CN117464993B

CN117464993B - Device and method for 3D printing gradient pore macroporous gelatin through multi-nozzle array

Info

Publication number: CN117464993B
Application number: CN202311349985.4A
Authority: CN
Inventors: 许忠斌; 苏铭洋; 黄兴; 宋晓波; 董贞运
Original assignee: Ningbo Linstant Polymer Materials Co ltd; Zhejiang University ZJU
Current assignee: Ningbo Linstant Polymer Materials Co ltd; Zhejiang University ZJU
Priority date: 2023-10-18
Filing date: 2023-10-18
Publication date: 2024-06-14
Anticipated expiration: 2043-10-18
Also published as: JP7751838B2; CN117464993A; JP2025069917A

Abstract

The present invention discloses a device and method for 3D printing of gradient pore macroporous gelatin with a multi-nozzle array. The device includes a 3D motion control module, a fluorinated liquid tank, a fluid focusing device and a mold. During the printing process, the mold is clamped on a slider of the 3D motion control module and is fully immersed in the fluorinated liquid tank. There are several independent bubble nozzles in the fluorinated liquid tank, and the bubble nozzles are respectively connected to fluid focusing devices of different sizes to generate bubbles of different sizes. The device and method for 3D printing macroporous gelatin of the present invention can realize the printing of macroporous gelatin with high internal phase and gradient pores across orders of magnitude, and coordinate the mold movement speed with the frequency and size of bubble generation in real time, thereby realizing precise regulation of the internal pores of the macroporous gelatin.

Description

Device and method for 3D printing gradient pore macroporous gelatin through multi-nozzle array

Technical Field

The invention belongs to the field of 3D printing macroporous hydrogel, and particularly relates to a device and a method for 3D printing gradient pore macroporous gelatin by using a multi-nozzle array.

Background

The macroporous hydrogel material refers to a composite porous material formed by further introducing macropores of micrometer to submillimeter scale outside the porous structure of the hydrogel polymer. Since the pore size of the hydrogel material itself is typically on the order of nanometers to micrometers, these additional incorporated micrometer to submillimeter scale pores are generally referred to in the art as macropores. In the past, macropores are generally introduced into the hydrogel through a foaming method, a pore-forming method, a freeze drying method, a phase separation method and the like, but the macropores with uncontrollable cell sizes and positions are often introduced into the hydrogel through the methods. And the 3D printing technology and the microfluidic template method are combined, so that the size and the position of the macropores introduced into the hydrogel can be well controlled.

The 3D printing controllable macroporous hydrogel mainly has two modes: one is to introduce the oil phase droplet which is prepared by the microfluidic template method and is insoluble with the hydrogel solution into the hydrogel solution, solidify the hydrogel after introducing the oil phase droplet, remove the oil phase droplet, thereby leaving the cells in the hydrogel, and control the size and position of the macropores after the hydrogel is molded by regulating the size and position of the oil phase droplet; the other is to introduce bubbles prepared by a microfluidic template method directly into the hydrogel solution, and after curing the hydrogel, cells are left in the hydrogel. At present, the hydrogel containing oil phase liquid drops or bubbles is deposited and stacked layer by layer on a hot bed to prepare a final required product, however, the pore size adjustment range of the 3D printing method is often smaller, the size and the position of the internal pores of the macroporous hydrogel are difficult to precisely control, and especially when the number of printing layers is large, the size and the position of the internal pores of the macroporous hydrogel are easy to be misplaced and collapsed. In addition, the 3D printing method can only prepare macroporous hydrogel with the porosity of about 65% at most, and when the porosity is continuously improved, the hydrogel is difficult to form in the printing process.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a device and a method for 3D printing gradient pore macroporous gelatin by using a multi-nozzle array, and can be expanded to 3D printing production of other types of hydrogels. The bubbles prepared by a microfluidic template method are deposited in the gelatin solution through buoyancy, the sizes and the generation frequencies of the die and the bubbles are matched, dislocation of the pore positions and collapse of macroporous gelatin are avoided to a great extent, preparation of macroporous gelatin with higher porosity can be realized, and preparation of macropores with different magnitudes is realized by arranging a plurality of bubble spray heads with the bubble sizes and the generation frequencies being finely adjustable within a certain range and larger difference between the bubble spray heads in a liquid tank.

