A dual-negative acoustic metamaterial gel material, a preparation method and application thereof

Abstract

The application provides a kind of double-negative acoustic superstructure gel material and its preparation method and application, belong to functional material technical field.The application is based on gas phase, water phase and oil phase to obtain water-in-oil-in-air emulsion, the water-in-oil-in-air emulsion includes oil phase and water-in-air microspheres dispersed in the oil phase;Remove the oil phase in the water-in-oil-in-air emulsion, then the obtained water-in-air microspheres are mixed with a composite hydrogel solution to obtain a 3D printing ink;The 3D printing ink is sequentially subjected to 3D extrusion printing and physical gelation to obtain a double-negative acoustic superstructure gel material.The application is based on microfluidic and 3D printing technology to prepare a double-negative acoustic superstructure gel material, which can accurately control the morphology, size and distribution of microspheres, and the finally prepared double-negative acoustic superstructure gel material can be applied in the ultrasonic imaging frequency range (0.5-15 MHz).

Description

Technical Field

[0001] This invention relates to the field of functional materials technology, and in particular to a double negative acoustic metagel material, its preparation method, and its application. Background Technology

[0002] Acoustic metamaterials are artificially designed structural materials that exhibit unique acoustic properties through structural design, such as negative refraction, acoustic cloaking, exceptional transmission, and subwavelength imaging. Currently, soft acoustic metamaterials are attracting widespread attention from researchers. Existing soft acoustic metamaterials are mainly prepared by traditional methods such as emulsion polymerization, dispersion polymerization and suspension polymerization. They utilize the difference in mechanical properties between the dispersed phase and the matrix to achieve negative equivalent acoustic parameters, such as negative equivalent mass density parameters and negative equivalent elastic modulus parameters (Brunet, T., et al., Sharp acoustic multipolar-resonances in highly monodispersemulsions. Applied Physics Letters, 2012. 101(1): p. 011913.; Brunet, T., et al., Soft 3D acoustic metamaterial with negative index. Nature Materials, 2015. 14(4): p. 384-388.; Brunet, T., J. Leng, and O. Mondain-Monval, Soft Acoustic Metamaterials. Science, 2013. 342(6156): p. 323-324.). However, these methods usually produce microspheres with polydispersity, poor reproducibility and poor tunable morphology. The resulting soft acoustic metamaterials have large microbubble sizes with an average radius of 160 μm. Furthermore, the soft acoustic metamaterials are mainly prepared using low-velocity silicone microspheres, which limits their operation to the low-frequency range (50–500 kHz). Summary of the Invention

[0003] The purpose of this invention is to provide a double negative acoustic metagel material, its preparation method and application. The method of this invention can precisely control the morphology, size and distribution of microspheres, and the resulting double negative acoustic metagel material can be used in the ultrasonic imaging frequency range (0.5-15MHz).

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] This invention provides a method for preparing a double negative acoustic metagel material, comprising the following steps:

[0006] An oil-in-water-in-gas emulsion was prepared based on a gas phase, an aqueous phase, and an oil phase. The oil-in-water-in-gas emulsion includes an oil phase and water-in-gas microspheres dispersed in the oil phase.

[0007] The oil phase in the oil-in-water-in-gas emulsion is removed, and then the resulting water-in-gas microspheres are mixed with the composite hydrogel solution to obtain 3D printing ink.

[0008] The 3D printing ink was sequentially subjected to 3D extrusion printing and physical gelation to obtain a double negative acoustic metagel material.

[0009] Preferably, the gas phase includes air, nitrogen, or an inert gas;

[0010] The aqueous phase includes a first gel material and water, wherein the first gel material includes chitosan, sodium alginate, polyvinyl alcohol, polyethylene glycol diacrylate, or methacrylated gelatin.

[0011] The oil phase includes silicone oil.

[0012] Preferably, the oil-in-water-in-gas emulsion is prepared in a multiphase flow microfluidic system;

[0013] The multiphase flow microfluidic system includes a tubular body. Along the material flow direction, a gas phase inlet, a water phase inlet, and an oil phase inlet are sequentially arranged on the tubular body. An oil phase microchannel communicating with the oil phase inlet is arranged inside the tubular body. A water phase microchannel communicating with the water phase inlet is arranged inside the oil phase microchannel. A gas phase microchannel communicating with the gas phase inlet is arranged inside the water phase microchannel. The radii of the gas phase microchannel, water phase microchannel, and oil phase microchannel are in the range of 5 to 500 μm, and the radius of the gas phase microchannel is smaller than that of the water phase microchannel, while the radius of the water phase microchannel is smaller than that of the oil phase microchannel.

