A near-infrared long-afterglow nanocomposite, preparation and application thereof in uric acid detection

Abstract

This invention discloses a near-infrared long-afterglow nanocomposite, its preparation, and its application in uric acid detection, belonging to the technical field of testing or analyzing materials by measuring their chemical or physical properties. The nanocomposite comprises a near-infrared long-afterglow luminescent center and an outer layer of organosilicon-doped mesoporous silicon containing tetrasulfide bonds. Under near-infrared light excitation, this nanocomposite exhibits excellent afterglow luminescence enhancement response to hydrogen peroxide. Since the product of uric acid decomposition by uricase is hydrogen peroxide, this composite enables highly sensitive and rapid detection of uric acid in blood. The composite provided by this invention has uniform particle size and high stability, effectively eliminating autofluorescence interference from biological components and improving detection accuracy.

Description

Technical Field

[0001] This invention relates to a near-infrared long-afterglow nanocomposite, its preparation, and its application in uric acid detection, belonging to the field of material testing or analysis technology by measuring the chemical or physical properties of materials. Background Technology

[0002] As the final product of purine metabolism, the accurate detection of uric acid is crucial for the diagnosis of gout, the monitoring of hyperuricemia, and research on related diseases. Currently, the "gold standard" for clinical uric acid testing is the uricase method, which involves the reaction of uric acid with uricase to produce hydrogen peroxide. A substrate is then added to react with the hydrogen peroxide, resulting in a colorimetric reaction, and uric acid is indirectly detected by detecting the hydrogen peroxide. However, the uricase method is susceptible to interference from endogenous and exogenous substances, severely affecting its accuracy and sensitivity. Therefore, developing novel methods for detecting hydrogen peroxide in biological systems is key to improving the accuracy and sensitivity of blood uric acid testing.

[0003] Fluorescence spectroscopy utilizes the oxidizing properties of hydrogen peroxide, measuring the intensity of the induced emission signal using a fluorescence detector to quantitatively analyze the concentration of hydrogen peroxide. This method effectively solves the problem of interference from various substances in spectrophotometry and has wide applications in hydrogen peroxide detection. However, the core bottleneck in practical applications of fluorescence spectroscopy lies in its reliance on continuous light source excitation. This can induce significant autofluorescence interference from biological components, thus greatly limiting the accuracy and sensitivity of the detection.

[0004] Long-persistent nanoprobes, as materials that continue to emit light even after the excitation source is turned off, can effectively eliminate autofluorescence interference from biological samples and significantly improve the signal-to-noise ratio. Based on this advantage, applying long-persistent nanoprobes to hydrogen peroxide sensing successfully overcomes the bottleneck problem caused by biological autofluorescence interference in traditional fluorescence detection. Therefore, developing bio-window excitation-capable long-persistent hydrogen peroxide nanoprobes is key to improving the accuracy and sensitivity of uric acid detection. Summary of the Invention

[0005] To address practical needs and the shortcomings of existing technologies, this invention provides a near-infrared long-afterglow nanocomposite, its preparation, and its application in uric acid detection. By accurately measuring hydrogen peroxide in biological systems with a high signal-to-noise ratio, it indirectly achieves accurate and highly sensitive detection of blood uric acid.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: The present invention provides a near-infrared long afterglow nanocomposite, comprising a near-infrared long afterglow luminescent center and an outer layer of organosilicon-doped mesoporous silicon containing tetrasulfide bonds; wherein the near-infrared long afterglow luminescent center is composed of transition metals zinc, gallium, germanium, chromium and oxygen.

[0007] The principle behind the near-infrared long-afterglow nanocomposite of the present invention for uric acid detection is as follows: urase decomposes uric acid to produce hydrogen peroxide. Hydrogen peroxide then undergoes a redox reaction with the tetrasulfide bonds in the near-infrared long-afterglow nanocomposite. After the tetrasulfide bonds break, the afterglow light that was originally absorbed by the tetrasulfide bonds is released under near-infrared light excitation. The luminescent center releases an enhanced afterglow light signal. By detecting this enhanced afterglow light signal, accurate and high signal-to-noise ratio quantitative analysis of hydrogen peroxide is achieved, further realizing accurate and highly sensitive detection of blood uric acid.

