CN110171131A - A kind of biomaterial for light-operated 3D printing - Google Patents

Abstract

The present invention provides a kind of for light-operated 3D printing biomaterial, it can be used as the raw material of 3D printing, or a kind of basic material that can be processed by 3D printer, it is processed by way of similar printing, and a kind of tissue or organ with labyrinth is formed, it is used directly for various uses.It include the macromolecular of photoresponse crosslinked group modification, the macromolecular of adjacent nitro benzyl class light trigger modification, photoinitiator for light-operated 3D printing biomaterial.

Description

A biomaterial for light-controlled 3D printing

technical field

The present invention relates to a 3D printing system, as well as biological materials used for printing.

Background technique

It is well known that there is a large clinical need for engineered tissues due to the shortage of donor tissues and organs. Although many approaches have been tried to create engineered tissues, such as electrospinning, extrusion 3D printing and textile techniques. However, they can only produce relatively simple three-dimensional structures, which cannot meet the needs of clinical applications. Therefore, there is an urgent need to fabricate complex and layered tissue constructs with high resolution for clinical use. Recently, digital light processing (DLP)-based 3D printing technology has been used to fabricate complex 3D microstructures with high printing speed, microscale resolution, thick vertical structures, and strong interlayer bonding properties. It can simulate the precise geometry of native tissue to create complex 3D vascularized tissue, which is a huge step in the field of tissue engineering.

3D printing technology is actually a rapid prototyping device using technologies such as light curing and paper lamination. The design process of 3D printing is: first establish a three-dimensional model through computer modeling software, then slice the abbreviated three-dimensional model into layer-by-layer sections, and then guide the printer to print layer by layer.

At present, in the medical field, the methods of printing living tissues include: DLP photocuring printing and extrusion printing. DLP photo-curing printing equipment includes a liquid tank that can hold resin, which is used to hold resin that can be cured after being irradiated by ultraviolet light of a specific wavelength. The DLP imaging system is placed under the liquid tank, and its imaging surface is just at the bottom of the liquid tank. Through energy and graphics control, a thin layer of resin with a certain thickness and shape can be cured each time (this layer of resin is exactly the same as the cross-sectional shape obtained by the previous cutting). A lifting mechanism for lifting the tray is set above the liquid tank, and the tray is stepped to form a layer-thick molding surface between the tray (or formed layer) and the liquid tank. After each cross-sectional exposure is completed, it is pulled up to a certain height (The height is consistent with the thickness of the layer), so that the currently cured solid resin is separated from the bottom of the liquid tank and bonded to the lifting plate or the last formed resin layer, so that a three-dimensional entity is generated by exposing and lifting layer by layer . For DLP 3D printers, the optical system is fixed, and the optical system only completes the printing of one layer thickness at a time. Generally, the method of first raising and then lowering is adopted, that is, if printing with a layer thickness of 0.1mm, first raise it by 5mm, and then lower it by 4.9mm. Each molding surface is on the liquid surface, and the model is immersed in the liquid after molding. However, this method also has problems. The surface tension of the material liquid will affect the thickness of the forming layer and the forming effect. Moreover, each molding surface is on the liquid level, so the liquid tank needs to be filled every time printing, even if the actual material volume of the entity to be formed is much smaller than the volume of the liquid tank, the liquid tank must be filled to ensure each printing The molding surface is on the liquid surface; and the remaining material liquid cannot be used again after molding. In addition, the lifting mechanism of DLP photocuring printing is also immersed in the material liquid, and in order to make the molding surface at the liquid level each time, it is necessary to balance the volume difference caused by the sinking of the lifting mechanism, so a balance block is also installed in the liquid tank to lift The mechanism, balance weight and tray are all located in the liquid tank, and the lifting mechanism and balance weight occupy the cross-sectional area of the liquid tank, resulting in an effective forming area (tray area) smaller than the cross-sectional area of the liquid tank, and the effective forming area is small.

The existing artificial soft tissue preparation method of extrusion and photocuring composite molding includes the following steps: 1. Modeling the artificial soft tissue to obtain the artificial soft tissue model; 2. Processing the contour of each layer in the artificial soft tissue model: using 3D The printing layering software calculates the contour information of each layer in the artificial soft tissue model, and generates the contour information into the running path of the extrusion nozzle; 3. Prepare the photocuring composite solution: first make living cells, growth factors and collagen solution Mix to obtain a mixed solution, then inject a photocurable hydrogel into the mixed solution, and then add a visible light photoinitiator to obtain a hydrogel composite that can maintain a certain shape; 4. The photocurable composite solution prepared in step 3 is Raw materials, 3D printer is used for artificial soft tissue preparation: 4-1, control the hydraulic extrusion head to extrude the hydrogel compound on the working platform according to the running path, forming a semi-solidified colloid layer; 4-2, carry out the colloid layer Light curing to obtain a cured layer. The hydraulic extrusion head is fixedly connected with the light curing head. When the hydraulic extrusion head is in working condition, the light curing head is closed; working status.

The disadvantages of this biological tissue molding method are as follows: 1. No matter it is DLP method or extrusion method, multiple materials cannot be used to cooperate to complete the molding task of a biological tissue, so the mixed processing of multiple materials cannot be realized. However, the active organism is a heterogeneous mixed system containing multiple structures and various material components, and the above-mentioned method cannot complete the formation of the heterogeneous mixed system. 2. The feeding and molding speed of DLP is fast, but there is a lot of wasted material liquid, and the one-time use rate of the material liquid is low. This also requires an improved design of the existing traditional printing, hoping to print bioactive materials with more complex structures.

So far, many materials including natural polymers: collagen, silk fibers, gelatin, alginate and synthetic polymers: polyethylene glycol (PEG) have been used for extrusion 3D printing, and these are used as materials for bio-3D printing, also called For "bio-ink". However, some of them exhibit poor mechanical properties or slow gel times, limiting their applications in DLP-based 3D printing.

Meanwhile, to address this issue, hybrid hydrogel-based biohydrogels with tunable mechanical properties and fast gelation are required. It is necessary to provide some improved bio-inks, which are suitable for printing complex biomaterials and meet actual needs.

Contents of the invention

On the one hand, one of the purposes of the present invention is to provide a 3D printing system that can realize alternate feeding of multiple materials and a non-uniform mixing system.

A 3D printing system, including an optical system, a feeding mechanism, a lifting platform and a cavity; the lifting platform and the cavity form a space for receiving incoming materials from the feeding mechanism, and the lifting platform is independent from the feeding mechanism; each time printing, the lifting platform is opposite to the optical system stepping.

The lifting platform steps one layer thickness at a time, and the purpose of stepping the lifting platform is to enable the optical system to focus on the layer to be formed and realize light curing. The feeding mechanism is outside the optical system, and the material liquid of the feeding mechanism is outside the light-curing area of the optical system. During printing, the light-curing can be carried out without shifting the material liquid. The independence of the lifting platform and the feeding mechanism means that the lifting platform is not integrated with the feeding mechanism, but is an independent mechanism. material.

optical system

The optical system adopts the optical imaging system of DLP technology, and the exposure area of the optical system is the same as the profile to be formed of each layer. Real-time imaging exposure can be carried out according to the cross-sectional graphics of different molding layers. The exposed area is irradiated on the liquid material, and the liquid material is solidified and formed, and the unirradiated area is still liquid.

Lifting platform

In some preferred modes, the lifting platform is a platform that can be lifted independently. The lifting platform accepts the feeding of the feeding mechanism. It does not directly cause the feed liquid to flow into the platform. The lifting platform is in the light-curing area of the optical system, and the material liquid in the lifting platform receives the light of the optical system to complete the light-curing molding.

In some preferred solutions, the optical system is on the lifting platform. Every time printing, the lifting platform steps down. Preferably, the lifting platform includes a piston, the piston is located in the cavity, the piston receives the material supply, and the piston is driven step by step by the platform driving member.

Preferably, the platform drive is located below the piston. Preferably, the upper surface of the piston is in contact with the feed liquid. In some preferred solutions, the platform driver is fixed to the bottom of the piston, the platform driver includes a drive motor, a screw mechanism and a slider, the screw is connected to the drive motor, the nut is fixed to the slider, and the slider is connected to the piston. The screw mechanism converts the torque of the driving motor into linear movement, and the slider moves the piston downward or upward, and the cavity serves as a guide for the piston movement. The platform driving part does not occupy the contact area and space between the piston and the material liquid, and all areas of the upper surface of the piston are effective areas that can be used for photocuring.

cavity

In some preferred manners, the chamber is used to accommodate feed liquid or bio-ink, or biomaterials, and the lifting platform moves up and down in the chamber. For each printing, the material liquid is added into the cavity, and when the material liquid level in the cavity reaches the layer thickness requirement, the optical system performs light curing.

In some preferred solutions, the printing system includes a frame, and the cavity is fixed on the frame. Preferably, the cavity is formed by a through hole provided on the block body, and the block body is fixed on the bracket. Preferably, the cross section of the cavity is a rectangle, or a square, or a circle, or an ellipse or other conventional shapes. Preferably, the block body is provided with channels or slots for receiving platform drives. The slide block of the platform driving part can move up and down in translation without interference in the channel or groove of the block body. Preferably, the block body is a rectangular plate, or a square plate, or a circle, or an ellipse or other conventional shapes.

supply

The feeding mechanism feeds the lifting platform, and the amount of each feed is basically equal to the amount of liquid required for forming the current layer. The so-called basically equal means that the amount of material supplied can meet the amount of material liquid required for molding, and the liquid level and layer thickness are within the effective curing range, not absolutely equal in the mathematical sense.

In some preferred solutions, the feeding mechanism has a feeding unit, and the feeding unit has its own barrel, feeding rod, discharge nozzle and quantitative driving mechanism, and the feeding rod is connected to the quantitative driving mechanism. The feeding rod pushes the material liquid in the barrel to be extruded from the discharge nozzle, and the discharge nozzle drips the material liquid onto the lifting platform.

Preferably, the quantity of the supply unit is one, or the quantity of the supply unit is multiple. Multiple means that the number of feeding units is ≥2.