[0014] When preparing the oil-in-water-in-gas emulsion, the flow rates of the gas phase, water phase and oil phase are independently 1 to 10 μL / min.

[0015] Preferably, the radius of the water-in-air microspheres is 15–50 μm.

[0016] Preferably, the composite hydrogel solution comprises a second gel material, an auxiliary curing material, and water; the concentration of the second gel material in the composite hydrogel solution is 10-20 wt%, and the concentration of the auxiliary curing material is 1-5 wt%.

[0017] Preferably, the second gel material includes chitosan, sodium alginate, polyvinyl alcohol, polyethylene glycol diacrylate, or methacrylated gelatin, and the auxiliary curing material includes carrageenan, gelatin, or agar.

[0018] Preferably, the volume fraction of water-in-gas microspheres in the 3D printing ink is 5-40%.

[0019] Preferably, the 3D extrusion printing is performed at room temperature, and the operating conditions of the 3D extrusion printing include: needle extrusion speed of 0.1 to 1 mm / s, needle movement speed of 0.1 to 1 mm / s; printing line spacing of <1 mm, printing thickness of 1 to 3 mm, and printing width of 4 to 6 mm.

[0020] The present invention provides a double negative acoustic metagel material prepared by the preparation method described above, comprising a gel matrix material and hollow microbubbles distributed in the gel matrix material, wherein the radius of the hollow microbubbles is 15-50 μm.

[0021] This invention provides the application of the double negative acoustic metagel material described above in the preparation of ultrasound penetration imaging formulations, wherein the high acoustic impedance media suitable for the ultrasound penetration imaging formulations include muscle or skull.

[0022] This invention provides a method for preparing a double-negative acoustic metagel material, comprising the following steps: preparing an oil-in-water-in-gas emulsion based on a gas phase, an aqueous phase, and an oil phase, wherein the oil-in-water-in-gas emulsion includes an oil phase and water-in-gas microspheres dispersed in the oil phase; removing the oil phase from the oil-in-water-in-gas emulsion, then mixing the obtained water-in-gas microspheres with a composite hydrogel solution to obtain a 3D printing ink; and sequentially performing 3D extrusion printing and physical gelation on the 3D printing ink to obtain the double-negative acoustic metagel material. This invention prepares the double-negative acoustic metagel material based on microfluidics and 3D printing technology, enabling precise control of the morphology, size, and distribution of the microspheres. The final prepared double-negative acoustic metagel material can be used in the ultrasonic imaging frequency range (0.5–15 MHz). Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the multiphase flow microfluidic system in this invention;

[0024] Figure 2 This is a schematic diagram of the 3D printing system in this invention. Detailed Implementation

[0025] This invention provides a method for preparing a double negative acoustic metagel material, comprising the following steps:

[0026] An oil-in-water-in-gas emulsion was prepared based on a gas phase, an aqueous phase, and an oil phase. The oil-in-water-in-gas emulsion includes an oil phase and water-in-gas microspheres dispersed in the oil phase.

[0027] The oil phase in the oil-in-water-in-gas emulsion is removed, and then the resulting water-in-gas microspheres are mixed with the composite hydrogel solution to obtain 3D printing ink.

[0028] The 3D printing ink was sequentially subjected to 3D extrusion printing and physical gelation to obtain a double negative acoustic metagel material.

[0029] In this invention, unless otherwise specified, all raw materials used are commercially available products known to those skilled in the art, and all equipment used is equipment known to those skilled in the art.

[0030] This invention prepares a water-in-oil, gas-in-oil emulsion based on a gas phase, an aqueous phase, and an oil phase. The water-in-oil, gas-in-oil emulsion comprises an oil phase and water-in-oil microspheres dispersed in the oil phase. In this invention, the gas phase preferably includes air, nitrogen, or an inert gas, more preferably air. In this invention, the aqueous phase preferably comprises a first gelling material and water; the first gelling material preferably includes chitosan, sodium alginate, polyvinyl alcohol, polyethylene glycol diacrylate, or methacrylated gelatin, more preferably polyvinyl alcohol; the mass fraction of the first gelling material in the aqueous phase is preferably 1-10%, more preferably 1.5-5%, and even more preferably 2%. This invention preferably uses the above-mentioned types of first gelling materials, which have the advantages of good biocompatibility, environmental friendliness, and safety and non-toxicity. In this invention, the oil phase preferably includes silicone oil.