[0008] In some embodiments, the molar ratio of zinc, gallium, germanium, and chromium in the near-infrared long-afterglow luminescent center is 1-2:1-2:0.05-0.2:0.004-0.006. Combining four specific transition metal ions—zinc, gallium, germanium, and chromium—as luminescent centers results in nanoparticles with excellent near-infrared long-afterglow performance. In this invention, the near-infrared long-afterglow luminescent center is stable in its ground state and emits light with a wavelength of 696 nm under red light, with an afterglow decay time greater than 24 hours.

[0009] In some embodiments, the molar ratio of zinc, gallium, germanium and chromium in the near-infrared long afterglow luminescent center is 1.1:1.8:0.1:0.005.

[0010] In some embodiments, the particle size of the near-infrared long-afterglow luminescent center is 200-350 nm. For example, 200 nm, 220 nm, 250 nm, 270 nm, 300 nm, 350 nm, etc.

[0011] A method for preparing the near-infrared long-afterglow nanocomposite described above, characterized by comprising the following steps: (1) Long afterglow nanoparticles were synthesized by hydrothermal method from a mixed solution of zinc ion salt, gallium ion salt, germanium ion salt and chromium ion salt, dried and collected to obtain long afterglow luminescent centers. (2) The long afterglow luminescent centers obtained in step (1) are coated with organic mesoporous silica containing tetrasulfide bonds by a two-phase method, dried and collected to obtain the near-infrared long afterglow nanocomposite.

[0012] In some embodiments, in step (1), the hydrothermal method is: a hydrothermal reaction is carried out at 180-220°C for 10-14 hours.

[0013] In some embodiments, the drying in steps (1) and (2) is carried out in a vacuum drying oven for more than 6 hours, such as 6 hours, 8 hours, 12 hours, etc.

[0014] In some embodiments, step (2) of the two-phase method includes the following steps: (1) Mix the near-infrared long afterglow luminescence center, template agent and water evenly to form an aqueous system; (2) Organic mesoporous silica containing tetrasulfide bonds is mixed with an organic solvent to form an organic phase system; (3) The organic phase system of step (2) is added to the aqueous phase system of step (1) to carry out a two-phase reaction, so that the organic fragment containing tetrasulfide bond is doped into the structure of mesoporous silica through copolymerization reaction, and an organosilicon-doped mesoporous silicon layer is formed on the surface of the long afterglow luminescence center. (4) After the reaction is complete, the product is collected and the template agent is removed to obtain the near-infrared long afterglow nanocomposite.

[0015] In some embodiments, the template agent is hexadecyltrimethylammonium bromide (CTAB), and the organic mesoporous silica containing tetrasulfide bonds includes BTES (bis-(3-triethoxysilylpropyl)tetrasulfide) and TEOS (tetraethyl orthosilicate).

[0016] In some embodiments, the volume ratio of bis-(3-triethoxysilylpropyl)tetrasulfide (BTES) to tetraethyl orthosilicate (TEOS) is 1:0.5-1.5.

[0017] In some embodiments, during the formation of the aqueous system, after adding the template agent, a triethanolamine (TEA) solution is added and stirred at 55-65°C.

[0018] In some embodiments, in step (2), the organic solvent is cyclohexane.

[0019] In some embodiments, step (3) specifically involves: slowly adding the organic phase system dropwise into the aqueous phase system and continuously stirring the reaction at 55-65°C for 22-26 hours.

[0020] In some embodiments, the specific operation of removing the template agent in step (4) is as follows: the collected product is dispersed in an NH4NO3 / ethanol solution and stirred and refluxed at 55-65°C to remove CTAB from the mesoporous structure.

[0021] Application of the above-mentioned near-infrared long afterglow nanocomposite in the preparation of uric acid detection reagent.

