RU2848685C2 - Cytter-ionic fluorescent probe modified with polyethylene glycol (variations) and preparation containing it - Google Patents

Abstract

FIELD: zwitterionic fluorescent probe, modified polyethylene glycol, lyophilised preparation containing a zwitterionic fluorescent probe.

SUBSTANCE: the fluorescent probe of the present invention is intended for fluorescent imaging in the near-infrared range.

EFFECT: thanks to a simple synthesis method, high fluorescence quantum yield, low non-specific fluorescence signal and high signal-to-noise ratio in tumour detection, the probe of the present invention has good biomedical properties and is suitable for industrial production and clinical implementation.

6 cl, 11 dwg, 1 tbl, 5 ex

Description

GIVE UP TECHNOLOGY

[0001] The invention relates to the technology of a new medicinal preparation, namely to a zwitterionic fluorescent probe modified with polyethylene glycol and a preparation containing it.

LEVEL OF TECHNOLOGY

[0002] Cancer poses a serious threat to human health, and despite the development of a variety of treatment methods, surgery remains the most common and effective treatment for many tumors. Statistically, approximately 50% of patients whose tumors have been completely removed experience no tumor recurrence. Therefore, accurate detection of all tumor foci and delineation of tumor borders, which ensures complete removal of tumor foci, is of great importance for improving the effectiveness of surgical tumor treatment. Currently, the clinical method of tumor identification primarily involves visual observation of the differences in color and hardness of tumor tissue from normal tissue. This method is usually effective only for larger tumors, but distinguishing small tumor tissue is difficult. To remove tumor tissue as thoroughly as possible, mass resection is widely used in clinical practice, which not only has significant side effects but also leads to anatomical leakage. In this regard, the development of new surgical navigation technologies that help doctors distinguish tumor tissues is of great importance in the clinic.

In recent years, near-infrared fluorescence imaging has become an ideal imaging method for surgical navigation due to its advantages such as real-time imaging, absence of ionizing radiation, safety, and convenience. The use of near-infrared fluorescence probes for tumor cell labeling, tumor border determination, detection of small tumor foci, guidance for precise surgical resection, and minimally invasive treatment is of great significance in improving the efficiency of tumor surgery. Compared with visible fluorescence imaging, near-infrared fluorescence imaging (600nm-900nm) has the advantages of high tissue penetration and weak tissue autofluorescence. Many clinical experiments have shown that near-infrared fluorescence imaging has significant advantages over visible fluorescence imaging in improving tumor detection rate, signal-to-noise ratio, and reducing probe dose.

Currently, indocyanine green (ICG) is the only near-infrared fluorescent dye that can be used clinically. After subcutaneous injection, ICG can return to sentinel lymph nodes, so it can be used to identify tumor sentinel lymph nodes. In addition, due to the difference in metabolism rates between liver cancer tissue and normal liver tissue, ICG is also used as a fluorescent tracer in surgical liver resection. However, since ICG does not target the tumor, it is difficult to use as a fluorescent tracer for most tumors other than liver cancer. Therefore, the development of highly specific and highly sensitive fluorescent molecular probes is of great clinical importance.

[0005] Currently, the most widely used near-infrared fluorescent dye is IRDye800CW, manufactured by the American company LI-COR. This dye is characterized by the presence of a heptamethyl chain linked by phenoxy bridges with a hexagonal rigid ring structure at the center. This structure imparts strong fluorescence intensity and fluorescence stability in the near-infrared range to the dye. In addition, IRDye800CW contains a carboxyl group, which allows it to be easily coupled with various tumor-targeted polypeptides, small molecules, antibodies, etc. to produce tumor-targeted fluorescent probes in the near-infrared range. Dozens of clinical experiments on surgical tumor navigation based on the IRDye800CW fluorescent probe are currently underway. However, an asymmetric structure like IRDye800CW also complicates and increases the cost of synthesis. To reduce the complexity of synthesis, scientists from Purdue University (USA) repositioned the carboxyl and sulfonate groups and designed LMNIR2. While maintaining the good optical properties of IRDye800CW, the symmetric structure of this dye significantly simplifies synthesis. Both LMNIR2 and IRDye800CW contain four sulfonic acid groups. This structure increases the dye's water solubility and prevents fluorescence quenching due to dye aggregation. However, studies have shown that excessive negative charge can lead to nonspecific adsorption of the dyes in the body, creating a strong background signal in the body. The chemical structural formulas of IRDye800CW and LMNIR2 are shown below:

[0006] In connection with the above, the present invention is proposed.

ESSENCE OF THE INVENTION

[0007] In order to solve the problems existing in the prior art, the present invention provides zwitterionic fluorescent probes modified with polyethylene glycol and a lyophilized tumor imaging preparation containing such probes.

[0008] In a first aspect of the present invention, there is provided a zwitterionic fluorescent probe modified with polyethylene glycol, characterized in that it has the following chemical structural formula:

,

where A is arginine, lysine, or a non-natural basic acid with a positively charged group on the side chain;

D is O, S, N, or absent;

R is C(CH ₃ ) ₂ , O, S or Se;

1<x≤3, 1<y≤3, 1<z≤4, 0≤d≤1, 0≤e≤2;

x, y, z, d are integers;

Ligand is an RGD polypeptide that targets the integrin receptor.

[0009] In one embodiment, the non-natural basic acid comprises one of 2-amino-4-guanidinobutyric acid, 2-amino-3-guanidinopropionic acid, 2,4-diaminobutyric acid, and 2,3-diaminopropionic acid;

x and y represent 3 respectively, and z represents 4.

[0010] In a second aspect of the present invention, there is provided a zwitterionic fluorescent probe modified with polyethylene glycol, characterized in that it has the following chemical structural formula:

,

where Ligand is an RGD polypeptide targeting an integrin receptor.

[0011] In one embodiment, the polyethylene glycol-modified zwitterionic fluorescent probe has the following chemical structural formula:

.

[0012] In a third aspect of the present invention, there is provided a lyophilized tumor imaging preparation comprising the above-mentioned zwitterionic fluorescent probe and a lyophilized protective agent.

[0013] In one embodiment, the lyophilized protective agent comprises one or more of glucose, sucrose, maltose, trehalose, galactose, fructose, mannitol, glutamic acid, alanine, glycine, sarcosine, arginine, polyethylene glycol, dextran, polyvinyl alcohol, polyvinylpyrrolidone.

BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to make the embodiments of the present invention or the technical proposals in the prior art more clear, the accompanying drawings used in describing the embodiments or the prior art will be briefly described below. It is obvious that the accompanying drawings in the following description represent only a part of the embodiments of the present invention, all other embodiments can be obtained by those skilled in the art based on the embodiments of the present invention, without creative work.

[0015] Fig. 1 shows the positive ion mass spectrum of MALDI-TOF PEG-Cy7-RP-RGD of the present invention;

[0016] Fig. 2 shows the positive ion mass spectrum of MALDI-TOF PEG-Cy7-RGD of the present invention;

[0017] Fig. 3 shows the positive ion mass spectrum of MALDI-TOF PEG-Cy7-R-RGD of the present invention;

[0018] Fig. 4 shows the absorption spectroscopy (concentration 1 μM) of PEG-Cy7-Cl, PEG-Cy7-COOH, PEG-Cy7-RGD, PEG-Cy7-R-RGD and PEG-Cy7-RP-RGD in the invention in PBS (pH=7.4);

[0019] Fig. 5 shows the fluorescence spectra (concentration 1 μM) of PEG-Cy7-Cl, PEG-Cy7-COOH, PEG-Cy7-RGD, PEG-Cy7-R-RGD and PEG-Cy7-RP-RGD in the invention in PBS (pH=7.4);