The aim of the invention is achieved by the following technical scheme:

a device for 3D printing gradient pore macroporous gelatin with a multi-nozzle array comprises a 3D motion control module, a fluoridized liquid tank, a fluid focusing device and a die;

The fluorination liquid tank and the die are both fixed on a cuboid frame of the 3D motion control module; the fluoride liquid tank comprises a hollow tank with an opening at the upper part and at least one bubble spray head fixed in the hollow tank, and the hollow tank is filled with fluoride liquid; the 3D motion control module drives the fluoride liquid tank to move in the Z-axis direction, and the 3D motion control module drives the die to move in the x-axis direction and the y-axis direction, so that the die can be immersed in the fluoride liquid tank in the 3D printing process, and bubbles sprayed out by the bubble spray head enter the die;

The bubble spray heads of the fluid focusing device are in one-to-one matching connection, and the bubble spray heads comprise a silicone oil injection device, an air injection device, a buffer tank, a three-way valve, a first thick capillary tube, a second thin capillary tube and a third thin capillary tube; the outer part of the first thick capillary tube is sealed and fixedly connected with the air inlet of the three-way valve; the second fine capillary tube is inserted into the first coarse capillary tube, and the outside of the second fine capillary tube is in sealing and fixing connection with the first coarse capillary tube; one end of the third thin capillary is also inserted into the first thick capillary, coaxially arranged with the second thin capillary, and the other end of the third thin capillary is communicated with the outlet of the three-way valve; one end of the second fine capillary tube is communicated with the air injection device; the gelatin solution inlet of the three-way valve is communicated with the outlet of the buffer tank through a gelatin solution conveying pipe, the buffer tank is filled with gelatin solution, and the inlet of the buffer tank is communicated with the outlet of the silicone oil injection device through a silicone oil conveying pipe; the outlet of the three-way valve is communicated with the bubble spray head in the fluoride liquid groove through a bubble input pipe, and bubbles generated by the fluid focusing device enter the die through the bubble input pipe and the bubble spray head.

Further, the device also comprises a hot bed, a hot bed support and a Z-axis screw nut device, wherein the hot bed is fixed on the 3D motion control module through the hot bed support, and the Z-axis screw nut device drives the hot bed support to move along the Z-axis direction; the liquid tank, the buffer tank and the three-way valve are all fixed on the hot bed, and the hot bed is used for synchronously heating the liquid in the liquid tank and the buffer tank.

Further, the buffer tank further comprises a strip-shaped groove plate, wherein a round groove and a strip-shaped groove are formed in the strip-shaped groove plate and are used for installing the buffer tank and the three-way valve respectively.

Further, the first thick capillary tube, the second thin capillary tube and the third thin capillary tube of each fluid focusing device are different in size, so that the size and the generation frequency of bubbles generated by each fluid focusing device are different, and the bubbles are released into the die through the bubble spray head.

Further, the fluoride liquid tank is made of transparent acrylic plates, and the bubble spray heads are vertically arranged in the fluoride liquid tank at equal intervals.

Further, all the pipeline joints are fixed by ultraviolet glue.

Further, the buffer tank further comprises a silicone oil inlet pipe and a gelatin solution outlet pipe which are fixed at the top of the buffer tank, wherein the silicone oil inlet pipe is shorter than the gelatin solution outlet pipe, the silicone oil inlet pipe is communicated with the silicone oil transportation pipe, and the gelatin solution outlet pipe is communicated with the gelatin solution transportation pipe.

Further, the fluid focusing device further comprises a three-way valve gelatin solution inlet pipe and a three-way valve bubble outlet pipe, one end of the three-way valve gelatin solution inlet pipe is inserted into the gelatin solution inlet of the three-way valve, the outside is glued by ultraviolet glue, and the other end of the three-way valve gelatin solution inlet pipe is communicated with the gelatin solution transportation pipe; one end of the three-way valve bubble outlet pipe is inserted into the outlet of the three-way valve, the outside is glued through ultraviolet glue, the other end of the third fine capillary pipe is inserted into the three-way valve bubble outlet pipe and fixed through ultraviolet glue, and the other end of the three-way valve bubble outlet pipe is connected with the bubble input pipe.

Further, the mold is a PDMS mold; the silicone oil injection device comprises a silicone oil injection pump and a silicone oil injector, and the air injection device comprises an air injection pump and an air injector.