[0022] The beneficial effects of this invention are: 1. High signal-to-noise ratio and extremely low background interference: This invention utilizes the unique luminescence properties of persistent luminescence materials, which continue to emit light even after photoexcitation is stopped. This effectively overcomes the autofluorescence interference present in conventional fluorescence detection of biological samples such as blood and serum, achieving "zero background" detection and significantly improving the signal-to-noise ratio and sensitivity of the detection (detection limit as low as 1.87 μM).

[0023] 2. Deep Tissue Penetration Ability: The long-afterglow nanoluminescent centers used in this invention have excitation and emission wavelengths in the near-infrared (NIR) region. Compared to visible light, NIR light has a deeper penetration depth and lower phototoxicity in biological tissues, making it suitable not only for highly sensitive analysis of ex vivo blood samples but also laying the foundation for future in-situ or in vivo real-time monitoring of uric acid. The probe invented in this application can be excited at both 320 nm and 659 nm. This is because tetrasulfide bonds (SSSS) have an absorption peak in the ultraviolet region but also strong absorption in the near-infrared region (659 nm is also strong). In this application, this absorption intensity is sufficient to form an optical switch. The innovation of this application lies in achieving detection under near-infrared excitation through modulation, thereby avoiding interference from the autofluorescence of biological components and improving the penetration depth of biological samples. This is something that cannot be achieved under 320 nm excitation light.

[0024] 3. Specific Chemical Response Mechanism: This invention innovatively dops an organosilicon component containing tetrasulfide bonds into a mesoporous silica layer. These tetrasulfide bonds exhibit a highly sensitive and specific oxidation response to hydrogen peroxide (H₂O₂) produced from the decomposition of uric acid by uricase. By inducing the breaking of the tetrasulfide bonds through H₂O₂ and triggering an enhancement of the afterglow signal, precise quantitative analysis of uric acid concentration is achieved, with a rapid and highly specific detection process.

[0025] 4. Excellent physicochemical stability and dispersibility: The organosilicon-doped mesoporous silicon layer coated by the two-phase method not only provides a rich microenvironment for chemical reactions but also significantly improves the dispersibility of long-afterglow luminescent centers in physiological buffer solutions and blood samples. The protective effect of the mesoporous layer effectively prevents signal attenuation caused by aggregation of luminescent centers or adsorption of biomolecules, enhancing the probe's lifespan and stability.

[0026] 5. Excellent Clinical Application Potential: Experimental results show that the near-infrared long-afterglow nanocomposite described in this invention exhibits excellent linearity within the clinically relevant concentration range of 0-800 μM, and demonstrates high spiked recovery in blood samples. This method is simple to operate and has a rapid response, providing a novel and reliable technical means for the clinical diagnosis of gout and early screening of hyperuricemia. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is the afterglow spectrum of the near-infrared long afterglow luminescent center (ZC) under different zinc, gallium and germanium ratios under near-infrared light (659nm) excitation.

[0029] Figure 2 This is a transmission electron microscope image of the near-infrared long afterglow emission center (ZC) of Example 2.

[0030] Figure 3 This is a transmission electron microscope image of the near-infrared long afterglow nanocomposite (ZC-M) of Example 3.

[0031] Figure 4 This is the afterglow emission spectrum of the near-infrared long afterglow emission center (ZC) of Example 2 at 320 nm.

[0032] Figure 5 This is the afterglow emission spectrum of the near-infrared long afterglow emission center (ZC) of Example 2 at 659 nm.

[0033] Figure 6 The emission spectrum (a) and afterglow spectrum (b) of the near-infrared long afterglow nanocomposite (ZC-M) and serum in Example 3 are shown.

[0034] Figure 7 This is the afterglow spectrum of the near-infrared long afterglow luminescent center (ZC) of Example 2 before and after mixing with hydrogen peroxide solution.

[0035] Figure 8 The Fourier transform infrared spectra of the near-infrared long-afterglow nanocomposite (ZC-M) of Example 3 before and after mixing with hydrogen peroxide solution are shown.