[0020] Fig. 6 shows images of PEG-Cy7-RGD, PEG-Cy7-R-RGD, PEG-Cy7-RP-RGD and IRDy800CW-RGD probes at different time points after administration to mice;

[0021] Fig. 7 shows signal-to-noise ratio data over time at the tumor site following administration of PEG-Cy7-RGD, PEG-Cy7-R-RGD, PEG-Cy7-RP-RGD, and IRDy800CW-RGD probes to mice;

[0022] Fig. 8 shows the fluorescence intensity data over time following administration of PEG-Cy7-RGD, PEG-Cy7-R-RGD, PEG-Cy7-RP-RGD, and IRDy800CW-RGD probes to mice;

[0023] Fig. 9 shows a diagram of a tumor in a mouse model with human brain glioma U87;

[0024] Fig. 10 shows a diagram of a tumor in the SKOV3 human ovarian cancer mouse model;

[0025] Fig. 11 shows the 4T1 mouse breast cancer lung metastasis model and the MB-49 human bladder cancer lung metastasis model.

EMBODIMENTS OF THE INVENTION

[0026] In order to provide greater clarity regarding the objectives, technical solutions and advantages of the embodiments of the present invention, the technical solutions according to the embodiments of the present invention are clearly and completely described. Of course, the embodiments presented in the following description are only some, and not all, embodiments of the present invention. All other embodiments obtained by persons skilled in the art based on the embodiments of the present invention, without creative work, will fall within the scope of protection of the present invention.

[0027] Embodiment 1

[0028] The fluorescent probe of this embodiment is PEG-Cy7-RP-RGD, including A - arginine, D - O, R - C(CH3)2, x, y - 3, z - 4, d - 1, e - 2. The route of synthesis of the fluorescent probe in this embodiment is as follows:

[0029] Including the preparation of compound A3:

[0030] Sulfoindole salt A1 (15 g) and 1-iodo-2-(2-(2-methoxyethoxy)ethoxy)ethane A2 (15 g) were reacted in acetonitrile with heating for 24 h. After rotary evaporation to remove the solvent, the product was dissolved in water, purified on a C18 reverse phase silica gel column, and after drying, about 9 g (38%) of product was obtained. 1H NMR (500 MHz, DMSO-d6) δ 8.04 (d, J = 1.5 Hz, 1H), 7.91 (d, J = 8.3 Hz, 1H), 7.82 (dd, J = 8.4, 1.6 Hz, 1H), 4.72 (t, J = 5.0 Hz, 2H), 3.90 - 3.85 (m, 2H), 3.50 - 3.43 (m, 2H), 3.42 - 3.37 (m, 4H), 3.32 (dd, J = 5.8, 3.4 Hz, 2H), 3.20 (s, 3H), 2.81 (s, 3H), 1.54 (s, 6H). Theoretical value of MS(ESI) [M+H]+=386.16, experimental value [M+H]+=386.2.

[0031] Preparation of PEG-Cy7-Cl compound

[0032] Compounds A3 (8.4 g), A4 (1.8 g), 5.48 ml of triethylamine were dissolved in 56 ml of ethanol and 7.4 ml of acetic anhydride, and the reaction was carried out at 120°C for 30 minutes, the product was purified on a C18 reverse phase silica gel column, and after drying, about 4 g of product (45%) was obtained. 1H NMR (500 MHz, DMSO-d6) δ 8.25 (d, J = 14.1 Hz, 2H), 7.80 (d, J = 1.7 Hz, 2H), 7.65 (dd, J = 8.3, 1.6 Hz, 2H), 7.38 (d, J = 8.4 Hz, 2H), 6.44 (d, J = 14.2 Hz, 2H), 4.42 (t, J = 5.2 Hz, 4H), 3.81 (t, J = 5.1 Hz, 4H), 3.53 - 3.48 (m, 4H), 3.44 - 3.36 (m, 8H), 3.32 - 3.29 (m, 4H), 3.17 (s, 6H), 2.70 (t, J = 6.1 Hz, 4H), 1.85 (p, J = 6.2 Hz, 2H), 1.68 (s, 12H). Theoretical value MS(ESI) [M+H]+=907.3, [M-H]-=905.3, experimental value [M+H]+=907.3, [M-H]-=905.3.

