A polyester resin containing a photo-reactive dopamine, and a preparation method and application thereof

Abstract

The application provides a polyester resin containing photoreactive dopamine and a preparation method and application thereof.The polyester resin containing photoreactive dopamine provided by the application is prepared from raw materials including dopamine methacrylamide (DMA), polypropylene fumarate (PPF), diethyl fumarate (DEF) and a photoinitiator.The dopamine molecules are integrated into the PPF crosslinking network structure through DMA, and the hydrophilicity of the material surface is significantly improved.The unsaturated polyester resin provided by the application can be applied to 3D printing technology based on face projection microstereolithography (PmuSL), the solidification forming process is simple, the three-dimensional structure is not limited, the application range is wide, and the final formed product can be used for further loading of bioactive substances, and has a wide application prospect in bone tissue engineering.The application further provides a preparation method and application of the polyester resin containing photoreactive dopamine.

Description

Technical Field

[0001] This invention belongs to the field of biomaterials technology, specifically relating to a polyester resin containing photoreactive dopamine, its preparation method, and its application. Background Technology

[0002] Bone tissue is a vital dynamic regenerative system in the human body, possessing a complex, multi-level porous structure and excellent mechanical properties. Many patients suffering from accidental injuries, bone tumors, or spinal cord injuries face bone defects, which not only affect their mobility but may also threaten their health. To address this issue, bone tissue engineering has emerged. As an innovative treatment strategy, it combines principles of life sciences and engineering, offering potential solutions by developing bio-alternatives capable of repairing, maintaining, or promoting the restoration of function and morphology in human tissues and organs.

[0003] Bone tissue engineering scaffolds are alternative implants made of bioactive and biocompatible materials that provide support for bone regeneration and mimic the extracellular matrix environment. The design and material selection of the scaffold are crucial; it must not only meet mechanical performance requirements but also possess good biodegradability and biocompatibility. Among numerous polymer biomaterials, photocrosslinkable poly(propylene fumarate) (PPF) has become a highly promising material in bone tissue engineering due to its excellent biocompatibility, injectability, and biodegradability. PPF can degrade in vivo into fumaric acid and propylene glycol, which are excreted through normal metabolism, making it a very promising bone tissue engineering material.

[0004] With the continuous development of 3D printing technology, especially in the field of tissue engineering, this technology can precisely design and manufacture complex three-dimensional biomimetic structures. Projection micro-stereolithography (PμSL), as a photopolymerization 3D printing technology, has become an ideal choice for manufacturing personalized bone tissue engineering scaffolds due to its ability to process micron-level complex structures with high resolution and precision, and its strong cross-scale processing capabilities. In PμSL technology, the selection of surface hydrophilic materials is crucial for promoting cell growth. The hydrophilicity of the material surface can effectively improve the contact between the scaffold and body fluids, reduce protein adsorption, and thus enhance the biocompatibility and tissue integration ability of the material. However, in the 3D printing application of PPF materials, the hydrophobicity of the PPF material surface limits its application in bone tissue engineering. Therefore, there is a need to develop a new PPF material suitable for 3D printing. Summary of the Invention

[0005] The present invention aims to at least solve one of the aforementioned technical problems existing in the prior art. To this end, the present invention provides a polyester resin containing photoreactive dopamine, in which dopamine molecules are integrated into the PPF crosslinking network structure through dopaminemethacrylamide (DMA), the hydrophilicity of the material surface is significantly improved, and it is suitable for 3D printing, especially PμSL technology.

[0006] The present invention also provides a method for preparing a polyester resin containing photoreactive dopamine.

[0007] The present invention also provides a biomedical material prepared from the polyester resin of the present invention.

[0008] The present invention also provides the application of polyester resin in 3D printing.

[0009] A first aspect of the present invention provides a polyester resin containing photoreactive dopamine, wherein the raw materials for preparation include DMA, PPF, diethyl fumarate (DEF) and a photoinitiator.

[0010] The present invention relates to a technical solution of a polyester resin containing photoreactive dopamine, which has at least the following beneficial effects:

[0011] One limitation of cross-linked PPF scaffolds is their surface hydrophobicity. Therefore, surface modification of PPF scaffolds can compensate for this limitation. Polydopamine, formed by the self-polymerization of dopamine under alkaline and oxygen-containing conditions, provides good hydrophilicity to implants through its active functional groups. Dopamine possesses good bioactivity and can be used as a modifier. Both dopamine monomers and polydopamine can promote osteoblast proliferation and mineralization, and induce osteogenic differentiation, by adsorbing the extracellular matrix and related proteins. Furthermore, due to the coordination ability of the catechol group in the dopamine molecule, it exhibits excellent adhesion properties and can further interact strongly with many bioactive substances such as bone morphogenetic protein-2 (BMP-2). Various dopamine derivatives, including DMA, are also used as surface-modifying molecules in bone tissue engineering.

[0012] This invention provides a polyester resin containing photoreactive dopamine. By integrating dopamine molecules into the PPF crosslinking network structure through DMA, the hydrophilicity of the material surface is significantly improved.

[0013] The unsaturated polyester resin provided by this invention can be applied to PμSL-based 3D printing technology. The curing process is simple, the three-dimensional structure is unrestricted, the application range is wide, and the final molded product can be further loaded with bioactive substances, showing broad application prospects in bone tissue engineering.

[0014] According to some embodiments of the present invention, the raw materials for preparation, by weight, include:

[0015] DMA: 5-15 copies

[0016] PPF: 42.5–47.5 parts

[0017] DEF: 42.5–47.5 parts

[0018] Photoinitiator: 0.45–3.3 parts.

