An optical sensor for multi-mode detection of hydrogen peroxide and its preparation method and application

Abstract

The present invention discloses an optical sensor for multi-mode detection of hydrogen peroxide, and a preparation method and application thereof. The present invention modifies the surface of a core-shell nanomaterial of a porous ZIF-8-wrapped nanoalloy UAAA structure with a chiral nanomaterial NiSx-L to obtain a composite material UA@ZIF-8-NiSx, which has both a chiral signal and a Raman "hot spot" for qualitative and quantitative detection of H2O2 in three sensing modes of colorimetry / chirality / Raman. In the presence of H2O2, as the chiral material is degraded, its CD signal decreases with the increase of H2O2. At the same time, under the catalysis of UAAA@ZIF-8, o-phenylenediamine (OPD) modified on the surface of UAAA@ZIF-8 can be rapidly catalyzed by H2O2, causing a change in color. In addition, under the detection of a Raman spectrometer, the Raman signal of OPD will also change, thereby realizing multi-mode detection of H2O2.

Description

Technical Field

[0001] The present invention belongs to the technical field of analysis and detection, and in particular relates to an optical sensor for multi-mode detection of hydrogen peroxide and a preparation method and application thereof. Background Art

[0002] Hydrogen peroxide (H2O2) is a major member of reactive oxygen species (ROS). To date, H2O2 is recognized as an important oxidative stress marker in aging and the progression of various diseases, and is involved in a wide range of physiological and pathological processes. As a potential biomarker, H2O2 is produced when non-phagocytic cells are stimulated by extracellular stimuli during the development of the disease. Under normal physiological conditions, low concentrations of H2O2 within the safe range of organelles can kill microorganisms, maintain the stability of cell functions, and do not cause harm to the human body. However, under pathological conditions, high concentrations of H2O2 (10-50 μmol / L) produced by cells can lead to proliferation and angiogenesis of tumor cells and epithelial cells to resist external stimuli and produce anti-inflammatory responses. In addition, this process increases the possibility of inflammation-related cancers. Studies have found that in some cancer cells, ROS can be produced by activating seven NADPH oxidase complexes located in the cell membrane. The flavoenzyme ERO1 in the endoplasmic reticulum has also been shown to use O2 as a two-electron acceptor to produce a certain amount of H2O2, providing a strong ROS flux in this subcellular region. Therefore, as a potential disease marker, H2O2 should be quantified to help doctors effectively diagnose diseases related to reactive oxygen species.

[0003] In order to elucidate the biological effects of ROS, quantify their real-time levels, and study their molecular mechanisms, it is crucial to develop effective probes to monitor ROS. Such probes can provide us with new research tools and clinical diagnostics. At present, a variety of probes and sensors have been developed for the in vivo or in vitro detection of H2O2, and these strategies have high sensitivity, low detection limits, and ingenious designs. However, the strategies designed in the past rely on large instruments and complex operations, and the detection time is too long, which cannot meet the trend of highly sensitive, faster, visual, and simpler analytical detection. Therefore, there is a real need to develop new probes with improved performance to detect ROS.

[0004] Chiral nanomaterials include single chiral nanoparticles and chiral nanoassemblies. Due to their flexible and adjustable scale, optical signals and synthesis strategies, they have been widely used in catalysis, biosensing, and the study of the interaction between chiral nanomaterials and biological systems. Amino acids and proteins existing in biological systems are chiral molecules, and their chiral signals are distributed in the ultraviolet region. Therefore, when the chiral signals of chiral nanomaterials are distributed in the visible light region, the interference of background chiral signals from organisms can be avoided, and they have been widely used in biological analysis. In addition, chiral materials can form multifunctional composite materials by modifying chemical molecules or self-assembling with other materials. They also have the advantages of high sensitivity and high resolution imaging. The Xu team reported a chiral core-shell nanoassembly that integrates chiral materials and upconversion nanomaterials through an organic metal framework ZIF-8. The advantage of this assembly is that it has both chiral optical signals and fluorescence signals, which can be used for imaging and semi-quantitative detection of reactive oxygen species in vivo. In addition, a GO-Au NP structure assembled by splint DNA chains was designed and synthesized. The dynamic chirality and SERS activity against target molecules were studied by incubating with live target cells (MCF-7), showing good selectivity and stability. It can be seen that chiral nanomaterials have great prospects in biological analysis and detection.

[0005] In order to meet the needs of highly sensitive, high-precision, faster and visual detection, optical biosensors have been widely studied. However, current optical sensors mainly rely on single signal analysis and are easily interfered by certain substances. In contrast, optical sensors based on dual signals, such as ratio sensors and dual-mode sensors, have the advantage of high precision. More importantly, dual-mode optical sensors using different types of signals are more conducive to improving sensitivity and accuracy, avoiding interference from complex matrices, and showing considerable applications. At present, various detection methods based on dual-modal optical signals have been reported, such as chirality and fluorescence, chirality and surface enhanced Raman scattering (SERS), fluorescence and SERS. Fluorescent probes can respond to analytes under certain specific conditions, especially fluorescent sensors, which have been widely studied and show advantages such as multiple detection capabilities and excellent sensitivity. On the other hand. SERS sensors can reflect the information of molecular vibrations, can well produce SERS enhancement effects, and are used for sensitive single-molecule detection. Their high sensitivity, high resolution, fast detection speed and fingerprint map advantages have become an important biosensing and trace analysis technology. Therefore, it has become a popular technology for ultra-sensitive detection of biomarkers and disease diagnosis. In recent years, dual-signal optical sensors based on SERS and fluorescence have been widely developed for detection applications. Summary of the invention

[0006] In view of the above shortcomings and deficiencies in the prior art, the primary purpose of the present invention is to provide a method for preparing an optical sensor for multi-mode detection of hydrogen peroxide.