The feeding method is controlled by the controller, which controls the feeding of the quantitative driving mechanism. Preferably, a certain feeding unit is designated to feed, or multiple feeding units alternately implement the feeding-photocuring process. For example, there are two units, the first feeding unit and the second feeding unit. The first feeding unit feeds and cures light, the lifting platform steps once, the second feeding unit feeds and cures light; the lifting platform steps Once, feeding and photocuring by the first feeding unit, ... In this way, multiple feeding units alternately perform feeding-photocuring. In this case, the primary feeding amount of each feeding unit meets the amount of material liquid required for the current layer forming.

Preferably, the alternate feeding is sequential feeding of multiple units, or cross feeding of different feeding units. In the case of sequential feeding, for example, there are the first feeding unit, the second feeding unit and the third feeding unit, and the feeding is in the order of the first, second, and third—photocuring. Different units cross-feed, such as the first supply unit, the second supply unit and the third supply unit, the first supply unit supplies - light curing, the second supply unit supplies - light curing, and then the second supply unit One supply unit supplies material - light curing, and the third supply unit supplies material - light curing, as long as the two feedings before and after are completed by different units.

Alternatively, multiple feeding units feed materials at the same time, and then photocure after the feeding is completed. For example, there are two units, the first feeding unit and the second feeding unit, and the first feeding unit and the second feeding unit feed at the same time, and the sum of the feeding volumes of all units meets the amount of material liquid required for the current layer forming , After the feeding is completed, light curing is carried out. The feeding positions of the two units are the same or different.

Alternatively, one or more feeding units feed first, and the other one or more feeding units feed after the first feeding is completed, and then photocure after all the feeding units complete feeding. For example, there are two units, the first feeding unit and the second feeding unit. The first feeding unit feeds first, and the second feeding unit feeds after the first feeding unit finishes feeding. All units The total amount of material supplied meets the amount of material liquid required for the current layer forming, and light curing is carried out after the material supply is completed. The dripping position of the unit that feeds later can be the same as that of the unit that feeds first, or the position can be different.

Alternatively, one or several molding stages adopt designated feeding unit for feeding, one or several molding stages adopt multi-unit simultaneous feeding, and one or several molding stages adopt multi-unit alternate feeding.

Or, designate a certain supply unit to feed, and other units to suspend work. In this way, printing of a single material is formed.

Quantitative drive mechanism

The quantitative driving mechanism is used to quantitatively push the feeding rod, control the quantitative driving mechanism, and realize the control of the feeding method. In some preferred solutions, the quantitative driving mechanism includes a feeding driving member, which is connected with the feeding rod. Preferably, the feeding driving part includes a clamp, and the feeding rod is clamped on the clamp to realize the connection between the feeding driving part and the feeding rod. When the gripper releases the feed rod, the feed rod disengages from the feed drive. The feeding drive adopts motor and transmission mechanism (such as screw mechanism), electric push rod, cylinder and so on.

Preferably, each cartridge has its own cartridge holder, and the cartridge is fixed on the cartridge holder. Preferably, the cartridge holder includes a fixed part and a movable part, the movable part is connected to the cartridge, and there is a locking piece between the movable part and the fixed part. After the movable part is displaced relative to the fixed part, the installation height of the barrel is raised. Preferably, multi-stage screw holes are provided in the height direction of the movable part, screw holes are provided in the fixed part, and the locking parts are screws or bolts and nuts. Each level of screw holes corresponds to an installation height. Preferably, the height direction of the fixing part is provided with multi-stage screw holes. Thereby increasing the installation height adjustment range of the barrel. The distance between the two-stage screw holes of the fixed part can be different from the distance between the two-stage screw holes of the movable part, so that there is differential step adjustment.

position adjustment mechanism

The position adjustment mechanism is used to adjust the position of the feeding mechanism, so that the feeding mechanism can drop the material liquid on the designated position of the lifting platform. In some preferred solutions, the 3D printer includes a position adjustment mechanism, and the feeding mechanism is installed on the position adjustment mechanism. Each feeding unit has an independent position adjustment mechanism. Alternatively, all feeding units are mounted on the same position adjustment mechanism. Alternatively, certain feeding units are installed on the same position adjustment mechanism, and the rest of the feeding units are installed on another position adjustment mechanism.

Preferably, the position adjustment mechanism includes a base, a position adjustment driver located on the base, and a position adjustment slider. The position adjustment slider is sloped, and one end of the slope near the lifting platform is lower and the other end is higher. The existence of the slope makes the material liquid in the barrel bear a certain gravity, avoiding the material liquid remaining in the nozzle, and maintaining the accuracy of the material liquid amount during feeding. Preferably, the position adjustment slider cooperates with the position adjustment guide rail, and the position adjustment limit switch is arranged on the base. The position adjustment limit switch limits the displacement interval of the position adjustment slider. The position adjustment driving parts use motors, cylinders, electric push rods and the like.

Preferably, the cartridge frame is fixed to the position adjustment slider. Adjust the installation height of the barrel so that the axis of the barrel is in line with the thrust direction of the quantitative drive mechanism.

drainage

In multi-material printing tasks, sometimes it is necessary to drain the first material liquid before adding the second material liquid. In some preferred solutions, the printing system has a liquid discharge mechanism. Preferably, preferably, the piston fits in a gap with the chamber, and the gap between the piston and the chamber serves as a drainage groove. When feeding, the amount of feed liquid is large, and the gap between the piston and the cavity is not discharged from the gap due to the surface tension of the feed liquid. After one photocuring, the amount of material liquid becomes very small, and the uncured liquid can be drained from the liquid drainage tank.

Alternatively, the piston is in sealing fit with the chamber, and the liquid discharge mechanism is a liquid suction pipe. When liquid needs to be drained, the suction tube extends into the non-forming area to suck up the remaining liquid. Preferably, the suction tube is installed on the liquid suction driving mechanism, and the liquid suction driving mechanism reciprocates to make the suction tube enter or withdraw from the cavity. Preferably, the suction pipe is connected with a negative pressure device. Rely on negative pressure to suck away the residual material liquid.

After the former feed liquid is drained, another feed liquid is added to avoid mutual influence and interference between the front and rear feed liquids.

In another aspect, the present invention provides a 3D printing method, the method comprising:

1) Prepare the 3D printing system and the material liquid, input the printing task, put the material liquid into the material cylinder that undertakes the material supply task, and install the material cylinder in place;

2), the lifting platform descends a layer thickness in the cavity;

3) The barrel feeds the material into the cavity, and the material liquid fills the space surrounded by the lifting platform and the cavity;

4) The optical system cures the material liquid by light to complete the curing of the current layer of material liquid.

In some solutions, when the printing job uses only one material for printing, after step 3), steps 2)-4) are repeated until the printing job is completed. The feeding mechanism provides enough material liquid for one layer of printing each time, so that the material liquid layer is always within the photocuring range of the optical system. There is no liquid drainage between the upper and lower layers, or after the previous layer thickness is solidified, the residual material liquid is drained away, but when feeding the next time, the amount of material liquid can satisfy the material liquid layer within the focus range of the optical system. How much material liquid is needed for the current printing layer, and the unsupplied material liquid is stored in the barrel, which can still be used for other printing tasks and improve the utilization rate of one feeding.

Moreover, when a cantilever or cantilever structure appears between the upper and lower layers, the material liquid is completely filled with the previous printing layer, and the buoyancy of the material liquid supports the cantilever or cantilever solidified in the current layer, avoiding the collapse of the cantilever or cantilever, and can form no cantilever (or cantilever) Cantilever) collapses and deforms the hollow structure, and the hollow structure increases the attachment area of active substances (such as cells).

In some schemes, after step 4), enter step 5A) to determine whether the current layer needs to use another material liquid to complete the printing task, if not, the lifting platform is lowered by one layer thickness, and the printing of the next layer is prepared; if so, then Drain the liquid and keep the lifting platform at the current floor position. In some schemes, when the current layer needs another material liquid to complete the printing of other structures, after the liquid is drained and the lifting platform is in the correct position, the feeding mechanism equipped with the specified material supplies material to the lifting platform. After the liquid supply is completed, the optical The system photocures the material liquid, and repeats step 5A) until the current layer is completed.

When performing the current layer, go to step 5A).

In some schemes, after step 4), enter step 5B), judge whether the next layer and the current layer use the same material, if not, then repeat steps 2)-5); if so, drain the liquid and keep the lifting platform at At the position of the current layer, the feeding mechanism equipped with the specified material supplies the material to the lifting platform. After the liquid supply is completed, the optical system will light-cure the material liquid.

After the printing task of the current layer is completed, go to step 5B).

Preferably, the method for keeping the elevating platform at the current position includes: after printing one layer, the elevating platform does not descend; or, after printing one layer, the elevating platform descends by one layer thickness; and then resets the elevating platform upward by one layer thickness. Drain the liquid first, and then keep the lifting platform at the current floor position, or first keep the lifting platform at the current floor position, and then drain the liquid, or keep the lifting platform at the current floor position and drain at the same time.

On the other hand, another object of the present invention is to provide a biomaterial or bioink, which can be used as a raw material for 3D printing, or a basic material that can be processed by a 3D printer, and can be processed in a manner similar to printing to form A tissue or organ with a complex structure that can be used directly for various purposes.

The purpose of the present invention is to provide a light-controlled 3D printing bio-ink and its application, which can improve the problems of poor mechanical properties and slow gelation time of existing 3D printing bio-inks.

The technical scheme adopted in the present invention is:

The invention provides a light-controlled 3D printing bio-ink. The glue is composed of a macromolecule modified by a photoresponsive crosslinking group, a macromolecule modified by an o-nitrobenzyl phototrigger, a photoinitiator and deionized water; The final mass concentration of the macromolecule modified by the photoresponsive cross-linking group and the macromolecule modified by the o-nitrobenzyl phototrigger is 0.1% to 10% in terms of deionized water mass, and the final mass concentration of the photoinitiator is deionized. The mass of ionic water is 0.001-1%; the graft substitution rate of the photo-responsive cross-linking group in the macromolecule modified by the photo-responsive cross-linking group is 10-90%, and the photo-responsive cross-linking group is methacrylic acid Amide, methacrylic anhydride, glycidyl methacrylate or acryloyl chloride; the graft substitution rate of the o-nitrobenzyl phototrigger in the macromolecule modified by the o-nitrobenzyl phototrigger is 1 to 100% .