[0031] In this invention, the oil-in-water-in-gas emulsion is preferably prepared in a multiphase flow microfluidic system. As one embodiment of this invention, such as... Figure 1 As shown, the multiphase flow microfluidic system includes a tubular body. Along the material flow direction, a gas phase inlet, a water phase inlet, and an oil phase inlet are sequentially arranged on the tubular body. An oil phase microchannel communicating with the oil phase inlet is arranged within the tubular body. A water phase microchannel communicating with the water phase inlet is arranged within the oil phase microchannel. A gas phase microchannel communicating with the gas phase inlet is arranged within the water phase microchannel. The radii of the gas phase microchannel, water phase microchannel, and oil phase microchannel are in the range of 5–500 μm, and the radius (R1) of the gas phase microchannel is smaller than the radius (R2) of the water phase microchannel, while the radius of the water phase microchannel is smaller than the radius (R3) of the oil phase microchannel. In an embodiment of the present invention, R1 is 50 μm, R2 is 100 μm, and R3 is 200 μm in the multiphase flow microfluidic system.

[0032] In this invention, when preparing the water-in-oil-gas-in-oil emulsion, the flow rates of the gas phase, aqueous phase, and oil phase are preferably independently 1–10 μL / min, more preferably the flow rate of the aqueous phase (V2) is less than the flow rate of the gas phase (V1), and the flow rate of the gas phase is less than the flow rate of the oil phase (V3). In an embodiment of this invention, when preparing the water-in-oil-gas-in-oil emulsion, V1 is 4 μL / min, V2 is 2 μL / min, and V3 is 8 μL / min. In this invention, the radius of the water-in-gas microspheres is preferably 15–50 μm, more preferably 20–40 μm, and even more preferably 30 μm. In this invention, the volume fraction of the water-in-gas microspheres in the water-in-oil-gas-in-oil emulsion is preferably 1–40%, more preferably 10–35%, even more preferably 20–33%, and even more preferably 30%. This invention preferably prepares the water-in-oil-gas-in-oil emulsion at room temperature.

[0033] In preparing the oil-in-water-in-gas emulsion, the present invention introduces the gas phase, aqueous phase, and oil phase into the multiphase flow microfluidic system. Due to the difference in mechanical properties between the first gel material in the aqueous phase and the gas phase, strong unipolar resonance will occur, forming gas-in-water (G / W) microspheres, i.e., hollow micro-resonance units (referring to the formation of hollow microbubble structures by the gel material encapsulating gas). The present invention is preferably based on microfluidic technology and keeps the flow rates of the gas phase, aqueous phase, and oil phase within the above-mentioned flow rate range (specifically, the flow rates of the gas phase, aqueous phase, and oil phase can be controlled by an automatic injection pump), which can precisely control the morphology, size, and distribution of the gas-in-water microspheres. In this invention, the higher the oil phase flow rate, the smaller the size of the formed gas-in-water microspheres. When the flow rates of the gas and oil phases are fixed, as the water phase velocity increases, the diameter of the gas-in-water microspheres decreases, and the spacing between the microspheres increases. When the automatic injection pumps for the gas, water, and oil phases are started, because the water phase flow rate is set higher than the gas phase flow rate and gas / water are insoluble, the gas phase injected into the water phase microchannel is sheared by the water phase, forming gas-in-water microspheres at the connection between the gas and water phase microchannels, with the first gel material aqueous solution as the intermediate liquid (water phase) and the gas phase distributed in the water phase. Simultaneously, because water / oil are insoluble, the gas-in-water microspheres at the outlet of the water phase microchannel are sheared by the oil phase and dispersed into the oil phase, forming a gas-in-water-in-oil (G / W / O) emulsion.