[0007] Another object of the present invention is to provide an optical sensor for multi-mode detection of hydrogen peroxide obtained by the above preparation method.

[0008] Another object of the present invention is to provide an application of the above optical sensor for multi-mode detection of hydrogen peroxide.

[0009] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0010] A method for preparing an optical sensor for multi-mode detection of hydrogen peroxide comprises the following steps:

[0011] Step 1: Mix HAuCl4 solution and water evenly, stir, then add silver nanoparticle (Ag NPs) solution and levodopa (L-DOPE) aqueous solution, continue stirring; add water to the reaction solution, centrifuge and wash, collect the precipitate, and disperse it in water to obtain a nano alloy particle (UAA-NCs) colloidal solution, referred to as UAA-NCs colloidal solution;

[0012] Step 2: Add hexadecyltrimethylammonium bromide (CTAB) solution to the UAA-NCs colloidal solution obtained in step 1, stir, then add 2-methylimidazole (2-MeIM) solution and Zn(NO3)2 solution respectively, react; centrifuge the reaction solution to collect the precipitate, which is the urchin-shaped nanoalloy (UAA@ZIF-8) particles wrapped in ZIF-8 (zeolite imidazole framework material), referred to as UAA@ZIF-8 particles; wash the UAA@ZIF-8 particles and disperse them in water to obtain a UAA@ZIF-8 aqueous solution;

[0013] Step 3: Take the UAA@ZIF-8 aqueous solution obtained in step 2, add the NiCl2 aqueous solution, stir to react, then add the D-type or L-type penicillamine (D / L-pen) aqueous solution to the mixed solution under vigorous stirring, then add the NaOH aqueous solution dropwise, continue to stir to react, and obtain the optical sensor for multimodal detection of hydrogen peroxide.

[0014] Furthermore, the concentration of the HAuCl4 solution in step 1 is 0.005-0.015 mol / L, preferably 0.01 mol / L.

[0015] Furthermore, the average particle size of the silver nanoparticles described in step 1 is 25 to 35 nm, preferably 35 nm; the silver nanoparticle solution is preferably prepared by the following method: 0.05 to 0.15 mol / L, preferably 0.1 mol / L NH2OH·HCl solution is added at a volume ratio of 100:2 to 4, preferably 100:3.3, and then 0.05 to 0.15 mol / L, preferably 0.1 mol / L AgNO3 solution is added to the resulting mixed solution at a flow rate of 0.6 to 0.7 mL / s, preferably 0.67 mL / s, and at a volume ratio of 8 to 10:1, preferably 9:1; the reaction container is inverted once to complete mixing, and the target product is obtained.

[0016] Furthermore, the concentration of the levodopa aqueous solution in step 1 is 0.005-0.015 mol / L, preferably 0.01 mol / L.

[0017] Furthermore, the volume ratio of the HAuCl4 solution, water, silver nanoparticle solution, levodopa aqueous solution, and water for dispersion described in step 1 is 4-5:8-9:1-2:9-10:9-11; preferably 4.8:8.6:1.8:9.6:10.

[0018] Furthermore, the stirring in step 1 is magnetic stirring in a water bath at 14-16°C, with a stirring speed of 100-300 rpm and a stirring time of 8-12 min; preferably, magnetic stirring in a water bath at 15°C, with a stirring speed of 200 rpm and a stirring time of 10 min.

[0019] Furthermore, the rotation speed of the centrifugal washing in step 1 is 3500-4500 rpm, and the time is 8-12 min; preferably, the rotation speed is 4000 rpm, and the time is 10 min.

[0020] Furthermore, the concentration of the hexadecyltrimethylammonium bromide solution in step 2 is 0.005-0.015 mol / L, preferably 0.01 mol / L.

[0021] Furthermore, the concentration of the 2-methylimidazole solution in step 2 is 1-2 mol / L, preferably 1.32 mol / L.

[0022] Furthermore, the concentration of the Zn(NO3)2 solution described in step 2 is 22-26 mmol / L, preferably 24 mmol / L.

[0023] Furthermore, the volume ratio of the UAA-NCs colloidal solution, hexadecyltrimethylammonium bromide solution, 2-methylimidazole solution, Zn(NO3)2 solution, and water for dispersion described in step 2 is 1-2:1-2:1-2:1-2:1-2; preferably 1:1.5:1:1:1.

[0024] Furthermore, the reaction in step 2 is carried out in a water bath at 35-45° C. for 2.5-3.5 h; preferably in a water bath at 40° C. for 3 h.

[0025] Furthermore, the rotation speed of the centrifugal separation in step 2 is 5500-6500 rpm, and the time is 8-12 min; preferably, the rotation speed is 6000 rpm, and the time is 10 min.

