Oxidase response type molecular probe as well as preparation method and application thereof

Abstract

The invention relates to an oxidase response type molecular probe as well as a preparation method and application thereof, and belongs to the technical field of medical imaging. Aiming at the problem that the inflammation activity is difficult to accurately evaluate in the prior art, the invention provides a molecular imaging probe capable of responding to the activity of in-vivo myeloperoxidase (MPO), and the molecular imaging probe can be used for real-time and non-invasive imaging monitoring of the activity of the in-vivo MPO, so that the activity of the inflammatory reaction of a focus is accurately evaluated. The invention provides a chelating agent with structural characteristics of a chelating unit and an enzyme response unit, and is characterized in that the enzyme response molecular probe is constructed by taking rigid framework cyclohexanediamine (CDTA) as a transition metal chelating unit and taking electron-rich functional groups (such as phenol, catechol or 5-hydroxytryptamine) as the enzyme response unit. The probe is chelated with paramagnetic metal (such as Mn < 2 + >) for magnetic resonance imaging (MRI) or radioactive metal (such as 68Ga) for positron emission tomography (PET), so that specific response to MPO activity is realized. The dynamic stability of the probe is remarkably improved; after the MPO is responded, the relaxation efficiency is improved by 2-3 times, and the sensitivity is optimized; the cytotoxicity is low; in an acute pancreatitis model, the MRI contrast noise ratio (delta CNR) reaches 77.39 + / -7.04 and is 4.2 times that of a control group, the PET uptake rate is remarkably improved, bimodal imaging is supported, and accurate positioning and quantitative evaluation of the inflammation activity are achieved.

Description

Technical Field

[0001] This invention belongs to the field of medical imaging technology and relates to oxidase-responsive molecular probes, their preparation methods, and applications. Background Technology

[0002] Overactive inflammatory responses are a significant driver of many diseases, and the resulting oxidative stress is closely related to tissue damage. Myeloperoxidase (MPO) is a key marker of inflammatory cell activation, including neutrophils, and plays a crucial role in the occurrence, development, and exacerbation of various inflammation-related diseases such as acute pancreatitis, cardiovascular disease, neurodegenerative diseases, and autoimmune diseases. However, traditional in vitro MPO detection methods, such as enzyme-linked immunosorbent assay (ELISA) and guaiacolase activity assay, cannot provide real-time, non-invasive monitoring of in vivo MPO activity, nor can they provide information on the spatiotemporal distribution of MPO activity at lesion sites.

[0003] Using MPO as an imaging biomarker to accurately assess the MPO activity level in lesions can provide crucial diagnostic information for determining inflammatory activity and the severity of related diseases, which is of great significance for the diagnosis, treatment strategy formulation, and prognostic assessment of related diseases. Currently, clinical imaging technologies (MRI and CT) can provide relatively detailed diagnostic information on the morphology and composition of inflammatory lesions, but they cannot directly visualize or quantify MPO activity, thus limiting the accurate assessment of inflammatory activity. Summary of the Invention

[0004] In view of this, the present invention aims to provide an oxidase-responsive molecular probe, a second objective is to provide a method for preparing an oxidase-responsive molecular probe, and a third objective is to provide an application of an oxidase-responsive molecular probe.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides an oxidase-responsive molecular probe, which is composed of a metal compound M and a ligand. The metal compound is a paramagnetic metal or a radioactive metal, and the ligand is any one of tyramine CDTA ligand, dopamine CDTA ligand, and 5-hydroxytryptophan CDTA ligand. The molecular structure of the oxidase-responsive molecular probe is shown below:

[0007]

[0008] Where M is Mn 2+ Fe 3+ , 18 F-Al, 64 Cu、 68 Any one of Ga;

[0009] R is Any one of them;

[0010] Preferably, the preparation method of tyramine CDTA ligand (2,2'-(((1S,2S)-2-((carboxymethyl)(2-((4-hydroxyphenethyl)amino)-2-oxoethyl)amino)cyclohexyl)azanediyl)diacetic acid) is as follows: 4-hydroxyphenethylamine is dissolved in dimethyl sulfoxide solution, and then CDTA monoacid anhydride is added to the solution. The molar ratio of 4-hydroxyphenethylamine to CDTA monoacid anhydride is 1:1. Under nitrogen protection, the reaction is stirred at room temperature for 24 h. The reaction solution is collected, dimethyl sulfoxide is removed by rotation, and the tyramine CDTA ligand is obtained by column chromatography purification.

