3D printing flexible hydrogel device for pancreas islet transplantation as well as preparation method and application of 3D printing flexible hydrogel device

Abstract

According to the 3D printing flexible hydrogel device for pancreas islet transplantation and the preparation method and application of the 3D printing flexible hydrogel device, functional ink containing N-acryloylurea amine and carboxylic acid betaine carbamido acrylate is developed, the digital light processing 3D printing technology is adopted, the ink formula and printing parameters are optimized, and the pancreas islet transplantation efficiency is improved. The 3D printing flexible hydrogel device for pancreas islet transplantation, which has excellent flexibility, biocompatibility and a controllable pore structure, is prepared. According to the device, a complex geometric structure of the hydrogel device is constructed layer by layer through a DLP printing technology, and accurate control over the porosity, the size and the shape of the device is achieved; the prepared hydrogel device can significantly improve the microenvironment after islet cell transplantation, provide effective protection, and improve the survival rate and transplantation success rate of islet cells.

Description

Technical Field

[0001] The present invention relates to the technical fields of biomedical materials, tissue engineering and regenerative medicine, and more specifically to a 3D printed flexible hydrogel device for pancreatic islet transplantation, and a preparation method and application thereof. Background Art

[0002] Type 1 diabetes is caused by an autoimmune disease, in which the body's immune system mistakenly attacks the pancreatic islets, causing damage or death to the β cells in the islets responsible for secreting insulin, thereby causing hyperglycemia. With the maturity of islet separation and purification technology, islet transplantation has gradually become one of the most promising and effective methods for treating type 1 diabetes. By transplanting healthy islet cells into patients, the secretion capacity of endogenous insulin can be restored, significantly improving blood sugar control. However, islet transplantation still faces many challenges. Transplanted islet cells are vulnerable to attacks by the host immune system, and they also have to withstand the threat of microenvironmental stress such as hypoxia and insufficient nutrient supply. These factors together lead to a significant decrease in the survival rate of islet cells. Therefore, it is particularly important to provide suitable protective packaging materials for islet cells. Currently, commonly used islet encapsulation materials still have many deficiencies in flexibility, biocompatibility and permeability. These materials are difficult to simultaneously meet the requirements of effective protection of islets and biological functional support. For example, unreasonable pore structure design may limit the effective exchange of oxygen and nutrients, and poor mechanical properties of the material may cause the device to easily break during transplantation. In addition, islet transplantation requires customization of the size and functional structure of the packaged device according to the individual needs of the patient. However, traditional preparation methods are difficult to achieve high-precision and complex structure processing, and the manufacturing efficiency is low, making it difficult to meet clinical application needs.

[0003] With the development of 3D printing technology, digital light processing (DLP) technology has shown great potential in biomaterial manufacturing due to its high resolution and fine processing capabilities. DLP technology can build complex geometric structures layer by layer through the selective curing of photoinitiators, and achieve precise control of the porosity, size and shape of hydrogel devices. By optimizing the printing formula and process parameters, DLP technology not only significantly improves the flexibility, biocompatibility and functionality of hydrogels, but also provides a reliable and flexible technical solution to meet the personalized needs of islet transplantation. Summary of the invention

[0004] The present invention overcomes the shortcomings of the prior art. Most pancreatic islet encapsulation materials have limitations in flexibility, biocompatibility and permeability, i.e. customization. A 3D printed flexible hydrogel device for islet transplantation and its preparation method and application are provided. The present invention develops a functional ink based on digital light processing (DLP) 3D printing technology. By optimizing the ink formula and rationally regulating the photoinitiator, porogen and process parameters, the resulting hydrogel has excellent flexibility, biocompatibility and controllable pore structure. At the same time, the complex geometric structure of the hydrogel device is constructed layer by layer through DLP printing technology, which realizes precise control of the porosity, size and shape of the device. The prepared hydrogel device can significantly improve the microenvironment after pancreatic islet cell transplantation, provide effective protection, and improve the survival rate and transplantation success rate of pancreatic islet cells.