[0026] Furthermore, the concentration of the NiCl2 aqueous solution described in step 3 is 0.1-0.3 mol / L; preferably 0.2 mol / L.

[0027] Furthermore, the concentration of the aqueous solution of penicillamine in step 3 is 0.1-0.3 mol / L, preferably 0.2 mol / L.

[0028] Furthermore, the concentration of the NaOH aqueous solution in step 3 is 0.1-0.3 mol / L, preferably 0.2 mol / L.

[0029] Furthermore, the volume ratio of the UAA@ZIF-8 aqueous solution, the NiCl2 aqueous solution, the penicillamine aqueous solution, and the NaOH aqueous solution described in step 3 is 0.5-2: 0.05-0.15: 0.05-0.15: 0.05-0.15; preferably 1: 0.1: 0.1: 0.1.

[0030] Furthermore, the stirring after adding the NiCl2 aqueous solution in step 3 is magnetic stirring, the stirring speed is 200-400 rpm, and the time is 25-35 min; the preferred stirring speed is 300 rpm, and the time is 30 min.

[0031] Furthermore, the stirring time after adding the NaOH aqueous solution in step 3 is 50 to 70 minutes, preferably 60 minutes.

[0032] Furthermore, after obtaining the optical sensor for multi-mode detection of hydrogen peroxide in step 3, it is centrifuged and washed, washed with water for multiple times to remove excess reactants and dispersed in water for storage.

[0033] The rotation speed of the centrifugal washing is 3000-4000 rpm, and the time is 8-12 min; the preferred rotation speed is 3500 rpm, and the time is 10 min.

[0034] An optical sensor for multi-mode detection of hydrogen peroxide is obtained by the preparation method.

[0035] Application of the optical sensor for multi-mode detection of hydrogen peroxide in multi-mode identification and / or quantification of hydrogen peroxide.

[0036] Furthermore, the specific operation of the application is: mixing the dispersion of the optical sensor with an o-phenylenediamine (OPD) solution to form a probe solution, then adding it to the system to be tested, incubating, observing the color change or using a circular dichroism spectrometer to detect the CD signal change of the system or using a Raman spectrometer to detect the characteristic peak signal change of o-phenylenediamine to identify and / or quantify hydrogen peroxide.

[0037] Furthermore, the concentration of the dispersion of the optical sensor is 0.05 to 2 mol / L; when hydrogen peroxide is identified and / or quantified by color change, the concentration is preferably 0.05 to 0.15 mol / L.

[0038] Furthermore, the concentration of the o-phenylenediamine solution is 0.05-0.15 mol / L, preferably 0.1 mol / L.

[0039] Furthermore, the volume ratio of the dispersion liquid of the optical sensor to the o-phenylenediamine solution is 0.1-0.5:0.5-1.5; preferably 0.2:1.

[0040] Furthermore, the incubation conditions are a temperature of 35-39° C. and a time of 25-35 min; preferably 37° C. and a time of 30 min.

[0041] Furthermore, the system to be tested is a solution or a biological sample containing hydrogen peroxide.

[0042] Furthermore, the biological sample includes but is not limited to living cells, tissues, blood, etc.

[0043] Furthermore, in the application, the detection range of hydrogen peroxide is 1 nmol / L to 400 μmol / L; preferably 1 nmol / L to 100 μmol / L; more preferably 0.1 μmol / L to 100 μmol / L.

[0044] Principle of the invention: The present invention modifies the surface of the core-shell nanomaterial of the porous ZIF-8 wrapped nano-alloy UAAA structure with the chiral nanomaterial NiSx-L to obtain the composite material UA@ZIF-8-NiSx, which has both chiral signals and Raman "hot spots" for qualitative and quantitative detection of H2O2 in three sensing modes: colorimetric / chiral / Raman. In the presence of H2O2, as the chiral material is degraded, its CD signal decreases with the increase of H2O2. At the same time, under the catalysis of UAA@ZIF-8, o-phenylenediamine (OPD) modified on the surface of UAA@ZIF-8 can be rapidly catalyzed by H2O2, causing a change in color. In addition, under the detection of the Raman spectrometer, the Raman signal of OPD will also change, thereby realizing multi-mode detection of H2O2.

[0045] Compared with the prior art, the present invention has the following advantages and effects:

[0046] (1) The present invention synthesizes a novel SERS optical sensor based on chiral materials, wherein the chiral nanomaterials (UAA@ZIF-8-NiSx) are modified on the surface of the core-shell nanomaterials of porous ZIF-8 encapsulating UAA-NCs structure. The optical sensor has both circular dichroic signals and Raman signals, and can be used for multi-mode detection of H2O2.

[0047] (2) In the presence of H2O2, the chiral nanomaterials on the surface of the optical sensor degrade, and the chiral material particles adsorbed on the surface of UAA@ZIF-8 gradually decrease. Under the detection of circular dichroism, its CD signal gradually decreases and eventually disappears. At the same time, UAA@ZIF-8 nanomaterials will quickly catalyze OPD in the presence of H2O2. On the one hand, obvious color changes can be observed by the naked eye. On the other hand, due to the catalysis of OPD, the characteristic peak signal of OPD will be significantly weakened under the detection of Raman spectrometer.