[0034] After obtaining the water-in-oil emulsion containing gas, this invention removes the oil phase from the emulsion. The resulting water-in-oil microspheres are then mixed with a composite hydrogel solution to obtain 3D printing ink. Preferably, this invention removes the oil phase from the emulsion by washing, which preferably includes alternating water washing and ethanol washing. The water used for the water washing is preferably ultrapure water, and the ethanol used for the ethanol washing is preferably anhydrous ethanol. In this invention, after each washing, the microspheres are allowed to settle completely to the bottom, the supernatant is discarded, and then the next washing is performed until the supernatant is clear. The final washing is preferably a water washing, followed by filtration to remove water, yielding the water-in-oil microspheres.

[0035] In this invention, the composite hydrogel solution preferably comprises a second gelling material, an auxiliary curing material, and water. The second gelling material preferably comprises chitosan, sodium alginate, polyvinyl alcohol, polyethylene glycol diacrylate, or methacrylated gelatin, more preferably polyvinyl alcohol. The auxiliary curing material preferably comprises carrageenan, gelatin, or agar, more preferably carrageenan; carrageenan can cure into a thermally reversible hydrogel at temperatures below 40°C, and when combined with the second gelling material as an auxiliary curing material, a composite hydrogel solution with room-temperature curing capability can be obtained; moreover, adding the auxiliary curing material helps to remove air from the solution. In this invention, the concentration of the second gelling material in the composite hydrogel solution is 10–20 wt%, more preferably 15 wt%; the concentration of the auxiliary curing material is 1–5 wt%, more preferably 2 wt%.

[0036] In this invention, the radius of the water-in-gas microspheres is denoted as r. Based on the filling ratio of the designed double negative acoustic metagel material (the volume percentage of water-in-gas microspheres in the double negative acoustic metagel material, denoted as φ), the number N of water-in-gas microspheres per unit volume of the double negative acoustic metagel material can be calculated: N = 3φ / (4πr) 3 Based on the volume parameters of the designed double negative acoustic metagel material (taking a material with a square cross-section as an example, with thickness denoted as h, and length and width both as w), Nw can be calculated. 2 h represents the total number of water-in-gas microspheres to be prepared and collected. Specifically, this invention involves mixing the water-in-gas microspheres with the composite hydrogel solution to obtain 3D printing ink. In this invention, the volume fraction of water-in-gas microspheres in the 3D printing ink is preferably 5-40%, more preferably 10-30%, and even more preferably 20%; the number of water-in-gas microspheres in the 3D printing ink is sufficient to meet the total number of water-in-gas microspheres (Nw) required for preparing the double negative acoustic metagel material. 2 h) is the benchmark.

[0037] After obtaining the 3D printing ink, this invention sequentially performs 3D extrusion printing and physical gelation on the 3D printing ink to obtain a double negative acoustic metagel material. In this invention, the 3D extrusion printing is preferably performed at room temperature, and the operating conditions for the 3D extrusion printing include: a needle extrusion speed (v) of 0.1–1 mm / s and a needle movement speed (v... s The printing speed is 0.1–1 mm / s; the printing line spacing (d) is <1 mm, the printing thickness (h) is 1–3 mm, and the printing width (w) is 4–6 mm. This invention prepares a double negative acoustic metagel material based on 3D printing technology. It is applicable to a wide range of materials and has accurate spatial guidance, allowing for more precise construction of desired structures. In this invention, during the 3D extrusion printing process, the printing line spacing is adjusted to achieve fusion between the printed lines. When the printing line spacing is relatively small (d < 1 mm), it is beneficial to achieve complete fusion of the printed lines. The printing thickness (i.e., height) is 1–3 mm, the printing width is 4–6 mm, and the printing length is equal to the width. The final precursor material obtained by 3D extrusion printing is a cuboid with a square cross-section. In the embodiments of this invention, the 3D extrusion printing is specifically performed in a 3D printing system, the structural schematic diagram of which is shown below. Figure 2 As shown, the invention includes a three-dimensional motion control platform, an extrusion feeding system, a syringe with a needle, a heat preservation device, a computer, and a control system. The computer controls the three-dimensional motion control platform, the extrusion feeding system, and the heat preservation device through the control system. The extrusion feeding system is connected to the syringe, and the heat preservation device controls the temperature of the 3D printing ink inside the syringe. Preferably, the 3D printing ink is poured into a heat-preserving syringe, extruded from the needle, and 3D extrusion printing is achieved by controlling the extrusion feeding system and the three-dimensional motion control platform. The extruded 3D printing ink rapidly completes its first cross-linking and curing at room temperature.

