Electronegativity-adjustable contrast agent film-forming agent composition, contrast agent and preparation method of contrast agent

Abstract

The invention relates to the field of biological medicine, in particular to an electronegativity-adjustable contrast agent film-forming agent composition, a contrast agent and a preparation method of the contrast agent. The electronegativity of the contrast agent film-forming agent composition is adjusted by changing at least one component in the composition, the contrast agent film-forming agent composition comprises lipid, an emulsifier, a positive charge regulator and a negative charge regulator, relative to 100 parts by weight of lipid, the content of the emulsifier is 20-50 parts by weight, and the content of the negative charge regulator is 20-50 parts by weight. The content of the positive charge regulator is 0-25 parts by weight, and the content of the negative charge regulator is 0-150 parts by weight. According to the composition and the preparation method disclosed by the invention, the inflated microbubbles of the obtained contrast agent have unique surface charge controllability, the biological distribution (such as liver, kidney, spleen and other main organs) and in-vivo cycle life of the ultrasonic contrast agent in blood can be steplessly regulated and controlled, and a powerful tool is provided for medical ultrasonic diagnosis and treatment.

Description

Technical Field

[0001] The present invention relates to the field of biomedicine, and in particular to a contrast agent film-forming agent composition with adjustable electronegativity, a contrast agent and a preparation method thereof. Background Art

[0002] Ultrasound contrast imaging technology uses microbubble contrast agents to enhance the reflection signal of ultrasound in human blood vessels, thereby improving the contrast and signal-to-noise ratio of vascular imaging. Generally speaking, traditional microbubble contrast agents are composed of a gas core and an outer shell, have good acoustic properties, and can produce strong echoes under ultrasound irradiation.

[0003] In fact, the electronegativity of the surface of microbubble contrast agents has an important influence on their behavior in vivo. Specifically, cell membranes are usually negatively charged due to the presence of many different molecules with negative charges, such as phosphatidylcholine and glycolipids. These negatively charged molecules attract positively charged ions and molecules and repel negatively charged substances. By modifying the surface of microbubbles with negative charges, nonspecific binding to negatively charged cells can be reduced, thereby increasing the circulation time of contrast agents in the blood, helping to obtain clearer and more continuous images and improving the accuracy of diagnosis. Correspondingly, by adjusting the electronegativity of microbubble contrast agents, their retention time in specific organs or tissues can also be increased. For example, the retention time of positively charged microbubbles in the liver is prolonged, which makes ultrasound imaging of liver lesions (such as liver cancer, cirrhosis, etc.) clearer. However, this does not mean that giving microbubble surfaces positive or negative charges is suitable for all application scenarios. For example, reducing the electronegativity of microbubbles (close to neutrality) can reduce the recognition and clearance of the immune system, thereby reducing immune responses and potential side effects. This further improves the biocompatibility and safety of microbubbles, which is particularly important for situations where multiple clinical scans or long-term use are required.

[0004] In addition to imaging applications, microbubbles with adjustable electronegativity are also more suitable as carriers of drugs and genes. By modifying specific functional groups on the surface of microbubbles, drugs or genes can be effectively loaded and targeted to specific cells or tissues. Pre-designed adjustment of the electronegativity of the microbubble surface to positive charge can also greatly promote the adsorption and endocytosis of microbubbles on the cell membrane, thereby controlling the release rate and efficiency of drugs or genes. This has important application prospects for targeted therapy and gene therapy, especially providing a new strategy for improving precision therapy.

[0005] Unfortunately, the surface charge characteristics of microbubbles, as an important factor affecting contrast performance and drug loading performance, have long been ignored. This situation highlights the urgency and importance of exploring and developing microbubble ultrasound contrast agent formulations and preparation methods that can achieve stepless regulation of surface charge with electronegativity ranging from positive to neutral to negative. Summary of the invention

[0006] In order to overcome the problems existing in the above-mentioned prior art, the present invention provides a contrast agent film-forming agent composition with adjustable electronegativity, a contrast agent and a preparation method thereof. The composition and preparation method of the present invention can achieve regulation of the electronegativity of the obtained contrast agent, thereby accurately controlling its residence time in the blood vessel, targeting, and ability to interact with other biological molecules.