[0011] The preferred method for preparing the dopamine CDTA ligand (2,2'-(((1S,2S)-2-((carboxymethyl)(2-((3,4-dihydroxyphenethyl)amino)-2-oxoethyl)amino)cycloh exyl)azanediyl)diaceticacid) is as follows: Dopamine hydrochloride is dissolved in dimethyl sulfoxide, and CDTA monoacid anhydride and triethylamine are added sequentially to the resulting solution, wherein the molar ratio of dopamine hydrochloride, CDTA monoacid anhydride and triethylamine is 1:(0.8-0.9):(1.2-1.3). The reaction is stirred for 24 hours under nitrogen protection at room temperature. After the reaction is completed, dimethyl sulfoxide is removed by rotary evaporation under reduced pressure, dissolved in water, and allowed to stand for crystallization for 12-24 hours. The precipitated white solid product is collected by filtration and dried to obtain the dopamine CDTA ligand.

[0012] Preferably, the preparation method of 5-hydroxytryptophan CDTA ligand (2,2'-(((1S,2S)-2-((2-((1-carboxy-2-(5-hydroxy-1H-indol-3-yl)ethyl)amino)-2-oxoethyl)(carboxy methyl)amino)cyclohexyl)azanediyl)diacetic acid) is as follows: 5-hydroxytryptophan is dissolved in dimethylformamide, and CDTA monoacid anhydride is added to the resulting solution, wherein the molar ratio of 5-hydroxytryptophan to CDTA monoacid anhydride is 1:(0.85~0.95). The reaction is stirred for 24 hours under nitrogen protection and at room temperature. After the reaction is completed, dimethylformamide is removed by rotary evaporation under reduced pressure. After dissolution, the solution is purified by column chromatography to obtain the 5-hydroxytryptophan CDTA ligand.

[0013] Furthermore, the preparation method of the oxidase-responsive molecular probe includes the following steps: preparing a metal salt solution and a ligand solution of equal concentration, and thoroughly mixing and chelating the metal salt solution and the ligand solution according to a molar ratio to form the molecular probe;

[0014] Preferably, the molar ratio of the metal salt solution to the ligand solution is 1:5-8:5;

[0015] Preferably, the metal salt solution is Mn. 2+ Fe 3+ , 18 F-Al, 64 Cu、 68 Any one of Ga;

[0016] The ligand solution is any one of tyramine CDTA ligand, dopamine CDTA ligand, and 5-hydroxytryptophan CDTA ligand;

[0017] Application of the oxidase-responsive molecular probe in resonance contrast agents or nuclear medicine tracers.

[0018] The beneficial effects of this invention are as follows:

[0019] 1. Significantly improved dynamic stability

[0020] The oxidase-responsive molecular probe of this invention has a 20-fold increase in endogenous metal Zn. 2+ Under competitive conditions, three novel paramagnetic Mn(II) chelate probes based on CDTA cyclic ligands (Mn-Ty-CDTA, Mn-DA-CDTA, and Mn-5HT-CDTA) exhibited dissociation half-lives of approximately 40 minutes, which is twice that of the structural analog Mn-CDTA. This improved kinetic stability enhances the probes' persistence in biological environments, ensuring their excretion in their original form, reducing the risk of metal ion leakage, and improving biosafety.