[0005] The purpose of the present invention is achieved through the following technical solutions.

[0006] A 3D printed flexible hydrogel device for islet transplantation and a preparation method thereof, wherein the hydrogel device is a hollow cylindrical structure, a pore structure is formed on the surface of the cylindrical structure of the hydrogel device, and the pore structure is distributed in an array, and the steps are as follows:

[0007] Step 1: N-acryloylureaamine (NASC) and carboxylic acid betaine urea acrylate (CBUIA) are dissolved in deionized water, dextran is added as a porogen, a photoinitiator phenyl (2,4,6-trimethylbenzoyl) lithium phosphate (LAP) and a light absorber tartrate are added, oxygen is fully removed from the mixed solution under nitrogen, and after being mixed evenly, a functional ink suitable for digital light processing (DLP) 3D printing is prepared;

[0008] Step 2: According to the pre-designed hydrogel model for islet encapsulation, the functional ink suitable for digital light processing (DLP) 3D printing prepared in step 1 is printed using the DLP 3D printer EFL-BP8600. The specific steps are as follows: first, the pre-designed stereolithography file is imported, and the model is sliced ​​along the Z direction by programming to generate a layer-by-layer printing path, and the printing parameters are set as light intensity, exposure time, and layer height, etc. The DLP 3D printer EFL-BP8600 is started, and the functional ink is solidified layer by layer under the coordinated control of the material trough and the image projection device, and the unsolidified functional ink is removed by ethanol and PBS, and finally a 3D printed flexible hydrogel device for islet transplantation is prepared.

[0009] In step 1, the total mass fraction of N-acryloylureaamine (NASC) and carboxylic acid betaine urea acrylate (CBUIA) in the solution is 10-30wt%, preferably 30wt%, the mass ratio of N-acryloylureaamine (NASC) and carboxylic acid betaine urea acrylate (CBUIA) is 0.25-4:1, preferably 2:1, the weight average molecular weight of dextran is 5000-10000, preferably 7000, the mass fraction of dextran in the solution is 5-20wt%, preferably 10wt%, the mass fraction of phenyl (2,4,6-trimethylbenzoyl) lithium phosphate (LAP) in the solution is 0.1-0.5wt%, preferably 0.1wt%, the mass fraction of lemon yellow in the solution is 0.05-0.2wt%, preferably 0.05wt%, and the mixed solution is deoxygenated under nitrogen for 10-30min, preferably 30min.

[0010] In step 2, the printing parameters are set as follows: the printing layer height is 10-200 μm, preferably 100 μm, and the printing light intensity is 0-30 mW / cm 2 , preferably 20mW / cm 2 The exposure time of each layer is 1-20s, preferably 10s, the number of base layers is 1-5 layers, preferably 2 layers, the exposure time of the base layer is 1-20s, preferably 10s, the peeling distance is 3-6mm, preferably 3mm, the peeling speed is 10-50mm / s, preferably 25mm / s, the platform temperature is 25-50℃, preferably 37℃, and the material tank temperature is 25-50℃, preferably 37℃.

[0011] In step 2, the geometric parameters of the printed model are as follows: the model diameter is 5-10 mm, preferably 7.5 mm, the model height is 0.5-2.5 mm, preferably 2.5 mm, the model wall thickness is 100-500 μm, preferably 250 μm, and the model pore size is 50-500 μm, preferably 200 μm.

[0012] Application of 3D printed flexible hydrogel devices for islet transplantation in biomedical materials, the tensile strength of the hydrogel is 1.25-1.59 MPa, the Young's modulus of the hydrogel is 0.40-0.44 MPa, the tensile modulus of the hydrogel device is 0.29-0.35 MPa, and the compression modulus of the hydrogel device is 0.53-0.57 MPa.