[0007] The inventors of the present invention have discovered that by simultaneously introducing a positive charge regulator and a negative charge regulator into the microbubble contrast agent formula, and then combining them with specific lipids and emulsifiers in specific ingredients, through an emulsification process, the charge amount of the resulting contrast agent film-forming agent composition can be changed within a certain range, thereby accurately controlling the electronegativity of the resulting microbubble contrast agent, thereby achieving stepless regulation of the surface charge of the microbubble contrast agent.

[0008] Therefore, the first aspect of the present invention provides a contrast agent film-forming agent composition with adjustable electronegativity, wherein the contrast agent film-forming agent composition adjusts its electronegativity by changing at least one component in its composition, and the contrast agent film-forming agent composition includes lipids, emulsifiers, positive charge regulators and negative charge regulators. Relative to 100 parts by weight of the lipids, the content of the emulsifier is 20 to 50 parts by weight, the content of the positive charge regulator is 0 to 25 parts by weight, and the content of the negative charge regulator is 0 to 150 parts by weight.

[0009] The positive charge regulator and the negative charge regulator in the contrast agent film-forming agent composition can achieve the purpose of the present invention. The term "charge regulator" refers to a substance in the contrast agent film-forming agent composition used to impart charge to the contrast agent film-forming agent composition. In the present invention, the positive charge regulator and the negative charge regulator can be metal ions, non-metal ions, organic molecules, polymers or their derivatives. The addition, replacement or removal of these components can achieve the electronegativity regulation of the contrast agent film-forming agent composition; in a preferred case, in order to better cooperate with other components, the positive charge regulator is selected from calcium ions (Ca²⁺), magnesium ions (Mg²⁺), zinc ions (Zn²⁺), distearyl trimethyl ammonium propionyl glycerol (DSTAP), dipalmitoyl trimethyl ammonium propionyl glycerol (DPTAP), dioleoyl trimethyl ammonium propionyl glycerol (DOTAP), dioleoyl dimethyl ammonium acetylated glycerol (DODAB), distearyl dimethyl ammonium acetylated glycerol (DSDAB), polyethylene imine (PEI, Polyethylenimine), chitosan (Chitosan), poly-L-lysine (PLL, The negative charge regulator is selected from one or more of phosphate ion (PO4³⁻), sulfonate ion (SO3²⁻), carboxylate ion (COO⁻), distearoylphosphatidylglycerol (DSPG), dipalmitoylphosphatidylglycerol (DPPG), dioleoylphosphatidylglycerol (DOPG), distearoylphosphatidylserine (DSPS), dipalmitoylphosphatidylserine (DPPS), dioleoylphosphatidylserine (DOPS), dioleoylphosphatidic acid (DOPA), dipalmitoylphosphatidic acid (DPPA), distearoylphosphatidic acid (DSPA), polyacrylic acid (PAA), hyaluronic acid (HA), polyglutamic acid (PGA), and carboxymethyl cellulose (CMC). One or more; more preferably, the positive charge regulator is DOTAP and the negative charge regulator is DSPG.

[0010] In the present invention, the lipid can be various electrically neutral phospholipids, among which synthetic phospholipids have the characteristics of stable properties, strong antioxidant properties, and stable finished products. Based on this, according to a preferred embodiment, the lipid is an electrically neutral synthetic phospholipid, and the synthetic phospholipid is selected from one or more of distearoylphosphatidylcholine (DSPC), dipalmitoylphosphatidylcholine (DPPC), dioleoylphosphatidylcholine (DOPC), dimyristoylphosphatidylcholine (DMPC), dilauroylphosphatidylcholine (DLPC), dipalmitoylphosphatidylethanolamine (DPPE), distearoylphosphatidylethanolamine (DSPE), dioleoylphosphatidylethanolamine (DOPE), and dimyristoylphosphatidylethanolamine (DMPE); more preferably, the synthetic phospholipid is DSPC.