[0033] Preparation of PEG-Cy7-COOH compound

[0034] 2.67 g of p-hydroxyphenylpropionic acid (A5) and 12.8 g of sodium hydroxide were dissolved in 50 ml of water and reacted for 30 min, PEG-Cy7-Cl was added, and the reaction was carried out for 6 h at 65°C. The reaction product was purified on a C18 reverse phase silica gel column, and after drying, about 1.8 g (43%) was obtained. 1H NMR (500 MHz, DMSO-d6) δ 7.81 (d, J = 14.1 Hz, 2H), 7.64 (d, J = 1.6 Hz, 2H), 7.60 (dd, J = 8.2, 1.6 Hz, 2H), 7.28 (dd, J = 22.6, 8.3 Hz, 4H), 7.07 - 7.01 (m, 2H), 6.28 (d, J = 14.2 Hz, 2H), 4.33 (t, J = 5.4 Hz, 4H), 3.76 (t, J = 5.1 Hz, 4H), 3.49 (dd, J = 5.8, 3.5 Hz, 4H), 3.43 - 3.37 (m, 8H), 3.32 (dd, J = 5.9, 3.5 Hz, 4H), 3.19 (s, 6H), 2.76 (t, J = 7.2 Hz, 2H), 2.69 (t, J = 6.1 Hz, 4H), 2.45 (t, J = 7.3 Hz, 2H), 1.96 - 1.88 (m, 2H), 1.28 (s, 12H). Theoretical value MS(ESI) [M-H]-=1035.4, [M+H]+=1037.4, experimental value [M-H]-=1035.4, [M+H]+=1037.4.

[0035] Preparation of PEG-Cy7-RP-RGD compound

[0036] The RP-RGD polypeptide was synthesized by a solid phase synthesis method. After reacting 248 mg PEG-Cy7-COOH, 93 mg HATU and 52 mg N,N-diisopropylethylamine in 5 ml DMF for 30 min, 205 mg RP-RGD was added and the reaction was continued overnight. The product was precipitated with ethyl acetate, dissolved in water, purified on a C18 reverse phase silica gel column, and after drying, about 250 mg of product (61%) was obtained. The theoretical MS(MALDI-TOF) value [M+H]+=2042.96, [M-H]-=2040.94, the experimental value [M+H]+=2042.91 (see Fig. 1), [M-H]-=2040.76. The HPLC detection purity (210 nm) is greater than 99%.

[0037] Embodiment 2

[0038] The structural formula of the fluorescent probe of this embodiment differs from embodiment 1 in that A is lysine, D is N, R is O, x and y are 3, z is 4, d and e are 0.

[0039] The route for synthesizing the fluorescent probe in this embodiment is as follows:

[0040] The specific synthesis method is adapted to the reactor ratio and reaction condition parameters according to embodiment 1.

[0041] Embodiment 3

[0042] The structural formula of the fluorescent probe of this embodiment differs from embodiment 1 in that A is 2-amino-4-guanidinobutanoic acid, D is absent, R is Se, x and y are 3, z is 4, d is 1, e is 2.

[0043] The route for synthesizing the fluorescent probe in this embodiment is as follows:

[0044] The specific synthesis method is adapted to the reactor ratio and reaction condition parameters according to Embodiment 1.

[0045] Embodiment 4

[0046] The structural formula of the fluorescent probe of this embodiment differs from embodiment 1 in that A is arginine, D is S, R is S, x and y are 3, z is 4, d is 0, e-2.

[0047] The route for synthesizing the fluorescent probe in this embodiment is as follows:

[0048] The specific synthesis method is adapted to the reactor ratio and reaction condition parameters according to Embodiment 1.

