 mg / dL for women. Clinical data show that when serum uric acid is consistently above 540 μmol / L, the incidence of tophi increases significantly. Abnormal uric acid can lead to gout, hypertension, kidney disease, and metabolic syndrome, with men and middle-aged and elderly people at higher risk. Regular uric acid testing has important clinical significance, as it can help identify purine metabolism abnormalities early, guide dietary and lifestyle interventions to reduce the risk of cardiovascular disease, and is also a key line of defense for protecting kidney function and guiding uric acid-lowering treatment. In addition, measuring the uric acid concentration at the site of tophi ulceration helps to clarify the degree of interference of urate deposition on tissue repair, providing a basis for precise debridement and anti-inflammatory treatment.

[0003] The development of uric acid detection technology is a continuous process of breakthroughs. Early phosphorescence methods, while achieving quantitative detection, suffered from poor specificity and susceptibility to interference. With technological advancements, a diversified detection system has emerged: optical methods are low-cost and easy to operate, suitable for high-throughput screening; fluorescence methods offer high sensitivity and selectivity, but require stringent conditions; electrochemical methods have low detection limits, strong resistance to color interference, and can be integrated with wearable devices for dynamic tracking, but suffer from electrode contamination and stability issues; surface-enhanced Raman scattering combines high sensitivity with molecular fingerprint specificity. In contrast, high-performance liquid chromatography (HPLC) and capillary electrophoresis, due to their complex operation and expensive equipment, have limited applications.

[0004] With the continuous advancement of nanotechnology, nanomaterials are becoming increasingly sophisticated. Nanozymes are a type of nanomaterial with enzyme-like activity. Natural enzymes have some inherent drawbacks, such as high cost, low operational stability, and difficulty in recycling. Nanozymes, possessing the size characteristics of nanomaterials, can easily bind to enzymes, antibodies, or aptamers, expanding their application range. Its functions also have the unique advantage of enzyme-like catalytic activity, showing great application potential in many fields.

[0005] Currently, colorimetric detection of uric acid based on nanozymes has been widely applied; however, most studies are limited to detection. Gout wounds are well known to be invasive, and the physiological environment makes rapid healing difficult. Therefore, it is necessary to develop a bifunctional nanozyme that can both detect uric acid and have antibacterial properties at the site of a gouty wound. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an iron-sodium hexametaphosphate nanomaterial loaded with histidine, its preparation method, and its application.

[0007] The technical solution of the present invention is as follows: This invention provides an iron-sodium hexametaphosphate nanomaterial loaded with histidine, which is prepared by loading histidine onto the iron-sodium hexametaphosphate nanomaterial, which is prepared by reacting ferric chloride hexahydrate and sodium hexametaphosphate.

[0008] The present invention also provides a method for preparing the above-mentioned iron-sodium hexametaphosphate nanomaterial loaded with histidine.

[0009] A method for preparing histidine-loaded iron-sodium hexametaphosphate nanomaterials, wherein the histidine-loaded iron-sodium hexametaphosphate nanomaterials are synthesized by a one-pot method, comprising the following steps: Ferric chloride hexahydrate solution was added dropwise to sodium hexametaphosphate solution under stirring. After the addition was complete, stirring was continued to obtain iron-sodium hexametaphosphate nanomaterial solution. Histidine solution was added dropwise to iron-sodium hexametaphosphate nanomaterial solution under stirring. After the addition was complete, the solution was allowed to stand, centrifuged, filtered, washed, and dried in sequence to obtain histidine-loaded iron-sodium hexametaphosphate nanomaterial.

[0010] According to a preferred embodiment of the present invention, the concentration of the ferric chloride hexahydrate solution is 2-5 M.

[0011] According to a preferred embodiment of the present invention, the concentration of the sodium hexametaphosphate solution is 5-8 mM.

[0012] According to a preferred embodiment of the present invention, after the ferric chloride hexahydrate solution is added dropwise, stirring is continued for 5 to 15 minutes; more preferably, stirring is continued for 10 minutes after the addition is completed.

[0013] According to the present invention, the concentration of the histidine solution is preferably 2.5~50mM; more preferably, the concentration is 20~30mM.

[0014] According to a preferred embodiment of the present invention, the stirring is performed using magnetic stirring, and the stirring speed is 500 rpm / min.

[0015] According to a preferred embodiment of the present invention, the settling time is 10-20 minutes; more preferably, the settling time is 15 minutes.