[0011] In the present invention, the emulsifier may be an emulsifier conventionally used in the art. Preferably, the emulsifier is selected from one or more of distearoylphosphatidylethanolamine-polyethylene glycol 2000 (DSPE-PEG2000), distearoylphosphatidylethanolamine-polyethylene glycol 3000 (DSPE-PEG3000), distearoylphosphatidylethanolamine-polyethylene glycol 4000 (DSPE-PEG4000), and distearoylphosphatidylethanolamine-polyethylene glycol 5000 (DSPE-PEG5000); more preferably, the emulsifier is DSPE-PEG2000.

[0012] The contrast agent film-forming agent composition of the present invention may also contain a drug component. The drug component may be various drugs used for actual treatment. For example, the drug includes but is not limited to sitagliptin, gefitinib, oxaliplatin, etc. Drugs that can be used in contrast agents in the art can be added to the present invention, and those skilled in the art can select specific substances and dosages according to needs to achieve the desired therapeutic effect.

[0013] The contrast agent film-forming agent composition of the present invention may also contain auxiliary agents commonly used in the art, and those skilled in the art may select them as needed as long as these auxiliary agents do not adversely affect the performance of other components. The content of these auxiliary agents may refer to the conventional usage amount in the art.

[0014] The second aspect of the present invention provides a contrast agent, which contains gas-filled microbubbles, wherein the gas-filled microbubbles are composed of a shell membrane and a gas coated by the shell membrane, and the shell membrane is produced by the contrast agent film-forming agent described in the first aspect of the present invention.

[0015] In the present invention, the contrast agent consists of a continuous phase and a dispersed phase, the dispersed phase is the gas-filled microbubbles, and the continuous phase can be a continuous phase commonly used in the art for preparing ultrasound contrast agents, such as phosphate buffered saline (PBS).

[0016] The gas is selected from one or more of air, oxygen, nitrogen, carbon dioxide, sulfur hexafluoride and fluorocarbon gas. Among them, perfluoropropane (C3F8) in fluorocarbon gas has extremely low solubility in water, which enables it to remain in the blood for a long time and is not easy to dissolve, thereby increasing the stability and imaging time of microbubbles; secondly, C3F8 is an inert gas, non-toxic and harmless to the human body, has good biocompatibility, and is suitable for medical imaging. Its density and sound velocity are greatly different from those of the surrounding medium, and it can effectively reflect ultrasound and improve the contrast and clarity of ultrasound angiography. Therefore, it is specially studied in the present invention. Therefore, according to a preferred embodiment of the present invention, the gas is C3F 8。

[0017] A third aspect of the present invention provides a method for preparing a contrast agent, the method comprising the following steps:

[0018] (1) uniformly mixing the contrast agent film-forming agent composition and an organic solvent to obtain a solution A;

[0019] (2) Taking an appropriate amount of solution A and uniformly dispersing it in an aqueous solvent to obtain solution B;

[0020] (3) Pass C3F8 into solution B;

[0021] (4) An emulsification process is used to evenly disperse the gas in solution B, ultimately obtaining a contrast agent.

[0022] In step (1), the organic solvent is one of ethanol, tert-butyl alcohol, chloroform and propylene glycol; the amount of the organic solvent is not particularly limited, as long as it can dissolve the composition of the present invention.

[0023] In step (2), the aqueous solution may be a hydration solution conventionally used in the art; preferably, the aqueous solution contains one or more of low-temperature plasma activated water, sodium chloride, glycerol, propylene glycol and phosphate; more preferably, the volume ratio of glycerol, propylene glycol and phosphate buffer is 1: (0.5-3): (5-12), and more preferably 1: (1-2): (7-10). There is no particularly strict restriction on the amount used, as long as the liposome or lipid membrane in the present invention can be evenly dispersed. Preferably, the concentration of the lipid in the solution is 0.5-8 mg / mL, preferably 1-5 mg / mL, and most preferably 2-4 mg / mL.

[0024] In step (2), the content of solution B is 30 to 36 parts by volume relative to 10 parts by volume of solution A. In step (3), the appropriate amount of solution A is added to solution B, so that the volume of solution B is 30 to 36 parts by volume, preferably 32 to 36 parts by volume, relative to 100 parts by volume of solution A.