[0049] Embodiment 5

[0050] The structural formula of the fluorescent probe of this embodiment differs from embodiment 1 in that Ligand is a glutamic acid urea derivative, a glutamine derivative targeting PSMA.

[0051] The route for synthesizing the fluorescent probe in this embodiment is as follows:

[0052] The specific synthesis method is adapted to the reactor ratio and reaction condition parameters according to Comparative Embodiment 1.

[0053] Comparative Embodiment 1

[0054] The fluorescent probe of the present comparative embodiment is PEG-Cy7- -RGD, the specific synthetic route is as follows:

[0055] The RGD polypeptide was synthesized by reactive solid-phase synthesis. For this, 248 mg of PEG-Cy7-COOH, 93 mg of HATU, and 52 mg of N,N-diisopropylethylamine were reacted for 30 min in 5 ml of DMF, then 124 mg of RP-RGD were added, and the reaction was continued overnight. The resulting product was precipitated with ethyl acetate, dissolved in water, and purified on a C18 reverse phase column; after drying, approximately 190 mg of product was obtained (yield 58%). The theoretical value of MS(MALDI-TOF) is [M+H]+ = 1638.71 and [M-H]- = 1636.7, the experimental value is [M+H]+ = 1638.39 (as shown in Fig. 2), [M-H]- = 1637.1. The high purity (more than 99%) was confirmed by HPLC (210 nm).

[0056] Comparative Embodiment 2

[0057] The fluorescent probe of the present comparative embodiment is PEG-Cy7-R-RGD, the specific synthetic route is as follows:

[0058] The RGD polypeptide was synthesized by reactive solid-phase synthesis. For this, 248 mg of PEG-Cy7-COOH, 93 mg of HATU, and 52 mg of N,N-diisopropylethylamine were reacted for 30 min in 5 ml of DMF, then 124 mg of RP-RGD were added, and the reaction was continued overnight. The resulting product was precipitated with ethyl acetate, dissolved in water, and purified on a C18 reverse phase column; after drying, approximately 190 mg of product was obtained (yield 58%). The theoretical value of MS(MALDI-TOF) is [M+H]+ = 1795.82 and [M-H]- = 1795.87, the experimental value is [M+H]+ = 1795.87 (as shown in Fig. 3), [M-H]- = 1793.61. The high purity (more than 99%) was confirmed by HPLC (210 nm).

[0059] Experiment Option 1

[0060] PEG-Cy7-Cl, PEG-Cy7-COOH, PEG-Cy7-RGD (Comparative Embodiment 1), PEG-Cy7-R-RGD (Comparative Embodiment 2), and PEG-Cy7-RP-RGD (Embodiment 1) were dissolved in PBS separately. The fluorescence spectrum (see Fig. 5) and absorption spectrum (see Fig. 4) of the probes were measured separately, the absorption and emission peak maxima were determined, the molar extinction coefficients were calculated, and the fluorescence quantum yield of the probes was determined (see Table 1) using ICG dissolved in DMSO as a standard value (fluorescence quantum yield 13%).

Table 1

PBS buffer solution (pH=7.4) 100% fetal bovine serum Name of the group PEG-Cy7-Cl PEG-Cy7-COOH PEG-
Cy7-RGD PEG-
Cy7-R-RGD PEG-
Cy7-RP-RGD PEG-Cy7-RP-RGD Molar extinction coefficient (M ^-1 cm ^-1 ) 198,000 228,000 215,000 158,000 174,000 184,000 Absorption peak (nm) 782 772 776 776 776 777 Peak emission (nm) 804 794 794 795 794 795 Stokes shift (nm) 22 22 18 20 18 18 Fluorescence quantum yield (%) 5 8.7 8.5 10.3 11.1 11.2 Brightness (molar extinction coefficient × fluorescence quantum yield) 9970 19800 18300 16300 19300 20700