[0016] According to a preferred embodiment of the present invention, the volume ratio of the ferric chloride hexahydrate solution, the sodium hexametaphosphate solution, and the histidine solution is 1:(40~67):(40~112).

[0017] According to a preferred embodiment of the present invention, the temperature is controlled at 20~25℃ during the preparation of the histidine-loaded iron-sodium hexametaphosphate nanomaterial.

[0018] The present invention also provides an application of the above-mentioned iron-sodium hexametaphosphate nanomaterial loaded with histidine in uric acid detection.

[0019] An application of histidine-loaded iron-sodium hexametaphosphate nanomaterial in uric acid detection, wherein the method for detecting uric acid using the histidine-loaded iron-sodium hexametaphosphate nanomaterial includes the following steps: (1) Standard uric acid solutions of different concentrations were mixed with uricase solution and Britton-Robinson buffer solution and reacted thoroughly. Then, iron-sodium hexametaphosphate nanomaterial solution loaded with histidine, NaAc-HAc buffer solution and 3,3',5,5',-tetramethylbenzidine (TMB) solution were added respectively. After the reaction was completed, the absorbance at 652 nm wavelength was measured to establish a standard curve of absorbance change with uric acid concentration. (2) Replace the standard uric acid solution in step (1) with the serum uric acid to be tested, construct the test system according to the method in step (1), measure the absorbance of the test system at a wavelength of 652 nm, and obtain the uric acid concentration in the serum by combining the standard curve.

[0020] According to a preferred embodiment of the present invention, in step (1), the final uric acid concentration in the reaction system is 0.1 μM to 250 μM.

[0021] According to a preferred embodiment of the present invention, in step (1), the concentration of the uricase solution is 10-30 U / mg; more preferably, the concentration is 15-20 U / mg.

[0022] According to a preferred embodiment of the present invention, in step (1), the pH of the Britton-Robinson buffer solution is 7 to 9.

[0023] According to a preferred embodiment of the present invention, in step (1), the temperature at which the standard uric acid solution, uricase solution, and Britton-Robinson buffer solution are mixed and reacted fully is 25~55℃, and the reaction time is 10~90min; preferably, the temperature is 30~40℃ and the time is 35~55min.

[0024] According to a preferred embodiment of the present invention, in step (1), the concentration of the iron-sodium hexametaphosphate nanomaterial solution loaded with histidine is 0.5~1.5 mg / mL; preferably, the concentration is 0.6~1.2 mg / mL.

[0025] According to a preferred embodiment of the present invention, in step (1), the pH of the NaAc-HAc buffer solution is 2 to 8, preferably 3 to 5.

[0026] According to a preferred embodiment of the present invention, in step (1), the concentration of the 3,3',5,5',-tetramethylbenzidine solution is 1~10 mM; preferably, the concentration is 2~7 mM.

[0027] According to a preferred embodiment of the present invention, in step (1), the temperature for complete reaction after adding the iron-sodium hexametaphosphate nanomaterial solution loaded with histidine, the NaAc-HAc buffer solution and the 3,3',5,5',-tetramethylbenzidine (TMB) solution is 25~55℃ and the time is 3~20min; preferably, the temperature is 30~40℃ and the time is 10~20min.

[0028] According to a preferred embodiment of the present invention, in step (1), the volume ratio of the standard uric acid solution, uricase solution, Britton-Robinson buffer solution, iron-sodium hexametaphosphate nanomaterial solution loaded with histidine, NaAc-HAc buffer solution and 3,3',5,5',-tetramethylbenzidine solution is 1:(0.3~0.7):(2.3~9):(0.7~1.7):(10~23.3):(0.8~1.7).

[0029] The present invention also provides the application of the above-mentioned iron-sodium hexametaphosphate nanomaterial loaded with histidine in the preparation of antibacterial drugs.

[0030] According to a preferred embodiment of the present invention, the drug is a topical drug, which is a patch or ointment.

[0031] Technical features and beneficial effects of the present invention: 1. The technical solution of the present invention introduces histidine into iron-sodium hexametaphosphate nanomaterials. Through the imidazole side chain of histidine, hydrogen bonds are formed with hydrogen peroxide, which weakens the OH bond strength of hydrogen peroxide and increases the negative charge of oxygen atoms in hydrogen peroxide, thereby improving the affinity for hydrogen peroxide and thus improving the catalytic efficiency. The nanomaterial of the present invention is a nanoenzyme, which improves the accuracy of uric acid concentration detection.