[0025] In step (3), specifically, by transferring the B solution obtained in step (2) into a container and sealing it, C3F8 is injected into the container to fully expel the air.

[0026] In step (4), the emulsification process adopts high-energy emulsification method, which is a technology that uses external energy to mix and emulsify lipid materials and aqueous phases. It mainly relies on the input of external energy, such as high pressure, high-speed shear or ultrasound, to overcome the interfacial energy between the contrast agent film-forming agent components and promote their dispersion and stability. Preferably, the specific implementation method of the high-energy emulsification method in step (4) is mechanical oscillation method.

[0027] For the mechanical oscillation method, the uniformly mixed B solution is usually placed in a sealed cillin bottle and filled with fluorine-phase gas in the upper layer. The cillin bottle is pressurized to 10-500 PSI, preferably 50-150 PSI, by continuously adding fluorine-phase gas to liquefy it. Then, the mixture in the cillin bottle is mechanically oscillated, and the oscillation frequency is controlled at 2000-10000 rpm, preferably 3500-5500 rpm, and the oscillation time is 20-180 seconds, preferably 30-80 seconds. By adjusting the oscillation frequency and time, the particle size of the gas-filled microbubbles can be controlled, and a higher oscillation frequency and a longer oscillation time usually generate smaller microbubbles, while a lower oscillation frequency and a shorter oscillation time generate larger microbubbles. In this way, a microbubble contrast agent with controllable particle size and good stability can be effectively prepared.

[0028] Through the above technical solution, the present invention has at least the following advantages compared with the prior art:

[0029] (1) Precise electronegativity control: The present invention can precisely adjust the electronegativity of the contrast agent film-forming agent composition by using a two-component charge regulator (a positive charge regulator and a negative charge regulator), thereby making the electronegativity adjustment of the microbubble contrast agent more flexible, thereby achieving stepless regulation of its surface charge.

[0030] (2) Optimizing the biodistribution of microbubble contrast agents: The present invention can optimize the biodistribution of ultrasound contrast agents in major organs (such as liver, kidney, spleen, etc.) by adjusting the ratio of the two-component charge regulator. This optimization not only improves the targeting and retention time of ultrasound contrast agents in these organs, but also significantly enhances the imaging quality and diagnostic accuracy, thereby effectively improving the effects of clinical diagnosis and treatment.

[0031] (3) Prolonging the life of microbubble contrast agents in the systemic circulation: The present invention can effectively prolong the life of microbubble contrast agents in the systemic circulation by adjusting the ratio of the two-component charge regulator. This optimization significantly improves the stability and persistence of the contrast agent in the blood, making it more suitable for long-term imaging and multiple imaging needs, thereby improving the accuracy and effect of diagnosis and meeting the needs of different clinical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The contrast agent S1 obtained in Example 1 and the contrast agent S4 obtained in Example 4 are images under an inverted fluorescence microscope;

[0033] Figure 2 The zeta potential of the contrast agent S1 obtained in Example 1 and the contrast agent S4 obtained in Example 4 were measured by a Malvern particle size analyzer. Specific implementation plan

[0034] The specific embodiments of the present invention are further described below. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the embodiments described below can be combined with each other as long as they do not conflict with each other.

[0035] The reagents and instruments used in the following examples are all commercially available, and the methods used in the examples are consistent with conventional methods unless otherwise specified.

[0036] The technical solution of the present invention is further described in detail below in conjunction with embodiments.

[0037] Example 1

[0038] (1) DSPC (lipid), DSPE-PEG2000 (emulsifier), DOTAP (positive charge regulator) and DSPG (negative charge regulator) were mixed in a weight ratio of 100:40:24:6 and fully dissolved in an organic solvent propylene glycol to obtain solution A, in which the concentration of DSPC was 3.8 mg / mL;

[0039] (2) mixing the solution A with a hydration solution (mixed with glycerol and PBS buffer in a volume ratio of 1:9) in a volume ratio of 1:2.4, and heating at 65° C. until completely mixed to obtain a solution B;

[0040] (3) Transfer 1.5 mL of solution B into a 3 mL vial and seal it. Inject C3F8 into the container for 5 min to expel the air.