[0019] According to some embodiments of the present invention, the number-average molecular weight of the PPF is 2489 and the weight-average molecular weight is 5014.

[0020] According to some embodiments of the present invention, in the preparation of raw materials, PPF is dissolved in an equal mass of DEF.

[0021] Dissolving PPF in an equal mass of DEF aims to reduce the viscosity of the resin, allowing it to maintain good flowability during 3D printing. DEF, as a reactive diluent, can participate in the photocrosslinking reaction of the polymer, thus preserving the original mechanical properties of the polymer.

[0022] According to some embodiments of the present invention, the photoinitiator preferably accounts for 0.5% to 3% of the total mass of DMA, PPF and DEF.

[0023] According to some embodiments of the present invention, the photoinitiator is more preferably 1 to 2% of the total mass of DMA, PPF and DEF.

[0024] According to some embodiments of the present invention, the method for synthesizing DMA includes the following steps: dissolving sodium tetraborate, sodium bicarbonate and dopamine hydrochloride in water, adjusting the pH of the system, then adding methacrylic anhydride dropwise, washing, extracting, drying and recrystallizing the product.

[0025] According to some embodiments of the present invention, sodium tetraborate, sodium bicarbonate and dopamine hydrochloride are dissolved in water, and the pH of the system is adjusted to be above 8.

[0026] According to some embodiments of the present invention, in the synthesis of DMA, the product is washed and extracted with ethyl acetate, then dried with anhydrous sodium sulfate, and finally recrystallized in hexane to obtain a gray solid DMA.

[0027] According to some embodiments of the present invention, during the synthesis of DMA, the molar ratio of dopamine hydrochloride to methacrylic anhydride is preferably 1:1.1 to 1.12.

[0028] According to some embodiments of the present invention, during the synthesis of DMA, the preferred reaction conditions are overnight at room temperature under a nitrogen or argon atmosphere.

[0029] According to some embodiments of the present invention, the synthesis method of the PPF includes the following steps: mixing DEF, 1,2-propanediol, catalyst and polymerization inhibitor, carrying out a first step reaction to obtain a di(hydroxypropyl) fumarate intermediate, and then carrying out a second step transesterification reaction to obtain the PPF after polycondensation.

[0030] According to some embodiments of the present invention, in the method for synthesizing PPF, the molar ratio of DEF, 1,2-propanediol, catalyst and polymerization inhibitor is preferably 1:2.8-3.5:0.008-0.02:0.002-0.003.

[0031] According to some embodiments of the present invention, in the method for synthesizing PPF, the molar ratio of DEF, 1,2-propanediol, catalyst and polymerization inhibitor is more preferably 1:2.9-3.2:0.009-0.015:0.002-0.003.

[0032] According to some embodiments of the present invention, the catalyst is preferably at least one of anhydrous zinc chloride and anhydrous aluminum chloride.

[0033] According to some embodiments of the present invention, the catalyst is more preferably anhydrous zinc chloride.

[0034] According to some embodiments of the present invention, the polymerization inhibitor is preferably at least one of hydroquinone, p-benzoquinone, and methylhydroquinone.

[0035] According to some embodiments of the present invention, the polymerization inhibitor is more preferably hydroquinone.

[0036] According to some embodiments of the present invention, in the method for synthesizing PPF, the conditions for the first step reaction are preferably to stir the reaction at 90-110°C for 0.5-1 h under an inert gas atmosphere, and then raise the temperature to 140-150°C for 6-8 h.

[0037] The preferred conditions for the second step reaction are vacuum conditions (less than 1 mmHg) at 90–100 °C for 0.5–1 h, followed by heating to 130–150 °C for 3–5 h until the desired molecular weight is obtained.

[0038] According to some embodiments of the present invention, the photoinitiator is preferably at least one of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (i.e., photoinitiator 819), (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, bis(1-(2,4-difluorophenyl)-3-pyrrolithyl)dicentectan (i.e., photoinitiator 784), or oxobis(ethane-2,1-diyl)bis(2-oxo-2-phenylacetic acid) (i.e., photoinitiator 754).

[0039] According to some embodiments of the present invention, the photoinitiator is more preferably photoinitiator 819.

[0040] A second aspect of the present invention provides a method for preparing the polyester resin of the first aspect of the present invention, comprising the following steps:

[0041] Under light-protected conditions, the PPF is dissolved in the DEF, then a DMA solution is added, and finally the photoinitiator is added. After mixing evenly, the polyester resin is obtained.

[0042] One technical solution of the present invention relating to the preparation method of polyester resin has at least the following beneficial effects:

[0043] This preparation method, by introducing DMA into the PPF crosslinking network, not only improves the material's hydrophilicity but also enhances its bioactivity and interaction with bioactive substances. Furthermore, this resin is suitable for PμSL-based 3D printing technology, enabling the fabrication of high-precision, personalized bone tissue engineering scaffolds, and can be loaded with bioactive substances to further improve bone regeneration. The simple preparation process and broad application prospects make this technology highly promising in the field of bone tissue engineering.

[0044] The preparation method of the present invention does not require expensive equipment and complex process control, the reaction conditions are not harsh, the raw materials are readily available, the production cost is low, and it is easy to industrialize.

[0045] According to some embodiments of the present invention, the solvent of the DMA solution is preferably N,N-dimethylformamide.

[0046] According to some embodiments of the present invention, the temperature of the mixing process is 80–120°C.