[0032] 2. The iron-sodium hexametaphosphate nanomaterial loaded with histidine provided by this invention exhibits peroxidase-like activity. Based on the peroxidase-like activity of this nanomaterial, a colorimetric method for detecting uric acid was constructed. This white nanomaterial enhances color contrast, reduces background interference, improves detection sensitivity, facilitates semi-quantitative detection with the naked eye, and reduces measurement errors when detecting uric acid.

[0033] 3. The histidine-loaded iron-hexametaphosphate nanomaterials provided by this invention have two functions. In addition to being used for colorimetric detection of uric acid, they can also be used for antibacterial treatment of gout wounds. Uricase decomposes uric acid to produce allantoin and hydrogen peroxide. The histidine-loaded iron-hexametaphosphate nanomaterials of this invention utilize the hydrogen peroxide produced by the reaction for antibacterial treatment. Under the action of the histidine-loaded iron-hexametaphosphate nanomaterials, hydrogen peroxide is decomposed to produce reactive oxygen species, which can effectively kill bacteria. The antibacterial rate against Escherichia coli and Staphylococcus aureus can reach more than 99%. Attached Figure Description

[0034] Figure 1 This is a SEM image of the iron-sodium hexametaphosphate nanomaterial loaded with histidine in Example 1 of the present invention; Figure 2 The image shows an infrared image of the iron-sodium hexametaphosphate nanomaterial loaded with histidine in Example 1 of this invention; wherein, blue represents the iron-sodium hexametaphosphate nanomaterial (Fe-SHMP), red represents histidine (His), and black represents the iron-sodium hexametaphosphate nanomaterial loaded with histidine (His@Fe-SHMP).

[0035] Figure 3 This is the absorbance graph of the iron-sodium hexametaphosphate nanomaterial loaded with histidine for uric acid detection in Example 2 of the present invention; Figure 4 This is a colorimetric diagram of the detection of uric acid by the iron-sodium hexametaphosphate nanomaterial loaded with histidine in Example 2 of the present invention. Figure 5 This is a line graph showing the detection of uric acid by the iron-sodium hexametaphosphate nanomaterial loaded with histidine in Example 2 of the present invention. Figure 6 This is an OD600 antibacterial diagram of the iron-sodium hexametaphosphate nanomaterial loaded with histidine against Escherichia coli in Example 3 of the present invention. Figure 7 This is an OD600 antibacterial diagram of the iron-sodium hexametaphosphate nanomaterial loaded with histidine against Staphylococcus aureus in Example 3 of the present invention. Figure 8 This is a photograph of the appearance of the iron-sodium hexametaphosphate nanomaterial loaded with histidine in Example 1 of the present invention. Detailed Implementation

[0036] The present invention will be further described below with reference to embodiments, but is not limited thereto. The described embodiments are some embodiments of the present invention. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. Unless otherwise specified in the embodiments of the present invention, existing technologies can be used.

[0038] Example 1 A method for preparing histidine-loaded iron-sodium hexametaphosphate nanomaterials, using a one-pot synthesis, includes the following steps: (1) First, take FeCl3•6H2O solution (3.0M, 60μL), control the reaction temperature at 25℃, and add sodium hexametaphosphate solution (6mM, 3.94mL) dropwise while stirring. After the addition is completed, continue stirring for 10 min to obtain iron-sodium hexametaphosphate nanomaterial solution (Fe-SHMP solution); then prepare histidine solution (25mM, 5ml), sonicate for 5min to dissolve, control the reaction temperature at 25℃, and stir at a speed of 500rpm / min. Add histidine solution dropwise to the iron-sodium hexametaphosphate nanomaterial solution obtained in step (1). After the addition is completed, let stand (15min), centrifuge, filter, wash with deionized water (3 times) in sequence, and then send it to a vacuum drying oven to dry at 60℃ to obtain iron-sodium hexametaphosphate nanomaterial loaded with histidine (His@Fe-SHMP), with a particle size of 40~50nm.