[0041] (4) The mixture in the vial is mechanically shaken at a frequency of 5000 rpm for 60 seconds to obtain a contrast agent, which is recorded as S1.

[0042] Example 2

[0043] The method of Example 1 is referred to, except that the weight ratio of lipid, emulsifier, positive charge regulator and negative charge regulator is changed to 100:40:22:8, and the total weight is kept unchanged.

[0044] Finally, the contrast agent is obtained and is recorded as S2.

[0045] Example 3

[0046] The method of Example 1 is referred to, except that the weight ratio of lipid, emulsifier, positive charge regulator and negative charge regulator is changed to 100:40:20:10, and the total weight is kept unchanged.

[0047] Finally, the contrast agent is obtained and is recorded as S3.

[0048] Example 4

[0049] The method of Example 1 is referred to, except that the weight ratio of lipid, emulsifier, positive charge regulator and negative charge regulator is changed to 100:40:15:90, and the total weight is kept unchanged.

[0050] Finally, the contrast agent is obtained and is recorded as S4.

[0051] Example 5

[0052] The method of Example 1 is referred to, except that the weight ratio of lipid, emulsifier, positive charge regulator and negative charge regulator is changed to 100:40:20:85, and the total weight is kept unchanged.

[0053] Finally, the contrast agent is obtained and is recorded as S5.

[0054] Example 6

[0055] The method of Example 1 is referred to, except that the weight ratio of lipid, emulsifier, positive charge regulator and negative charge regulator is changed to 100:40:25:80, and the total weight is kept unchanged.

[0056] Finally, the contrast agent is obtained and is recorded as S6.

[0057] Comparative Example 1

[0058] The method of Example 1 is referred to, except that no negative charge modifier is added; specifically, in step (1), DSPC, DSPE-PEG2000, DOTAP, DSPG, etc., which are equal in weight to DSPC, DSPE-PEG2000, DOTAP, DSPG, etc. in Example 1, are mixed and dissolved in an equal amount of organic solvent propylene glycol as in Example 1 in a weight ratio of 100:40:24 to obtain a solution A.

[0059] Finally, the contrast agent is obtained and is recorded as D1.

[0060] Comparative Example 2

[0061] The method of Example 3 is referred to, except that no negative charge modifier is added; specifically, in step (1), DSPC, DSPE-PEG2000, DOTAP, DSPG, etc., which are equal in weight to DSPC, DSPE-PEG2000, DOTAP, DSPG, etc. in Example 3, are mixed and dissolved in an equal amount of organic solvent propylene glycol as in Example 1 in a weight ratio of 100:40:20 to obtain solution A.

[0062] Finally, the contrast agent is obtained and is recorded as D2.

[0063] Comparative Example 3

[0064] The method of Example 4 is referred to, except that no positive charge modifier is added; specifically, in step (1), DSPC, DSPE-PEG2000, DOTAP, DSPG, etc., which are equal in weight to DSPC, DSPE-PEG2000, DOTAP, DSPG in Example 4, are mixed and dissolved in an equal amount of organic solvent propylene glycol as in Example 1 in a weight ratio of 100:40:90 to obtain solution A.

[0065] Finally, the contrast agent is obtained and is recorded as D3.

[0066] Comparative Example 4

[0067] The method of Example 6 is referred to, except that no positive charge modifier is added; specifically, in step (1), DSPC, DSPE-PEG2000, DOTAP, DSPG, etc., which are equal in weight to DSPC, DSPE-PEG2000, DOTAP, DSPG in Example 6, are mixed and dissolved in an equal amount of organic solvent propylene glycol as in Example 1 in a weight ratio of 100:40:80 to obtain solution A.

[0068] The contrast agent finally obtained is recorded as D4.