[0061] As can be seen from the data in Table 1, the fluorescence quantum yield of PEG-Cy7-COOH increases by 3.7%, and the fluorescence brightness increases twofold compared to PEG-Cy7-Cl, which indicates the importance of the presence of phenoxybridging compounds. The fluorescence quantum yields and molar extinction coefficients of PEG-Cy7-RGD and PEG-Cy7-COOH are comparable, which indicates that the attachment of target molecules does not significantly affect the fluorescence of the dyes. The significant increase in the fluorescence quantum yields of PEG-Cy7-R-RGD, PEG-Cy7-RP-RGD compared to PEG-Cy7-RGD and PEG-Cy7-COOH indicates the importance of the arginine linkage between the dye and the target molecule in increasing the fluorescence quantum yield. However, the molar extinction coefficient and fluorescence brightness of PEG-Cy7-R-RGD are significantly reduced compared to PEG-Cy7-COOH, while those of PEG-Cy7-RP-RGD are significantly increased compared to PEG-Cy7-R-RGD, demonstrating the importance of the polyethylene glycol chain linkage between the dye and the target molecule for enhancing probe fluorescence. Since the fluorescent properties of probes are significantly altered by interaction of the fluorescent probe with serum proteins (e.g., ICG and IRDye800CW), probe interaction with serum increases the background probe signal in the body, leading to greater probe uptake by the liver. The inventor found that the fluorescent properties of PEG-Cy7-RP-RGD in 100% fetal bovine serum did not change significantly compared to PBS, indicating low interaction of PEG-Cy7-RP-RGD with serum proteins and better in vivo imaging performance.

[0062] Experiment Option 2

[0063] In this embodiment, the performance of three probes, PEG-Cy7-RGD, PEG-Cy7-R-RGD, and PEG-Cy7-RP-RGD, in vivo were investigated and compared with the IRDy800CW probe (IRDye800CW-RGD from LI-COR) with attached RGD. A mouse model with a subcutaneous tumor of human bladder cancer cells was constructed by injecting MB-49 human bladder cancer cells into the legs of Balb/c nude mice. After the tumor grew to an appropriate size, four fluorescent probes were administered intravenously (2 nmol of probe per mouse), and then the mice were subjected to fluorescence imaging at different time points after administration. As shown in Fig. 6, the fluorescence intensity of the four probes at the tumor site gradually decreased over time, and the fluorescence signals of the four probes did not have significant differences. However, the signal-to-noise ratio (TBR, the ratio of the tumor signal to the fluorescence signal of the surrounding normal tissue) of PEG-Cy7-RP-RGD at the tumor site was significantly higher than that of the other three probes. As shown in Fig. 7, 24 hours after administration, the TBR of PEG-Cy7-RP-RGD was more than twice that of the other three probes. The TBR of PEG-Cy7-RGD and PEG-Cy7-R-RGD was significantly lower than that of IRDye800CW-RGD, as shown in Fig. 8. The excellent performance of PEG-Cy7-RP-RGD is primarily due to its ultra-low nonspecific signal in normal tissues, which indicates the importance of polyethylene glycol modification and charge balance.

[0064] Experiment Option 3

[0065] This embodiment examined the imaging of PEG-Cy7-RP-RGD in various tumor models. A U87 mouse human brain glioma tumor model, a SKOV3 in situ human ovarian cancer model, a 4T1 mouse breast cancer lung metastasis model, and an MB-49 human bladder cancer lung metastasis model were established. As shown in Fig. 9-11, after intravenous administration of 2 nmol of PEG-Cy7-RP-RGD, a strong fluorescence signal can be observed in the tumor region after 4 hours, indicating the versatility of this fluorescent probe for various tumors.