[0039] Example 2 Example 1 describes a method for detecting uric acid using iron-sodium hexametaphosphate nanomaterials loaded with histidine, comprising the following steps: 50 μL of standard uric acid solutions of different concentrations (including 2 μM, 10 μM, 20 μM, 100 μM, 200 μM, 600 μM, 1 mM, 1.6 mM, 2 mM, 4 mM, and 5 mM) were added to separate centrifuge tubes. Then, 20 μL of uricase solution (20 U / mg) and 180 μL of Britton-Robinson buffer (pH=8.5) were added to each centrifuge tube. The tubes were incubated at 37°C for 45 min. Next, 50 μL of His@Fe-SHMP solution (1 mg / mL), 50 μL of TMB solution (5 mM), and 650 μL of NaAc-HAc buffer (pH=4, 0.1 M) were added to each centrifuge tube, and the tubes were shaken to allow for complete reaction. The final uric acid concentrations in the systems were 0.1 μM, 0.5 μM, 1.0 μM, 5.0 μM, 10.0 μM, and 10.0 μM, respectively. The absorbance at 652 nm was measured using UV-Vis at μM, 30 μM, 50 μM, 80 μM, 100 μM, 200 μM, and 250 μM, and the results are as follows: Figures 3-5 As shown. By Figure 3 It was found that the absorbance value gradually increased with the increase of uric acid concentration; from Figure 4It was found that as the concentration of uric acid increased, the color of the solution gradually deepened; from Figure 5 The results showed that the histidine-loaded iron-sodium hexametaphosphate nanomaterial exhibited a linear relationship in the detection of uric acid concentrations from 0.1 to 250 μM, with a detection limit of 0.095 μM. The standard curve regression equation was calculated as Abs... 652 =9.037*10 -4 c UA +0.099.

[0040] Add 50 μL of serum uric acid to a centrifuge tube, then add 20 μL of uricase solution (20 U / mg, 20 μL) and 180 μL of Britton-Robinson buffer (pH=8.5). Incubate at 37℃ for 45 min. Then add His@Fe-SHMP solution (1 mg / mL, 50 μL), TMB solution (5 mM, 50 μL), and NaAc-HAc buffer (pH=4, 0.1 M, 700 μL) to the centrifuge tube. Shake to allow for complete reaction. Finally, measure the absorbance of the resulting solution at 652 nm using UV-vis. The serum uric acid concentration is then obtained by combining the standard curve regression equation formula.

[0041] Example 3 Antibacterial tests were conducted on the iron-sodium hexametaphosphate nanomaterials loaded with histidine prepared in Example 1.

[0042] To simulate the environment of a gout wound, OD was used. 600 The in vitro antibacterial activity of His@Fe-SHMP was evaluated using an assay. Two typical microorganisms, Escherichia coli and Staphylococcus aureus, were used as experimental subjects, and an assay of 1×10⁻⁶ was performed. 6 A concentration-dependent study of antibacterial activity was conducted using CFU / mL concentrations.

[0043] The sample was incubated under the following conditions: 1) HAc-NaAc buffer solution (0.1M, 180μL), bacterial suspensions of Escherichia coli and Staphylococcus aureus (20μL, 1×10⁻⁶). 6 After culturing with CFU / mL for 2 h, 20 μL of the culture solution and 180 μL of Luria-Bertani medium were mixed and added to a 96-well plate and incubated at 37 °C for 12 h. OD was then measured using a microplate reader after incubation. 600 To evaluate the antibacterial effect.

[0044] 2) His@Fe-SHMP solution (1 mg / mL, 60 μL), 20 μL of bacterial suspension of Escherichia coli and Staphylococcus aureus (20 μL, 1×10⁻⁶). 6After culturing with CFU / mL for 2 h, 20 μL of the culture solution and 180 μL of Luria-Bertani medium were mixed and added to a 96-well plate and incubated at 37 °C for 12 h. OD was then measured using a microplate reader after incubation. 600 To evaluate the antibacterial effect.

[0045] 3) Uric acid solution (4mM, 40μL), 20μL of bacterial suspension of Escherichia coli and Staphylococcus aureus (20μL, 1×10⁻⁶ mM), and 10 μL of bacterial suspension of Escherichia coli and Staphylococcus aureus. 6 After culturing with CFU / mL for 2 h, 20 μL of the culture solution and 180 μL of Luria-Bertani medium were mixed and added to a 96-well plate and incubated at 37 °C for 12 h. OD was then measured using a microplate reader after incubation. 600 To evaluate the antibacterial effect.