[0069] Test Case

[0070] (1) Particle size and zeta potential detection of microbubble contrast agents

[0071] The volume average particle size and zeta potential of the microbubble contrast agent were measured using a Malvern particle size analyzer, and the results are recorded in Table 1;

[0072] (2) Detection of in vivo circulation life of microbubble contrast agents

[0073] The in vivo circulation life of microbubble contrast agents is characterized by half-life, which refers to the time required for the concentration of the contrast agent in the body to decrease to half of its initial value. The specific implementation plan is as follows: Balb / c experimental mice are used as experimental subjects, and microbubble contrast agents are injected through the tail vein of mice. The concentration of the microbubble contrast agent is adjusted to 1×10 8 / ml, the injection dose is 100 μL, the contrast intensity of the mouse abdominal aorta is continuously recorded, and the time corresponding to when the contrast intensity drops to half of the peak intensity is set as the half-life of the microbubble contrast agent. The half-life results of the contrast agents of the embodiment and the comparative example are recorded in Table 1 respectively;

[0074] (3) Biodistribution detection of microbubble contrast agents

[0075] The in vivo biodistribution of microbubble contrast agents was reflected by measuring the contrast intensity of the kidney, liver, and spleen of mice 15 minutes after injection. The specific implementation plan is as follows: Balb / c experimental mice were used as experimental subjects, and microbubble contrast agents were injected through the tail vein of mice. The concentration of microbubble contrast agents was adjusted to 1×10 8 / ml, the injection dose was 100 μL, and 15 minutes after injection, the contrast images of the kidney, liver, and spleen of the mouse were recorded respectively, and then the regions of interest were selected to analyze the average contrast intensity of each organ. The average contrast intensity results of each organ measured by the contrast agents of the embodiment and the comparative example are recorded in Table 1 respectively.

[0076] Table 1

[0077] Particle size (μm) Zeta potential (mV) Half-life (s) Contrast intensity of mouse kidney at 15 minutes (au) Mouse liver contrast intensity at 15 minutes (au) Mouse spleen contrast intensity at 15 minutes (au) S1 2.50 36.42 374 46 58 19 S2 2.73 32.28 382 51 54 21 S3 2.47 28.34 391 55 46 24 S4 2.64 -36.09 749 49 31 39 S5 2.55 -32.77 726 52 33 37 S6 2.49 -28.69 705 57 37 34 D1 2.71 40.31 144 17 25 9 D2 2.58 28.94 197 25 12 11 D3 2.54 -41.03 255 22 13 10 D4 2.66 -26.42 201 28 16 8

[0078] As can be seen from Table 1, the gas-filled microbubbles of the contrast agent obtained by the contrast agent composition of the present invention have almost the same particle size as that of the prior art (without changing the acoustic properties of the contrast agent), and have flexible surface charge controllability (can achieve stepless regulation). Furthermore, by appropriately increasing the surface charge of the microbubbles, the systemic circulation life of the microbubble contrast agent can be extended. In addition, the appropriate surface electrical properties of the microbubble contrast agent can be selected according to the target organ to optimize its biodistribution in the main organs.

[0079] The above description is only a description of the preferred embodiments of the present invention and does not limit the scope of the present invention. Without departing from the overall spirit and concept of the present invention, any modification, equivalent substitution and improvement of the technical solution of the present invention made by those skilled in the art shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A contrast agent film-forming agent composition with adjustable electronegativity, characterized in that: The contrast agent film-forming agent composition adjusts its electronegativity by changing at least one component in its composition. The contrast agent film-forming agent composition includes lipids, emulsifiers, positive charge regulators and negative charge regulators. Relative to 100 parts by weight of the lipids, the content of the emulsifier is 20 to 50 parts by weight, the content of the positive charge regulator is 0 to 25 parts by weight, and the content of the negative charge regulator is 0 to 150 parts by weight.

2. The contrast agent film-forming agent composition according to claim 1, wherein The positive charge regulator includes but is not limited to positively charged metal ions, organic molecules, polymers or their derivatives. The addition, replacement or removal of these components can achieve the electronegativity regulation of the contrast agent film-forming agent composition; preferably, the positive charge regulator is selected from one or more of calcium ions (Ca²⁺), magnesium ions (Mg²⁺), zinc ions (Zn²⁺), distearyltrimethylammonium propionylglycerol (DSTAP), dipalmitoyltrimethylammonium propionylglycerol (DPTAP), dioleoyltrimethylammonium propionylglycerol (DOTAP), dioleoyldimethylammonium acetylated glycerol (DODAB), distearyldimethylammonium acetylated glycerol (DSDAB), polyethyleneimine (PEI, Polyethylenimine), chitosan (Chitosan), and poly-L-lysine (PLL, Poly-L-lysine).