A method of multi-jet array 3D printing gradient pore macroporous gelatin, the method being implemented based on a multi-jet array 3D printing gradient pore macroporous gelatin apparatus, the method comprising:

Step one: before printing, respectively debugging and measuring the range of gas flow and liquid flow which can enable each fluid focusing device to stably generate bubbles;

Step two: before printing, collecting data of a bubble size change range and a bubble generation frequency generated by each fluid focusing device;

step three: according to the internal macroporous distribution condition of the required product, setting the injection flow change condition of each silicone oil injection pump and the moving path and moving speed of the mould in the printing process, so that the moving speed of the mould is matched with the size and the generating frequency of bubbles; in the printing process, parameters of the injection pump are changed to control the liquid flow so as to control the generation frequency and the size of the bubbles in real time, and the moving speed of the mould is synchronously changed under the condition that the generation frequency and the size of the bubbles are changed, so that the position of the target bubble group is regulated and controlled.

The beneficial effects of the invention are as follows:

1. Compared with the traditional 3D printing method for depositing the gelatin solution containing oil phase liquid drops or bubbles layer by layer on a hot bed, the method provided by the invention has the advantages that the bubbles prepared by the microfluidic template method are deposited layer by layer from top to bottom in the mold filled with the gelatin solution through the action of floating force, firstly, the situation that the macroporous gelatin has shape deviation, collapse or even can not be molded under the condition of high porosity can be prevented; secondly, the size and the position of the pores in the macroporous gelatin can be controlled more accurately.

2. Compared with the traditional device for 3D printing of macroporous gelatin by using a single spray head, the device provided by the invention is communicated with the bubble spray heads in the fluoridized liquid tank by arranging a plurality of fluid focusing devices with different sizes, not only has the characteristic that the pore size of the macroporous gelatin can be regulated and controlled in a small range, but also can ensure that the pore size of the macroporous gelatin can be changed in a larger range even in a trans-order manner.

Drawings

Fig. 1 is a positive three-axis perspective view of the overall structure of the 3D motion control module and a schematic diagram of the positional relationship among the fluoride liquid tank 23, the three-way valve 26, the buffer tank 25 and the bar-shaped fixed slot plate 24.

Fig. 2 is a schematic diagram of the structure of the fluorinated liquid tank 23 and the bubble jet and bubble input pipe therein.

Fig. 3 is a schematic view of the structure of the bar-shaped fixing groove plate 24.

Fig. 4 is a schematic diagram of the buffer tank 25 and the three-way valve 26.

Fig. 5 is a schematic structural diagram of a reverse fluid focus device.

FIG. 6 is a schematic diagram of the connection between four reverse fluid focus devices and a bubble jet.

Fig. 7 is a schematic structural diagram of several simple PDMS molds.

Fig. 8 is a picture of bubbles continuously generated in a bubble jet photographed by a high-speed camera.

Fig. 9 is a schematic diagram of one of the motion paths of the bubble jet relative to the mold when printing cuboid macroporous gelatin in 3D.

In the figure, an aluminum profile 1, a right angle connector 2, a y-axis holder 3, a y-axis 4, an x-axis holder 5, a y-axis linear bearing 6, an x-axis 7, a slider 8, an x-axis linear bearing 9, a jig 10, an x-and y-axis stepper motor holder 11, a z-axis and stepper motor holder 12, a z-axis 13, a screw 14, a stepper motor 15, a coupling 16, a synchronizing wheel 17, a movable holder 18, a hot-bed holder 19, a z-axis linear bearing 20, a screw nut 21, a hot-bed 22, a fluorinated liquid tank 23, a strip-shaped fixed groove plate 24, a buffer tank 25, a three-way valve 26, a bubble jet 27, a bubble input tube 28, a silicone oil inlet tube 29, a gelatin solution outlet tube 30, a first coarse capillary 31, a second fine capillary 32, a gelatin solution inlet tube 33, a bubble outlet tube 34, a third fine capillary 35, an ultraviolet glue 36, a silicone oil injection pump 37, a silicone oil injector 38, an air injection pump 39, an air injector 40, a silicone oil transport tube 41, a gelatin solution transport tube 42, an air transport tube 43, a mold 44, a teflon tube one 45, and a teflon tube two 46.

Detailed Description

The objects and effects of the present invention will become more apparent from the following detailed description of the preferred embodiments and the accompanying drawings, it being understood that the specific embodiments described herein are merely illustrative of the invention and not limiting thereof.