[0047] A third aspect of the present invention provides a biomedical material prepared from the polyester resin of the first aspect of the present invention.

[0048] One technical solution of the present invention relating to biomedical materials has at least the following beneficial effects:

[0049] The biomedical material provided by this invention optimizes its hydrophilicity and bioactivity by introducing photoreactive dopamine molecules, significantly enhancing its application in bone tissue engineering. This material promotes cell adhesion, proliferation, and differentiation, supports bone regeneration, is suitable for personalized 3D printing technology, and possesses good biodegradability and mechanical properties, enabling efficient and precise treatment for patients. Its simple preparation process and broad application prospects make this material a promising candidate in the biomedical field.

[0050] According to some embodiments of the present invention, the biomedical materials include repair materials, implantable materials, drug delivery materials, diagnostic materials, surface treatment materials, biosensing materials, and gene and cell therapy materials.

[0051] Repair materials are used to repair and replace damaged human tissues or organs, providing support and promoting repair in the damaged area. These include bone tissue engineering materials, soft tissue engineering materials, and joint and cartilage replacement materials. Bone tissue engineering materials, such as bone tissue engineering scaffolds and bone replacement materials, are primarily used for the repair and regeneration of bone defects. Soft tissue engineering materials are used to repair damage to soft tissues such as skin, muscles, nerves, and cardiovascular systems. Examples include biodegradable dressings or synthetic skin materials used for wound healing. Joint and cartilage replacement materials are used to repair damaged articular cartilage, typically using scaffolds made from biomaterials (such as hydroxyapatite and polymer composites).

[0052] Implantable materials are typically used as artificial replacements, implanted in the human body long-term or permanently to replace or support physiological functions.

[0053] Drug delivery materials are used to precisely deliver active ingredients such as drugs, genes, and proteins to designated locations.

[0054] Diagnostic materials are used in biomedical imaging, in vitro diagnostics, and other fields to help medical personnel detect and diagnose diseases.

[0055] Surface treatment materials are used to improve the biocompatibility or performance of implant surfaces.

[0056] Biosensing materials and tissue engineering materials combine the principles of biology, materials science, and engineering to prepare artificial biomaterials that can mimic the structure of human tissues and organs.

[0057] Gene and cell therapy materials are used to deliver gene or cell therapy agents to promote the treatment of diseases or tissue repair.

[0058] The fourth aspect of the present invention provides the application of the polyester resin of the first aspect of the present invention in 3D printing.

[0059] By applying the polyester resin of this invention to 3D printing technology, high-precision, personalized bone tissue engineering scaffolds can be manufactured. The beneficial effects of this application include enhanced scaffold bioactivity, improved hydrophilicity, optimized mechanical properties, and improved therapeutic efficacy, while also simplifying the fabrication process and reducing costs. The application of 3D printing also enables personalized treatment, further improving the precision and effectiveness of clinical treatment. Therefore, the application of the polyester resin of this invention in 3D printing provides a new solution for bone tissue engineering and other medical fields, with broad prospects for clinical application.

[0060] According to some embodiments of the present invention, the 3D printing technology is PμSL technology.

[0061] According to some embodiments of the present invention, no additional light-blocking agent is required during the 3D printing process. Attached Figure Description

[0062] Figure 1 This is a schematic diagram of the DMA synthesis process.

[0063] Figure 2 This is a schematic diagram of the 3D printing process of unsaturated polyester resin containing photoreactive dopamine.

[0064] Figure 3 This is a schematic diagram of loading bioactive substances onto the surface of a 3D printed scaffold.

[0065] Figure 4 It is the nuclear magnetic resonance of dopamine hydrochloride and DMA. 1 H spectrum.

[0066] Figure 5 It is the nuclear magnetic resonance of dopamine hydrochloride and DMA. 13 C-spectrum.

[0067] Figure 6 These are Fourier transform infrared spectra of dopamine hydrochloride, DMA, and photocrosslinked samples.

[0068] Figure 7 These are the test results of the gel fraction and swelling rate of the photocrosslinked sample.

[0069] Figure 8 These are the water contact angle test results for the photocrosslinked sample.

[0070] Figure 9 This is the result of the friction coefficient test on the surface of the photocrosslinked sample.

[0071] Figure 10 These are the test results of the tensile and compressive mechanical properties of the photocrosslinked sample.

[0072] Figure 11This is the result of cytotoxicity testing on the photocrosslinked sample.

[0073] Figure 12 These are the test results of the effect of photocrosslinked samples on promoting osteodifferentiation of MC3T3 cells.

[0074] Figure 13 This is the 3D printing "working curve" of unsaturated polyester resin.

[0075] Figure 14 It is a 3D printed biomimetic structure scaffold made of 10% DMA / PPF / DEF unsaturated polyester resin.

[0076] Figure 15 It is a 3D printed biomimetic structure scaffold made of PPF / DEF unsaturated polyester resin. Detailed Implementation

[0077] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0078] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0079] Unless otherwise specified, "room temperature" in this invention means 25±5℃.

[0080] Unless otherwise specified, "about" in this invention means that the allowable error is within ±2%.

[0081] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0082] Example 1

[0083] A polyester resin containing photoreactive dopamine was prepared by the following method:

[0084] 1) DMA synthesis: such as Figure 1 As shown, 20g of sodium tetraborate and 8g of sodium bicarbonate were dissolved in 200mL of deionized water, and high-purity nitrogen (argon) was bubbled through the solution for 20min. Then, 10g of dopamine hydrochloride (52.73 mmol) was added to the solution.