3. The contrast agent film-forming agent composition according to claim 1, wherein The negative charge regulator includes but is not limited to negatively charged non-metallic ions, organic molecules, polymers or their derivatives. The addition, replacement or removal of these components can achieve the electronegativity regulation of the contrast agent film-forming agent composition; preferably, the negative charge regulator is selected from one or more of phosphate ions (PO4³⁻), sulfonate ions (SO3²⁻), carboxylate ions (COO⁻), distearoylphosphatidylglycerol (DSPG), dipalmitoylphosphatidylglycerol (DPPG), dioleoylphosphatidylglycerol (DOPG), distearoylphosphatidylserine (DSPS), dipalmitoylphosphatidylserine (DPPS), dioleoylphosphatidylserine (DOPS), dioleoylphosphatidic acid (DOPA), dipalmitoylphosphatidic acid (DPPA), distearoylphosphatidic acid (DSPA), polyacrylic acid (PAA, Polyacrylic acid), hyaluronic acid (Hyaluronic acid, HA), polyglutamic acid (PGA, Polyglutamic acid), and carboxymethylcellulose (CMC, Carboxymethylcellulose).

4. The contrast agent film-forming agent composition according to claim 1, wherein The lipids include, but are not limited to, one or more of distearoylphosphatidylcholine (DSPC), dipalmitoylphosphatidylcholine (DPPC), dioleoylphosphatidylcholine (DOPC), dimyristoylphosphatidylcholine (DMPC), dilauroylphosphatidylcholine (DLPC), dipalmitoylphosphatidylethanolamine (DPPE), distearoylphosphatidylethanolamine (DSPE), dioleoylphosphatidylethanolamine (DOPE), and dimyristoylphosphatidylethanolamine (DMPE).

5. The contrast agent film-forming agent composition according to claim 1, wherein The emulsifier includes, but is not limited to, one or more of distearoylphosphatidylethanolamine-polyethylene glycol 2000 (DSPE-PEG2000), distearoylphosphatidylethanolamine-polyethylene glycol 3000 (DSPE-PEG3000), distearoylphosphatidylethanolamine-polyethylene glycol 4000 (DSPE-PEG4000), and distearoylphosphatidylethanolamine-polyethylene glycol 5000 (DSPE-PEG5000).

6. A contrast agent, characterized in that: The contrast agent is a gas-filled microbubble, which is composed of a shell membrane and a gas wrapped in the shell membrane, and the shell membrane is produced by the contrast agent film-forming agent composition according to claims 1-5.

7. The contrast agent according to claim 6, wherein The gas includes but is not limited to one or more of air, oxygen, nitrogen, carbon dioxide, sulfur hexafluoride and fluorocarbon gas; preferably, the gas is perfluoropropane (C3F8).

8. A method for preparing a contrast agent, characterized in that: The method comprises the following steps: (1) uniformly mixing the contrast agent film-forming agent composition according to claims 1 to 5 with an organic solvent to obtain a solution A; (2) Taking an appropriate amount of solution A and uniformly dispersing it in an aqueous solvent to obtain solution B; (3) Passing the gas described in claims 6-7 into solution B; (4) An emulsification process is used to evenly disperse the gas in solution B, ultimately obtaining a contrast agent.

9. The method according to claim 8, characterized in that In step (1), the organic solvent is one of ethanol, tert-butyl alcohol, chloroform and propylene glycol; in step (2), the aqueous solution also contains one or more of low-temperature plasma activated water, sodium chloride, glycerol, propylene glycol and phosphate; in step (2), the content of B solution is 30-36 parts by volume relative to 10 parts by volume of A solution.

10. The method according to claim 8, characterized in that In step (4), the emulsification process is produced by a high-energy emulsification method. Preferably, the specific implementation method of the high-energy emulsification method is a mechanical oscillation method.

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