[0021] 2. Optimization of relaxation efficiency and sensitivity

[0022] In in vitro enzyme response tests, the three novel oxidase-responsive molecular probes of this invention exhibited a 2–3 times higher relaxation efficiency compared to Mn-Tyr-EDTA in previous work. Among them, Mn-Ty-CDTA showed the fastest response rate and the highest response sensitivity (r1 value reached 15.0 at HRP=5U, higher than 5.0 of Mn-Tyr-EDTA), enhancing the signal output capability of magnetic resonance imaging (MRI) and enabling highly sensitive dynamic monitoring of MPO activity in inflammatory lesions.

[0023] 3. Low cytotoxicity and biocompatibility

[0024] The oxidase-responsive molecular probe of this invention showed no statistically significant difference in cell viability compared to the control group after 24 hours of treatment with 0.5 mM Mn-Ty-CDTA and Mn-CDTA in a CCK-8 cytotoxicity assay. Its biocompatibility is comparable to that of the clinically commonly used contrast agent Gd-BOPTA, ensuring the safety of the probe for in vivo application and supporting its potential for clinical translation.

[0025] 4. Excellent in vivo inflammation imaging performance

[0026] Animal model validation showed that the ΔCNR (contrast-to-noise ratio) of the inflammatory area in the Mn-Ty-CDTA group was 77.39±7.04, which was 4.2 times that of the control group Mn-CDTA (18.54±4.2) (p<0.0001).

[0027] PET imaging: 68 The uptake rate of Ga-Ty-CDTA in the SAP pancreas (1.15±0.29% ID g-1) was significantly higher than that in the SAP pancreas. 68 Ga-CDTA (0.01% ID g) -1 Furthermore, the baseline inflammatory activity in the limbs / muscles is extremely low. The signal enhancement originates from MPO-specific activation, enabling non-invasive, precise imaging localization and quantitative assessment of lesion inflammatory activity.

[0028] 5. Dual-modal imaging compatibility

[0029] The ligands (Ty-CDTA, DA-CDTA, and 5HT-CDTA) designed based on the rigid structure of CDTA in this invention exhibit excellent transition metal chelating ability (thermodynamic and dynamic stability), and can chelate paramagnetic metals (such as Mn). 2+ Fe 3+ It is used in MRI and can also be used to chelate and label radioactive metals (such as...). 68 Ga、 64 Cu is used in PET imaging. The electron-rich groups in the ligand structure can respond rapidly and sensitively to peroxidases, providing dual-modal imaging capabilities for inflammatory lesions in both magnetic resonance and nuclear medicine, thus enhancing the flexibility of clinical applications.

[0030] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0031] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0032] Figure 1 The kinetic inertness of manganese(II) complexes under different ligand chelation;

[0033] Figure 2 To compare the response performance of probes to myeloperoxidase (MPO): (ad) shows the relaxation rate changes of Mn-Tyr-EDTA, Mn-Ty-CDTA, Mn-DA-CDTA, and Mn-5HT-CDTA after responding to different enzyme activities HRP, respectively; Figure e shows the relaxation efficiencies r1 and r2 of Mn-Tyr-EDTA after responding to the enzyme; (f) and (g) show the relaxation efficiencies r1 and r2 of the three new probes after responding to the enzyme.

[0034] Figure 3 To assess the effects of different concentrations of Mn-Ty-CDTA, Mn-CDTA, and Gd-BOPTA on pancreatic ductal epithelial cells at 37°C for 24 hours using the CCK-8 assay kit (n=3 replicates, data are presented as mean ± standard deviation).

[0035] Figure 4 The magnetic resonance imaging (MRI) results of Mn-Ty-CDTA are as follows: (a) Representative images of rat cross-sectional T2 and T1-weighted MR imaging obtained before intravenous injection of Mn-Ty-CDTA (0.1 mmol / kg) and at 30, 60, 120 and 360 minutes after injection; (b) Curve of change in pancreatic contrast-to-noise ratio (ΔCNR) over time (experimental repetitions n=3, data are presented as mean ± standard deviation).