[0048] (3) Compared with the current technology for detecting H2O2, the method established by the present invention has the main advantage that it can be directly detected by colorimetry in the presence of high concentrations of the target, avoiding the need for complex instruments. In addition, the optical sensor we designed combines chirality with Raman to achieve rapid, visual, and highly sensitive detection of H2O2. Most importantly, the three-mode detection method not only improves the efficiency of H2O2 detection, but also improves the reliability of the detection results, while expanding the scope of detection. This strategy highlights the potential of chiral nanocomponents in ROS detection and opens up a new path for the development of chiral nanomaterials for biomedical and bioanalysis toolboxes. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1Transmission electron microscopy images of nanomaterials during the preparation process of UAA@ZIF-8-NiSx optical sensor; a is UAA-NCs nanoparticles, b is UAA@ZIF-8 nanoparticles; c is UAA@ZIF-8-NiSx, d is UAA@ZIF-8-NiSx treated with 0.1mmol / L H2O2, and the chiral material is degraded;

[0050] Figure 2 Figure 2 shows the results of the SERS performance study of the UAA@ZIF-8-NiSx optical sensor. a is the Raman spectra of UAA-NCs, UAA@ZIF-8, and UAA@ZIF-8-NiSx, and b is the 641 cm-1 corresponding to a. -1 Comparison of Raman enhancement effect at c; c is the time-dependent Raman spectrum of UAA@ZIF-8-NiSx, d is the 641cm corresponding to c -1 The Raman intensity at , RSD is 4.188%;

[0051] Figure 3 TEM image of chiral nanomaterial NiSx-L prepared in the presence of L-pen;

[0052] Figure 4 The figure is a verification result of the reaction between chiral nanomaterials and H2O2; wherein, a is the CD spectrum of NiSx-L, b is the UV-visible spectrum of NiSx-L, c is the UV-visible spectrum of NiSx-L after being treated with NiSx-L and 0.1mmol / L H2O2, and d is the UV-visible spectrum of NiSx-L after being treated with NiSx-L and 0.1mmol / L H2O2;

[0053] Figure 5 The figure is a verification result of the feasibility of the detection strategy of the UAA@ZIF-8-NiSx optical sensor; wherein, a is the CD spectra of UAA@ZIF-8-NiSx and UAA@ZIF-8-NiSx treated with 0.1mmol / L H2O2, and b is the SERS spectra of UAA@ZIF-8-NiSx and UAA@ZIF-8-NiSx treated with 0.1mmol / L H2O2;

[0054] Figure 6 The verification results of the catalytic performance of the UAA@ZIF-8-NiSx optical sensor are shown in Figure 1. a is the UAA@ZIF-8-NiSx sensor, b is 0.1mmol / L OPD added to H2O2 and incubated at 37℃ for 30mins, and c is the UAA@ZIF-8-NiSx sensor added with OPD and H2O2 and incubated at 37℃ for 30min.

[0055] Figure 7The result diagram of colorimetric detection of H2O2; wherein, a is the color change of the detection system when the H2O2 concentration ranges from 0 to 100 μmol / L (reacted in a 37°C water bath for 30 mins), and b is the UV-Vis spectrum;

[0056] Figure 8 The results of circular dichroism detection of H2O2 are shown in Figure 1; wherein a and c are CD spectra of the detection system in the absence and presence of different concentrations of H2O2, b is the standard curve of H2O2 corresponding to a, and d is the standard curve of H2O2 corresponding to b (the error bars represent the standard deviation of three measurements);

[0057] Fig. 9 The results of SERS detection of H2O2 are shown in Figure 1. a is the SERS spectrum of the detection system in the presence of different concentrations of H2O2; b is the SERS spectrum of the detection system in the range of 450-800 cm -1 The variation of Raman peak intensity with increasing H2O2 concentration in the range; c is the standard curve of H2O2 (the error bar indicates the standard deviation of three measurements);

[0058] Fig.10 Figure 3 is the specificity research result of UAA@ZIF-8-NiSx optical sensor; among them, a is the bright field image of the detection without H2O2 treatment, b is the fluorescence image corresponding to a, c is the bright field image of the detection system incubated with OPD for 6h and H2O2 for 60min, and d is the fluorescence image corresponding to c. DETAILED DESCRIPTION

[0059] The present invention is further described in detail below in conjunction with examples and drawings, but the embodiments of the present invention are not limited thereto.

[0060] Example 1: Preparation and characterization of UAA@ZIF-8-NiSx optical sensor

[0061] Step 1: Preparation of silver nanoparticles (AgNPs)

[0062] The synthesis of Ag NPs mainly refers to the reported method. First, prepare a 0.1mmol / L AgNO3 solution. In addition, add 3.3mL NaOH (0.1mol / L) to 100mL NH2OH·HCl (0.1mmol / L) solution and mix well. Then add 9mL of the above mixed solution to a centrifuge tube. Without stirring, add 1mL AgNO3 to the centrifuge tube at a flow rate of 0.67mL / s. Finally, invert the centrifuge tube once to complete the mixing to obtain a gray-green solution, which is stored at 4°C away from light.