Further, the o-nitrobenzyl phototrigger modified macromolecule is shown in formula (I), in formula (I), R ₁ is -H or selected from -CO(CH ₂ )xCH ₃ , -CO( CH ₂ CH ₂ O) _x CH ₃ , -CO(CH ₂ ) _x (CH ₂ CH ₂ O) _y CH ₃ ester bonds, selected from -(CH ₂ ) _x CH ₃ , -(CH ₂ CH ₂ O ) _x CH ₃ , -(CH ₂ ) _x (CH ₂ CH ₂ O) _y CH ₃ , Ether linkages, carbonates selected from -COO(CH ₂ ) _x CH ₃ , -COO(CH ₂ CH ₂ O) _x CH ₃ , -COO(CH ₂ ) _x (CH ₂ CH ₂ O) _y CH ₃ Bonds, isocyanate bonds selected from -CONH(CH ₂ ) _x CH ₃ , -CONH(CH ₂ CH ₂ O) _x CH ₃ , -CONH(CH ₂ ) _x (CH ₂ CH ₂ O) _y CH ₃ , Wherein x and y≥0 and are integers; R ₂ is -H or selected from -O(CH ₂ ) _x CH ₃ , -O(CH ₂ CH ₂ O) _x CH ₃ , -O(CH ₂ ) _x (CH ₂ CH ₂ O) _y CH ₃ substituents, wherein x and y≥0 and are integers; R ₃ is selected from amino linkage -O(CH ₂ ) _x CONH(CH ₂ ) _y NH-, halogenation linkage Bond -O(CH ₂ ) _x - and carboxyl-type linkage -O(CH ₂ ) _x CO-, where x and y≥1 and are integers; R ₄ is -H or -CONH(CH ₂ ) _x CH ₃ , Where x≥0 and is an integer; P ₁ is a macromolecule;

Further, preferably, the o-nitrobenzyl phototrigger is o-nitrobenzyl.

Further, the natural biomacromolecules in the photoresponsive crosslinking group-modified macromolecule and the o-nitrobenzyl phototrigger-modified macromolecule are all dextran, hyaluronic acid, gelatin, sodium alginate, sulfuric acid One of chondroitin, silk fibroin, chitosan, carboxymethyl cellulose or collagen, polyethylene glycol or citric acid polymer (PEGMC).

Further, the photoinitiator is 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone (2-Hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, I2959) or one of phenyl (2,4,6-trimethylbenzoyl) phosphate lithium salt (lithium phenyl-2,4,6-trimethylbenzoylphosphinate, LAP); the photoinitiator is cross-linked with light response The mass ratio of the macromolecules modified by the group grafting is 1-3:100.

Further, the graft substitution rate of the macromolecule modified by the light-responsive crosslinking group is 10-30%; the graft substitution rate of the macromolecule modified by the o-nitrobenzyl-like phototrigger is 1-20%.

Further, the macromolecules modified by the photoresponsive crosslinking group are methacrylic anhydride-modified gelatin with a graft substitution rate of 10%, methacrylamide-modified gelatin with a graft substitution rate of 90%, graft-substituted methacrylic anhydride-modified gelatin with a graft substitution rate of 40%, methacrylamide-modified gelatin with a graft substitution rate of 20%, methacrylic anhydride-modified collagen with a graft substitution rate of 30%, and a graft substitution rate of 90% methacrylic anhydride-modified chondroitin sulfate or methacrylamide-modified carboxymethyl cellulose with a graft substitution rate of 10%, acryloyl chloride-modified polyethylene glycol with a graft substitution rate of 10%, One of glycidyl methacrylate-modified dextran with a graft substitution rate of 20%.

Further, the macromolecule modified by the o-nitrobenzyl-like phototrigger is o-nitrobenzyl-modified hyaluronic acid with a graft substitution rate of 100%, or o-nitrobenzyl-modified hyaluronic acid with a graft substitution rate of 50%. Sodium alginate, chondroitin sulfate modified with o-nitrobenzyl group with graft substitution rate of 10%, gelatin modified with o-nitrobenzyl group with graft substitution rate of 30%, ortho-nitrobenzyl group with graft substitution rate of 90% Nitrobenzyl-modified silk fibroin, o-nitrobenzyl-modified collagen with a graft substitution rate of 100% or o-nitrobenzyl-modified chitosan with a graft substitution rate of 10%, and 10% o-nitrobenzyl-modified chitosan One of the benzyl-modified citric acid polymers (PEGMC).

Further, the final concentration of the macromolecular mass modified by the photoresponsive crosslinking group is 3-10% by the mass of deionized water, and the final concentration of the macromolecular mass modified by the o-nitrobenzyl phototrigger is by the mass of deionized water It is calculated as 2-4%, and the final mass concentration of the photoinitiator is 0.03-0.2% based on deionized water mass.

The present invention also provides an application of the light-controlled 3D printing ink in repairing skin damage.

The present invention also provides an application of the light-controlled 3D printing ink in repairing articular cartilage defects.

Further, the application is: using the digital light processing (DLP)-based 3D printing technology to print the light-controlled 3D printing ink into a scaffold and implant it into a skin defect to achieve skin tissue repair.

The invention utilizes the principle that the o-nitrobenzyl phototrigger generates aldehyde groups after light excitation, and the generated aldehyde groups and amino groups can react to form strong chemical bonds. At the same time, macromolecules modified by light-responsive crosslinking groups solidify rapidly under light , the double cross-linked network enhances the mechanical properties, and the porous microstructure of 3D printing can achieve the purpose of rapid repair of defects. It is an ideal light-controlled 3D printing ink for the repair of skin defects or osteochondral defects.

The advantages of the present invention are for newly designed printers:

1. The feeding mechanism feeds material to the area surrounded by the lifting platform and the chamber in the way of dripping. The feeding mechanism and the lifting platform are mutually independent mechanisms, and no pre-feeding is required; The amount of feed liquid is matched to increase the utilization rate of one feed and greatly reduce the waste of feed liquid.

2. The thickness of each feeding is one layer thick. When printing the hollow structure, the uncured area remains liquid. When the next layer is printed, the liquid material can support the new material, thereby avoiding the collapse of the next layer of material. Accurately complete the printing form.

3. Through the control of the feeding unit, it is possible to realize multiple feeding printing modes such as alternate printing of various materials layer by layer, non-uniform mixed printing of multiple materials on the same layer, and single material printing. The heterogeneous mixing system is formed, which more realistically simulates the actual biological system.

4. By adjusting the position of the extrusion feeding mechanism, it can control the position where the feed liquid drips in, and more realistically simulate the actual biological system.

5. The area of the liquid surface is basically equal to the lifting platform, and the effective light curing area is large.

In addition, compared with the prior art, the present invention is mainly reflected in:

The mechanical properties of the light-controlled 3D printing ink of the present invention can be controlled by light activation. Before light excitation, the bioglue does not contain aldehyde groups and cannot react with amino groups to form a double-layer network, so its mechanical properties are poor. After being activated by light, aldehyde groups are generated on the molecules of the o-nitrobenzyl photoplate machine, which can quickly react with amino groups to light-control the 3D printing ink, so that the bio-glue has better mechanical properties. The mechanical properties can be increased by increasing the concentration of o-nitrobenzyl-like phototrigger-modified macromolecules. The present method adopts macromolecules modified by light-responsive cross-linking groups and o-nitrobenzyl phototrigger-modified macromolecules, which have good biological safety and simple usage, and can be used in the field of tissue defect repair and regenerative medicine to realize perfect tissue repair.

Description of drawings

Fig. 1 is a model diagram (upper frame) of cartilage printing in the present invention.

Fig. 2 is an overall structural diagram of the printer of the present invention.

Fig. 3 is a structural diagram of the platform driving part and the lifting platform.

Fig. 4 is a structural diagram of the lifting platform support.

FIG. 5 is a schematic diagram of the feeding mechanism 2 feeding the lifting platform 3 .

Fig. 6 is a structural diagram of a feeding unit with a liftable cartridge rack.

Fig. 7 is a structural diagram of a feeding unit with a fixed-height cartridge rack.

Fig. 8 is a structural diagram of a position adjustment mechanism.

Fig. 9 is a structural diagram of the lifting platform piston.

Fig. 10 is a schematic diagram of printing a three-dimensional leather hollow structure using one material.

FIG. 11 is a schematic perspective view of the grid layer and column array layer of FIG. 10 being molded from the same material.

FIG. 12 is a schematic perspective view of the grid layer and column array layer in FIG. 1 formed with two different materials.

Fig. 13 is a schematic diagram of the continuous N layers in Fig. 10 being formed using one material and the remaining layers being formed using another material.

Fig. 14 is an actual picture of the printed leather modeled in Fig. 10 according to the present invention.

FIG. 15A is a top view microstructural view of the corium shown in FIG. 14 , and FIG. 15B is a cross-sectional view of the corium shown in FIG. 14 .

16A-16C are confocal microstructure representations of skin scaffolds printed with the bio-ink of the present invention (cantilever beam structure, micron-scale high-precision 3-axis communicating holes).

Figures 17A-17C are the confocal microstructure characterization diagrams of skin scaffolds printed with the bio-ink of the present invention. Among them, the confocal photos of the cell activity characterization of live cells released from organs, the volume is 1 cubic millimeter, and the cell proliferation is not affected, 7 days activity greater than 95%).

Fig. 18 is a diagram of a cartilage model in a specific embodiment of the present invention.

Fig. 19 is a top view microstructure diagram of different holes printed.

Figure 20 is a physical picture of different holes printed out.