[0036] Figure 5 For Radio-HPLC 68 Ga-Ty-CDTA and 68 Ga-CDTA detection and Mn-Ty-CDTA nuclear medicine imaging (PET) manifestations: (a) 68 The retention time of Ga-Ty-CDTA was 6.35 min; (b) 68 The retention time of Ga-CDTA was 2.96 min; (c) 68 Ga-Ty-CDTA and 68 Ga-CDTA SAP rat PET imaging; (d) 120 min after injection, the effect of SAP rat pancreas on... 68 Ga-Ty-CDTA and 68 Ga-CDTA uptake (experiment repeated n=3 times, data are presented as mean ± standard deviation). Detailed Implementation

[0037] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0038] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0039] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0040] Example 1: Synthesis method of tyramine CDTA ligand

[0041] 4-Hydroxyphenethylamine (1.06 g, 7.73 mmol) was dissolved in 8 mL of dimethyl sulfoxide (DMSO) solution, and then CDTA monoacid anhydride (2.50 g, 7.62 mmol) was added to the solution. The reaction mixture was stirred at room temperature for 24 h under nitrogen protection. The reaction solution was collected to remove DMSO by rotary evaporation. Subsequently, the product was dissolved and purified by column chromatography. The pure product (white solid, yield 68.1%) was obtained. Characterization data:

[0042] 2,2'-(((1S,2S)-2-((carboxymethyl)(2-((4-hydroxyphenethyl)amino)-2-oxoethyl)amino)cyclohexyl)azanediyl)dacetic acid.:13C NMR(101MHz,D2O)δ172.79,170.47,153.77,131.03,130.08,115.39,62.92,24.06,24.03,23.94.1H NMR(400MHz,D2O)δ7.02(d,J=8.4Hz 2H,HAr),6.68(d,J=8.4Hz 2H, HAr), 2.47-3.73 (m, 14H, CH, CH2), 1.66-2.07 (m, 4H, CH2), 1.05-1.31 (m, 4H, CH2). ESI-MS: m / z=466.1[M+H]+; calcd.: 466.21.

[0043] Example 2: Synthesis method of dopamine CDTA ligand

[0044] Dopamine hydrochloride (0.70 g, 3.69 mmol) was dissolved in 10 mL of dimethyl sulfoxide (DMSO) solution. CDTA monoacid anhydride (1.01 g, 3.07 mmol) was then added to the solution, followed by triethylamine (640 μL, 4.60 mmol). The reaction mixture was stirred at room temperature for 24 h under nitrogen protection. The reaction solution was collected, the DMSO was removed by rotary evaporation, and the solution was dissolved in water. After standing overnight, a white solid precipitated, which was filtered and dried to obtain the pure product (white solid, yield 71.9%).

[0045] Characterization data:

[0046] 2,2'-(((1S,2S)-2-((carboxymethyl)(2-((3,4-dihydroxyphenethyl)amino)-2-oxoethyl)amino)cyclohex yl)azanediyl)dacetic acid: 13C NMR(101MHz,D2O)δ170.45,143.74,142.17,132.26,121.23,116.69,116.27,40 .45,33.50,24.24,24.08.1HNMR(400MHz,D2O)δ6.69-6.72(m,2H,HAr),6.58-6. 61(m,1H,HAr),2.55-3.77(m,14H,CH,CH2),1.90-2.03(m,2H,CH2),1.67-1.75( m,2H,CH2),1.04-1.34(m,4H,CH2).ESI-MS: m / z=482.1[M+H]+; calcd.:482.21.