[0085] If necessary, add 1M sodium hydroxide to the solution to bring the pH of the system above 8. Then dissolve 9.4 mL of methacrylic anhydride (59.3 mmol) in 50 mL of tetrahydrofuran and add it dropwise to the solution. The system is then reacted overnight at room temperature under a nitrogen (argon) atmosphere.

[0086] Remove the white precipitate at the bottom of the flask by centrifugation twice (wash the precipitate three times with deionized water), transfer the mixture after reaction into a separatory funnel, and wash twice with 100 mL of ethyl acetate.

[0087] Add concentrated hydrochloric acid to lower the pH of the solution to below 2. At this point, DMA precipitates out of the solution. Then, extract the DMA with 100 mL of ethyl acetate, shake and let stand for 20 min. Repeat this process three times. Mix the ethyl acetate layers after the three extractions and dry with anhydrous sodium sulfate. Remove the precipitate by centrifugation twice (wash the precipitate three times with ethyl acetate). Reduce the solution volume to about 50 mL by rotary evaporation.

[0088] Finally, 450 mL of hexane was added to the solution and stirred vigorously. The resulting suspension was left to stand overnight at 4 °C to allow the product to recrystallize from hexane. The product was then vacuum dried (freeze-dried) to obtain a gray solid powder.

[0089] 2) Synthesis of PPF: 220g DEF and 290.51g 1,2-propanediol were added sequentially to a three-necked flask and stirred at 150rpm for 20min under a nitrogen atmosphere (flow rate: 3-5 bubbles per second). Then, 1.73g zinc chloride and 0.28g hydroquinone were added and reacted at 100℃ and 300rpm for 30min. The temperature was then raised to 150℃ and reacted for 7h. Finally, the temperature was lowered to 100℃ to obtain the di(hydroxypropyl) fumarate intermediate.

[0090] A vacuum was applied, and the reaction was carried out at 100°C for 1 hour. The temperature was then increased to 150°C and the reaction was carried out for 4 hours. The product was purified and dried to obtain PPF with a number average molecular weight of 2489 and a weight average molecular weight of 5014.

[0091] 3) Preparation of unsaturated polyester resin DMA / PPF / DEF containing photoreactive dopamine: Under light-protected conditions, 9g of PPF was dissolved in 9g of DEF. Then, 2g of DMA (10% of the total mass of DMA, PPF, and DEF) was dissolved in 2mL of N,N-dimethylformamide and added to the mixture. After mixing, 0.2g of photoinitiator 819 (1% of the total mass of DMA, PPF, and DEF) was added to the mixture. The mixture was kept at 100℃ and thoroughly mixed. The resulting unsaturated polyester resin is designated as 10% DMA / PPF / DEF.

[0092] Example 2

[0093] A polyester resin containing photoreactive dopamine was prepared.

[0094] The difference from Example 1 is that in Example 2, the masses of DMA, PPF, and DEF are 1g, 9.5g, and 9.5g, respectively, and 1g of DMA is dissolved in 1mL of N,N-dimethylformamide. The remaining components and preparation process are the same as in Example 1. The resulting unsaturated polyester resin is designated as 5% DMA / PPF / DEF.

[0095] Example 3

[0096] A polyester resin containing photoreactive dopamine was prepared.

[0097] The difference from Example 1 is that in Example 3, the masses of DMA, PPF, and DEF are 3g, 8.5g, and 8.5g, respectively. 3g of DMA is dissolved in 3mL of N,N-dimethylformamide. The remaining components and preparation process are the same as in Example 1. The resulting unsaturated polyester resin is designated as 15% DMA / PPF / DEF.

[0098] Comparative Example 1

[0099] A polyester resin was prepared.

[0100] The difference from Example 1 is that Comparative Example 1 only contains PPF, DEF, and photoinitiator 819. The mass of PPF and DEF is 10g each, and the mass of photoinitiator 819 is 0.2g (1% of the total mass of PPF and DEF). The preparation process is similar to that of Example 1. The resulting unsaturated polyester resin is denoted as PPF / DEF.

[0101] Example 4

[0102] Take the unsaturated polyester resins from Examples 1-3 respectively, transfer the homogeneous mixture into a 0.5 mm thick silicone mold, clamp it between two 2.1 mm thick glass plates, and then irradiate it under ultraviolet light (365 nm) for 40 min (7 cm away from the UV lamp head). After the cross-linked sheet has cooled to room temperature, remove it, and then cut samples of different sizes and shapes from the sheet and dry them. Except for the samples used to determine the gel fraction and swelling rate, soak them in acetone for two days to remove the uncross-linked parts, and then vacuum dry them for experimental characterization. The samples used to determine the gel fraction and swelling rate are used directly for experimental characterization without acetone treatment.

[0103] Comparative Example 2

[0104] The difference from Example 4 is that the PPF / DEF unsaturated polyester resin in Comparative Example 2 is used instead of the resin in Example 4, and the preparation process is the same as that in Example 4.

[0105] Example 5

[0106] Printing of three-dimensional porous scaffolds: The unsaturated polyester resin from Example 1 was used for photocrosslinking 3D printing (see schematic diagram). Figure 2 (As shown).

[0107] Includes the following steps:

[0108] 1) Model design: A 3D model of a spherical hole support was constructed in Abaqus software. The support has an overall cylindrical shape with a diameter of 3mm and a height of 4mm.