[0013] The beneficial effects of the present invention are as follows: the present invention provides a 3D printed flexible hydrogel device for islet transplantation and a preparation method thereof. The preparation method is simple. By optimizing the printing ink formula and DLP 3D printing technology, the hydrogel device is comprehensively improved in terms of flexibility, mechanical strength, biocompatibility and pore structure, providing effective protection and an ideal microenvironment for islet cells, significantly improving the success rate and cell survival rate of islet transplantation, that is, the application of the hydrogel of the present invention in the preparation of devices for encapsulating and / or transplanting islet cells. In addition, the present invention supports personalized customization to meet the treatment needs of different patients. At the same time, the manufacturing process is efficient and simple, providing a practical solution for the clinical application of islet transplantation. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the preparation process of the DLP 3D printed P (NASC-co-CBUIA) hydrogel of the present invention;

[0015] Figure 2 1 is a graph showing the tensile properties test results of the hydrogel prepared in Example 6, the hydrogel prepared in Example 7, the hydrogel prepared in Example 8, and the hydrogel prepared in Example 9 of the present invention;

[0016] Figure 3 This is a graph showing the tensile properties test results of the hydrogel prepared in Example 5 of the present invention;

[0017] Figure 4 is a graph showing the tensile properties test results of the hydrogel prepared in Example 6 of the present invention;

[0018] Figure 5 It is a diagram showing the cell activity test results of the hydrogel prepared in Example 5, the hydrogel prepared in Example 6, and the hydrogel prepared in Example 10 of the present invention;

[0019] Figure 6 It is a diagram showing the cell adhesion test results of the hydrogel prepared in Example 5, the hydrogel prepared in Example 6, and the hydrogel prepared in Example 10 of the present invention;

[0020] Figure 7 1 is a graph showing the contact angle test results of the hydrogel prepared in Example 5, the hydrogel prepared in Example 6, and the hydrogel prepared in Example 10 of the present invention;

[0021] Figure 8 This is a printing demonstration photo of the DLP 3D printed P(NASC-co-CBUIA) hydrogel in the present invention;

[0022] Fig. 9are diagrams of the hydrogel device model of Example 1, the hydrogel device model of Example 2, the hydrogel device model of Example 3, and the hydrogel device model of Example 4 of the present invention;

[0023] Fig.10 This is a photo of the pores on the surface of the hydrogel device prepared in Example 1 of the present invention;

[0024] Fig.11 This is a diagram of the hydrogel device prepared in Example 3 of the present invention being used for islet cell encapsulation and then implanted subcutaneously in mice, as well as blood glucose monitoring in mice. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further described below through specific embodiments.

[0026] Example 1

[0027] Step 1, weigh 0.2000g N-acryloylureaamine (NASC) and 0.1000g carboxylic acid betaine urea acrylate (CBUIA), dissolve in 1mL deionized water, and use vortex stirring until completely dissolved. Then add 100mg of dextran with a molecular weight of 7000kDa as a porogen, add 5mg of photoinitiator phenyl (2,4,6-trimethylbenzoyl) lithium phosphate (LAP) and 1mg of light-blocking agent lemon yellow to the solution. The mixed solution is fully oxygen-free under nitrogen environment, and after being mixed evenly, a functional ink suitable for digital light processing (DLP) 3D printing is prepared.

[0028] Step 2: Transfer the ink from step 1 to the printer tank (EFL-BP8600) and load the pre-designed hydrogel model for islet encapsulation, whose geometric parameters are 10 mm in diameter, 2.5 mm in height, and 300 μm in wall thickness. Slice the model along the Z axis through programming to generate a layer-by-layer printing path, and set the printing parameters: layer height is 100 μm, light intensity is 20 mW / cm 2 , the exposure time of each layer is 10s, the number of base layers is 2, the exposure time of the base layer is 10s, the peeling distance is 3mm, the peeling speed is 25mm / s, and the platform and trough temperatures are both 37°C. After printing, ethanol and PBS are used to wash and remove the uncured material, and finally a hydrogel device that meets the needs of islet encapsulation is formed.