The apparatus for 3D printing gradient pore macroporous gelatin with a multi-nozzle array of this embodiment includes a 3D motion control module, a fluorinated liquid tank 23, a fluid focusing device, and a mold 44.

As shown in fig. 1, the 3D motion control module (3D printer) includes a cuboid integral frame formed by an aluminum profile 1 and a right angle connecting piece 2, a right angle connecting piece is arranged between every two aluminum profiles to connect, two groups of four y optical axis brackets 3 are installed on four corners of the aluminum profile at the top of the cuboid frame, a y optical axis 4 is installed between each group of y optical axis brackets, two x optical axis brackets 5 are respectively installed on the two y optical axes through y axis linear bearings 6, two x optical axes 7 are installed between the x optical axis brackets, a clamp 10 is installed on a slide block 8, and the x optical axis is fixed through x axis linear bearings 9. The frame top is also provided with two stepping motor brackets 11, stepping motors for controlling the movement of the x and y axes are respectively arranged on the two brackets and are not marked in the drawing, and a synchronous belt is connected with a synchronous wheel 17 and an idle wheel through the synchronous belt so as to control the winding method of the synchronous belt in the movement drawing of the x and y axes, two groups of four z optical axis brackets 12 are respectively arranged on aluminum profiles on the two sides of the bottom and the top of the frame in a centering way, four z optical axes 13, two lead screws 14 and a stepping motor 15 for controlling the movement of the z axis are all fixed on the z optical axis brackets, the z axis stepping motor is connected with the lead screws through a coupler 16, two movable brackets 18 are connected with the z optical axis and the lead screws through a z axis linear bearing 20 and a lead screw nut 21, so that the movement in the z axis can be realized, a hot bed bracket 19 is fixed between the two movable brackets, and a hot bed 22 is fixed on the hot bed bracket. The fluoridation liquid tank 23 is filled with a proper amount of fluoridation liquid of model hfe-7500, and is placed on a hot bed, and the strip-shaped fixed tank plate 24 is provided with a detachable three-way valve 26 and a buffer tank 25 and is placed on the hot bed.

As shown in fig. 2, the structure of the fluorinated liquid tank 23, the bubble jet 27 and the bubble input pipe 28 is schematically shown, the fluorinated liquid tank is made of transparent acrylic material, and the bubble jet 27 and the bubble input pipe 28 are glass capillaries with the same inner diameter and slightly larger than the maximum size of the transported bubbles. The bubble input pipe 28 passes through the wall surface of the fluorinated liquid tank 23 and is fixed to the wall surface by ultraviolet glue. The bubble jet 27 is vertically fixed in the fluorinated liquid tank 23, and the bubble jet 27 and the bubble input pipe 28 are connected by a teflon pipe 45 of an appropriate size.

As shown in fig. 3, a schematic structure of the strip-shaped fixing groove 24 is shown, on which a circular groove and a strip-shaped groove for installing the buffer tank 25 and the three-way valve 26 are formed.

As shown in fig. 4, the buffer tank 25 and the three-way valve 26 are schematically constructed, the buffer tank 25 is initially filled with gelatin solution, and a silicone oil inlet pipe 29 and a gelatin solution outlet pipe 30 are provided thereon, and silicone oil is introduced into and discharged from the gelatin solution during operation. One of the inlets of the three-way valve 26 is connected to a thicker, thicker capillary tube 31, a thinner, thinner capillary tube 32 is provided within the thicker capillary tube for air input, the other inlet of the three-way valve is connected to a properly sized dispenser needle, the inlet is provided with a three-way valve gelatin solution inlet tube 33, the outlet of the three-way valve is also connected to a properly sized dispenser needle, the outlet is provided with a three-way valve bubble outlet tube 34, and a thinner capillary tube 35 is provided within the three-way valve 26, not shown here, and described in fig. 5.