[0109] 2) Model slicing: Export the 3D support model as a binary STL format, import it into Creationworkshop slicing software and slice it into a 2D projection graphic;

[0110] 3) Input the image information into the computer for layer-by-layer photocrosslinking 3D printing. The printer model is nanoArch P140 (Chongqing Mofang Precision Technology Co., Ltd., BMF Precision Tech Inc.). The layer thickness is 20μm per layer, the ultraviolet wavelength is 405nm, the exposure time per layer is 30s, and the ultraviolet light intensity is 6.5mW / cm². 2 The printing temperature is controlled at 50℃;

[0111] 4) Carefully remove the support from the printing platform with a blade, and remove excess resin from the pores by centrifugation at a speed of 5000 r / min for 5 min.

[0112] 5) After placing the scaffold in the curing chamber, it was cured for 1.5 hours. The wavelength of the curing chamber was 405nm, and a three-dimensional porous scaffold was obtained.

[0113] Comparative Example 3

[0114] The difference between Comparative Example 3 and Example 5 is that the PPF / DEF unsaturated polyester resin from Comparative Example 1 was used instead of the resin in Example 5, the exposure time for each layer was 2.5 s, and the ultraviolet light intensity was 35 mW / cm². 2 The remaining preparation process is the same as in Example 5.

[0115] Example 6

[0116] The three-dimensional porous scaffold obtained in Example 5 was further loaded with bioactive substances (such as BMP-2) on its surface and used to promote osteogenic regeneration, as shown in the schematic diagram. Figure 3 As shown.

[0117] Includes the following steps:

[0118] Different masses of BMP-2 protein were dissolved in phosphate buffer solution to form BMP-2 protein solutions of different concentrations (1, 5 and 10 μg / mL). The scaffold was then immersed in the solution and incubated on a shaker at 4°C for 24 h. The scaffold was washed three times with phosphate buffer solution to remove unbound BMP-2 protein. Finally, the surface-functionalized scaffold was freeze-dried.

[0119] Effect Example

[0120] 13 mg of the DMA synthesized in Example 1 was dissolved in 0.55 mL of deuterated dimethyl sulfoxide, with tetramethylsilane as an internal standard, and nuclear magnetic resonance was performed at room temperature. 1 H spectrum and 13 The C-spectrum determination results are as follows: Figure 4 , Figure 5 As shown.

[0121] The chemical shifts of all spectral peaks can be well attributed to the corresponding protons in the compound structure. 1 In the H spectrum, the resonance signal with a chemical shift of 1.84 ppm is attributed to the methyl proton, and the resonance signals with chemical shifts of 5.29 and 5.61 ppm are attributed to the olefin proton. Compared with the spectrum of dopamine hydrochloride, the appearance of absorption peaks at these two positions indicates the success of the methacrylation reaction. 13 In the C spectrum, the resonance signal with a chemical shift of 18.52 ppm is attributed to the methyl carbon atom, the resonance signals with chemical shifts of 118.63 and 139.99 ppm are attributed to the alkenyl carbon atom, and the resonance signal with a chemical shift of 167.21 ppm is attributed to the carbonyl carbon atom. Compared with the spectrum of dopamine hydrochloride, the appearance of absorption peaks at these positions indicates the success of the methacrylation reaction.

[0122] Fourier transform infrared spectroscopy (FTIR) was performed on the DMA synthesized in Example 1, the photocrosslinked samples obtained in Example 4 and Comparative Example 2. The DMA powder was ground and compressed with potassium bromide in transmission mode, while the photocrosslinked samples were analyzed in attenuated total reflectance mode. The results are as follows: Figure 6 As shown.

[0123] In the infrared spectrum of DMA, 1649 cm⁻¹ -1 and 1718cm -1 The absorption peaks at these positions are generated by the stretching vibrations of carbon-carbon double bonds and carbon-oxygen double bonds, respectively. Compared with the spectrum of dopamine hydrochloride, the appearance of absorption peaks at these two positions indicates the success of the methacrylation reaction.

[0124] The gel fraction and swelling rate of the photocrosslinked samples obtained in Example 4 and Comparative Example 2 were measured.

[0125] After drying, the sample is weighed and recorded as W0. The sample is then immersed in dichloromethane for two days to reach swelling equilibrium. After removing the sample and quickly blotting off the surface liquid with filter paper or cloth, it is immediately weighed and recorded as W. s The sample was then vacuum dried and weighed, denoted as W. d The sample gel fraction is given by formula W. d The swelling ratio in dichloromethane, calculated by / W0, is given by the formula (W s -W d ) / W d The calculation yielded the result.

[0126] The sample was then immersed in phosphate buffer solution for two days. After removing the sample and quickly blotting off the surface liquid with filter paper or cloth, it was weighed immediately and recorded as W. s’ The swelling ratio of the sample in phosphate buffer solution is given by the formula (W s’ -W d ) / W d The calculations show that the gel fraction reflects the efficiency of polymer chain crosslinking and determines the integrity of the crosslinked product.

[0127] The results are as follows Figure 7 As shown, the gel fraction of the cross-linked network prepared by PPF / DEF is close to 0.9. With the increase of DMA content in the cross-linked network, the gel fraction shows a decreasing trend, while the swelling rate in dichloromethane gradually increases. All samples hardly swell in phosphate buffer solution.

[0128] The surface water contact angle of the photocrosslinked samples obtained in Example 4 and Comparative Example 2 was measured. 1 μL of ultrapure water was dropped onto the sample surface, and after standing for 30 seconds, the water contact angle was measured using the seated drop method. The results are as follows: Figure 8As shown, as the DMA content in the crosslinked network increases from 0% to 15%, the water contact angle decreases from 71.7° to 55.4°, indicating that the hydrophilicity of the material surface is improved due to the presence of dopamine molecules.