[0063] Step 2: Preparation of urchin-like alloy nanoparticles (UAA-NCs)

[0064] Reference Adv Mater 26(15)(2014)2431-9. First, 4.8 mL of HAuCl4 solution (0.01 mol / L) and 8.6 mL of ultrapure water were added to a 25 mL flask and mixed evenly, and magnetically stirred (300 rpm, 10 min) in a low-temperature water bath at 15°C, followed by adding 1.8 mL of previously prepared Ag NPs (30 nm) and 9.6 mL of L-DOPE (0.01 mol / L) aqueous solution, and continued to stir in a low-temperature water bath for 15 mins, and then centrifuged and washed with water (4000 rpm, 10 min), and dispersed in 10 mL of water to form a UAA-NCs solution.

[0065] Step 3: Synthesis of ZIF-8-encapsulated urchin-like nanoalloy (UAA@ZIF-8)

[0066] 1 mL of UAA-NCs colloidal solution was added to 1.5 mL of CTAB (0.1 mmol / L), magnetically stirred for 5 min to mix well, and then 1 mL of 2-MeIM (1.32 mol / L) and 1 mL of Zn(NO3)2 (24 mmol / L) were added and placed in a 40 °C water bath for 3 hours. In this way, the ZIF-8-wrapped UAA-NCs structure was formed in the solution, and it was collected by centrifugation (6000 rpm, 10 min) to remove some unwrapped ZIF-8 particles, washed and dispersed in 1 ml of water.

[0067] Step 4: Synthesis of surface modified chiral material UAA@ZIF-8 (UAA@ZIF-8-NiSx)

[0068] Reference J Am Chem Soc. 141 (49) (2019) 19373-19378. The method disclosed in the reference. First, 1 mL of the previously prepared UAA@ZIF-8 aqueous solution was added to a 5 mL flask, followed by 0.1 ml of NiCl2 (0.2 mol / L) aqueous solution, and magnetic stirring was performed for 30 min (speed was 300 rpm). Then, 0.1 mL of D / L-pen (0.2 mol / L) aqueous solution was added to the mixed solution under vigorous stirring, and then 0.1 mL of NaOH (0.2 mol / L) aqueous solution was added dropwise, and the stirring reaction was continued for 1 hour, followed by centrifugal washing (3500 rpm, 10 min), and the excess reactants were removed by water washing twice and dispersed in water.

[0069] Transmission electron microscopy (TEM) images were used to observe the changes in nanomaterials during the preparation process. Figure 1 As shown, from Figure 1It can be clearly seen from ac that the UAAA-NPs nanomaterial was first synthesized, then wrapped with ZIF-8 material to form the UAA@ZIF-8 core-shell structure material, and then the chiral material was modified on the surface, and most of the MOF material on the surface was etched.

[0070] Example 2: SERS performance of UAA@ZIF-8-NiSx optical sensor

[0071] UAA@ZIF-8-NiSx optical sensor is a new SERS substrate based on MOF. Due to the unique structure and properties of MOF, the substrate is endowed with excellent properties, which improves the sensing performance of traditional SERS substrates, such as chemical enhancement and molecular enrichment. In addition, due to the etching of chiral materials, the Raman "hot spots" are enhanced, so this new SERS substrate has excellent Raman enhancement ability. Figure 2 As shown in a and b, under the same conditions, OPD at 641cm -1 The Raman signal of the nanostructured UAAA-NPs is three times that of single unencapsulated UAAA-NPs.

[0072] Since the Raman reporter molecule OPD is encapsulated in the MOF and chiral nanomaterial structure, it can generate Raman signals with good reproducibility and high stability. Time-dependent Raman spectra such as Figure 2 As shown in c. UAA@ZIF-8-NiSx nanomaterials at 641cm -1 Compared with other peaks, the Raman peak at has high signal intensity and maintains good stability during the acquisition process, with a relative standard deviation (RSD) of 4.188% ( Figure 2 In (d), based on the SERS signal intensity and probe stability, we selected 641 cm -1 The peak at is taken as the characteristic peak for H2O2 detection.

[0073] Example 3: Verification of the feasibility of the UAA@ZIF-8-NiSx optical sensor detection strategy

[0074] The first step is to prepare a single dispersed chiral nanomaterial NiSx-L: The preparation of NiSx-NPs is based on the method reported in existing articles. First, 0.1 mL of L-pen or D-Pen (0.2 mol / L) aqueous solution is added to the NiCl2 (0.2 mol / L) aqueous solution, and then 0.1 mL of NaOH (0.2 mol / L) aqueous solution is added dropwise. After magnetic stirring for 1 hour, a dispersed NiSx-NPs solution is obtained.

[0075] The TEM image of NiSx-L is shown in Figure 3. The detection results show that it has strong circular dichroism (CD) signals at 440nm and 530nm ( Figure 4a), with ultraviolet absorption signal around 490nm ( Figure 4 (b)

[0076] In the second step, the reaction between the chiral nanomaterial NiSx-L and H2O2 was verified: First, 200 μL of UAA@ZIF-8-NiSx(AZN) solution and 1 mL of OPD solution (0.1 mol / L) were added to a quartz cuvette and mixed with a pipette to form a probe solution. 500 μL of H2O2 solution of predetermined concentration (concentrations of 0, 0.1 μmol / L, 1 μmol / L, 10 μmol / L, 50 μmol / L, 100 μmol / L, 200 μmol / L, 400 μmol / L) were added to the probe solution respectively, and the mixture was incubated in a 37°C water bath for 30 mins. The color change was observed at room temperature.