[0046] 4) Uric acid solution (4mM, 40μL), uricase solution (20U / mg, 50μL), and bacterial suspensions of Escherichia coli and Staphylococcus aureus (20μL, 1×10⁻⁶). 6 After culturing with CFU / mL for 2 h, 20 μL of the culture solution and 180 μL of Luria-Bertani medium (LB) were mixed and added to a 96-well plate and incubated at 37 °C for 12 h. OD was then measured using a microplate reader after incubation. 600 To evaluate the antibacterial effect.

[0047] 5) Add uric acid solution (4mM, 40μL) to centrifuge tubes, then add uricase solution (20U / mg, 20μL) and Britton-Robinson buffer (180μL, pH=8.5) to each centrifuge tube. Incubate at 37℃ for 45min. Then add His@Fe-SHMP solution (1mg / mL, 50μL), NaAc-HAc buffer (pH=4, 0.1M, 700μL), and bacterial suspensions of Escherichia coli and Staphylococcus aureus (1×10⁻⁶) to each centrifuge tube. 6 CFU / mL, 20 μL) was cultured for 2 h. 20 μL of the culture solution was then mixed with 180 μL of Luria-Bertani medium (LB) and added to a 96-well plate, incubated at 37°C for 12 h. OD was measured using a microplate reader after incubation. 600 To evaluate the antibacterial effect.

[0048] The antibacterial effects under different conditions are shown in Table 1.

[0049] Table 1. Results of antibacterial effects under different conditions

[0050] As shown in Table 1, the cell mortality rate was highest, exceeding 99%, under the conditions of His@Fe-SHMP + uric acid + uricase. This indicates that the iron-sodium hexametaphosphate nanomaterial loaded with histidine of the present invention has a good antibacterial effect on gout wounds when uric acid is detected.

[0051] Experimental Example 1 The catalytic performance of the iron-sodium hexametaphosphate nanomaterial loaded with histidine prepared in Example 1 was tested.

[0052] (1) Add 50 μL His@Fe-SHMP solution (1 mg / mL) to 860 μL NaAc-HAc buffer (pH=4, 0.1 M), then add 40 μL H2O2 and incubate for five minutes, then add 50 μL TMB solution (5 mM). Measure the absorbance at 652 nm using UV-vis. Measure the absorbance at 652 nm using UV-vis for 50 μL TMB solution (5 mM) + 950 μL NaAc-HAc buffer (pH=4, 0.1 M), 40 μL H2O2 + 960 μL NaAc-HAc buffer (pH=4, 0.1 M), and 50 μL His@Fe-SHMP solution (1 mg / mL) + 950 μL NaAc-HAc buffer (pH=4, 0.1 M). The comparison results are shown in Table 2.

[0053] Table 2. Absorbance values ​​of different systems at 652 nm

[0054] Table 2 shows that when only TMB or hydrogen peroxide is present in the buffer solution, the absorbance at 652 nm is close to 0, indicating that no reaction has occurred in the system. When His@Fe-SHMP and hydrogen peroxide are present in the system, there is a large absorbance value at 652 nm, indicating that His@Fe-SHMP and hydrogen peroxide can catalyze the oxidation of TMB to blue when they coexist.

[0055] (2) Add 50 μL of His@Fe-SHMP solution (1 mg / mL) and Fe-SHMP solution (1 mg / mL) to 860 μL of NaAc-HAc buffer (pH=4, 0.1 M), then add 40 μL of H2O2 and incubate for five minutes, then add 50 μL of TMB solution (5 mM), and measure the absorbance at 652 nm using UV-vis. Add 50 μL of His@Fe-SHMP and Fe-SHMP solution (1 mg / mL) to 900 μL of NaAc-HAc buffer (pH=4, 0.1 M), then add 50 μL of TMB solution (5 mM), and measure the absorbance at 652 nm using UV-vis; the comparison results are shown in Table 3.

[0056] Table 3 Comparison of peroxidase-like activities of His@Fe-SHMP and Fe-SHMP

[0057] As shown in Table 2, His@Fe-SHMP exhibits a higher absorbance value after the addition of hydrogen peroxide compared to Fe-SHMP, indicating that His@Fe-SHMP has higher peroxidase-like activity.

[0058] Experimental Example 2 The selectivity of the histidine-loaded iron-sodium hexametaphosphate nanomaterials prepared in Example 1 for uric acid, other interfering biomacromolecules and ions was tested.