Detailed description with accompanying drawings

As shown in Figure 2, a 3D printing system includes an optical system 1, a feeding mechanism 2, a lifting platform 3 and a chamber 302; The feeding mechanism 2 is independent; each time printing, the lifting platform 3 steps relative to the optical system. Figure 1 is the hollowed-out skin tissue produced by the 3D printing system.

The lifting platform steps one layer thickness at a time, and the purpose of stepping the lifting platform is to enable the optical system to focus on the layer to be formed and realize light curing. The feeding mechanism is outside the optical system, and the material liquid of the feeding mechanism is outside the light-curing area of the optical system. During printing, the light-curing can be carried out without shifting the material liquid. The independence of the lifting platform and the feeding mechanism means that the lifting platform is not integrated with the feeding mechanism, but is an independent mechanism. material.

optical system

The optical system adopts the optical imaging system of DLP technology, and the exposure area of the optical system is the same as the profile to be formed of each layer. Real-time imaging exposure can be carried out according to the cross-sectional graphics of different molding layers. The exposed area is irradiated on the liquid material, and the liquid material is solidified and formed, and the unirradiated area is still liquid.

Lifting platform

The lifting platform is a platform that can be lifted independently. The lifting platform accepts the feeding of the feeding mechanism. After the lifting platform steps, it can send a signal to the feeding mechanism that it needs to feed, but the stepping of the lifting platform does not directly lead to the inflow of the material liquid. platform. The lifting platform is in the light-curing area of the optical system, and the material liquid in the lifting platform receives the light of the optical system to complete the light-curing molding.

As shown in FIG. 2 , in some preferred solutions, the optical system 1 is on the lifting platform 3 . Every time printing, the lifting platform 3 steps down. The lifting platform 3 includes a piston 301, which is located in the cavity 302, and the piston 301 accepts the material supply, and the piston 301 is driven step by step by the platform driving member 5.

As shown in FIG. 9 , when the piston 301 is in sealing connection with the cavity 302 , a sealing ring 303 is provided on the piston 301 .

Preferably, the platform drive is located below the piston. Preferably, the upper surface of the piston is in contact with the feed liquid. As shown in Figure 3, in some preferred solutions, the bottom of the platform driver 5 and the piston 301 is fixed, the platform driver 5 includes a drive motor 501, a screw mechanism 502 and a slide block 503, the screw mechanism 502 and the drive motor 501 Connection, the nut is fixed with the slider, and the slider 503 is connected with the piston 301. The screw mechanism 502 converts the torque of the drive motor 501 into linear movement, the slider 503 moves the piston 301 downward or upward, and the cavity 302 serves as a guide for the piston 301 when it moves. The platform driving part does not occupy the contact area and space between the piston and the material liquid, and all areas of the upper surface of the piston are effective areas that can be used for photocuring.

cavity

The cavity is used to accommodate the material liquid, and the lifting platform moves up and down in the cavity. For each printing, the material liquid is added into the cavity, and when the material liquid level in the cavity reaches the layer thickness requirement, the optical system performs light curing.

As shown in FIG. 4 , in some preferred solutions, the printing system includes a bracket 4 on which the cavity 302 is fixed. The cavity is formed by a through hole provided on the block body, and the block body is fixed on the bracket. The cross-section of the cavity is a rectangle, or a square, or a circle, or an ellipse and other conventional shapes. The block body is provided with channels or slots to accommodate the platform drive. The slide block of the platform driving part can move up and down in translation without interference in the channel or groove of the block body. The block body is a rectangular plate, or a square plate, or a circle, or an oval and other conventional shapes.

supply

As shown in FIG. 5 , the feeding mechanism 2 feeds materials to the lifting platform 3 , and the feeding amount each time is basically equal to the amount of liquid material required for forming the current layer. The so-called basically equal means that the amount of material supplied can meet the amount of material liquid required for molding, and make the liquid level within the effective curing range, there may be a slight margin, not absolute equality in the mathematical sense.

As shown in Figures 6 and 7, in some embodiments, the feeding mechanism 2 has a feeding unit 6, and the feeding unit 6 has a respective barrel 601, a feeding rod 602, a discharge nozzle 603 and a quantitative driving mechanism 604, The feeding rod 602 is connected with the quantitative driving mechanism 604 . The feeding rod 602 pushes the feed liquid in the barrel 601 to extrude from the discharge nozzle 603, and the discharge nozzle 603 drips the feed liquid on the lifting platform.

The quantity of the supply unit is 1, or the quantity of the supply unit is multiple. Multiple means that the number of feeding units is ≥2.

The feeding method is controlled by the controller, which controls the feeding of the quantitative driving mechanism. Preferably, a certain feeding unit is designated to feed, or multiple feeding units alternately implement the feeding-photocuring process. For example, there are two units, the first feeding unit and the second feeding unit. The first feeding unit feeds and cures light, the lifting platform steps once, the second feeding unit feeds and cures light; the lifting platform steps Once, feeding and photocuring by the first feeding unit, ... In this way, multiple feeding units alternately perform feeding-photocuring. In this case, the primary feeding amount of each feeding unit meets the amount of material liquid required for the current layer forming.

In some embodiments, alternate feeding is sequential feeding of multiple units, or cross-feeding of different feeding units. In the case of sequential feeding, for example, there are the first feeding unit, the second feeding unit and the third feeding unit, and the feeding is in the order of the first, second, and third—photocuring. Different units cross-feed, such as the first supply unit, the second supply unit and the third supply unit, the first supply unit supplies - light curing, the second supply unit supplies - light curing, and then the second supply unit One supply unit supplies material - light curing, and the third supply unit supplies material - light curing, as long as the two feedings before and after are completed by different units.

Alternatively, in some embodiments, multiple feeding units feed materials at the same time, and then photocure after the feeding is completed. For example, there are two units, the first feeding unit and the second feeding unit, and the first feeding unit and the second feeding unit feed at the same time, and the sum of the feeding volumes of all units meets the amount of material liquid required for the current layer forming , After the feeding is completed, light curing is carried out. The feeding positions of the two units are the same or different.

Or, in some embodiments, one or more feeding units feed first, and the other one or more feeding units feed after the first feeding is completed. After all the feeding units complete feeding, Then light curing. For example, there are two units, the first feeding unit and the second feeding unit. The first feeding unit feeds first, and the second feeding unit feeds after the first feeding unit finishes feeding. All units The total amount of material supplied meets the amount of material liquid required for the current layer forming, and light curing is carried out after the material supply is completed. The dripping position of the unit that feeds later can be the same as that of the unit that feeds first, or the position can be different.

Or, in some embodiments, one or several molding stages use designated feeding unit to feed, one or several molding stages use multi-unit simultaneous feeding, and one or several molding stages use multi-unit alternate feeding .

Or, in some embodiments, a certain feeding unit is designated to feed, and other units are suspended. In this way, printing of a single material is formed.

Quantitative drive mechanism

As shown in FIG. 6 and FIG. 7 , the quantitative driving mechanism 604 is used to push the feeding rod 602 quantitatively, and the control of the quantitative driving mechanism realizes the control of the feeding mode. In some embodiments, the quantitative driving mechanism includes a feeding driving member 605 , and the feeding driving member 605 is connected with the feeding rod 602 . Preferably, the feeding driving member 605 includes a clamp 606 , and the feeding rod 602 is clamped on the clamp 606 to realize the connection between the feeding driving member 605 and the feeding rod 602 . When the clamp 606 releases the feeding rod 602 , the feeding rod 602 is separated from the feeding driving member 605 . The feeding drive adopts motor and transmission mechanism (such as screw mechanism), electric push rod, cylinder and so on. Each barrel has its own barrel frame, and the barrel is fixed on the barrel frame.

As shown in FIG. 7 , in some embodiments, the cartridge holder 607 includes a fixed part 608 and a movable part 609 , the movable part 609 is connected to the cartridge 601 , and there is a locking member 610 between the movable part 609 and the fixed part 608 . After the movable part 609 is displaced relative to the fixed part 608, the installation height of the barrel 601 is raised. Preferably, multi-stage screw holes are provided in the height direction of the movable part, screw holes are provided in the fixed part, and the locking parts are screws or bolts and nuts. Each level of screw holes corresponds to an installation height. Preferably, the height direction of the fixing part is provided with multi-stage screw holes. Thereby increasing the installation height adjustment range of the barrel. The distance between the two-stage screw holes of the fixed part can be different from the distance between the two-stage screw holes of the movable part, so that there is differential step adjustment.

position adjustment mechanism

The position adjustment mechanism is used to adjust the position of the feeding mechanism, so that the feeding mechanism can drop the material liquid on the designated position of the lifting platform. As shown in FIG. 2 , in some embodiments, the 3D printer includes a position adjustment mechanism 7 , and the feeding mechanism 2 is installed on the position adjustment mechanism 7 . Each feeding unit has an independent position adjustment mechanism. Alternatively, all feeding units are mounted on the same position adjustment mechanism. Alternatively, certain feeding units are installed on the same position adjustment mechanism, and the rest of the feeding units are installed on another position adjustment mechanism.

As shown in FIG. 8 , the position adjustment mechanism includes a base 701 , a position adjustment driver 702 located on the base, and a position adjustment slider 703 . The position adjustment slider 703 is sloped. The existence of the slope enables the material liquid in the barrel to bear a certain gravity, avoiding the material liquid remaining in the nozzle, and maintaining the accurate amount of material liquid during feeding. . The position adjustment limit switch limits the displacement interval of the position adjustment slider. The position adjustment driving parts use motors, cylinders, electric push rods and the like.

The barrel frame is fixed on the position adjustment slider. Adjust the installation height of the barrel so that the axis of the barrel is in line with the thrust direction of the quantitative drive mechanism.

drainage

In multi-material printing tasks, sometimes it is necessary to drain the first material liquid before adding the second material liquid. The two feed liquids before and after can be the same feed liquid or different feed liquids.