[0077] The results are as follows Figure 4 As shown in c and d, both the CD spectrum and the UV absorption spectrum have changed, indicating that H2O2 can degrade chiral materials, confirming the feasibility of this detection strategy.

[0078] The third step is to verify the feasibility of the UAA@ZIF-8-NiSx optical sensor for the detection strategy: Prepare the UAA@ZIF-8-NiSx optical sensor with reference to Example 1 and detect its circular dichroism.

[0079] The results are as follows Figure 5 As shown in the figure, the results show that the material also has circular II signals at 440nm and 530nm, and the circular II signals are weakened after adding H2O2 ( Figure 5 In addition, UAA@ZIF-8-NiSx was used as a SERS probe to detect the changes in Raman signals before and after the addition of H2O2. Figure 5 Figure b shows that the Raman signal of the characteristic peak of OPD is weakened due to the catalysis of OPD by H2O2.

[0080] The fourth step is to verify the catalytic performance of the nanomaterials: a solution containing only the UAA@ZIF-8-NiSx optical sensor is prepared ( Figure 6 a), and a blank group in which H2O2 and OPD reacted alone without the presence of an optical sensor ( Figure 6 (b)

[0081] The results show that at the same temperature and time, the reaction color will turn into dark green ( Figure 6 c), compared with the blank group without the participation of nanocomposites, verifies that the nanomaterials have catalytic effects.

[0082] Example 4: Application of UAA@ZIF-8-NiSx optical sensor

[0083] (1) Colorimetric detection of H2O2

[0084] First, 200 μL of UAA@ZIF-8-NiSx(AZN) solution (0.1 mol / L) and 1 mL of LOPD solution (0.1 mol / L) were added to a quartz cuvette and mixed with a pipette to form a probe solution. Then, 500 μL of H2O2 solution of predetermined concentrations (0, 0.1 μmol / L, 1 μmol / L, 10 μmol / L, 50 μmol / L, 100 μmol / L, 200 μmol / L, 400 μmol / L) were added to the probe solution, and the mixture was incubated in a 37°C water bath for 30 min. The color change was observed at room temperature.

[0085] Figure 7 Figure a shows the response of different concentrations of H2O2. As the concentration of H2O2 increases from 0 to 400 μmol / L, the color of the detection system changes from colorless to yellow-green. The color change at a concentration as low as 0.1 μmol / L can be observed by the naked eye. Subsequently, we measured the UV absorption changes of the blank control solution and the UAA@ZIF-8-NiSx optical sensor during the detection of H2O2. Figure 7 Figure b plots the UV-Vis absorption spectra of the blank control solution and the detection system before and after. The experimental data show that in the presence of H2O2, the detection system will exhibit ultraviolet absorption at 430nm, but there is no linear relationship with changes in concentration.

[0086] (2) Detection of H2O2 by circular dichroism

[0087] First, 200 μL of UAA@ZIF-8-NiSx(AZN) solution (1 mol / L) and 1 mL of OPD solution (0.1 mol / L) were mixed with a pipette to form a probe solution, and then 500 μL of H2O2 solution of predetermined concentration (concentrations of 0, 1 nmol / L, 10 nmol / L, 100 nmol / L, 1 μmol / L, 10 μmol / L, 100 μmol / L) were added to the probe solution, and the mixture was incubated in a 37°C water bath for 30 min. The resulting solution was used for spectral measurement.

[0088] Figure 8 Figures a and c plot the CD spectra of the detection system solution in the absence and presence of different concentrations of H2O2. The experimental data show that as the H2O2 concentration increases, the CD signals at 440nm and 530nm of the detection system gradually weaken. The changes in the CD signals at 440nm and 530nm reveal a good linear correlation with the H2O2 concentration in the range of 0.1 to 100μmol / L ( Figure 8b and d). The limit of detection (LOD) of this chiral assay was 0.1 μmol / L. This LOD level is comparable or better than that reported for colorimetric and fluorescence methods for detecting H2O2.

[0089] (3) SERS detection of H2O2

[0090] First, 200 μL of UAA@ZIF-8-NiSx(AZN) solution (1 mol / L) and 1 mL of OPD solution (0.1 mol / L) were mixed with a pipette to form a probe solution, and then 100 μL of H2O2 solution of predetermined concentration (concentrations were 0, 0.1 μmol / L, 0.5 μmol / L, 2 μmol / L, 5 μmol / L, 10 μmol / L, 20 μmol / L, 50 μmol / L, 100 μmol / L) was added to the probe solution, and the mixture was incubated in a 37°C water bath for 30 min. The resulting solution was used for SERS detection.

[0091] The results showed that with the increase of H2O2 concentration, the characteristic peak of OPD reporter molecule at 641cm -1 The Raman intensity of the signal probe decreases with the increase of H2O2 concentration. The experimental results show that there is a negative correlation between the Raman intensity of the characteristic peak of the signal probe and the H2O2 concentration ( Fig. 9 b), there is a good linear relationship between the two, and the standard curve is as follows Fig. 9 As shown in c, its detection range is from 1nmol / L to 100μmol / L, and the lowest concentration of H2O2 that can be detected can reach 1nmol / L.