[0129] Take the photocrosslinked samples obtained in Example 4 and Comparative Example 2, fix them on the flat plate fixture of the rotational rheometer, fill the space between the sample surface and another fixture with water, rotate the fixture at a constant speed of 50 rpm, and apply normal force linearly from 0 N to 3 N over time. Record the torque T and normal force W. The frictional force f is calculated by the formula f = 4T / 3r, where r is the sample radius. Finally, the coefficient of friction μ is calculated by the formula μ = f / W.

[0130] like Figure 9 As shown, the results indicate that the coefficient of friction on the material surface is significantly reduced compared to PPF / DEF due to the introduction of dopamine molecules into the cross-linked network. However, the coefficient of friction increases again with increasing DMA content, which may be due to the adhesiveness of the catechol groups. This further demonstrates that dopamine molecules can be used to improve the surface properties and interfacial interactions of materials.

[0131] The dumbbell-shaped specimens and solid cylindrical photocrosslinked samples obtained in Example 4 and Comparative Example 2 were subjected to mechanical property tests, including uniaxial tension and compression, using a constant deformation rate of 0.25 mm / min. The tensile / compressive Young's modulus, tensile strength, and fracture strain were characterized. The results are as follows: Figure 10 As shown.

[0132] With the increase of DMA content in the cross-linked network, the tensile and compressive Young's modulus both decrease significantly, while the tensile strength and fracture strain show an upward trend.

[0133] The photocrosslinked samples obtained in Example 4 and Comparative Example 2 were used for cytotoxicity detection. MC3T3 cells were exposed to sterile disc samples in culture medium to detect the cytotoxicity of the material leachate. The fused MC3T3 cells were digested and prepared into a cell suspension at a concentration of 15,000 cells / cm³. 2 Cells were seeded at a density of 1 mL in 24-well plates. After 4 hours, sterile photocrosslinked discs were placed in Transwell chambers, and then the Transwell chambers, along with the samples, were placed into 24-well plates. 0.3 mL of culture medium was added to each Transwell chamber. Positive controls consisted of the same cell density but without the sample, while negative controls consisted of blank wells. Cells were counted at 1, 2, 4, and 7 days using a cell counting kit, and absorbance was measured at 450 nm using a microplate reader. The ratio of absorbance values ​​of the experimental group to those of the positive control group represented cell viability.

[0134] like Figure 11As shown, the results indicate that the cell survival rate of each experimental group was above 95%, indicating that no toxic molecules leach out from the samples, and all samples have good compatibility with MC3T3 cells.

[0135] The photocrosslinked samples obtained in Example 4 and Comparative Example 2 were sterilized and used for culturing MC3T3 cells. The fused MC3T3 cells were digested to prepare a cell suspension, and cultured at 15,000 cells / cm³. 2 Cells were seeded at a density on the surface of photocrosslinked samples and cultured in MEMα medium for one day, then replaced with osteogenic induction differentiation medium for seven days, with fresh differentiation medium replaced every three days. The degree of osteogenic differentiation was then assessed. On one hand, alkaline phosphatase is one of the osteogenic-specific matrix proteins, and alkaline phosphatase activity is the most widely recognized marker of osteoblast activity. MC3T3 cells cultured on the material surface were fixed with 4% paraformaldehyde at room temperature for 30 min, then stained with working solution prepared using the BCIP / NBT alkaline phosphatase staining kit. Cells were incubated with the working solution at room temperature in the dark for 50 min, the staining working solution was discarded, and the cells were washed 1-2 times with phosphate buffer solution before observation and photography under a microscope. On the other hand, alizarin red staining solution can stain small amounts of calcium deposits and is suitable for staining calcium salt tissues during osteogenic induction differentiation of cells. MC3T3 cells cultured on the material surface were fixed with 4% paraformaldehyde at room temperature for 30 min. 2 mL of alizarin red working solution was added to each well and stained at room temperature for 2 h. The alizarin red staining solution was removed, and the cells were gently washed 2-3 times with phosphate buffer solution to remove excess staining solution. The cells were then observed and photographed under a microscope.

[0136] The results are as follows Figure 12 As shown, in alkaline phosphatase staining, compared with the PPF / DEF group, the photocrosslinked sample containing DMA showed significantly more stained cells and a deeper color, with the 10% DMA / PPF / DEF group exhibiting the best osteogenic differentiation effect. In Alizarin Red staining, the cells in both the 10% DMA / PPF / DEF and 15% DMA / PPF / DEF groups stained more deeply, and the 15% DMA / PPF / DEF group showed the presence of calcium nodules. These results indicate that the photocrosslinked sample containing DMA can significantly promote osteogenic differentiation of MC3T3 cells.

[0137] Unsaturated polyester resins from Example 1 and Comparative Example 1 were subjected to photocrosslinking 3D printing under ultraviolet light of different intensities at the same time. The actual cured layer thickness was then measured under a microscope to obtain the relationship between the cured layer thickness and the initial ultraviolet light energy of the resin surface. According to formula C... d =D p ·(lnE max -lnE c Linear fitting was performed to obtain the "working curve" of the unsaturated polyester resin, where C dD represents the curing depth. p For penetration depth, E max E is the maximum exposure energy for the resin surface. c This is the critical exposure energy.

[0138] The results are as follows Figure 13 As shown, D can be calculated from the slope and x-intercept of the fitted line. p With E c 10% DMA / PPF / DEF resin has a higher D than PPF / DEF resin. p With E c To meet the printing accuracy requirements, a UV light intensity of 6.5 mW / cm² was selected. 2 A biomimetic three-dimensional structure was prepared by 3D printing 10% DMA / PPF / DEF resin under an exposure time of 30s, and the corresponding curing depth was 96.5μm.