[0059] Using deionized water as a solvent, different substances (uric acid, Pro, Cd) are mixed. 2+ Glu, ATP, Mg 2+ Zn 2+ NO 3- Cu 2+ and Na + Solutions of different substances were prepared to a concentration of 4 mM. 40 μL of each solution was added, along with 50 μL of uricase (20 U / mg) and 180 μL of Britton-Robinson buffer solution (pH=8.5). The solutions were incubated at 37°C for 45 minutes, followed by the addition of 50 μL of His@Fe-SHMP solution (1 mg / mL) and 50 μL of TMB solution (5 mM). The absorbance at 652 nm was measured using UV-vis. The absorbance change (ΔA) results are shown in Table 4.

[0060] Table 4. Changes in absorbance values ​​of different substances

[0061] As shown in Table 4, the intensity of uric acid at 652 nm is many times that of other interfering ions, indicating that His@Fe-SHMP has good selectivity for uric acid.

[0062] Experimental Example 3 Cytotoxicity experiments were conducted on the histidine-loaded iron-sodium hexametaphosphate nanomaterials prepared in Example 1. His@Fe-SHMP was dispersed in physiological saline to prepare His@Fe-SHMP solutions of different concentrations (1 mg / mL, 2 mg / mL, 3 mg / mL, 4 mg / mL, and 5 mg / mL). Cytotoxicity was detected using 1% red blood cells. A positive control group and different concentration experimental groups were set up. For each experimental group, 0.5 mL of red blood cells and 1 mL of His@Fe-SHMP solution of different concentrations were used. For the positive control group, 0.5 mL of red blood cells and 1 mL of Triton-x100 were used. All groups, including the positive control group and the different concentration experimental groups, were incubated at 37°C for 4 hours, centrifuged, and the absorbance at 450 nm was measured using a centrifuge. The results are shown in Table 5.

[0063] Table 5. Hemolysis rate results of His@Fe-SHMP solutions at different concentrations

[0064] Table 5 shows that the hemolysis rate of His@Fe-SHMP solutions at different concentrations was low, indicating that His@Fe-SHMP is a nanozyme with very low cytotoxicity.

[0065] Test Example 4 The iron-sodium hexametaphosphate nanomaterial loaded with histidine prepared in Example 1 was used for a serum uric acid spike recovery experiment.

[0066] 50 μL of standard uric acid solutions of different concentrations (including 100 μM, 150 μM, and 200 μM) were added to different centrifuge tubes. Then, 20 μL of uricase solution (20 U / mg) and 180 μL of serum solution (diluted 20 times) were added to each centrifuge tube. The tubes were incubated at 37 °C for 45 min. Then, His@Fe-SHMP solution (1 mg / mL, 50 μL), TMB solution (5 mM, 50 μL), and NaAc-HAc buffer solution (pH=4, 0.1 M, 700 μL) were added to each centrifuge tube. The tubes were shaken to allow for complete reaction. Finally, the absorbance of the resulting solution at 652 nm was measured by UV-vis.

[0067] Table 6. Detection results of uric acid solutions of different concentrations in serum.

[0068] As shown in Table 6, the recoveries for the three concentrations were all between 99.27% ​​and 102.34%, indicating that the method of the present invention has high accuracy in determining the concentration of uric acid in serum; and the relative standard deviation (RSD) decreased with increasing concentration, indicating that the method of the present invention has good repeatability at higher concentrations.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications and equivalent changes made to the above technical content without departing from the scope of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention and shall be included within the protection scope of the present invention.

Claims

1. A histidine-loaded iron-sodium hexametaphosphate nanomaterial, characterized in that, The iron-sodium hexametaphosphate nanomaterial was prepared by loading histidine onto the nanomaterial via the reaction of ferric chloride hexahydrate and sodium hexametaphosphate.

2. The iron-sodium hexametaphosphate nanomaterial loaded with histidine according to claim 1, characterized in that, The particle size of the iron-sodium hexametaphosphate nanomaterial loaded with histidine is 40~50nm.