[0038] In this invention, the physical gelation preferably includes: freezing and thawing the precursor material obtained after 3D extrusion printing; the number of freezing and thawing cycles is preferably 3 to 4. In this invention, the temperature for each freezing cycle is preferably -10 to -40°C, more preferably -18°C; the holding time is preferably 10 to 12 hours, more preferably 11 hours; the freezing is preferably performed in a refrigerator. In this invention, the temperature for each thawing cycle is preferably room temperature, and the holding time is preferably 1 to 2 hours, more preferably 1.5 to 2 hours. In this invention, during the physical gelation process, the precursor material obtained after 3D extrusion printing completes a second crosslinking and curing process to obtain a double negative acoustic metagel material.

[0039] This invention provides a double-negative acoustic metagel material prepared by the method described above, comprising a gel matrix material and hollow microbubbles distributed within the gel matrix material. In this invention, the radius of the hollow microbubbles is 15–50 μm; the volume fraction of the hollow microbubbles in the double-negative acoustic metagel material is preferably 5–40%. In this invention, the operating frequency of the double-negative acoustic metagel material is 0.5–15 MHz, more preferably 5 MHz. The double-negative acoustic metagel material provided by this invention is suitable for application in the ultrasonic imaging frequency range and can be used for ultrasonic penetration imaging of high acoustic impedance media; the high acoustic impedance media can be, for example, muscle or skull.

[0040] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0041] Example 1

[0042] Using a 2% (w / w) polyvinyl alcohol aqueous solution as the aqueous phase, air as the gas phase, and silicone oil as the oil phase, the following method was employed: Figure 1 An oil-in-water-in-gas emulsion was prepared using a multiphase flow microfluidic system with the structure shown. The gas phase microchannels in the multiphase flow microfluidic system have a radius (R1) of 50 μm, the aqueous phase microchannels have a radius (R2) of 100 μm, and the oil phase microchannels have a radius (R3) of 200 μm. An automatic injection pump controls the gas phase flow rate (V1) to 4 μL / min, the oil phase flow rate (V3) to 8 μL / min, and the aqueous phase flow rate (V2) to 2 μL / min. The shear force of the multiphase flow microfluidic system is used to obtain water-in-gas microspheres (i.e., hollow microbubbles encapsulated in polyvinyl alcohol with a radius of 30 μm) dispersed in the oil phase.

[0043] Polyvinyl alcohol, carrageenan, and water were mixed, heated in a water bath to 90°C, and stirred until completely dissolved. The mixture was then kept in a water bath at 50°C for 1 hour to obtain a composite hydrogel solution. The concentration of polyvinyl alcohol in the composite hydrogel solution was 15 wt%, and the concentration of carrageenan was 2 wt%. The above water-in-oil emulsion was washed alternately with ultrapure water and anhydrous ethanol. After each wash, the mixture was allowed to stand to allow the water-in-oil microspheres to completely settle to the bottom of the washing container. The upper layer of liquid was removed, and the next wash was performed until the upper layer of liquid was clear. The last wash was a water wash. After the water wash, the water was filtered out. The obtained water-in-oil microspheres were mixed with the composite hydrogel solution to obtain 3D printing ink. The volume fraction of water-in-oil microspheres in the 3D printing ink was 20%.

[0044] use Figure 2The 3D printing system of the described structure performs 3D extrusion printing of the 3D printing ink at room temperature (25°C). After being extruded, the 3D printing ink is rapidly pre-cured at room temperature to obtain a precursor material. The operating conditions for the 3D extrusion printing include: needle extrusion speed of 0.5 mm / s, needle movement speed of 0.5 mm / s, printing line spacing of 0.5 mm, printing thickness of 1 mm, printing width of 4 mm, and printing length equal to printing width. The final printed precursor material is a cuboid with a square cross-section.

[0045] The precursor material is subjected to freeze-thaw cycles to achieve physical gelation, resulting in a double negative acoustic metagel material. The freeze-thaw cycle is repeated three times, with each freeze cycle at -18°C and a holding time of 11 hours. Each thawing cycle is performed at room temperature and a holding time of 2 hours.