[0139] The three-dimensional porous scaffolds obtained in Example 5 and Comparative Example 3 were photographed and characterized by SEM. The results are as follows: Figure 14 , Figure 15 As shown.

[0140] As can be seen from the figure, the 3D printed biomimetic scaffold structure prepared from 10% DMA / PPF / DEF unsaturated polyester resin is complete, with interconnected pores and ideal printing accuracy, indicating that the novel unsaturated polyester resin containing photoreactive dopamine in this invention can be applied to PμSL-based 3D printing technology.

[0141] In some embodiments of the present invention, a biomedical material is also provided, which is prepared from the polyester resin of the present invention.

[0142] The introduction of dopamine molecules into the polyester resin modifies the surface of the prepared material, significantly improving its hydrophilicity. This modification effectively improves the material's contact with surrounding biological tissues, enhancing its biocompatibility. Materials with better biocompatibility can reduce immune rejection and adverse reactions, providing a favorable microenvironment for tissue repair and regeneration.

[0143] Dopamine and its derivatives (such as DMA) can interact with the extracellular matrix and related proteins (such as BMP-2) through their active functional groups. This enables the biomedical material to promote the adhesion, proliferation, and differentiation of osteoblasts and other related cells, and in particular, it can effectively promote bone regeneration and repair in bone tissue engineering.

[0144] The catechol group in dopamine molecules has excellent adhesion properties and biological activity, which can adsorb bioactive substances such as growth factors and cytokines, further enhancing their biological effects in vivo and promoting tissue repair and regeneration.

[0145] Furthermore, the polyester resin used in this biomedical material is suitable for PμSL-based 3D printing technology. PμSL technology allows for the precise fabrication of complex three-dimensional scaffold structures to meet the personalized treatment needs of different patients. 3D printing enables the scaffold to be customized according to the specific bone defect area of ​​the patient, ensuring higher adaptability and treatment effectiveness.

[0146] In addition, the high resolution and precision of 3D printing ensure the structural integrity and accuracy of the scaffold, which helps the scaffold to better integrate with bone tissue in the body and provide long-term support.

[0147] It is understood that the biomedical material of this invention not only provides an ideal growth environment for osteoblasts, but also can be loaded with bioactive substances (such as BMP-2) to further promote bone regeneration. The loading of bioactive substances can effectively promote the bone tissue repair process and improve the healing speed and quality of bone defect areas.

[0148] Modification with dopamine and its derivatives enhances the surface of the scaffold, improving its cell adsorption properties and growth factor binding capacity, thereby strengthening the function of the bone tissue engineering scaffold and further promoting osteogenic differentiation and mineralization.

[0149] PPF itself is biodegradable, which allows biomedical materials made from it to gradually degrade in vivo, avoiding the potential negative effects of long-term implantation. The degradation rate and mechanical properties of the material can be adjusted by regulating the resin formulation and cross-linking degree, thereby achieving coordination with tissue growth.

[0150] The mechanical properties of the material can be adjusted according to actual needs to ensure its supporting role in the bone regeneration process and avoid premature degradation that could lead to instability at the bone defect site.

[0151] Furthermore, the method for preparing this biomedical material is simple and efficient, employing a dissolution and mixing process under light-protected conditions, which can produce resins with excellent properties in a short time. Compared with traditional biomedical material preparation methods, this process has higher efficiency and lower cost, making it suitable for large-scale production and clinical applications.

[0152] This biomedical material can be used not only in bone tissue engineering, but also in other fields such as soft tissue repair, tissue engineering, and drug delivery systems. Its excellent biocompatibility, biodegradability, and bioactivity make it a promising candidate for application in regenerative medicine.

[0153] Therefore, the biomedical material provided by this invention optimizes its hydrophilicity and bioactivity by introducing photoreactive dopamine molecules, significantly enhancing its application in bone tissue engineering. This material promotes cell adhesion, proliferation, and differentiation, supports bone regeneration, is suitable for personalized 3D printing technology, and possesses good biodegradability and mechanical properties, enabling efficient and precise treatment for patients. Its simple preparation process and broad application prospects make this material a material with enormous potential in the biomedical field.

[0154] In some embodiments of the present invention, the application of the polyester resin of the first aspect of the present invention in 3D printing is provided.

[0155] It should be noted that the polyester resin of this invention can be effectively applied to PμSL, a high-precision 3D printing technology. PμSL technology has extremely high resolution and precision, enabling the fabrication of complex three-dimensional structures at the micrometer level. This technology allows for the precise fabrication of intricate and complex bone tissue engineering scaffolds to meet personalized treatment needs, and is particularly suitable for customized design and manufacturing for specific bone defect areas in patients.

[0156] The resin curing process is not limited by traditional manufacturing processes, and it is possible to design and print scaffold structures of any complex shape to ensure a perfect match between the scaffold and the bone defect site, thereby improving the treatment effect.

[0157] It is understandable that by adjusting the resin formulation and printing parameters (such as exposure intensity and exposure time), the degree of crosslinking, mechanical properties, and degradation rate of the material can be adjusted to meet the needs of different bone defect repairs. This makes the resin more widely applicable in 3D printing applications, enabling personalized customization for different patients' diverse needs.