As shown in fig. 5, which is a schematic structural principle of the fluid focusing device, the silicone oil inlet pipe 29 of the buffer tank 25 is a relatively short needle of the dispenser, and only needs to extend into the buffer tank 25, and the silicone oil inlet pipe is connected with the silicone oil injector 38 through a silicone oil transport pipe 41 made of teflon and having a size matched with that of the silicone oil inlet pipe, and the injection flow of the silicone oil injector 38 is controlled by the silicone oil injection pump 37. The gelatin solution outlet tube 30 of the buffer tank 25 is a longer dispenser needle extending into the bottom of the buffer tank, and the gelatin solution outlet tube 30 is connected to the gelatin solution inlet tube 33 of the three-way valve 26 by a gelatin solution transport tube 42 of teflon and of a size matching the gelatin solution outlet, and the gelatin solution inlet tube 33 of the three-way valve is a dispenser needle bonded to one of the three-way valve holes by ultraviolet glue. The other inlet of the three-way valve 26 is adhered with a thicker glass capillary tube called a first thick capillary tube 31 through ultraviolet glue 36, the inside of the first thick capillary tube 31 is adhered with a second thin capillary tube 32 through ultraviolet glue, the first thick capillary tube 31 is connected with an air injector 40 through an air transportation tube 43 made of Teflon, and the injection flow of the air injector 40 is controlled by an air injection pump 39. The bubble outlet pipe 34 of the three-way valve 26 is adhered to the outlet of the three-way valve through ultraviolet glue, and a third fine capillary tube 35 with the same size as the second fine capillary tube 32 is adhered to the inside of the bubble outlet pipe 34 through ultraviolet glue. The gelatin solution transported by the gelatin solution inlet flows into the first thick capillary tube 31, and cuts air transported by the second thin capillary tube 32 at the orifice of the third thin capillary tube 35 to generate bubbles, and the bubbles and the gelatin solution are transported into the bubble outlet of the three-way valve through the third thin capillary tube 35.

As shown in fig. 6, which is a schematic diagram of the connection relationship between the four fluid focusing devices and the bubble jet 27, the bubble outlet tube 34 of the fluid focusing device is connected to the bubble inlet tube 28 through a teflon tube two 46.

For ease of observation, the mold 44 of this embodiment is a PDMS mold. As shown in fig. 7, which is a schematic structural view of several simple PDMS molds, each of the two sides of the PDMS mold has a square hole, and the jig 10 can be inserted into the square hole to fix the PDMS mold. The hollow part in the middle of the PDMS mould is the region where the 3D printing of macroporous gelatin is carried out, and is also the overall shape of the final product, i.e. the shape of the hollow part of the PDMS mould is determined by the shape of the required macroporous gelatin.

In another aspect, the embodiment provides a method for 3D printing gradient pore macroporous gelatin by using a multi-nozzle array based on the device, which comprises the following steps:

The following is an example of 3D printing of cuboid macroporous gelatin, and illustrates a method for using the device for 3D printing gradient pore macroporous gelatin by using a multi-nozzle array according to the invention:

S1: before printing is performed, data of a bubble size variation range and a bubble generation frequency generated by each fluid focus device need to be acquired. The collecting method is that a fluid focusing device is connected to a bubble spray head 27, a silicone oil injection pump 37 and an air injection pump 39 are started at a certain temperature, namely the temperature in the subsequent printing process, and a high-speed camera is used for shooting the condition that bubbles are generated in the bubble spray head at a fixed sampling frequency.

S2: the following describes data on how to take the bubble generation in the bubble jet head, as an example. A gelatin solution of 12.5% gelatin +0.2% sodium dodecyl sulfate +0.04% polyethylene oxide was prepared using silicone oil having a viscosity of 50 CS. If the first-size thick capillary tube 31 adopts a glass capillary tube with the inner diameter of 0.5mm, the second-size thin capillary tube 32 and the third-size thin capillary tube 35 adopt glass capillary tubes with the inner diameter of 0.1mm, the gelatin solution inlet tube 33 of the three-way valve, the silicone oil inlet light 29 of the buffer tank and the gelatin solution outlet tube 30 adopt a 20G dispensing machine needle, the injection flow rate of the silicone oil injection pump 37 can be changed within the range of 2-4mL/h under the condition that the injection flow rate of the air injection pump 39 is 3mL/h, so that the fluid focusing device can stably generate bubbles. Then, under the conditions of air flow rate of 3mL/h and silicone oil flow rates of 2,3 and 4mL/h, the high-speed camera is used for shooting the bubbles generated in the bubble nozzle at a fixed sampling frequency, and one sampling picture is shown in FIG. 8. The size data of the bubbles obtained by the analysis are shown in table 1, and the generation frequency data of the bubbles are shown in table 2:

TABLE 1 bubble size data

Number (air flow-silicone oil flow)	Average bubble size	Standard deviation of
			3mL/h-2mL/h	0.448mm	0.00563mm
3mL/h-3mL/h	0.397mm	0.00106mm
			3mL/h-4mL/h	0.336mm	0.00592mm

TABLE 2 bubble generation frequency data

Air flow rate

Flow rate of silicone oil

Total number of pictures

Picture interval

Number of bubbles

Duration of time

Frequency of

3mL/h

2mL/h

141

10ms

18.5

1400ms

75.67568 Ms/min

3mL/h

151

10ms

18.5

1500ms

81.08108 Ms/min

3mL/h

4mL/h

129

10ms

13

1280ms

98.46154 Ms/min

S3: and collecting size data and generation frequency data of bubbles generated by each reverse fluid focusing device according to the step S2.

S4: before printing starts, the injection flow rate change condition of each silicone oil injection pump 37, including the size of the injection flow rate and the time node of the change, is set in the injection pump flow rate control software of the upper computer according to the internal macroporous distribution condition of the required product. The path of movement and speed of movement of the die 44 during printing is related to the internal macropore distribution of the desired product, and further, the speed of movement of the die needs to be matched to the bubble size and frequency of generation. If the movement path of the shower head is set as shown in fig. 9, the relation between the movement speed of the PDMS mold, the bubble size and the generation frequency is further calculated:

the width of the hollow area in the PDMS mould is recorded as b (mm), the diameter of the bubble is recorded as d (mm), the generation frequency is F (ms/min), the time required for filling a certain cuboid area by the bubble on the moving path is recorded as t(s), the total moving distance of the PDMS mould in the t time is recorded as s (mm), the moving distance of the PDMS mould on the long side is recorded as x (mm), and the moving speed of the nozzle is recorded as F (mm/min):

t＝xbf/1000d²

s＝x(b/d+1)

F＝s/t＝60000d(b+d)/bf

That is, in the Gcode of the 3D motion control module, the relation between the PDMS mold moving speed and the bubble size and the generation frequency was calculated, for example, when the air flow rate and the silicone oil flow rate were both 3mL/h, the bubble size was 0.397mm, the bubble generation frequency was 81 ms/each, and the broadside b was assumed to be 20mm, and at this time, the corresponding head moving speed was calculated to be 302mm/min.

S5: a gelatin solution of 12.5% gelatin +0.2% sodium dodecyl sulfate +0.04% polyethylene oxide was formulated and the x, y, z axes of the 3D motion control module were zeroed. A fluorination liquid tank 23 and a strip-shaped fixed tank plate 24 are mounted on the hot bed 22, and a proper amount of hfe-7500 fluorination liquid is poured into the fluorination liquid tank. A buffer tank 25 filled with gelatin solution in advance and a three-way valve 26 were mounted on the bar-shaped fixed groove plate 24, and the respective channels were connected by teflon tubes in the manner of connection of the drawings. And opening the heating functions of the hot bed and the temperature control box to slowly heat the fluoridized solution and the gelatin solution in the buffer tank to a preset temperature, wherein the step is to control the printing environment in the whole process and the temperature of the gelatin solution in the 3D printing process.

S6: the gelatin solution is filled in the mold 44 and then cooled in a refrigerator at 4 ℃ until the gelatin is gelled, then the mold is clamped on the clamp 10, and the x, y and z axis positions of the 3D motion control module are adjusted to submerge the mold in the fluoride liquid tank, so that the gelled gelatin in the mold can prevent the PDMS mold from entering bubbles during submerging. After the mold is immersed in the liquid bath, the gelatin in the mold is slowly heated to the same temperature as the printing environment, and the silicone oil injection pump 37 and the air injection pump 39 are turned on during the waiting, and after a while, the bubble jet 27 starts to generate bubbles and continues to input into the fluorinated liquid.

S7: and starting the flow control software of the injection pump to control the flow change of the silicone oil injection pump 37, and starting the G code of the 3D motion control module to perform 3D printing until printing is completed, wherein the mold is still immersed in the fluoride liquid tank when printing is completed. In the printing process, because each layer of the 3D printing is formed by more bubbles, the porosity is high, and the bubbles cannot move in the gelatin solution in the die.