[0029] Example 2

[0030] Step 1, weigh 0.2000g N-acryloylureaamine (NASC) and 0.1000g carboxylic acid betaine urea acrylate (CBUIA), dissolve in 1mL deionized water, and use vortex stirring until completely dissolved. Then add 100mg of dextran with a molecular weight of 7000kDa as a porogen, add 5mg of photoinitiator phenyl (2,4,6-trimethylbenzoyl) lithium phosphate (LAP) and 1mg of light-blocking agent lemon yellow to the solution. The mixed solution is fully oxygen-free under nitrogen environment, and after being mixed evenly, a functional ink suitable for digital light processing (DLP) 3D printing is prepared.

[0031] Step 2: Transfer the ink in step 1 to the printer tank (EFL-BP8600) and load the pre-designed hydrogel model for islet encapsulation, whose geometric parameters are 7.5 mm in diameter, 2.5 mm in height, and 250 μm in wall thickness. Slice the model along the Z axis through programming to generate a layer-by-layer printing path, and set the printing parameters: layer height is 100 μm, light intensity is 20 mW / cm 2 , the exposure time of each layer is 10s, the number of base layers is 2, the exposure time of the base layer is 10s, the peeling distance is 3mm, the peeling speed is 25mm / s, and the platform and trough temperatures are both 37°C. After printing, ethanol and PBS are used to wash and remove the uncured material, and finally a hydrogel device that meets the needs of islet encapsulation is formed.

[0032] Example 3

[0033] Step 1, weigh 0.2000g N-acryloyl ureaamine (NASC) and 0.1000g carboxylic acid betaine urea acrylate (CBUIA), dissolve in 1mL deionized water, and use a vortex to stir until completely dissolved. Then add 5mg of photoinitiator phenyl (2,4,6-trimethylbenzoyl) lithium phosphate (LAP) and 1mg of light-blocking agent lemon yellow to the solution. The mixed solution is fully oxygen-free under nitrogen, and after being mixed evenly, a functional ink suitable for digital light processing (DLP) 3D printing is prepared.

[0034] Step 2: Transfer the ink in step 1 to the printer tank (EFL-BP8600) and load the pre-designed hydrogel model for islet encapsulation, whose geometric parameters are 10 mm in diameter, 2.5 mm in height, 300 μm in wall thickness, and 200 μm in pore size. Slice the model along the Z axis through programming to generate a layer-by-layer printing path, and set the printing parameters: layer height is 100 μm, light intensity is 20 mW / cm 2, the exposure time of each layer is 10s, the number of base layers is 2, the exposure time of the base layer is 10s, the peeling distance is 3mm, the peeling speed is 25mm / s, and the platform and trough temperatures are both 37°C. After printing, ethanol and PBS are used to wash and remove the uncured material, and finally a hydrogel device that meets the needs of islet encapsulation is formed.

[0035] Example 4

[0036] Step 1, weigh 0.2000g N-acryloyl ureaamine (NASC) and 0.1000g carboxylic acid betaine urea acrylate (CBUIA), dissolve in 1mL deionized water, and use a vortex to stir until completely dissolved. Then add 5mg of photoinitiator phenyl (2,4,6-trimethylbenzoyl) lithium phosphate (LAP) and 1mg of light-blocking agent lemon yellow to the solution. The mixed solution is fully oxygen-free under nitrogen, and after being mixed evenly, a functional ink suitable for digital light processing (DLP) 3D printing is prepared.

[0037] Step 2: Transfer the ink in step 1 to the printer tank (EFL-BP8600) and load the pre-designed hydrogel model for islet encapsulation, whose geometric parameters are 7.5 mm in diameter, 1.25 mm in height, 250 μm in wall thickness, and 200 μm in pore size. Slice the model along the Z axis through programming to generate a layer-by-layer printing path, and set the printing parameters: layer height is 100 μm, light intensity is 20 mW / cm 2 , the exposure time of each layer is 10s, the number of base layers is 2, the exposure time of the base layer is 10s, the peeling distance is 3mm, the peeling speed is 25mm / s, and the platform and trough temperatures are both 37°C. After printing, ethanol and PBS are used to wash and remove the uncured material, and finally a hydrogel device that meets the needs of islet encapsulation is formed.