[0036] Figure 9 This is a graph showing the relationship between the change in afterglow intensity enhanced by the near-infrared long afterglow nanocomposite (ZC-M) of Example 3 and the hydrogen peroxide concentration.

[0037] Figure 10 This is a graph showing the relationship between the change in afterglow intensity enhanced by the near-infrared long afterglow nanocomposite (ZC-M) of Example 3 and the change in uric acid concentration.

[0038] Figure 11The image shows the enhanced afterglow luminescence of the near-infrared long afterglow nanocomposite (ZC-M) in Example 3 under the action of 200 μM H2O2 at different ratios of TEOS and BTES.

[0039] Figure 12 This is a graph showing the anti-interference test results of Example 4. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.

[0041] Example 1: Exploration of the molar ratio of zinc, gallium, and germanium Adjust the molar ratio of zinc, gallium, and germanium using the formula Zn 1+x Ga 2-2x Ge x O4:Cr 0.005 Among them, the values ​​of x = 0.05, 0.1, and 0.2 were explored.

[0042] 1. Weigh zinc nitrate, gallium nitrate, sodium germanate and chromium nitrate according to the corresponding molar ratio, dissolve them in deionized water, and then rapidly inject ammonia water under vigorous stirring to adjust the pH of the mixed solution to about 6.5. Stir continuously at room temperature for 2 hours.

[0043] 2. Transfer the above solution to a reaction vessel and carry out a hydrothermal reaction at 200°C for 12 hours.

[0044] 3. After the reaction was complete, the product was allowed to cool naturally to room temperature. The product was centrifuged (10,000 rpm / min, 10 min), washed three times with deionized water, and dried into powder at 60°C to obtain near-infrared long afterglow luminescent centers (ZC).

[0045] 4. Take 10 mg of the prepared ZC sample, place it on the spectrometer sample stage, excite it with 659 nm red light for 5 min, and measure the afterglow spectrum of ZC-M. Figure 1 As shown.

[0046] Depend on Figure 1As can be seen from the data, the afterglow emission intensity is strongest when x=0.1 (excitation wavelength: 659nm). This means that under a 659nm excitation source, the proportion of Zn... 1.1 Ga 1.8 Ge 0.1 O4:Cr 0.005 This is the optimal ratio because it maximizes the number of traps that can be formed. After being excited, electrons transition from the ground state to the excited state. These excited electrons are then trapped and gradually return to the ground state to release the afterglow. In this process, increasing the number of traps can enhance the intensity of the afterglow.

[0047] Example 2: Preparation of near-infrared long-afterglow luminescent centers (ZC) In this embodiment, the near-infrared long-afterglow luminescence center is composed of transition metals zinc, gallium, germanium, and chromium. The specific steps are as follows: 1. Weigh zinc nitrate, gallium nitrate, sodium germanate and chromium nitrate in a molar ratio of 1.1:1.8:0.1:0.005, dissolve them in deionized water, and then rapidly inject ammonia water while stirring vigorously to adjust the pH of the mixed solution to about 6.5. Stir continuously at room temperature for 2 hours.

[0048] 2. Transfer the above solution to a reaction vessel and carry out a hydrothermal reaction at 200°C for 12 hours.

[0049] 3. After the reaction was complete, the product was allowed to cool naturally to room temperature. The product was centrifuged (10,000 rpm / min, 10 min), washed three times with deionized water, and dried into powder at 60°C to obtain near-infrared long afterglow luminescent centers (ZC).

[0050] Example 3: Preparation of near-infrared long afterglow nanocomposite (ZC-M) In this embodiment, a two-phase method is used to coat the surface of ZC particles with mesoporous silica containing tetrasulfide bonds: 1. Aqueous phase preparation: Weigh 50 mg of ZC prepared in Example 2 and 0.75 g of cetyltrimethylammonium bromide (CTAB) and disperse them in 30 mL of deionized water. Sonicate for 30 min. Then add 0.375 mL of TEA solution (25% w / v) and stir for 1 h in an oil bath at 60 °C and 300 rpm.