3. The method for preparing the iron-sodium hexametaphosphate nanomaterial loaded with histidine according to claim 1, used for preparing the iron-sodium hexametaphosphate nanomaterial loaded with histidine according to claim 1, characterized in that, The iron-sodium hexametaphosphate nanomaterial loaded with histidine was synthesized via a one-pot method, including the following steps: Ferric chloride hexahydrate solution was added dropwise to sodium hexametaphosphate solution under stirring. After the addition was complete, stirring was continued to obtain iron-sodium hexametaphosphate nanomaterial solution. Histidine solution was added dropwise to the iron-sodium hexametaphosphate nanomaterial solution under stirring. After the addition was complete, the solution was allowed to stand, centrifuged, filtered, washed, and dried in sequence to obtain histidine-loaded iron-sodium hexametaphosphate nanomaterial.

4. The preparation method according to claim 3, characterized in that, Includes one or more of the following conditions: i. The concentration of the ferric chloride hexahydrate solution is 2-5 M; ii. The concentration of the sodium hexametaphosphate solution is 5-8 mM; iii. After the ferric chloride hexahydrate solution is added dropwise, continue stirring for 5 to 15 minutes; preferably, continue stirring for 10 minutes after the addition is complete.

5. The preparation method according to claim 3, characterized in that, Includes one or more of the following conditions: The concentration of the histidine solution is 2.5~50mM; preferably, the concentration is 20~30mM. The stirring is performed using magnetic stirring at a speed of 500 rpm / min. The settling time is 10 to 20 minutes; preferably, the settling time is 15 minutes. The volume ratio of the ferric chloride hexahydrate solution, sodium hexametaphosphate solution, and histidine solution is 1:(40~67):(40~112).

6. The application of the iron-sodium hexametaphosphate nanomaterial loaded with histidine as described in claim 1 in uric acid detection, characterized in that, The method for detecting uric acid using iron-sodium hexametaphosphate nanomaterials loaded with histidine includes the following steps: (1) Standard uric acid solutions of different concentrations were mixed with uricase solution and Britton-Robinson buffer solution and reacted thoroughly. Then, iron-sodium hexametaphosphate nanomaterial solution loaded with histidine, NaAc-HAc buffer solution and 3,3',5,5',-tetramethylbenzidine (TMB) solution were added respectively. After the reaction was completed, the absorbance at 652 nm wavelength was measured to establish a standard curve of absorbance change with uric acid concentration. (2) Replace the standard uric acid solution in step (1) with the serum uric acid to be tested, construct the test system according to the method in step (1), measure the absorbance of the test system at a wavelength of 652 nm, and obtain the uric acid concentration in the serum by combining the standard curve.

7. The application according to claim 6, characterized in that, Includes one or more of the following conditions: In step (1), the final uric acid concentration in the reaction system is 0.1 μM to 250 μM; In step (1), the concentration of the uricase solution is 10-30 U / mg; preferably, the concentration is 15-20 U / mg. In step (1), the pH of the Britton-Robinson buffer solution is 7-9; In step (1), the temperature at which the standard uric acid solution, uricase solution, and Britton-Robinson buffer solution are mixed and reacted fully is 25-55°C, and the reaction time is 10-90 min; preferably, the temperature is 30-40°C and the time is 35-55 min.

8. The application according to claim 6, characterized in that, Includes one or more of the following conditions: In step (1), the concentration of the iron-sodium hexametaphosphate nanomaterial solution loaded with histidine is 0.5~1.5 mg / mL; preferably, the concentration is 0.6~1.2 mg / mL. In step (1), the pH of the NaAc-HAc buffer solution is 2-8, preferably 3-5; In step (1), the concentration of the 3,3',5,5',-tetramethylbenzidine solution is 1~10 mM; preferably, the concentration is 2~7 mM. In step (1), after adding the iron-sodium hexametaphosphate nanomaterial solution loaded with histidine, the NaAc-HAc buffer solution and the 3,3',5,5',-tetramethylbenzidine (TMB) solution, the reaction temperature is 25~55℃ and the time is 3~20min; preferably, the temperature is 30~40℃ and the time is 10~20min. In step (1), the volume ratio of the standard uric acid solution, uricase solution, Britton-Robinson buffer solution, iron-sodium hexametaphosphate nanomaterial solution loaded with histidine, NaAc-HAc buffer solution and 3,3',5,5',-tetramethylbenzidine solution is 1:(0.3~0.7):(2.3~9):(0.7~1.7):(10~23.3):(0.8~1.7).

9. The application of the iron-sodium hexametaphosphate nanomaterial loaded with histidine as described in claim 1 in the preparation of antibacterial drugs.

10. The application according to claim 9, characterized in that, The drug is a topical drug, which includes patches and ointments.

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