[0038] Example 5

[0039] Step 1, weigh 0.2000g N-acryloyl ureaamine (NASC) and 0.1000g carboxylic acid betaine urea acrylate (CBUIA), dissolve in 1mL deionized water, and use a vortex to stir until completely dissolved. Then add 5mg of photoinitiator phenyl (2,4,6-trimethylbenzoyl) lithium phosphate (LAP) and 1mg of light-blocking agent lemon yellow to the solution. The mixed solution is fully oxygen-free under nitrogen, and after being mixed evenly, a functional ink suitable for digital light processing (DLP) 3D printing is prepared.

[0040] Step 2: Transfer the ink from step 1 to the printer tank (EFL-BP8600), load the pre-designed rectangular model, whose geometric parameters are length 40mm, width 10mm, height 1mm. Slice the model along the Z axis through programming, generate a layer-by-layer printing path, and set the printing parameters: layer height is 100μm, light intensity is 20mW / cm 2 , the exposure time of each layer is 10s, the number of base layers is 2, the exposure time of the base layer is 10s, the peeling distance is 3mm, the peeling speed is 25mm / s, and the platform and trough temperatures are both 37°C. DLP P(NASC-co-CBUIA)-20-10 hydrogel was printed.

[0041] Example 6

[0042] 0.2000g N-acryloylureaamine (NASC) and 0.1000g carboxylic acid betaine urea acrylate (CBUIA) were weighed and dissolved in 1mL deionized water and stirred with a vortex until completely dissolved. Then 5mg of photoinitiator phenyl (2,4,6-trimethylbenzoyl) lithium phosphate (LAP) was added to the solution. The mixed solution was fully oxygen-free under nitrogen, and after being mixed evenly, it was irradiated under ultraviolet light for 60min to initiate free radical polymerization to obtain P(NASC-co-CBUIA)-20-10 hydrogel.

[0043] Example 6

[0044] 0.1800 g of N-acryloylureaamine (NASC) and 0.1200 g of carboxylic acid betaine urea acrylate (CBUIA) were weighed and dissolved in 1 mL of deionized water and stirred with a vortex until completely dissolved. Then 5 mg of photoinitiator phenyl (2,4,6-trimethylbenzoyl) lithium phosphate (LAP) was added to the solution. The mixed solution was fully oxygenated under nitrogen, and after being mixed evenly, it was irradiated under ultraviolet light for 60 min to initiate free radical polymerization to obtain P (NASC-co-CBUIA) -18-12 hydrogel.

[0045] Example 7

[0046] 0.1500 g of N-acryloylureaamine (NASC) and 0.1500 g of carboxylic acid betaine urea acrylate (CBUIA) were weighed and dissolved in 1 mL of deionized water and stirred with a vortex until completely dissolved. Then 5 mg of photoinitiator phenyl (2,4,6-trimethylbenzoyl) lithium phosphate (LAP) was added to the solution. The mixed solution was fully oxygenated under nitrogen, and after being mixed evenly, it was irradiated under ultraviolet light for 60 min to initiate free radical polymerization to obtain P (NASC-co-CBUIA) -15-15 hydrogel.

[0047] Example 8

[0048] 0.1330 g NASC and 0.0670 g carboxylic acid betaine urea acrylate (CBUIA) were weighed and dissolved in 1 mL of deionized water and vortexed until completely dissolved. Then 5 mg of photoinitiator phenyl (2,4,6-trimethylbenzoyl) lithium phosphate (LAP) was added to the solution. The mixed solution was fully oxygenated under nitrogen, and after being mixed evenly, it was irradiated under ultraviolet light for 60 min to initiate free radical polymerization to obtain P (NASC-co-CBUIA) -16.7-8.3 hydrogel.