[0051] 2. Organic phase preparation: Dissolve 600 μL of tetraethyl orthosilicate (TEOS) and 600 μL of bis-(3-triethoxysilylpropyl)tetrasulfide (BTES) in 8 mL of cyclohexane.

[0052] 3. Coating reaction: The organic phase was added dropwise to the aqueous system and the reaction was carried out by stirring at 60°C for 24 hours.

[0053] 4. Post-processing: The reaction product was collected by centrifugation (10,000 rpm, 10 min), and the obtained sample was washed with water and ethanol alternately three times or more.

[0054] 5. Template agent removal: The product was dispersed in a 0.6% NH4NO3 / ethanol solution and stirred in an oil bath at 60℃ for 2 hours. Then, it was washed three times alternately with water and ethanol to obtain the near-infrared long afterglow nanocomposite (hereinafter referred to as ZC-M).

[0055] Test Example 1: Morphological and Structural Characterization 1. Morphological observation: The samples obtained in Examples 2 and 3 were redispersed in a 0.6% NH4NO3 / ethanol solution to obtain ZC dispersion and ZC-M dispersion, both with a concentration of 0.5 mg·mL. -1 ZC dispersion and ZC-M dispersion were respectively dropped onto the surface of a copper mesh and allowed to air dry at room temperature to prepare observation samples. The results were observed by transmission electron microscopy (TEM), as shown in Figures 2 and 2. Figure 3 As shown, ZC is in the form of regular spheres or near-spheres. After being coated by the two-phase method, a distinct mesoporous layer structure is visible on the surface of ZC-M, with the particle size uniformly distributed between 200-350 nm.

[0056] 2. Composition Analysis: 10 mg of ZC-M prepared in Example 3 was reacted with 1 mL of 200 μM hydrogen peroxide for 5 minutes, and then the solid particles were separated by centrifugation. The Fourier Transmission Infrared (FT-IR) spectra of ZC-M before and after the reaction with hydrogen peroxide were measured separately: First, spectrally pure potassium bromide (KBr) powder was dried, ground using an agate mortar, and pressed into a blank slide for background correction. Then, the sample and KBr were accurately weighed and mixed at a mass ratio of 1:100, thoroughly ground under infrared lamp irradiation until the particle size was uniform, and finally pressed into a transparent thin film under specific pressure for spectral acquisition within a specified wavenumber range. Figure 8 As shown, under the action of hydrogen peroxide, sulfur-oxygen stretching vibrations appeared in ZC-M, indicating that the tetrasulfide bonds in ZC-M did indeed break chemically before and after the addition of hydrogen peroxide. The results confirmed the successful introduction of organosilicon components and tetrasulfide bonds.

[0057] Test Example 2: Spectral Performance Test 1. Afterglow Spectrum: Take 10 mg of the ZC-M sample prepared in Example 3, place it on the spectrometer sample stage, and excite it with 320 nm and 659 nm red light for 5 min respectively. Measure the afterglow spectrum of ZC-M. The afterglow spectrum at 320 nm is shown below. Figure 4As shown, the afterglow spectrum at 659 nm is as follows Figure 5 As shown. By Figure 4 and Figure 5 It can be seen that the near-infrared long-afterglow nanocomposite has good luminescence properties, and can be excited with afterglow spectra at both 320 nm and 659 nm, with the afterglow emission peak located at 696 nm in the biological window.

[0058] 2. Bioenvironmental stability: 10 mg of the near-infrared long-afterglow nanocomposite ZC-M prepared in Example 3 was mixed thoroughly with 2 ml of serum. The emission and afterglow spectra of the mixture were measured separately. Figure 6 As shown, ZC-M exhibits numerous and broad peaks in its emission spectrum from serum solution, but a distinct afterglow peak can be detected in its afterglow spectrum, indicating that the afterglow of ZC-M can significantly shield the fluorescence interference from other components in the serum. The results demonstrate that this complex maintains stable luminescent properties even in complex biological matrices.