In some embodiments, the printing system has a drainage mechanism. Preferably, as shown in FIG. 4 and FIG. 9 , the piston 301 and the cavity 302 are in clearance fit, and the gap between the piston 301 and the cavity 302 serves as a liquid drainage groove. When feeding, the amount of feed liquid is large, and the gap between the piston and the cavity is not discharged from the gap due to the surface tension of the feed liquid. After one photocuring, the amount of material liquid becomes very small, and the uncured liquid can be drained from the liquid drainage tank.

Alternatively, in some embodiments, the piston is sealingly engaged with the cavity and the liquid discharge mechanism is a pipette. When liquid needs to be drained, the suction tube extends into the non-forming area to suck up the remaining liquid. Preferably, the suction tube is installed on the liquid suction driving mechanism, and the liquid suction driving mechanism reciprocates to make the suction tube enter or withdraw from the cavity. Preferably, the suction pipe is connected with a negative pressure device. Rely on negative pressure to suck away the residual material liquid.

After the former feed liquid is drained, another feed liquid is added to avoid mutual influence and interference between the front and rear feed liquids.

In another aspect, the present invention provides a 3D printing method, the method comprising:

1), prepare 3D printing system and material liquid;

2), the lifting platform descends a layer thickness in the cavity;

3) The barrel feeds the material into the cavity, and the material liquid fills the space surrounded by the lifting platform and the cavity;

4) The optical system cures the material liquid by light to complete the curing of the current layer of material liquid.

The feeding mechanism provides enough material liquid for one layer of printing each time, so that the material liquid layer is always within the photocuring range of the optical system. There is no liquid drainage between the upper and lower layers, or after the previous layer thickness is solidified, the residual material liquid is drained away, but when feeding the next time, the amount of material liquid can satisfy the material liquid layer within the focus range of the optical system. How much material liquid is needed for the current printing layer, and the unsupplied material liquid is stored in the barrel, which can still be used for other printing tasks and improve the utilization rate of one feeding.

In some embodiments, when the printing task uses only one material for printing, after step 3), steps 2)-4) are repeated until the printing task is completed. The printing task includes which barrels are used for feeding, the order of feeding, the amount and position of feeding liquid, and the light curing profile of the optical system.

Take printing the three-dimensional hollow structure shown in Figure 1 as an example. The three-dimensional hollow structure is composed of grid layers and column arrays at intervals. When the hollow structure is not a single material, the printing material is loaded into the barrel, and the barrel feeds the material into the cavity in a liquid state. Initially, the lift platform is flush with the top surface of the chamber.

Start printing, the lifting platform descends one layer thick, the barrel feeds the material, the optical system irradiates the liquid surface of the material, and the liquid solidifies and forms according to the pattern of light, as shown in Figures 10 and 11, forming a grid-shaped D1 with alternating skeletons and holes Layer; one layer is printed. The lifting platform is lowered by one layer thickness, and the material barrel is fed again to make the liquid level rise to the top of the chamber; the optical system irradiates the material liquid surface, and the material liquid is solidified and formed according to the pattern of light, as shown in Figures 10 and 11, forming the D2 of the column array The column is located at the intersection of the skeleton of the D1 layer; the cross section of the column is square, and the three-dimensional effect of the superposition of the D1 layer and the D2 layer is shown in Figure 15. The lifting platform is lowered by one layer thickness, and the material barrel is fed again to make the liquid level rise to the top of the chamber; the optical system irradiates the material liquid surface, and the material liquid is solidified and formed according to the pattern of light, as shown in Figure 10, forming D3 above the D2 layer The structure of the D3 layer is consistent with that of the D1 layer. From the top view, the D1 layer and the D3 layer are completely overlapped. When layer C is formed, the material liquid fills the space between the columns of layer B. Therefore, the buoyancy of the material liquid supports the suspended part of the skeleton of layer C. At the edge, the buoyancy of the material liquid supports the cantilevered beams protruding from the columns to avoid The cantilever or cantilever collapse can form a three-dimensional hollow structure without cantilever (or cantilever) collapse and deformation, and the hollow structure increases the attachment area of active substances (such as cells). The lifting platform is lowered by one layer thickness, and then a layer of column array is printed... In this way, a three-dimensional hollow structure of one layer of grid layer and one layer of column array layer is formed as shown in Figure 1. When printing on two adjacent layers, the residual material liquid after photocuring can be discharged first before feeding, or it can be directly fed to print on the next layer.

When feeding the same material, it can be completed by one barrel; it can also be done by a group of barrels, and multiple barrels in a set of barrels are feeding into the cavity from different positions. In some embodiments, a method of 3D printing, suitable for use with two materials in each layer, comprising:

1) Prepare the 3D printing system and the material liquid, input the printing task, put the material liquid into the barrel that undertakes the feeding task, put material A into barrel A, material B into barrel B, put barrel A and material Tube B is installed in place;

2), the lifting platform descends a layer thickness in the cavity;

3) When printing material A first and then printing material B in the printing task, barrel A feeds material into the cavity, and material A fills the space surrounded by the lifting platform and the cavity;

4) The optical system cures the material A with light to complete the curing of the material A; the lifting platform descends a layer thickness in the cavity;

5A), judging that the printing task and material B are not completed:

5A1), the material A is discharged, and the lifting platform is raised by one layer thickness;

5A2), inject material B into the cavity, and the liquid level of material B is flush with the top surface of the cavity;

5A3), the optical system cures the material B with light;

5A4) All materials in the current layer are printed; the liquid material B is drained away, and the lifting platform is lowered by one layer thickness; the latter layer thickness is used as the current printing task; repeat steps 3)-5A). In some embodiments, this printing method enables the same layer to be composed of two different materials. The material liquid injected every time fills the space surrounded by the lifting platform and the cavity, and the material liquid is within the focus range of the optical system.

Take printing the three-dimensional hollow structure shown in Figure 1 as an example. The three-dimensional hollow structure is composed of grid layers and column arrays at intervals. When the same layer of the hollow structure is composed of different materials (such as when printing biological organs, muscle tissue and blood vessel tissue are in the same layer, and the material for printing muscle tissue is different from the material for blood vessel tissue), the two materials are respectively loaded into the Cartridge A and cartridge B (or cartridge group A and cartridge group B), the cartridge feeds the cavity in liquid state. Initially, the lift platform is flush with the top surface of the cavity. Initially, the lift platform is flush with the top surface of the cavity. Prepare to print the first layer, the lifting platform is lowered by one layer thickness, material is supplied by cylinder A, the optical system irradiates the material liquid surface, and the material liquid is solidified and formed according to the pattern of light, as shown in Figure 12, a grid-shaped main body (representing muscle tissue), the main body includes orthogonal grid bars, and the grid bars intersect to form holes; after forming, the residual material liquid of material A is discharged; the lifting platform is lowered by a layer thickness and then reset by a layer thickness, and the barrel B feeds the material, and the optical system The surface of the feed liquid is irradiated, and the feed liquid is solidified and shaped according to the light pattern of the first layer, as shown in Figure 12, forming the walls around the hole (representing vascular tissue). The printing task of the first layer is completed, and the residual material liquid of material B is discharged. When the second layer is ready to be printed, the lifting platform is lowered by one layer thickness, and the barrel A supplies material to form the main body of the column array (representing the muscles). The columns are located at the intersection of the grid bars on the first layer. After molding, discharge the residual material liquid of material A; the lifting platform is lowered by one layer thickness and then reset by one layer thickness, feeding cylinder B, the optical system irradiates the material liquid surface, and the material liquid is solidified and formed according to the illumination pattern of the second layer , the surface of each column forms a wall (representing vascular tissue), and in the direction of looking down, the wall of the first layer and the wall of the second layer overlap; the printing task of the second layer is completed, and the residual liquid of material B is discharged. The molding method and lighting pattern of the third layer are the same as the first layer; the molding method and lighting pattern of the fourth layer are the same as the second layer; ... the molding method and lighting pattern of the odd-numbered layer are the same as the first layer; the even-numbered layer The molding method and lighting pattern are the same as the second layer. Odd-numbered layers alternate with even-numbered layers, printing to form a spatial hollow structure with different material organization in each layer. When the same layer is extended to use two or more materials, it is only necessary to prepare the corresponding material barrel, and after molding one material each time, keep the lifting platform at the position of the corresponding layer, add more materials, and control the light pattern to form the desired shape. required structure. .

In step 3), the order of each material has been set in the printing task, and the forming order of steps 3)-5A) is carried out according to the preset order. Or, in step 3), if the order of various materials is not arranged in the printing task, one material is randomly selected and printed first until all materials are printed.

In some embodiments, a method of 3D printing, which is suitable for each layer with only one material, but the entire tissue is made of two or more materials (for example, including material A, material B, material C) , the method includes the following steps:

1) Prepare the 3D printing system and the material liquid, input the printing task, put the material liquid into the barrel that undertakes the feeding task, put material A into barrel A, material B into barrel B, and material C into the barrel C, install barrel A, barrel B and barrel C in place;

2), the lifting platform descends a layer thickness in the cavity;

3) Identify the current printing task, print material A in the printing task, material barrel A feeds into the cavity, and material A fills the space surrounded by the lifting platform and the cavity;

4) The optical system cures the material A with light to complete the curing of the material A; the lifting platform descends one layer thickness in the cavity, discharges the uncured material A, and reads the next layer as the current printing task;

5B1), identify the current printing task, such as printing material B in the printing task, barrel B feeds material into the cavity, and material B fills the space surrounded by the lifting platform and the cavity; the optical system cures material B with light, and completes the printing of material B Curing; the lifting platform descends a layer thickness in the cavity, discharges the uncured material B, and reads the next layer as the current printing task;

5B2), identify the current printing task, such as printing material C in the printing task, the barrel C feeds the material into the cavity, and the material C fills the space surrounded by the lifting platform and the cavity; the optical system cures the material C to complete the material C Curing; the lifting platform descends a layer thickness in the cavity, discharges the uncured material B, and reads the next layer as the current printing task;

In this way, each time the material in the current printing task is identified, feeding, curing, and liquid discharge are performed until all printing tasks are completed.