[0047] Example 3: Synthesis method of serotonin CDTA ligand

[0048] 5-Hydroxytryptophan (1.53 g, 6.94 mmol) was dissolved in 15 mL of dimethylformamide (DMF) solution, and then CDTA monoacid anhydride (2.05 g, 6.25 mmol) was added to the solution. The reaction mixture was stirred at room temperature for 24 h under nitrogen protection. The reaction solution was collected to remove DMF by rotation. Subsequently, the product was dissolved and purified by column chromatography. The pure product (pinkish-purple solid, yield 52%). Characterization data:

[0049] 13C NMR(101MHz,D2O)δ175.55,175.36,170.67,148.67,148.66,131.43,131.27,127.56,125.84,125 .71,112.77,111.59,108.34,102.65,102.55,63.36,53.79,26.54,23.96,23.79,23.67,23.52.1H NMR(400MHz,D2O)δ7.18(d,J=8.4Hz 1H,HAr),7.09(d,J=6.0Hz1H,HAr),6.92-6.94(m,1H,HAr),6.64(dd,J1=8.8Hz,J2=2.0Hz,1H,HAr),2.35-3.7 6(m,13H,CH,CH2),1.59-1.98(m,4H,CH2),0.93-1.59(m,4H,CH2).ESI-MS: m / z=549.2[M+H]+; calcd.:549.21.

[0050] The CDTA ligand synthesis process is shown below:

[0051]

[0052] Example 4: Synthesis of Contrast Agent

[0053] Manganese-based contrast agents: Given the presence of free Mn 2+ R²≈40s -1 After coordination, R2 decreases to 4–6 s. -1 The two solutions differ significantly, and the optimal coordination ratio can be determined by utilizing the change in T2 relaxation rate with coordination state. The specific steps are as follows: Prepare 5 mmol L⁻¹ MnO₂ solution and ligand solutions of equal concentration; according to n(MnO₂)... 2+ Mn was determined by a gradient of n(ligand) values ​​of 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, and 1.6. Appropriate amounts of each solution were taken, mixed, and brought to a final volume of 1 mL. The T2 relaxation time of each sample was measured using a 0.47T magnetic resonance spectrometer. The corresponding ΔR2 value was calculated, and a ΔR2–molar ratio plot was generated. The trend was fitted to obtain Mn. 2+ The optimal coordination ratio with the ligand is determined. Subsequently, materials are fed according to this coordination ratio to obtain the target complex.

[0054]

[0055] Characterization data: Mn-Ty-CDTA.ESI-MS: [M+2H]+m / z=519.1, calcd.:519.13. [2M+3H]-m / z=1037.1, calcd.:1037.13.

[0056] Preparation of nuclear medicine probes: Elute the germanium-gallium generator (cyclotron accelerator, Department of Nuclear Medicine, Affiliated Hospital of North Sichuan Medical College) with 2 ml of 0.1 M HCl, collect 1 ml of the above solution, adjust the pH to 4.2 with 70 μl of 2 M sodium acetate, add 50 μl of 2 mM Ty-CDTA (CDTA), and react at room temperature for 15 min to finally form... 68 Ga-Ty-CDTA ( 68 (The Ga-CDTA procedure is the same). Detection was performed by Radio-HPLC. 1–2 μCi / 10 μL of the radionuclide-labeled and purified product was analyzed by Radio-HPLC. Analytical conditions: Shim-pack C18 column (4.6 × 150 mm, 3 μm). Phase A – 0.1% TFA aqueous solution, Phase B – 0.1% TFA acetonitrile solution. Time program: 0–6 min, 5% B → 90% B; 6–8 min, 90% B → 90% B; 10 min, hold 5% B; 10.01 min, stop; Injection volume: 10 μL. Column temperature: 40℃. See [link to table]. Figure 5 a and 5b.

[0057] The specific steps for using Fe-based contrast agents are as follows:

[0058] Based on the optimal coordination ratio of MnO and Ty-CDTA ligand, FeCl3 6H2O and the ligand were added according to the coordination ratio, and the mixture was stirred at room temperature for 2 hours to obtain the complex.