[0059] Test Example 3: Response Test to Hydrogen Peroxide (H2O2) Take 10 mg of the long-afterglow luminescent center ZC obtained in Example 2 and mix it with 1 mL of water to prepare an aqueous solution of ZC. Take 10 mg of ZC and mix it with 1 mL of 600 μM hydrogen peroxide to prepare a mixed solution. Place the solution on the sample stage of the spectrometer and excite it with 659 nm red light for 5 min. Measure the afterglow spectra of the aqueous solution of ZC and the mixture of ZC and hydrogen peroxide, respectively. Figure 7 As shown, hydrogen peroxide did not enhance the afterglow intensity of the long afterglow luminescent center ZC, indicating that the long afterglow luminescent center ZC alone has no response to H2O2.

[0060] Take 10 mg of the ZC-M sample prepared in Example 3 and place it in 1 mL of hydrogen peroxide at concentrations of 0, 5, 10, 20, 50, 100, 200, 500, and 800 μM, respectively. After sonicating at room temperature for 5 seconds, excite with red light at a wavelength of 659 nm and collect the afterglow signal using a CCD for 90 seconds. Figure 9 As shown, the change in afterglow intensity exhibits a good linear relationship with H2O2 concentration in the range of 0-1000 μM, with the following linear equations: y = 34.246x + 2.96; y = 2.5461x + 1432.9. The correlation coefficient R0... 2 >0.99.

[0061] The simple long-afterglow luminescent center ZC is unresponsive to H2O2, while the ZC-M coated with organosilicon containing tetrasulfide bonds has good responsiveness to H2O2, indicating that the coating of organosilicon containing tetrasulfide bonds is necessary.

[0062] Test Example 4: Establishment of a standard curve for the detection of uric acid concentration 10 mg of ZC-M sample was dispersed in 1 mL of uric acid samples with concentrations of 0, 5, 10, 20, 50, 100, 200, 500, and 800 μM, respectively. An appropriate amount of uricase (0.01 mg / mL) was added, and the samples were sonicated at room temperature for 5 seconds. Then, the samples were excited with red light at a wavelength of 659 nm. The afterglow signal was collected using a CCD with an exposure time of 90 seconds, and the corresponding gray values ​​were analyzed to construct a standard curve.

[0063] 1. As shown in Figure 10, the intensity of the afterglow signal increases synchronously with the increase of uric acid concentration.

[0064] 2. Linear regression analysis yielded the standard curve equation: y = 6.442x + 62.051, with a linear correlation coefficient R0. 2 =0.9964.

[0065] 3. The calculated limit of detection (LOD) for serum uric acid is 1.87 μM.

[0066] Test Example 5: Blood Sample Analysis and Recovery Experiment Uric acid levels in blood samples were detected using ZC-M assay: 10 mg of ZC-M sample was dispersed in 1 mL of the blood sample to be tested, and uricase (Maclean, U833293, ≥20 U / mg) was added to achieve a final uricase concentration of 0.01 mg / mL. After sonication at room temperature for 5 seconds, the sample was excited with red light at a wavelength of 659 nm. The afterglow signal was acquired using a CCD with an exposure time of 90 seconds, and the corresponding grayscale values ​​were analyzed. The corresponding uric acid concentration was calculated based on the standard curve from test example 4. The results were compared with the clinical standard method (traditional uricase method), demonstrating high accuracy.

[0067] Spiked recovery experiments were conducted: Based on the above test examples, 200 μM uric acid was added to each sample. Except for the control group, uricase was added to the other groups. After reacting for 5 minutes, the samples were observed under a CCD, and the uric acid content was detected by grayscale analysis. This was repeated three times. The recovery rate was obtained by subtracting the uric acid concentration of the measured sample from the recovered uric acid concentration, dividing by the amount of uric acid added, and multiplying by 100%.

[0068] The results are shown in Table 1. The recovery rate was between 98.62% and 100.61%, indicating that the method has extremely high reliability and is suitable for rapid screening of clinical blood samples.