In some embodiments, a 3D printing method is suitable for each layer with only one material, but the entire tissue is made of two or more materials (such as including material A, material B), but, Continuous N layer thicknesses are material A; the method comprises the following steps:

1) Prepare the 3D printing system and the material liquid, input the printing task, put the material liquid into the barrel that undertakes the feeding task, put material A into barrel A, material B into barrel B, and material C into the barrel C, install barrel A, barrel B and barrel C in place;

2), the lifting platform descends a layer thickness in the cavity;

3) Identify the current printing task, print material A in the printing task, material barrel A feeds into the cavity, and material A fills the space surrounded by the lifting platform and the cavity;

4) The optical system cures the material A with light to complete the curing of the material A; the lifting platform descends a layer thickness in the cavity;

5), read the next layer as the current printing task, judge the current printing task, the current layer uses material A, then the barrel A feeds the material; the optical system cures the material A to complete the curing of the material A; the lifting platform is in the cavity Decrease one layer thickness; ..., so, until all layers of material A are printed continuously;

6), read the next layer as the current printing task, judge the current printing task and the material B used in the current layer, then drain the residual liquid of material A, and feed the material in cylinder B; the optical system will light-cure material B to complete the material Curing of B; the lifting platform descends a layer thickness in the cavity; ..., so, until all layers of material B are printed continuously;

Repeat step 6) until all printing tasks are completed.

For example, when printing skin, the epidermal layer of the skin has a different tissue than the dermis, and therefore, different materials are used for molding. Take printing the structure shown in Figure 1 as an example. The front N layers represent the dermis layer, and the material used for the dermis layer is the same (such as using material A). The next layer represents the skin layer, and the same material is used for the skin layer (such as using material B). But the material of the dermis is different from the material of the epidermis. As shown in Figure 13, when forming, the first N layers are formed with material A (whether it is a grid layer or a column array layer); after the first N layers are printed, the N+1 layer needs to be formed with material B. Before N+1 layer feeding, the residual material liquid of material A should be discharged, then material B should be injected into the cavity, and the liquid level should reach the top of the cavity; layer N+1 should be formed; subsequent layers should be printed with material B .

As shown in Figure 14, use the above two methods to print teeth. The tooth has enamel, dentin and pulp. The apex of the tooth root has only dentin, followed by several layers of dentin outside and pulp inside; then several layers of enamel outside, dentin in the middle, and pulp inside; finally Is several layers only enamel. When simulating and printing these material properties of natural teeth, when molding from the root to the crown, for example, use material C as enamel, material A as dentin, and material B as pulp.

In some embodiments, for example, several layers of dentin are printed, and several layers of dentin, pulp. A method of 3D printing, which is suitable for some layers with only one material (such as material A), and some layers using multiple materials (such as A and B); the whole tissue is composed of two or more materials of; the method includes the following steps:

1) Prepare the 3D printing system and the material liquid, input the printing task, put the material liquid into the barrel that undertakes the feeding task, put material A into barrel A, material B into barrel B, and material C into the barrel C, install barrel A, barrel B and barrel C in place;

2), the lifting platform descends a layer thickness in the cavity;

3) Identify the current printing task, print material A in the printing task, material barrel A feeds into the cavity, and material A fills the space surrounded by the lifting platform and the cavity;

4) The optical system cures the material A with light to complete the curing of the material A; the lifting platform descends a layer thickness in the cavity;

5), read the next layer as the current printing task, judge the current printing task, the current layer uses material A, then the barrel A feeds the material; the optical system cures the material A to complete the curing of the material A; the lifting platform is in the cavity Decrease one layer thickness; ..., so, until all layers of material A are printed continuously;

6), read the next layer as the current printing task, the current printing task (the current layer uses materials A and B), material B is printed first, then the residual liquid of material A is drained, and material is supplied by barrel B; the optical system controls the material Light curing of material B completes the curing of material B; the lifting platform lowers one layer thickness in the cavity; the lifting platform rises one layer thickness, the residual liquid of material B is drained, and the barrel A feeds the material; the optical system cures material A by light, Complete the curing of material A;

Repeat steps 5)-6) until all printing tasks are completed.

In some embodiments, such as printing several layers of enamel, and several layers of dentin, pulp, and enamel, use material C for the enamel, material A for the dentin, and material B for the pulp. A 3D printing method, which is suitable for each layer with multiple materials, and a tissue is composed of two or more materials (such as including material A, material B, material C), the method includes the following steps:

1) Prepare the 3D printing system and the material liquid, input the printing task, put the material liquid into the barrel that undertakes the feeding task, put material A into barrel A, material B into barrel B, and material C into the barrel C, install barrel A, barrel B and barrel C in place;

2), the lifting platform descends a layer thickness in the cavity;

3) Identify the current printing task, the current layer has only one material C, the barrel C feeds the material into the cavity, and the material A fills the space surrounded by the lifting platform and the cavity;

4) The optical system cures material C with light to complete the curing of material C; the lifting platform descends one layer thickness in the cavity, discharges the remaining material liquid, and reads the next layer as the current printing task;

5A1), identify the current printing task, the printing task includes materials A, B and C, assuming that material B is printed first (including the order set in the task and the case where material B is randomly selected to print first); barrel B feeds material into the cavity , the material B fills the space surrounded by the lifting platform and the cavity; the optical system cures the material B with light to complete the curing of material B; the residual material liquid is discharged, the lifting platform falls in the cavity by one layer thickness, and then the lifting platform rises by one layer thickness , that is, return to the height when material B is fed;

5A2), barrel C feeds material into the cavity, and material C fills the space surrounded by the lifting platform and the cavity; the optical system cures material C with light, and completes the curing of material C. At this time, all materials in the current layer are printed; The lifting platform descends one layer thickness in the cavity, discharges the residual material liquid, and reads the next layer as the current printing task;

5A3), barrel A feeds material into the cavity, and material A fills the space surrounded by the lifting platform and the cavity; the optical system cures material A with light, and completes the curing of material A. At this time, all materials in the current layer are printed; The lifting platform descends one layer thickness in the cavity, discharges the residual material liquid, and reads the next layer as the current printing task; repeat steps 5A1)-5A3) until all materials of the current printing task are completed;

Repeat steps 3)-5A3) until all printing tasks are completed.

In some embodiments, as shown in FIG. 15 , for example, when printing a certain tissue, there are specific one or several materials. In addition to the main material, the materials for forming these parts need to be added with specified other materials. For example, when printing muscle tissue, specific parts need to be highly active, and the active parts need to be naturally diffused in a non-uniform mixed state in the muscle tissue. Therefore, on the basis of muscle tissue, it is also necessary to add high activity factors ( such as stem cells)

A 3D printing method, which is suitable for a layer including material A (representing muscle tissue) and material B (representing a high-activity factor solution), and material B is located at the specified position of material A, and material A and material B are fused ; the method includes the following steps:

1) Prepare the 3D printing system and the material liquid, input the printing task, put the material liquid into the barrel that undertakes the feeding task, put material A into barrel A, material B into barrel B, put barrel A and material Tube B is installed in place;

2), the lifting platform descends a layer thickness in the cavity;

3) Barrel A supplies a certain amount of material A, the position adjustment device adjusts barrel B to a designated position, and barrel B supplies a certain amount of material B; barrel A and barrel B together provide the current layer of material liquid;

4) The optical system cures the current layer liquid with light.

Material B is dropped into material A to form a natural diffusion state, so that a non-uniform mixed system in which the two materials naturally diffuse can be printed.

material, liquid

The material or material liquid mentioned in the present invention refers to a material or mixture used for processing by the printer. When processing with the 3D printer of the present invention, some existing biological materials can be used for printing. For example, many materials including natural polymers: collagen, silk fibers, gelatin, alginate and synthetic polymers: polyethylene glycol (PEG) or any combination thereof can be processed by the printer of the present invention. These serve as bio-3D printing materials, also known as "bio-inks". Although the materials themselves are traditional materials, they can all be printed with the invented printing equipment and methods. This printed biomaterial has a three-dimensional structure, or has a four-dimensional space, and can be provided with arbitrary through holes. The through hole here generally refers to a planar structure or a three-dimensional structure. For example, there is a hole in the plane, and the shape of the hole can be any shape, such as circle, rectangle, square, rhombus and so on. When multiple surfaces are in different dimensions, a three-dimensional shape is formed. Each surface or multiple surfaces of the three-dimensional shape has a hole structure, and these holes have a certain depth. Here, the holes can be connected or not. communicated, or partially communicated, thus forming a passage through the entire three-dimensional structure or part of the three-dimensional structure. Such a structure can be easily realized by using the printer of the present invention.

In some embodiments, the cartridge is a container for different materials, and different cartridges can be used to hold the same material. Optionally, different materials or bio-inks can be contained in the barrel. For example, barrel A holds a kind of biological material, and barrel B holds another kind of biological material. The properties of the two materials are not the same. The printing technology of the present invention can realize the printing of complex biological tissues or organs. This is because a biological material or organ is not uniform in structure, but has differences in structure or biological properties. For example, the skin material of mammals has epidermis, dermis, and dermis has blood vessels and tissues connected to muscles. The structures of these different parts are different, the thickness is different, and the transitional structure between various tissues is also different. Including density, pore size, etc. In this way, if it needs to be printed by traditional printing, all structures or tissues are the same, but by the printing technology of the present invention, biological materials with different structures can be processed at one time.

In some ways, the material of the present invention can be mixed with stem cells for processing or printing. In this way, the material can be used as a scaffold structure, and the cells can be differentiated as an active cost, and finally, an active tissue can be formed. Of course, it is also possible to print out the scaffold structure, and then let stem cells fill the space of the skeleton, and eventually form a living tissue.

In conclusion, the newly designed printer of the present invention can print any suitable material.

In some specific ways, the present invention provides a new 3D printing bio-ink, also known as a new material. In some specific ways, the present invention provides a light-controlled 3D printing bioink or material, which includes macromolecules modified by photoresponsive crosslinking groups, macromolecules modified by o-nitrobenzyl phototriggers, photosensitive Initiator. In some instances, water, such as deionized water, is also included. In fact, before printing, the biological material of the present invention is actually a base material. When printing is required, it can be mixed with a solvent to form a solution state, or a fluid state, and the base material can be in a dry form. exist. Of course, it can also be stored directly in liquid form. Optional, so as a base material for "bio-ink".