[0092] (4) Visual detection of H2O2 in living cells

[0093] HeLa cells were cultured overnight in Dulbecco's Modified Eagle Medium (DMEM) containing 10% heat-inactivated fetal bovine serum (FBS) and 100 μg / mL penicillin / streptomycin at 37°C, 5% CO2, and 95% relative humidity. 4 The cells were seeded into each well of a 96-well plate and divided into two groups:

[0094] Group 1: 200 μL UAA@ZIF-8-NiSx(AZN) solution (1 mol / L) and 1 mL OPD solution (0.1 mol / L) were mixed with a pipette to form a probe solution. The probe (final concentration of OPD was 10 -3 mol / L) were added to the wells and incubated for 30 min, then the original medium was discarded and filled with fresh medium, and finally H2O2 solution was added and incubated for another 60 min;

[0095] Group 2: 200 μL UAA@ZIF-8-NiSx(AZN) solution (1 mol / L) and 1 mL OPD solution (0.1 mol / L) were mixed with a pipette to form a probe solution. The probe (final concentration of OPD was 10 -3 mol / L) were added to the wells and incubated for 30 min, then the original medium was discarded and filled with fresh medium.

[0096] Confocal laser scanning microscopy images were acquired on a confocal microscope system (Leica) with an excitation wavelength of 502 nm.

[0097] The results are as follows Fig.10 As shown, the results show that the probe molecule OPD used in the chiral UAA@ZIF-8-NiSx optical sensor is fluorescent. When H2O2 is added, the nanomaterial prompts it to quickly catalyze OPD, causing its fluorescence to significantly weaken, while there will be no fluorescence weakening changes for other common anions. Therefore, this probe is expected to be used to specifically identify H2O2 in living cells. Initially, HeLa cells were treated with the probe. As a control, fluorescence confocal images of HeLa cells treated with and without H2O2 solution were taken and compared. The results clearly show that the probe shows fluorescence in the absence of H2O2, while the fluorescence of the probe treated with H2O2 is significantly weakened. These data demonstrate the potential of OPD as a sensitive fluorescent probe, and this optical sensor can be used to specifically detect H2O2 in cells.

[0098] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the described embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principles of the present invention shall be equivalent replacement methods and shall be included in the protection scope of the present invention.

Claims

1. A method for preparing an optical sensor for multi-mode detection of hydrogen peroxide, characterized in that: The steps include: Step 1: Mix HAuCl4 solution and water evenly, stir, then add silver nanoparticle solution and levodopa aqueous solution, continue stirring; add water to the reaction solution, centrifuge and wash, collect the precipitate, and disperse it in water to obtain a nano alloy particle colloidal solution, referred to as UAA-NCs colloidal solution; Step 2: Add hexadecyltrimethylammonium bromide solution to the UAA-NCs colloidal solution obtained in step 1, stir, then add 2-methylimidazole solution and Zn(NO3)2 solution respectively, react; centrifuge the reaction solution to collect the precipitate, which is the sea urchin-shaped nano-alloy particles wrapped in ZIF-8, referred to as UAA@ZIF-8 particles; wash the UAA@ZIF-8 particles and disperse them in water to obtain a UAA@ZIF-8 aqueous solution; Step 3: Take the UAA@ZIF-8 aqueous solution obtained in step 2, add the NiCl2 aqueous solution, stir to react, then add the D-type or L-type penicillamine aqueous solution to the mixed solution under vigorous stirring, then add the NaOH aqueous solution dropwise, continue to stir to react, and obtain the optical sensor for multimodal detection of hydrogen peroxide.

2. The method for preparing an optical sensor for multi-mode detection of hydrogen peroxide according to claim 1, characterized in that: The silver nanoparticle solution described in step 1 is prepared by the following method: 0.05-0.15 mol / L NaOH solution is added to 0.05-0.15 mol / L NH2OH·HCl solution at a volume ratio of 100:2-4, and then 0.05-0.15 mol / L AgNO3 solution is added to the obtained mixed solution at a flow rate of 0.6-0.7 mL / s and a volume ratio of 8-10:1; the reaction container is inverted once to complete mixing, and the target product is obtained.

3. The method for preparing an optical sensor for multi-mode detection of hydrogen peroxide according to claim 1 or 2, characterized in that: The concentration of the HAuCl4 solution described in step 1 is 0.005-0.015 mol / L; The concentration of the levodopa aqueous solution in step 1 is 0.005 to 0.015 mol / L; The volume ratio of the HAuCl4 solution, water, silver nanoparticle solution, levodopa aqueous solution, and water for dispersion described in step 1 is 4-5:8-9:1-2:9-10:9-11; The stirring in step 1 is magnetic stirring in a water bath at 14 to 16° C., with a stirring speed of 100 to 300 rpm and a stirring time of 8 to 12 min; The rotation speed of the centrifugal washing described in step 1 is 3500-4500 rpm, and the time is 8-12 min.