[0059] 18 Preparation of F-Al probes:

[0060] Prepare NaOAc buffer solution (pH = 4.5, 10 mM). Prepare AlCl3 (4 mmol / L) and Ty-CDTA (4 mmol / L) NaOAc solutions separately. Take 12 μL of AlCl3 solution and 20 μL of Ty-CDTA solution, shake thoroughly, and prepare the [Al(Ty-CDTA)] complex solution. Take 5 mCi Na 18 F (produced in-house by the cyclotron accelerator of the Department of Nuclear Medicine, Affiliated Hospital of North Sichuan Medical College) was added to the above complex solution, ultimately forming [Al(Ty-CDTA)]. 18 F).

[0061] 64 Preparation of Cu probe:

[0062] Take 2mCi 64 Cu (cyclotron accelerator, Department of Nuclear Medicine, Affiliated Hospital of North Sichuan Medical College), evaporated to dryness, added 500 μL of 0.1M NaAc / Hac buffer (pH=4.2), and 50 μL of 2 mM Ty-CDTA (in the above buffer). Reacted at room temperature for 15 min, finally forming... 64 Cu-Ty-CDTA.

[0063] Example 5 Performance Test

[0064] In this embodiment, taking EDTA linear ligands and CDTA cyclic ligands as examples, the kinetic inertness of manganese(II) complexes under different ligand chelation is investigated.

[0065] At 20 times Zn 2+ Under competitive conditions, Mn-EDTA and Mn-Tyr-EDTA rapidly dissociate, while the dissociation half-lives of the three novel probes reach approximately 40 minutes, which is twice that of the structural analog Mn-CDTA (approximately 20 minutes). Figure 1 )

[0066] In magnetic resonance imaging (MRI), relaxation rate refers to the ability of a contrast agent to shorten the longitudinal or transverse relaxation time of proton spins in neighboring water molecules. This is typically assessed using spin inversion recovery experiments and is the first step in characterizing contrast agent efficacy. Longitudinal relaxation rate (T1 relaxation rate, r1) and transverse relaxation rate (T2 relaxation rate, r2) are used to quantify the effect of a unit concentration of contrast agent on relaxation time. (The r1 value is 5 for three novel probes based on the CDTA framework, while the r1 value for Mn-Tyr-EDTA is 3.4).

[0067] To compare the response performance of probes to myeloperoxidase (MPO) in vitro, 0.5 mM probe solutions were co-incubated with 0, 5, 50, and 500 U HRP, with H2O2 added in a gradient (0–5 eq). T1 / T2 relaxation times were measured in real time, and relaxation efficiency was calculated based on the plateau phase. Results showed that the relaxation efficiency of all three probes after responding to HRP was 2–3 times higher than that of Mn-Tyr-EDTA, with Mn-Ty-CDTA showing the most significant improvement, a faster response rate, and significantly enhanced sensitivity (e.g., ...). Figure 2 ).

[0068] After in vitro screening, the optimally responsive Mn-Ty-CDTA was used in in vivo experiments, with Mn-CDTA (without a responsive group) serving as a positive control. Potential cytotoxicity was assessed using CCK-8 in pancreatic ductal epithelial cells, with Gd-BOPTA as a reference. Figure 3As shown, the cell viability of the two Mn(II) complexes under 0.5mM and 24h conditions was not statistically different from that of the control group, the toxicity was negligible, and the biocompatibility was comparable to that of Gd-BOPTA, suggesting that Mn-Ty-CDTA has excellent safety for in vivo application.