[0069] Table 1. Measurement of uric acid in blood

[0070] Comparative Example 1 In Example 3, the ratio of TEOS to BTES was adjusted to 0.5, 1, and 2, respectively, to prepare ZC-M samples with different TEOS / BTES ratios. 10 mg of each prepared ZC-M sample was placed in 1 mL of 200 μM hydrogen peroxide solution, sonicated at room temperature for 5 seconds, excited with red light at a wavelength of 659 nm, and the afterglow signal was acquired using a CCD for an exposure time of 90 seconds. Figure 11 As shown, when the ratio of TEOS to BTES is 1, the change in afterglow enhancement reaches its maximum value, indicating that the detection sensitivity is highest at this point.

[0071] Example 4: Anti-interference test 10 mg of ZC-M nanoparticles prepared in Example 3 were dispersed in 500 μL of deionized water, and 200 μmol / L uric acid (containing uricase) was added. Then, 4.5 mmol / L glucose (Group 2), 5 mmol / L urea (Group 3), 50 μmol / L ascorbic acid (Group 4), and 10 mg / mL immunoglobulin G (Group 5) were added to different groups, respectively. After mixing by ultrasonic treatment at room temperature, the samples were excited with 659 nm red light for five minutes, and the afterglow signal was acquired using a CCD camera. The experimental results are shown in Table 2 and... Figure 12 As shown.

[0072] Table 2

[0073] From Table 2 and Figure 12 The quantitative analysis results showed that the afterglow signal of ZC-M did not change significantly when glucose, urea, ascorbic acid and immunoglobulin G interfering agent were added respectively, indicating that common blood substances do not interfere with the determination of uric acid by ZC-M.

[0074] In summary, the near-infrared long-afterglow nanocomposite (ZC-M) described in this invention exhibits significantly superior performance compared to existing technologies in uric acid detection. Its inventive logic and unexpected technical effects are mainly reflected in the following aspects: 1. Non-obvious synergistic effects among components Experiments have confirmed that simple long-afterglow luminescent centers (ZCs) exhibit complete optical inertness to H₂O₂ (e.g., Figure 7 (As shown). However, when a mesoporous organosilicon-doped silicon layer containing tetrasulfide bonds is coated on its surface, the tetrasulfide bonds undergo specific breakage under the action of H2O2 (as shown). Figure 8 (Confirmed by infrared spectroscopy) This unexpectedly triggered a significant enhancement of the signal from the internal luminescent center. This synergistic sensing mechanism of "chemical bond breaking triggering physical signal release" means that this invention is not a simple superposition of components, but rather achieves a specific optical response to metabolites through a specific encapsulation structure.

[0075] 2. Breakthrough autofluorescence shielding capability and detection accuracy Because blood samples contain a large number of biomolecules with background fluorescence (such as hemoglobin and bilirubin), traditional fluorescent probes often exhibit significant systematic errors in actual clinical samples. This invention cleverly utilizes the characteristic of long-afterglow materials to continue emitting light after excitation ceases. Through time-resolved detection, signals are acquired during the afterglow phase, successfully achieving complete removal of autofluorescent background in the extremely complex serum matrix (e.g., ...). Figure 6 (As shown). Experimental results show that the spiked recovery rate of this invention is consistently between 98.62% and 100.61% in blood samples without complex pretreatment, demonstrating extremely high detection accuracy and fidelity.

[0076] 3. Trace sensitivity resulting from specific ratio adjustment This invention makes a significant inventive contribution to the exploration of the luminescent center and the ratio of the coating layer. Experimental data ( Figure 1 and Figure 11 This indicates that when the matrix composition of the luminescent center is confined to Zn 1.1 Ga 1.8 Ge 0.1 When the volume ratio of TEOS to BTES in the coating layer is approximately 1:1, the probe's afterglow enhancement exhibits a significant non-linear peak. This specific optimization enabled the complex to successfully lower the limit of detection (LOD) for uric acid to 1.87 μM. This sensitivity is far below the clinical diagnostic criteria for hyperuricemia, effectively capturing minute fluctuations in uric acid levels in the human body.