[0158] It is also understandable that by precisely controlling the structure of materials, the mechanical properties of the scaffold can be adapted to biological tissues, ensuring that the scaffold provides sufficient support to surrounding tissues during bone regeneration, while avoiding premature degradation or insufficient strength.

[0159] This resin retains the hydrophilicity and bioactivity of DMA during the printing process. Dopamine molecules can interact with the extracellular matrix and bioactive substances (such as BMP-2) through their active functional groups, enhancing the adhesion, proliferation, and differentiation capacity of the scaffold surface to cells. This can effectively promote osteoblast proliferation and mineralization, contributing to the repair and regeneration of bone defects.

[0160] The resin surface can effectively adsorb and load various bioactive substances (such as growth factors and cytokines), further promoting the bone regeneration process.

[0161] It is understood that using the polyester resin of this invention for 3D printing can efficiently and rapidly produce customized bone tissue scaffolds. Compared with traditional manufacturing methods, 3D printing can significantly reduce production time and labor costs. Especially in personalized treatment, 3D printing can precisely manufacture suitable scaffolds according to the patient's specific bone defect, avoiding the fitting problems of prefabricated prostheses used in traditional surgery.

[0162] Furthermore, the resin preparation process is simple, employing a dissolution and mixing process, and it is well compatible with 3D printing technology, enabling more efficient production, especially suitable for large-scale production and clinical applications.

[0163] It is understandable that this resin is derived from PPF and has good biodegradability. The printed bone tissue scaffold can gradually degrade in the body, avoiding complications or immune rejection that may be caused by long-term implantation.

[0164] By adjusting the different components of the resin formulation, the degradation rate of the scaffold can be controlled to meet the needs of repairing various bone defects. The degradation of the material is coordinated with the rate of new bone growth, thereby achieving an ideal tissue repair process.

[0165] 3D printing technology can customize personalized bone tissue engineering scaffolds according to the specific needs of patients. Different patients have different bone defects in shape, size, and depth, and prostheses made using traditional methods often cannot achieve a perfect match. 3D printing can provide personalized solutions, improve surgical success rates, and make treatment more precise.

[0166] Wide range of clinical applications: This resin can be widely used in clinical fields such as bone defect repair, bone grafting, spinal surgery, and joint repair, and has broad market prospects and application potential.

[0167] Besides bone tissue engineering, the polyester resin of this invention can also be widely used in other medical fields, such as soft tissue repair, drug delivery systems, and nerve regeneration. With the support of 3D printing technology, it can meet a variety of medical needs and provide more innovative solutions.

[0168] Bioactive substance loading: The scaffold surface can be effectively loaded with bioactive substances, such as growth factors, proteins, and gene drugs, further expanding its application potential in regenerative medicine and personalized medicine.

[0169] Therefore, by applying the polyester resin of this invention to 3D printing technology, high-precision, personalized bone tissue engineering scaffolds can be manufactured. The beneficial effects of this application include enhanced scaffold bioactivity, improved hydrophilicity, optimized mechanical properties, and improved therapeutic efficacy, while also simplifying the fabrication process and reducing costs. The application of 3D printing also enables personalized treatment, further improving the precision and effectiveness of clinical treatment. Therefore, the application of the polyester resin of this invention in 3D printing provides a new solution for bone tissue engineering and other medical fields, with broad prospects for clinical application.

[0170] The present invention has been described in detail above with reference to the embodiments. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A polyester resin containing photoreactive dopamine, characterized in that, The raw materials for preparation, by weight, include: Dopamine methacrylamide: 5-15 parts Polypropylene fumarate: 42.5~47.5 parts, Diethyl fumarate: 42.5~47.5 parts, Photoinitiator: 0.45~3.3 parts.

2. The polyester resin according to claim 1, characterized in that, The preparation method of the dopamine methacrylamide includes the following steps: dissolving sodium tetraborate, sodium bicarbonate and dopamine hydrochloride in water, adjusting the pH of the system, then adding methacrylic anhydride dropwise, washing, extracting, drying and recrystallizing the product.

3. The polyester resin according to claim 1, characterized in that, The preparation method of the polypropylene fumarate includes the following steps: mixing diethyl fumarate, 1,2-propanediol, catalyst and polymerization inhibitor, carrying out the first step reaction to obtain di(hydroxypropyl) fumarate intermediate, and then carrying out the second step transesterification reaction, and obtaining the polypropylene fumarate after polycondensation.

4. The polyester resin according to claim 1, characterized in that, The photoinitiator includes at least one of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, (2,4,6-trimethylbenzoyl)diphenylphosphine oxide, bis(1-(2,4-difluorophenyl)-3-pyrrolithyl)dicenoctane or oxobis(ethane-2,1-diyl)bis(2-oxo-2-phenylacetate).

5. A method for preparing a polyester resin containing photoreactive dopamine as described in any one of claims 1 to 4, characterized in that, The process includes the following steps: under light-protected conditions, the polypropylene glycol fumarate is dissolved in diethyl fumarate, then dopamine methacrylamide solution is added, and finally the photoinitiator is added. After mixing evenly, the polyester resin is obtained.

6. The method according to claim 5, characterized in that, The mixing process takes place at a temperature of 80~120℃.

7. A biomedical material, characterized in that, It is prepared from any one of the polyester resins containing photoreactive dopamine according to claims 1 to 4.

8. The biomedical material according to claim 7, characterized in that, The biomedical materials include repair materials, implantable materials, drug delivery materials, diagnostic materials, surface treatment materials, biosensing materials, and gene and cell therapy materials.

9. The application of the polyester resin containing photoreactive dopamine according to any one of claims 1 to 4 in 3D printing.

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