[0069] With its advantages of high kinetic inertness, sensitive MPO response, excellent post-activation relaxation efficiency, and low cytotoxicity, Mn-Ty-CDTA was used in this study to verify its inflammatory imaging capabilities in a taurocholate-induced SAP rat model. MRI showed that the ΔCNR of the inflammatory area in the Mn-Ty-CDTA group reached 77.39±7.04 at 60 min, which was 4.2 times that of the Mn-CDTA group (18.54±4.2) (p<0.0001); there was no difference between the sham-operated group (9.14±2.81) and the Mn-CDTA group (p>0.05). PET images ( Figure 5 c) and 120 min in vitro biological distribution experiment ( Figure 5 d) Further confirmation: 68 Ga-Ty-CDTA uptake in the pancreas of SAP was 1.15 ± 0.29% ID g. - 1, significantly higher than 68 Ga-CDTA (0.01% ID g) - 1), while the baseline levels in the limbs and muscles were extremely low. These results clearly indicate that the signal enhancement originated from MPO-specific activation, rather than interference from surgical trauma.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An oxidase-responsive molecular probe, characterized in that: The oxidase-responsive molecular probe is composed of a metal compound M and a ligand, wherein the metal compound is a paramagnetic metal or a radioactive metal, and the ligand is any one of tyramine CDTA ligand, dopamine CDTA ligand, and 5-hydroxytryptophan CDTA ligand; the structural formula of the oxidase-responsive molecular probe is shown below: Where M is Mn 2+ Fe 3+ , 18 F-Al, 64 Cu、 68 Any one of Ga; R is Any one of them.

2. The oxidase-responsive molecular probe according to claim 1, characterized in that, The preparation method of tyramine CDTA ligand is as follows: 4-hydroxyphenylethylamine is dissolved in dimethyl sulfoxide solution, and then CDTA monoacid anhydride is added to the solution. The molar ratio of 4-hydroxyphenylethylamine to CDTA monoacid anhydride is 1:

1. Under nitrogen protection, the reaction is stirred at room temperature for 24 h. The reaction solution is collected to remove dimethyl sulfoxide, and the tyramine CDTA ligand is obtained by column chromatography purification.

3. The oxidase-responsive molecular probe according to claim 1, characterized in that, The preparation method of dopamine CDTA ligand is as follows: Dopamine hydrochloride is dissolved in dimethyl sulfoxide, and CDTA monoacid anhydride and triethylamine are added to the resulting solution in sequence, wherein the molar ratio of dopamine hydrochloride, CDTA monoacid anhydride and triethylamine is 1:(0.8-0.9):(1.2-1.3). The reaction is stirred at room temperature under nitrogen protection for 24 hours. After the reaction is completed, dimethyl sulfoxide is removed by rotary evaporation under reduced pressure. The product is dissolved in water, allowed to stand for crystallization for 12-24 hours, and the precipitated white solid product is collected by filtration and dried to obtain the dopamine CDTA ligand.

4. The oxidase-responsive molecular probe according to claim 1, characterized in that, The preparation method of 5-hydroxytryptophan CDTA ligand is as follows: 5-hydroxytryptophan is dissolved in dimethylformamide, and CDTA monoacid anhydride is added to the resulting solution, wherein the molar ratio of 5-hydroxytryptophan to CDTA monoacid anhydride is 1:(0.85-0.95). The reaction is stirred for 24 hours under nitrogen protection and at room temperature. After the reaction is completed, dimethylformamide is removed by rotary evaporation under reduced pressure. After dissolution, the solution is purified by column chromatography to obtain the 5-hydroxytryptophan CDTA ligand.

5. The method for preparing the oxidase-responsive molecular probe according to claim 1, characterized in that, The preparation steps are as follows: prepare metal salt solutions and ligand solutions of equal concentration, and mix the metal salt solutions and ligand solutions thoroughly according to the molar ratio to form the molecular probe.

6. The preparation method according to claim 5, characterized in that: The metal salt solution is Mn 2+ Fe 3+ , 18 F-Al, 64 Cu、 68 Any one of Ga.

7. The preparation method according to claim 5, characterized in that: The molar ratio of metal salt solution to ligand solution is 1:5-8:

5.

8. The preparation method according to claim 5, characterized in that: The ligand solution is any one of the ligands in claims 2-4.

9. The application of the oxidase-responsive molecular probe according to any one of claims 1-4 in resonance contrast agents or nuclear medicine tracers.

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