In some preferred manners, the final mass concentration of the photoresponsive cross-linking group-modified macromolecule and the o-nitrobenzyl phototrigger-modified macromolecule is both 0.1-10% by mass of deionized water.

In some preferred manners, the final mass concentration of the photoinitiator is 0.001-1% based on the mass of deionized water.

In some preferred modes, the graft substitution rate of the photoresponsive crosslinking group in the macromolecule modified by the photoresponsive crosslinking group is 10-90%, and the photoresponsive crosslinking group is methacrylamide, form Acrylic anhydride, glycidyl methacrylate or acryloyl chloride.

In some preferred modes, the graft substitution rate of the o-nitrobenzyl phototrigger in the o-nitrobenzyl phototrigger modified macromolecule is 1-100%.

In some preferred modes, further, the o-nitrobenzyl phototrigger-modified macromolecule is shown in formula (I), in formula (I), R ₁ is -H or selected from -CO(CH ₂ )xCH ₃ , -CO(CH ₂ CH ₂ O) _x CH ₃ , -CO(CH ₂ ) _x (CH ₂ CH ₂ O) _y CH ₃ ester bonds, selected from -(CH ₂ ) _x CH ₃ , -(CH ₂ CH ₂ O) _x CH ₃ , -(CH ₂ ) _x (CH ₂ CH ₂ O) _y CH ₃ , Ether linkages, carbonates selected from -COO(CH ₂ ) _x CH ₃ , -COO(CH ₂ CH ₂ O) _x CH ₃ , -COO(CH ₂ ) _x (CH ₂ CH ₂ O) _y CH ₃ Bonds, isocyanate bonds selected from -CONH(CH ₂ ) _x CH ₃ , -CONH(CH ₂ CH ₂ O) _x CH ₃ , -CONH(CH ₂ ) _x (CH ₂ CH ₂ O) _y CH ₃ , Wherein x and y≥0 and are integers; R ₂ is -H or selected from -O(CH ₂ ) _x CH ₃ , -O(CH ₂ CH ₂ O) _x CH ₃ , -O(CH ₂ ) _x (CH ₂ CH ₂ O) _y CH ₃ substituents, wherein x and y≥0 and are integers; R ₃ is selected from amino linkage -O(CH ₂ ) _x CONH(CH ₂ ) _y NH-, halogenation linkage Bond -O(CH ₂ ) _x - and carboxyl-type linkage -O(CH ₂ ) _x CO-, where x and y≥1 and are integers; R ₄ is -H or -CONH(CH ₂ ) _x CH ₃ , Wherein x≥0 and is an integer; P ₁ is a macromolecule;

Further, preferably, the o-nitrobenzyl phototrigger is o-nitrobenzyl.

In some preferred modes, the natural biomacromolecules in the photoresponsive crosslinking group-modified macromolecule and the o-nitrobenzyl phototrigger-modified macromolecule are all dextran, hyaluronic acid, gelatin, One of sodium alginate, chondroitin sulfate, silk fibroin, chitosan, carboxymethyl cellulose or collagen, polyethylene glycol or citric acid polymer (PEGMC).

In some preferred modes, the photoinitiator is 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone (2-Hydroxy-4'-(2-hydroxyethoxy)-2 -methylpropiophenone, I2959) or phenyl (2,4,6-trimethylbenzoyl) phosphate lithium salt (lithium phenyl-2,4,6-trimethylbenzoylphosphinate, LAP); the photoinitiator The mass ratio of the graft-modified macromolecule to the photoresponsive crosslinking group is 1-3:100.

In some preferred modes, the graft substitution rate of the macromolecule modified by the photoresponsive crosslinking group is 10-30%; the graft substitution rate of the macromolecule modified by the o-nitrobenzyl phototrigger is 1-20%.

In some preferred modes, the photoresponsive crosslinking group modified macromolecules are gelatin modified with methacrylic anhydride with a graft substitution rate of 10%, methacrylamide modified gelatin with a graft substitution rate of 90%. Gelatin, methacrylic anhydride-modified gelatin with a graft substitution rate of 40%, methacrylamide-modified gelatin with a graft substitution rate of 20%, methacrylic anhydride-modified collagen with a graft substitution rate of 30%, chondroitin sulfate modified with methacrylic anhydride with a graft substitution rate of 90% or methacrylamide-modified carboxymethyl cellulose with a graft substitution rate of 10%, acryloyl chloride modified with a graft substitution rate of 10% Polyethylene glycol, one of glycidyl methacrylate-modified dextran with a graft substitution rate of 20%.

In some preferred modes, the o-nitrobenzyl-like phototrigger-modified macromolecules are o-nitrobenzyl-modified hyaluronic acid with a graft substitution rate of 100%, ortho-nitrobenzyl-modified hyaluronic acid with a graft substitution rate of 50%. Sodium alginate modified by nitrobenzyl, chondroitin sulfate modified by o-nitrobenzyl with graft substitution rate of 10%, gelatin modified by o-nitrobenzyl group with graft substitution rate of 30%, graft substitution rate 90% o-nitrobenzyl-modified silk fibroin, 100% o-nitrobenzyl-modified collagen or 10% o-nitrobenzyl-modified chitosan, 10% of one of the o-nitrobenzyl modified citric acid polymers (PEGMC).

In some preferred modes, the final concentration of the macromolecular mass modified by the photoresponsive crosslinking group is 3-10% based on the mass of deionized water, and the final concentration of the macromolecular mass modified by the o-nitrobenzyl phototrigger It is 2-4% based on deionized water mass, and the final mass concentration of the photoinitiator is 0.03-0.2% based on deionized water mass.

The present invention also provides an application of the light-controlled 3D printing ink in repairing skin damage.

The present invention also provides an application of the light-controlled 3D printing ink in repairing articular cartilage defects.

Further, the application is: using the digital light processing (DLP)-based 3D printing technology to print the light-controlled 3D printing ink into a scaffold and implant it into a skin defect to achieve skin tissue repair.

The invention utilizes the principle that the o-nitrobenzyl phototrigger generates aldehyde groups after light excitation, and the generated aldehyde groups and amino groups can react to form strong chemical bonds. At the same time, macromolecules modified by light-responsive crosslinking groups solidify rapidly under light , the double cross-linked network enhances the mechanical properties, and the porous microstructure of 3D printing can achieve the purpose of rapid repair of defects. It is an ideal light-controlled 3D printing ink for the repair of skin defects or osteochondral defects. The material here can exist in any form, and can exist in the form of solid. When needed, it can be configured in the form of liquid for printing, or directly configured in the form of liquid, and can be printed directly when printing is required.

Here, materials and bio-inks can be interchanged. Generally, substances that are processed as printing can be called materials, and can also be called inks or bio-inks or bio-ink materials. The materials or inks here can include some active components, such as Including stem cells or cells or other ingredients, of course, it is also possible to print or process only the material or ink itself, and then add active ingredients.

specific implementation

The present invention provides specific implementation examples to illustrate the printing method of the present invention and the bio-ink material used. It can be understood that these examples are only to further explain how to realize the present invention, and cannot constitute any limitation to the present invention. The scope is defined by the claims.

Example 1: 3D printed skin for injury repair

For example, as shown in Figures 10, 11, 12 and 13, the printed material is modeled first, and then the established model is controlled by the program, and then printed. For example, the established model is shown in Figures 10 and 12, Figure 10 is a model of the dermis, and Figure 12 is the combination of the epidermis and the dermis. FIG. 11 is a schematic diagram of the printing process taking 3 layers as an example. For example, the black one represents the bracket that needs to be printed, which is similar to the structure of a three-dimensional cube, and the 12 sides of the bracket use the printed bracket, and the bracket forms a hollowed-out three-dimensional structure 102, forming a unit for printing the bracket, multiple The combination of elements forms a porous structure in the form of cantilever beams. The whole unit can form a dermis support of any size, for example, the diameter can be 8 mm, the thickness of the epidermis is 1 mm, and the thickness of the dermis is 1 mm, thus forming a skin with a thickness of 2 mm. The double-layer structure is designed to simulate the epidermis and dermis of the skin. The structure of the epidermis is dense and the structure of the dermis is loose. Therefore, the upper structure is designed as a solid cylinder, and the lower structure is designed as a cantilever beam porous structure, which is suitable for cell proliferation and differentiation and blood vessels. grow in.

The ratio of the materials used in the scaffold structure is as follows: gelatin (GelMA) grafted with methacrylic anhydride and N-(2-aminoethyl)-4-(4-(hydroxymethyl)-2-methoxy -5-nitroso-containing phenoxy) butanamide (NB) grafted hyaluronic acid (HA-NB). The concentrations of the two are respectively: 2.5% and 0.625%, the photosensitizer concentration is 2% of the total volume, the phenol red concentration is 0.4%, and the rest is water.

Using biomaterials according to the model shown in Figure 10, taking 3 layers as an example to describe the printing process (Figure 13), as follows:

Step 1. Load the material used in the support structure into the barrel. Initially, the lifting platform is flush with the top surface of the cavity;

Step 2. The lifting platform is lowered by one layer thickness. The material barrel injects the biological material into the cavity. The liquid level of the biological material is flush with the top surface of the cavity. The optical system irradiates the liquid level of the material liquid. curing to form the first layer A of the grid;

Step 3. The lifting platform is lowered by one layer thickness. The material barrel injects the biological material into the cavity. The liquid level of the biological material is flush with the top surface of the cavity. The optical system irradiates the material liquid level. At the intersection of the grid bars of the layers, the biological material is solidified after being illuminated to form the second layer B of the column array;

Step 4. The lifting platform is lowered by one layer thickness. The material barrel injects the biological material into the cavity. The liquid level of the biological material is flush with the top surface of the cavity. Grid, the biological material solidifies after light to form the third layer C of the grid; when the third layer is formed, the biological material fills the space between the columns of the second layer, so the buoyancy of the biological material supports the third layer of grid For the suspended part of the bar, at the edge, the buoyancy of the material liquid supports the grid bar extending out of the column to form a cantilever beam, so as to avoid the suspension beam and the suspended part from collapsing; in the subsequent steps, the column array layer and the grid layer are formed alternately, forming a shape as shown in Figure 10 The three-dimensional hollow structure without collapse and deformation is shown. The light intensity of all the above prints is 50, and the exposure time: 1000ms.