4. The method for preparing an optical sensor for multi-mode detection of hydrogen peroxide according to claim 1 or 2, characterized in that: The concentration of the hexadecyltrimethylammonium bromide solution in step 2 is 0.005 to 0.015 mol / L; The concentration of the 2-methylimidazole solution described in step 2 is 1 to 2 mol / L; The concentration of the Zn(NO3)2 solution described in step 2 is 22-26 mmol / L; The volume ratio of the UAA-NCs colloidal solution, hexadecyltrimethylammonium bromide solution, 2-methylimidazole solution, Zn(NO3)2 solution, and water for dispersion described in step 2 is 1-2:1-2:1-2:1-2:1-2; The reaction described in step 2 is carried out in a water bath at 35-45°C for 2.5-3.5 h; The centrifugal separation described in step 2 has a rotation speed of 5500 to 6500 rpm and a time of 8 to 12 min.

5. The method for preparing an optical sensor for multi-mode detection of hydrogen peroxide according to claim 1 or 2, characterized in that: The concentration of the NiCl2 aqueous solution described in step 3 is 0.1-0.3 mol / L; The concentration of the aqueous solution of penicillamine in step 3 is 0.1-0.3 mol / L; The concentration of the NaOH aqueous solution in step 3 is 0.1-0.3 mol / L; The volume ratio of the UAA@ZIF-8 aqueous solution, the NiCl2 aqueous solution, the penicillamine aqueous solution, and the NaOH aqueous solution described in step 3 is 0.5-2: 0.05-0.15: 0.05-0.15: 0.05-0.15; The stirring after adding the NiCl2 aqueous solution in step 3 is magnetic stirring, the stirring speed is 200 to 400 rpm, and the time is 25 to 35 minutes; The stirring time after adding the NaOH aqueous solution in step 3 is 50 to 70 minutes.

6. The method for preparing an optical sensor for multi-mode detection of hydrogen peroxide according to claim 1 or 2, characterized in that: The concentration of the HAuCl4 solution described in step 1 is 0.01 mol / L; The silver nanoparticle solution described in step 1 is prepared by the following method: 0.1 mol / L NaOH solution is added to 0.1 mol / L NH2OH·HCl solution at a volume ratio of 100:3.3, and then 0.1 mol / L AgNO3 solution is added to the resulting mixed solution at a flow rate of 0.67 mL / s and a volume ratio of 9:1; the reaction container is inverted once to complete mixing, and the target product is obtained; The concentration of the levodopa aqueous solution described in step 1 is 0.01 mol / L; The volume ratio of the HAuCl4 solution, water, silver nanoparticle solution, levodopa aqueous solution, and water for dispersion described in step 1 is 4.8:8.6:1.8:9.6:10; The stirring in step 1 is magnetic stirring in a 15°C water bath, with a stirring speed of 200 rpm and a stirring time of 10 min; The centrifugal washing described in step 1 is performed at a speed of 4000 rpm for 10 min; The concentration of the hexadecyltrimethylammonium bromide solution described in step 2 is 0.01 mol / L; The concentration of the 2-methylimidazole solution described in step 2 is 1.32 mol / L; The concentration of the Zn(NO3)2 solution described in step 2 is 24 mmol / L; The volume ratio of the UAA-NCs colloidal solution, hexadecyltrimethylammonium bromide solution, 2-methylimidazole solution, Zn(NO3)2 solution, and water for dispersion described in step 2 is 1:1.5:1:1:1; The reaction described in step 2 is carried out in a water bath at 40°C for 3 h; The centrifugal separation in step 2 is performed at a speed of 6000 rpm for 10 min; The concentration of the NiCl2 aqueous solution described in step 3 is 0.2 mol / L; The concentration of the aqueous solution of penicillamine in step 3 is 0.2 mol / L; The concentration of the NaOH aqueous solution described in step 3 is 0.2 mol / L; The volume ratio of the UAA@ZIF-8 aqueous solution, the NiCl2 aqueous solution, the penicillamine aqueous solution, and the NaOH aqueous solution described in step 3 is 1:0.1:0.1:0.1; The stirring after adding the NiCl2 aqueous solution in step 3 is magnetic stirring, the speed is 300 rpm, and the time is 30 min; The stirring time after adding the NaOH aqueous solution in step 3 is 60 min.

7. An optical sensor for multi-mode detection of hydrogen peroxide, characterized in that: The method is obtained by the preparation method described in any one of claims 1 to 6.

8. Use of the optical sensor for multi-mode detection of hydrogen peroxide as claimed in claim 7 in multi-mode identification and / or quantification of hydrogen peroxide.

9. The use according to claim 8, characterized in that: The specific operation of the application is: mixing the dispersion of the optical sensor with an o-phenylenediamine solution to form a probe solution, then adding it to the system to be tested, incubating, observing the color change or using a circular dichroism spectrometer to detect the CD signal change of the system or using a Raman spectrometer to detect the characteristic peak signal change of o-phenylenediamine to identify and / or quantify hydrogen peroxide; The concentration of the dispersion of the optical sensor is 0.05 to 2 mol / L; The concentration of the o-phenylenediamine solution is 0.05-0.15 mol / L; The volume ratio of the dispersion liquid of the optical sensor to the o-phenylenediamine solution is 0.1-0.5:0.5-1.5; The incubation conditions are as follows: a temperature of 35 to 39° C. and a time of 25 to 35 min.

10. The use according to claim 9, characterized in that: The system to be tested is a solution or a biological sample containing hydrogen peroxide; The biological samples include living cells, tissues, and blood; The detection range of the hydrogen peroxide is from 1 nmol / L to 400 μmol / L.

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