[0049] Example 9

[0050] 0.1670 g of N-acryloylureaamine (NASC) and 0.0830 g of carboxylic acid betaine urea acrylate (CBUIA) were weighed and dissolved in 1 mL of deionized water and stirred with a vortex until completely dissolved. Then 5 mg of photoinitiator phenyl (2,4,6-trimethylbenzoyl) lithium phosphate (LAP) was added to the solution. The mixed solution was fully oxygenated under nitrogen, and after being mixed evenly, it was irradiated under ultraviolet light for 60 min to initiate free radical polymerization to obtain P (NASC-co-CBUIA) -16.7-8.3 hydrogel.

[0051] Example 10

[0052] 0.3000 g of N-acryloylureaamine (NASC) was weighed and dissolved in 1 mL of deionized water, and vortexed until completely dissolved. Then 5 mg of photoinitiator phenyl (2,4,6-trimethylbenzoyl) lithium phosphate (LAP) was added to the solution. The mixed solution was fully oxygenated under nitrogen, and after being mixed evenly, it was irradiated under ultraviolet light for 60 min to initiate free radical polymerization to obtain PNASC-30 hydrogel.

[0053] Mechanical properties test: The mechanical properties of P(NASC-co-CBUIA) hydrogel and DLP(NASC-co-CBUIA)-20-10 hydrogel were tested using an electronic universal testing machine (Instron 2344). The hydrogel was prepared into 35×2.1×1 mm 3 The dumbbell-shaped specimens were subjected to tensile test at a strain rate of 50 mm / min. The compression test was conducted by preparing the hydrogel sample into a cylindrical shape and then performing the compression test at a compression rate of 10 mm / min. Figure 2As shown in the figure, with the increase of total solid content, the tensile strength and Young's modulus of the hydrogel increased (the tensile strength and Young's modulus increased from 0.67±0.04MPa and 0.32±0.04MPa to 1.42±0.17MPa and 0.42±0.02MPa, respectively), and with the increase of the proportion of NASC in the copolymer component, the tensile strength and Young's modulus of the hydrogel also showed an increasing trend (the tensile strength and Young's modulus increased from 0.08±0.01MPa and 0.06±0.03MPa to 1.42±0.17MPa and 0.42±0.02MPa, respectively). Figure 3 and Figure 4 As shown in the figure, the tensile modulus and compression modulus of the P(NASC-co-CBUIA)-20-10 hydrogel prepared by the mold were 0.50±0.05MPa and 0.68±0.14MPa, respectively, while the tensile modulus and compression modulus of the P(NASC-co-CBUIA)-20-10 hydrogel printed by DLP were 0.32±0.03MPa and 0.55±0.02MPa, respectively, indicating that compared with the P(NASC-co-CBUIA) hydrogel prepared by the mold, the P(NASC-co-CBUIA) hydrogel printed by DLP has a decrease in mechanical properties, but still maintains a relatively high strength.

[0054] Cytotoxicity test: The in vitro MTT method and live-dead staining method were used to test the cytotoxicity of PNASC-30 hydrogel, P(NASC-co-CBUIA)-20-10 hydrogel and DLP P(NASC-co-CBUIA)-20-10 hydrogel on L929 mouse fibroblasts. Figure 5 As shown, the cell viability of all hydrogels was above 100%, indicating that the P(NASC-co-CBUIA) hydrogels prepared by mold and DLP printing had good cell compatibility.

[0055] Cell adhesion test: PNASC-30 hydrogel, P(NASC-co-CBUIA)-20-10 hydrogel and DLP P(NASC-co-CBUIA)-20-10 hydrogel were tested for cell adhesion of L929 mouse fibroblasts. Figure 6 As shown, P(NASC-co-CBUIA) hydrogels prepared by mold and DLP printing had lower cell adhesion compared with the control group and PNASC hydrogel group.