[0066] In particular, Fig. 9 shows a human brain glioma U87 tumor model in mice, after intravenous administration of 2 nmol PEG-Cy7-RP-RGD, fluorescence imaging was performed in the mouse head with skin dissection after 4 hours, which resulted in a strong fluorescence signal in the tumor area, the signal-to-noise ratio was 6.3. Further, by dissecting the mouse brain, the exact localization of the tumor was revealed, which was confirmed by additional tissue sections, where the location of the tumor is indicated by arrows.

[0067] Fig. 10 shows the SKOV3 human ovarian cancer tumor model in mice, after intravenous administration of 2 nmol PEG-Cy7-RP-RGD, the mouse was divided after 4 hours, which made it possible to observe a strong fluorescence signal in the ovarian tumor area. The signal-to-noise ratio was about 4, where the arrows indicate the location of the tumor.

[0068] Fig. 11 separately shows the 4T1 mouse breast cancer lung metastasis model and the MB-49 human bladder cancer lung metastasis model, after intravenous administration of 2 nmol PEG-Cy7-RP-RGD, the mouse was divided after 4 hours, which made it possible to observe small metastatic foci in the lungs, the signal/noise ratio was about 4.

[0069] Studies were also conducted on fluorescent probes synthesized according to Examples 2-5. Compared with the fluorescent probe obtained according to embodiment 1, the reaction efficiency in embodiment 2 was low, and the fluorescence of the product was blue-shifted, but the Stokes shift increased, but did not interfere with its use for targeted fluorescence imaging of tumors. The fluorescent probe obtained according to embodiment 3 had equal fluorescence with the product of embodiment 1 and could also be used for targeted fluorescence imaging of tumors. Compared with the product of embodiment 1, the fluorescent probe obtained in embodiment 4 had a fluorescence spectrum that was red-shifted, but the fluorescence quantum yield decreased, but it was also suitable for targeted fluorescence imaging of tumors. The fluorescent probe obtained in embodiment 5 could bind to PSMA, which is highly expressed in prostate cancer, and provide fluorescence imaging of prostate cancer. Experimental data showed that the results obtained in embodiments 2-5 were similar to those of embodiment 1. Due to space limitations, all results are not presented.

[0070] The foregoing description of the preferred embodiments of the invention and the scope of the invention are not necessarily limited by this description, as a result of which all equivalent changes and replacements made by those skilled in the art based on the embodiments of the present invention will fall within the scope of protection of the present invention.

Claims (17)

1. A zwitterionic fluorescent probe modified with polyethylene glycol, characterized in that it has the following chemical structural formula: , where A is arginine, lysine, or a non-natural basic acid with a positively charged group on the side chain; D is O, S, N, or absent; R is C(CH ₃ ) ₂ , O, S or Se; 1<x≤3, 1<y≤3, 1<z≤4, 0≤d≤1, 0≤e≤2; x, y, z, d are integers; Ligand is an RGD polypeptide that targets the integrin receptor. 2. A zwitterionic fluorescent probe according to claim 1, wherein the non-natural basic acid comprises one of 2-amino-4-guanidinobutyric acid, 2-amino-3-guanidinopropionic acid, 2,4-diaminobutyric acid, and 2,3-diaminopropionic acid; x and y represent 3 respectively, and z represents 4. 3. A zwitterionic fluorescent probe modified with polyethylene glycol, characterized in that it has the following chemical structural formula: , where Ligand is an RGD polypeptide targeting an integrin receptor. 4. A zwitterionic fluorescent probe according to claim 3, characterized in that it has the following chemical structural formula: . 5. A lyophilized tumor imaging preparation comprising a zwitterionic fluorescent probe according to any one of claims 1 to 4, characterized in that the lyophilized preparation also includes a lyophilized protective agent. 6. A lyophilized preparation according to claim 5, characterized in that the lyophilized protective agent contains one or more of glucose, sucrose, maltose, trehalose, galactose, fructose, mannitol, glutamic acid, alanine, glycine, sarcosine, arginine, polyethylene glycol, dextran, polyvinyl alcohol, polyvinylpyrrolidone.