The actual picture of the printed result is shown in Figure 14, which is the actual picture of the leather structure. Among them, in terms of microstructure, it can be seen from the top view of the dermis that there is a structure similar to a hollow (like a window or hole structure 101), FIG. 15B.

It can be seen from FIGS. 16A-16C that in the confocal microstructure, the beam is the support structure 101 of the printing material, and has a hollow structure 104 inside. It has a three-dimensional spatial structure, and the gray beams of light represent the skeleton structure 104, and there is space around each beam of light, forming a three-dimensional spatial structure. The three-dimensional spatial solution structure can include stem cells or active ingredients, which is beneficial to The division of cells, so that the printed ones are more biologically active.

As shown in Figures 17A-17C, there are fibroblasts in the scaffold structure printed by this printing method. After 1 week of culture, 95% of the cells are still biologically active. Figure 17A is the fluorescence of the photo of the entire fibroblast survival Fig. 17B is a phase diagram of the fluorescence of dead cells, and Fig. 17C is a fitted image of live and dead cells. As can be seen from the figure, very few cells died. After culturing for 15 days, the survival rate was 90%, after culturing for 20 days, the survival rate was 88%, and after culturing for 1 month, the survival rate was 85%.

However, materials printed by traditional printing technology have a very high cell death rate. After one week of cultivation, the general death rate is above 90%, and the survival time is very short, up to 2-4 days, which is basically not practical.

It can be understood that it is possible to just print the dermis. The size of the dermis is determined based on the size of the repaired wound. After the dermis is printed, the dermis is covered on the wound, and then a layer of epidermis is applied, and then cured by light to repair the wound. The dermis may have fibroblasts or other active ingredients.

Example 2: 3D printing cartilage repair

For example, as shown in Figures 1 and 18, the printed material is modeled first, and then the program is controlled according to the established model, and then printed. For example, the model established is shown in Figures 1 and 18, and Figure 18 is a model of a cartilage support, which includes an upper support 901 and a lower support 902, wherein the upper support is 30 circular holes 900, and the side also has 30 circular holes 903, each circle The holes have the same intersection, for example, each of the upper circular holes 900 communicates with the lateral circular holes 903 , as can be seen in FIG. 1 . The diameter of the scaffold is 4mm, the thickness of the upper layer is 1mm, and the thickness of the lower layer is 2mm. In fact, the lower layer also has corresponding 30 holes which are the same as the 30 holes in the upper layer, and next time there are no side holes.

This design is to use the scaffold for cartilage repair. The lower scaffold has 30 holes in the top view, the purpose of which is to allow bone marrow mesenchymal stem cells to migrate to the upper layer and contribute to cartilage repair. The upper scaffold is designed with holes in the middle for the migration of bone marrow mesenchymal stem cells to the cartilage layer, and holes on the side for the migration of chondrocytes to the damaged site, so as to better repair cartilage defects. The addition of KGN small molecules can maintain the chondrocyte phenotype and promote the differentiation of bone marrow mesenchymal stem cells into chondrocytes.

The ratio of the materials used in the scaffold structure is as follows: the upper and lower layers are 8M methacrylic anhydride grafted gelatin (GelMA) with a concentration of 15%. The photosensitizer is 10% v/v, and the concentration of phenol red is 0.8%. KGN small molecules were added to the upper bracket, and the final dilution concentration was 50uM.

Using biomaterials according to the model shown in Figure 18, and taking 3 layers as an example to describe the printing process (Figure 1), as follows: Taking the gradual additive molding from bottom to top as an example, using biomaterials according to the printing method of the cartilage scaffold model The process is as follows:

Step 1. Slice the cartilage scaffold model according to the thickness of the layer, and the pattern of each slice is used as the illumination pattern of the layer; put the biological material into the barrel, and initially, the lifting platform is flush with the top surface of the cavity;

Step 2. The lifting platform is lowered by one layer thickness. The material cylinder injects the biological material into the cavity, and the liquid level of the biological material is flush with the top surface of the cavity. The position corresponding to the hole is not covered by light, and the biological material is cured after illumination to form the first layer; repeat step 2 until the lower layer of support is completed;

Step 3. When printing the arc of the lower half of the radial through hole of the upper bracket, repeat step 2;

Step 4. When printing the upper half arc of the radial through hole of the upper bracket, the last printing layer protrudes from the previous printing layer and a suspended part appears, the lifting platform is lowered by one layer thickness, and the barrel injects the biological material into the cavity, The liquid level of the biomaterial is flush with the top surface of the cavity; on the inner wall of the radial through hole, the liquid of the uncured biomaterial in the previous printing supports the suspended part of the current layer to avoid the collapse of the suspended part, thereby printing out the inner wall Radial through holes in a precise arc, repeating steps 3 and 4 until the upper support is printed. The light intensity of all the above prints is 50, and the exposure time: 1000ms.

As shown in FIG. 20 , the physical mechanism diagram of the stent structure printed by this printing method. Fig. 19 is a microstructure view of each layer, wherein, from the top views of different void sizes, it can be seen that the side holes and the holes in the top view are in the same arrangement. At the same time, the fluorescence structure diagram of 400um was observed under a fluorescence microscope.

The invention shown and described herein can be practiced in the absence of any element, limitation, specifically disclosed herein. The terms and expressions employed are used as terms of description and not of limitation, and there is no intention in the use of these terms and expressions to exclude any equivalents of the features shown and described or parts thereof, and it should be recognized that each Both modifications are possible within the scope of the invention. It is therefore to be understood that while the invention has been specifically disclosed by way of various embodiments and optional features, modifications and variations of the concepts described herein can be employed by those of ordinary skill in the art and are considered to be within the scope of the within the scope of the invention as defined by the appended claims.

The contents of articles, patents, patent applications, and all other literature and electronically available information described or recorded herein are hereby incorporated by reference in their entirety to the same extent as if each individual publication were specifically identified Same as pointing out individually for reference. Applicants reserve the right to incorporate into this application any and all materials and information from any such articles, patents, patent applications, or other documents.

Claims (12)

1. one kind is used for light-operated 3D printing biomaterial, the material includes the macromolecular of photoresponse crosslinked group modification, adjacent nitre The macromolecular of base benzyl class light trigger modification, photoinitiator.

2. biomaterial according to claim 1, wherein further include deionized water.

3. biomaterial according to claim 2, wherein the macromolecular and adjacent nitro of the photoresponse crosslinked group modification The macromolecular quality final concentration of benzyl class light trigger modification is 0.1~10% with deionized water meter.

4. biomaterial according to claim 3, wherein the photoinitiator quality final concentration is with deionized water meter It is 0.001~1%.

5. according to biomaterial described in claim 3 or 4, wherein in the macromolecular of the photoresponse crosslinked group modification The grafting Replacement rate of photoresponse crosslinked group is 10~90%.

6. biomaterial described in one of -5 according to claim 1, wherein photoresponse crosslinked group is Methacrylamide, first Base acrylic anhydride, one of glycidyl methacrylate or acryloyl chloride or several.

7. biomaterial described in one of -6 according to claim 1, wherein big point of the adjacent nitro benzyl class light trigger modification The grafting Replacement rate of adjacent nitro benzyl class light trigger is 1~100% in son.

8. biomaterial according to claim 7, wherein the macromolecular such as formula of the adjacent nitro benzyl class light trigger modification (I) shown in, in formula (I), R₁For-H or it is selected from-CO (CH₂)xCH₃、-CO(CH₂CH₂O)_xCH₃、-CO(CH₂)_x(CH₂CH₂O)_yCH₃ Ester bond class, selected from-(CH₂)_xCH₃、-(CH₂CH₂O)_xCH₃、-(CH₂)_x(CH₂CH₂O)_yCH₃、Ehter bond class, be selected from-COO (CH₂)_xCH₃、-COO(CH₂CH₂O)_xCH₃、-COO(CH₂)_x(CH₂CH₂O)_yCH₃Carbonic acid ester bond class, be selected from-CONH (CH₂)_xCH₃、-CONH(CH₂CH₂O)_xCH₃、-CONH(CH₂)_x(CH₂CH₂O)_yCH₃Isocyanic acid ester bond class, wherein x and y >=0 and to be whole Number；R₂For-H or it is selected from-O (CH₂)_xCH₃、-O(CH₂CH₂O)_xCH₃、-O(CH₂)_x(CH₂CH₂O)_yCH₃Substituent group, wherein x and y >=0 and be integer；R₃Selected from amino connecting key-O (CH₂)_xCONH(CH₂)_yNH-, halogenated class connecting key-O (CH₂)_xAnd carboxyl Class connecting key-O (CH₂)_xCO-, wherein x and y >=1 and be integer；R₄For-H or-CONH (CH₂)_xCH₃, wherein x >=0 and to be whole Number；P₁For macromolecular；

9. biomaterial according to claim 7, wherein the adjacent nitro benzyl class light trigger is adjacent nitro benzyl.

10. biomaterial according to claim 1, wherein the macromolecular and adjacent nitro of photoresponse crosslinked group modification Benzyl class light trigger modification macromolecular in natural biological macromolecular be glucan, hyaluronic acid, gelatin, sodium alginate, One in chondroitin sulfate, fibroin, chitosan, carboxymethyl cellulose or collagen, polyethylene glycol or lemon acid polymer (PEGMC) Kind.

11. application of the light-operated 3D printing biomaterial described in a kind of one of claim 1-10 in skin injury reparation.

12. light-operated 3D printing biomaterial answering in Articular cartilage repair described in a kind of one of claim 1-10 With.