[0056] Contact angle test: The water contact angles on PNASC-30 hydrogel, P(NASC-co-CBUIA)-20-10 hydrogel and DLP P(NASC-co-CBUIA)-20-10 hydrogel were measured using a contact angle analyzer (JC2000D, Shanghai Zhongchen Instrument Co., Ltd.) to analyze their hydrophilicity and hydrophobicity. Figure 7 As shown, both the P(NASC-co-CBUIA) hydrogels prepared by mold and printed by DLP have smaller contact angles, indicating that they are more hydrophilic.

[0057] like Figure 8 As shown in the figure, the inventor team designed some complex three-dimensional structures, including a flat five-petal flower, a three-dimensional five-petal flower with a cavity, a cylinder, and a square hollow tube. Through observation of the printed model, it was found that both tiny holes and complex three-dimensional structures can be reproduced with high quality through DLP 3D printing. This shows that P(NASC-co-CBUIA) hydrogel has a high printing resolution.

[0058] like Fig. 9 As shown in Figure 1, the inventor team has developed several models for islet cell encapsulation, covering different diameters, heights, and surface pore sizes. Fig.10 As shown in the figure, we selected a hydrogel device model with a diameter of 10 mm, a height of 2.5 mm, a wall thickness of 300 μm, and a pore size of 200 μm for DLP 3D printing, and compared the pores on the surface of the printed device with the model design, as well as the changes after swelling equilibrium in PBS. The results showed that the pore size of the printed hydrogel device was consistent with the design model and did not change significantly in PBS.

[0059] like Fig.11 As shown in the figure, the inventor team prepared a hydrogel device with a diameter of 10 mm, a height of 2.5 mm, a wall thickness of 300 μm, and a pore size of 200 μm by DLP 3D printing, and used it for islet cell encapsulation after sufficient swelling equilibrium in PBS. The results showed that the islet cells were evenly distributed inside the hydrogel device. The hydrogel device encapsulated with islet cells was implanted subcutaneously into diabetic mice, and their blood sugar levels were monitored daily. It was observed that the blood sugar of the mice dropped below the standard blood sugar for diabetes on the seventh day. This shows that the DLP 3D printed hydrogel device can effectively protect islet cells and improve their survival rate, thereby significantly improving the success rate of transplantation.

[0060] According to the content of the present invention, the process parameters can be adjusted to achieve the preparation of hydrogels, and the performance shown by the test is basically consistent with the present invention. The above is an exemplary description of the present invention. It should be noted that without departing from the core of the present invention, any simple deformation, modification or other equivalent replacement that can be done by other technicians in this field without spending creative labor falls within the protection scope of the present invention.

Claims

1. A method for preparing a 3D printed flexible hydrogel device for pancreatic islet transplantation, characterized in that: Follow the steps below: Step 1: dissolving N-acryloyl ureaamine and carboxylic acid betaine urea acrylate in deionized water, adding dextran as a porogen, adding a photoinitiator phenyl (2,4,6-trimethylbenzoyl) lithium phosphate and a light absorber tartrate, fully removing oxygen from the mixed solution under nitrogen, and mixing evenly to prepare a functional ink suitable for digital light processing 3D printing; Step 2: According to the pre-designed hydrogel model for islet encapsulation, use the digital light processing 3D printer EFL-BP8600 to print the functional ink suitable for digital light processing 3D printing prepared in step 1. The specific steps are as follows: first, import the pre-designed stereolithography file, slice the model along the Z direction through programming, generate a layer-by-layer printing path, and set the printing parameters such as light intensity, exposure time and layer height, start the digital light processing 3D printer EFL-BP8600, and solidify the above functional ink layer by layer under the coordinated control of the material trough and the image projection device, and remove the uncured functional ink with ethanol and PBS, and finally prepare a 3D printed flexible hydrogel device for islet transplantation.