[0077] 4. Excellent linear range and stability This invention exhibits extremely strong correlation (R0) over a wide linear range of 5-800 μM. 2 = 0.9964), and the material exhibits good mechanical and chemical stability under operating conditions such as room temperature and ultrasound, which makes it extremely promising for application in rapid clinical testing (such as POCT equipment).

[0078] 5. Overcome technological bias Those skilled in the art would typically assume that lowering the excitation energy would result in ineffective filling of electron traps. However, this application, by altering the trap distribution through a specific ratio of Ge doping, unexpectedly achieves highly efficient excitation of low-energy red light. This counterintuitive technical performance is a powerful testament to the inventiveness of this application.

[0079] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A near-infrared long afterglow nanocomposite, characterized in that, It includes a near-infrared long-afterglow luminescent center and an outer layer of organosilicon-doped mesoporous silicon containing tetrasulfide bonds; the near-infrared long-afterglow luminescent center is composed of transition metals zinc, gallium, germanium, chromium and oxygen; in the near-infrared long-afterglow luminescent center, the molar ratio of zinc, gallium, germanium and chromium is 1-2:1-2:0.05-0.2:0.004-0.

006.

2. The near-infrared long afterglow nanocomposite according to claim 1, characterized in that, In the near-infrared long afterglow luminescent center, the molar ratio of zinc, gallium, germanium and chromium is 1.1:1.8:0.1:0.

005.

3. The near-infrared long afterglow nanocomposite according to claim 1, characterized in that, The particle size of the near-infrared long afterglow luminescent center is 200-350 nm.

4. A method for preparing a near-infrared long-afterglow nanocomposite according to any one of claims 1 to 3, characterized in that, Includes the following steps: (1) Long afterglow nanoparticles were synthesized by hydrothermal method from a mixed solution of zinc ion salt, gallium ion salt, germanium ion salt and chromium ion salt, dried and collected to obtain long afterglow luminescent centers. (2) The long afterglow luminescent centers obtained in step (1) are coated with organic mesoporous silica containing tetrasulfide bonds by a two-phase method, dried and collected to obtain the near-infrared long afterglow nanocomposite.

5. The preparation method according to claim 4, characterized in that, In step (1), the hydrothermal method is: a hydrothermal reaction is carried out at 180-220℃ for 10-14 hours.

6. The preparation method according to claim 4, characterized in that, The two-phase method includes the following steps: (1) Mix the near-infrared long afterglow luminescence center, template agent and water evenly to form an aqueous system; (2) Organic mesoporous silica containing tetrasulfide bonds is mixed with an organic solvent to form an organic phase system; (3) The organic phase system of step (2) is added to the aqueous phase system of step (1) to carry out a two-phase reaction, so that the organic mesoporous silica containing tetrasulfide bonds is coated on the surface of the long afterglow luminescence center to form an organic silicon-doped mesoporous silicon layer. (4) After the reaction is complete, the product is collected and the template agent is removed to obtain the near-infrared long afterglow nanocomposite.

7. The preparation method according to claim 6, characterized in that, The template agent is hexadecyltrimethylammonium bromide, and the organic mesoporous silica containing tetrasulfide bonds includes bis-(3-triethoxysilylpropyl)tetrasulfide and tetraethyl orthosilicate.

8. The preparation method according to claim 7, characterized in that, The volume ratio of the bis-(3-triethoxysilylpropyl)tetrasulfide to tetraethyl orthosilicate is 1:0.5-1.

5.

9. The preparation method according to claim 6, characterized in that, During the formation of the aqueous system, after adding the template agent, a triethanolamine (TEA) solution is also added, and the mixture is stirred at 55-65°C.

10. The use of the near-infrared long-afterglow nanocomposite according to any one of claims 1 to 3 in the preparation of uric acid detection reagents.

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