[0046] As can be seen from the above embodiments, this invention utilizes a multiphase flow microfluidic system to form an oil-in-water-in-gas emulsion using immiscible multiphase fluids, and then generates hollow hydrogel microspheres through ion crosslinking technology. This allows for precise control of the size, morphology, and composition of the water-in-gas microspheres. The hollow hydrogel microspheres form microresonant units, which can achieve unipolar resonance and generate a negative equivalent elastic modulus under ultrasonic excitation. Subsequently, combined with 3D printing technology, based on the water-in-gas microspheres and composite hydrogel solutions, and with the help of computer and software-designed models, double-negative acoustic metagel materials with different morphologies can be constructed through layer-by-layer solidification. In this invention, the high-density stacked water-in-gas microspheres generate dipole resonance, which can be generated under ultrasonic excitation, thus producing a negative equivalent mass density. The material as a whole exhibits double-negative acoustic characteristics, with an operating frequency of 0.5–15 MHz, suitable for application in the ultrasonic imaging frequency range, and can be used for ultrasonic penetration imaging of high acoustic impedance media. Therefore, the combination of microfluidics and 3D printing technology in this invention provides a design-related and controllable solution for developing double negative acoustic metagel materials.

[0047] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a double negative acoustic metagel material, comprising the following steps: An oil-in-water-in-gas emulsion was prepared based on a gas phase, an aqueous phase, and an oil phase. The oil-in-water-in-gas emulsion includes an oil phase and water-in-gas microspheres dispersed in the oil phase. The radius of the water-in-gas microspheres is 15~50μm. The oil phase in the oil-in-water-in-gas emulsion is removed, and then the resulting water-in-gas microspheres are mixed with a composite hydrogel solution to obtain a 3D printing ink. The volume fraction of the water-in-gas microspheres in the 3D printing ink is 5-40%. The 3D printing ink was sequentially subjected to 3D extrusion printing and physical gelation to obtain a double negative acoustic metagel material.

2. The preparation method according to claim 1, characterized in that, The gas phase includes air, nitrogen, or an inert gas; The aqueous phase includes a first gel material and water, wherein the first gel material includes chitosan, sodium alginate, polyvinyl alcohol, polyethylene glycol diacrylate, or methacrylated gelatin. The oil phase includes silicone oil.

3. The preparation method according to claim 2, characterized in that, The oil-in-water-in-gas emulsion was prepared in a multiphase flow microfluidic system. The multiphase flow microfluidic system includes a tubular body. Along the material flow direction, a gas phase inlet, a water phase inlet, and an oil phase inlet are sequentially arranged on the tubular body. An oil phase microchannel communicating with the oil phase inlet is arranged inside the tubular body. A water phase microchannel communicating with the water phase inlet is arranged inside the oil phase microchannel. A gas phase microchannel communicating with the gas phase inlet is arranged inside the water phase microchannel. The radii of the gas phase microchannel, water phase microchannel, and oil phase microchannel are in the range of 5~500μm, and the radius of the gas phase microchannel is smaller than the radius of the water phase microchannel, while the radius of the water phase microchannel is smaller than the radius of the oil phase microchannel. When preparing the oil-in-water-in-gas emulsion, the flow rates of the gas phase, water phase and oil phase are independently 1~10 μL / min.

4. The preparation method according to claim 1, characterized in that, The composite hydrogel solution comprises a second gel material, an auxiliary curing material, and water; the concentration of the second gel material in the composite hydrogel solution is 10~20wt%, and the concentration of the auxiliary curing material is 1~5wt%.

5. The preparation method according to claim 4, characterized in that, The second gel material includes chitosan, sodium alginate, polyvinyl alcohol, polyethylene glycol diacrylate, or methacrylated gelatin, and the auxiliary curing material includes carrageenan, gelatin, or agar.

6. The preparation method according to claim 1, characterized in that, The 3D extrusion printing is performed at room temperature. The operating conditions for the 3D extrusion printing include: needle extrusion speed of 0.1~1mm / s, needle movement speed of 0.1~1mm / s; printing line spacing of <1mm, printing thickness of 1~3mm, and printing width of 4~6mm.

7. The double negative acoustic metagel material prepared by the preparation method according to any one of claims 1 to 6 comprises a gel matrix material and hollow microbubbles distributed in the gel matrix material, wherein the radius of the hollow microbubbles is 15 to 50 μm and the volume fraction of the hollow microbubbles in the double negative acoustic metagel material is 5 to 40%.

8. The application of the double negative acoustic metagel material of claim 7 in the preparation of ultrasound penetration imaging formulations, wherein the high acoustic impedance media suitable for the ultrasound penetration imaging formulations include muscle or skull.

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