2. The method for preparing a 3D printed flexible hydrogel device for islet transplantation according to claim 1, characterized in that: In step 1, the total mass fraction of N-acryloylureaamine and carboxylic acid betaine urea acrylate in the solution is 10-30wt%, and the mass ratio of N-acryloylureaamine to carboxylic acid betaine urea acrylate is 0.25-4:

1.

3. The method for preparing a 3D printed flexible hydrogel device for islet transplantation according to claim 2, characterized in that: In step 1, the total mass fraction of N-acryloyl ureaamine and carboxylic acid betaine urea acrylate in the solution is 30wt%, and the mass ratio of N-acryloyl ureaamine to carboxylic acid betaine urea acrylate is 2:

1.

4. The method for preparing a 3D printed flexible hydrogel device for islet transplantation according to claim 1, characterized in that: In step 1, the number average molecular weight of dextran is 5000-10000, the mass fraction of dextran in the solution is 5-20wt%, the mass fraction of phenyl (2,4,6-trimethylbenzoyl) phosphate lithium salt in the solution is 0.1-0.5wt%, the mass fraction of tartrazine in the solution is 0.05-0.2wt%, and the mixed solution is deoxygenated under nitrogen for 10-30min.

5. The method for preparing a 3D printed flexible hydrogel device for islet transplantation according to claim 4, characterized in that: In step 1, the number average molecular weight of dextran is 7000, the mass fraction of dextran in the solution is 10wt%, the mass fraction of phenyl (2,4,6-trimethylbenzoyl) phosphate lithium salt in the solution is 0.1wt%, the mass fraction of tartrazine in the solution is 0.05wt%, and the mixed solution is deoxygenated under nitrogen for 30 minutes.

6. The method for preparing a 3D printed flexible hydrogel device for pancreatic islet transplantation according to claim 1, characterized in that: In step 2, the printing parameters are set as follows: printing layer height is 10-200μm, printing light intensity is 0-30mW / cm 2 , the exposure time of each layer is 1-20s, the number of base layers is 1-5, the exposure time of the base layer is 1-20s, the peeling distance is 3-6mm, the peeling speed is 10-50mm / s, the platform temperature is 25-50℃, and the material trough temperature is 25-50℃.

7. The method for preparing a 3D printed flexible hydrogel device for islet transplantation according to claim 6, characterized in that: In step 2, the printing parameters are set as follows: the printing layer height is 100 μm, the printing light intensity is 20 mW / cm 2 , the exposure time of each layer is 10s, the number of base layers is 2, the exposure time of the base layer is 10s, the peeling distance is 3mm, the peeling speed is 25mm / s, the platform temperature is 37℃, and the material trough temperature is 37℃.

8. The method for preparing a 3D printed flexible hydrogel device for pancreatic islet transplantation according to claim 1, characterized in that: In step 2, the geometric parameters of the printed model are as follows: the model diameter is 5-10 mm, preferably 7.5 mm, the model height is 0.5-2.5 mm, preferably 2.5 mm, the model wall thickness is 100-500 μm, preferably 250 μm, and the model pore size is 50-500 μm, preferably 200 μm.

9. A 3D printed flexible hydrogel device for islet transplantation prepared by the preparation method of any one of claims 1 to 8, characterized in that: The hydrogel device is a hollow cylindrical structure, a pore structure is formed on the surface of the cylindrical structure of the hydrogel device, and the pore structure is distributed in an array.

10. The use of the 3D printed flexible hydrogel device for islet transplantation in biomedical materials according to claim 9, characterized in that: The tensile strength of the hydrogel is 1.25-1.59 MPa, the Young's modulus of the hydrogel is 0.40-0.44 MPa, the tensile modulus of the hydrogel device is 0.29-0.35 MPa, and the compression modulus of the hydrogel device is 0.53-0.57 MPa, such as the application in the preparation of devices for encapsulating and / or transplanting pancreatic islet cells.

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