S8: and stopping the temperature control box and the hot bed heating device of the 3D motion control module, cooling at room temperature and waiting for gelatin gelation in the PDMS mold, and accelerating the cooling process of gelatin by replacing the overheated hfe-7500 in the fluoridation liquid tank with the pre-frozen hfe-7500.

S9: and adjusting the x, y and z axis positions of the 3D motion control module, taking out the mould, putting the mould and the gelatinised gelatin therein into a freeze dryer for freeze drying, slightly shrinking the gelatinised gelatin after freeze drying, and automatically falling off from the mould.

It will be appreciated by persons skilled in the art that the foregoing description is a preferred embodiment of the invention, and is not intended to limit the invention, but rather to limit the invention to the specific embodiments described, and that modifications may be made to the technical solutions described in the foregoing embodiments, or equivalents may be substituted for elements thereof, for the purposes of those skilled in the art. Modifications, equivalents, and alternatives falling within the spirit and principles of the invention are intended to be included within the scope of the invention.

Claims

1. The device for 3D printing of gradient pore macroporous gelatin by using the multi-nozzle array is characterized by comprising a 3D motion control module, a fluoridized liquid tank, a fluid focusing device and a die;

2. The device for 3D printing gradient pore macroporous gelatin with a multi-nozzle array according to claim 1, further comprising a thermal bed, a thermal bed support and a Z-axis screw nut device, wherein the thermal bed is fixed on the 3D motion control module through the thermal bed support, and the Z-axis screw nut device drives the thermal bed support to move along the Z-axis direction; the liquid tank, the buffer tank and the three-way valve are all fixed on the hot bed, and the hot bed is used for synchronously heating the liquid in the liquid tank and the buffer tank.

3. The device for 3D printing gradient pore macroporous gelatin with a multi-nozzle array according to claim 2, further comprising a strip-shaped groove plate, wherein the strip-shaped groove plate is provided with a circular groove and a strip-shaped groove, and the circular groove and the strip-shaped groove are respectively used for installing the buffer tank and the three-way valve.

4. The apparatus for 3D printing gradient pore macroporous gelatin of claim 1, wherein the size of the first coarse capillary, the second fine capillary and the third fine capillary of each of the fluid focusing devices is different, such that the size and the generation frequency of bubbles generated by each of the fluid focusing devices are different and released into the mold through the bubble jet.

5. The apparatus for 3D printing gradient pore macroporous gelatin with multiple spray head arrays according to claim 1, wherein the fluorination liquid tank is made of transparent acrylic plate, and the bubble spray heads are vertically installed in the fluorination liquid tank at equal intervals.

6. The apparatus for 3D printing gradient pore macroporous gelatin with multiple nozzle arrays of claim 1, wherein all pipe joints are fixed by uv glue.

7. The apparatus for 3D printing gradient pore macroporous gelatin with a multi-jet array of claim 1, wherein the buffer tank further comprises a silicone oil inlet tube fixed on top of the buffer tank, a gelatin solution outlet tube, the silicone oil inlet tube being shorter than the gelatin solution outlet tube, the silicone oil inlet tube being in communication with the silicone oil transport tube, the gelatin solution outlet tube being in communication with the gelatin solution transport tube.

8. The device for 3D printing gradient pore macroporous gelatin with multi-nozzle array according to claim 1, wherein the fluid focusing device further comprises a three-way valve gelatin solution inlet pipe and a three-way valve bubble outlet pipe, one end of the three-way valve gelatin solution inlet pipe is inserted into the gelatin solution inlet of the three-way valve, the outside is glued by ultraviolet glue, and the other end is communicated with the gelatin solution transport pipe; one end of the three-way valve bubble outlet pipe is inserted into the outlet of the three-way valve, the outside is glued through ultraviolet glue, the other end of the third fine capillary pipe is inserted into the three-way valve bubble outlet pipe and fixed through ultraviolet glue, and the other end of the three-way valve bubble outlet pipe is connected with the bubble input pipe.

9. The apparatus for 3D printing gradient pore macroporous gelatin with multi-jet array of claim 1, wherein the mold is a PDMS mold; the silicone oil injection device comprises a silicone oil injection pump and a silicone oil injector, and the air injection device comprises an air injection pump and an air injector.

10. A method of multi-jet array 3D printing gradient pore macroporous gelatin, characterized in that the method is implemented based on the device of multi-jet array 3D printing gradient pore macroporous gelatin as claimed in any one of claims 1 to 9, characterized in that the method comprises: