A photo-crosslinking polyethylene glycol hydrogel material, preparation method and application

Abstract

The application discloses a photo-crosslinking polyethylene glycol hydrogel material, a preparation method and application, wherein the photo-crosslinking polyethylene glycol hydrogel material comprises component A and component B, the component A is a vinylated self-assembled tripeptide modified polyethylene glycol, and the component B is a photo initiator; the component A and the component B are crosslinked to form the photo-crosslinking polyethylene glycol hydrogel material in an aqueous medium. The application provides the photo-crosslinking polyethylene glycol hydrogel material, the preparation method and the application, the hydrogel is constructed by introducing a vinylated self-assembled short peptide into a polyethylene glycol macromolecular chain end, a unique 'physical-chemical' bimodal crosslinking network is constructed, a precursor system has a highly sensitive and temperature controllable'sol-gel' reversible conversion characteristic, after photo-crosslinking, a nano-enhanced network structure formed by self-assembly of the short peptide is realized, and the material mechanics and toughness are simultaneously improved.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, and more particularly to a photocrosslinked polyethylene glycol hydrogel material, its preparation method, and its application. Background Technology

[0002] Photocrosslinked hydrogels are soft materials that rapidly crosslink under mild light irradiation, forming a 3D polymer network structure. Leveraging the superior spatiotemporal controllability, rapid prototyping capabilities, and in-situ molding characteristics of phototriggered fabrication, photocrosslinked hydrogels have demonstrated immense application potential in high-end manufacturing fields such as tissue engineering scaffolds, drug delivery carriers, and bio-3D printing. Among numerous hydrogel-based framework materials, polyethylene glycol (PEG) has become the preferred framework material for constructing synthetic bio-hydrogels due to its excellent biocompatibility, extremely low protein non-specific adsorption, and precisely designable end-group functionalization properties.

[0003] However, existing photocrosslinked polyethylene glycol hydrogels still face certain technical bottlenecks in their progress towards high-performance biomanufacturing (especially high-precision 3D printing). Firstly, there are rheological defects in the aqueous solutions of PEG precursors. Conventional photocrosslinked PEG monomer precursor solutions typically exhibit low-viscosity fluid characteristics and lack necessary thixotropy, preventing them from achieving physical self-support during extrusion 3D printing, leading to interlayer collapse and structural diffusion. Furthermore, in emerging technologies such as volumetric photopolymerization (VAM) 3D printing, low-viscosity systems struggle to withstand buoyancy effects, micro-flow disturbances, or sedimentation during the molding process, severely limiting manufacturing precision. Secondly, there is an inherent contradiction in mechanical properties. The hardness (modulus) and toughness of single-component PEG hydrogels often present an irreconcilable trade-off. When using high molecular weight PEG, the low density of crosslinking points per unit volume results in a material with some ductility but low hardness and poor structural support. Conversely, using low molecular weight PEG to increase hardness by increasing the density of crosslinking groups leads to a highly dense and non-uniform crosslinking network, resulting in ineffective dispersion of local stress and extreme brittleness in the hydrogel. These factors collectively hinder the widespread application of one-component polyethylene glycol hydrogels in the field of biomanufacturing.

[0004] Currently, to address the aforementioned shortcomings of photocrosslinked polyethylene glycol (PEG) hydrogels, existing research and inventions often focus on using them as blending components, combining them with other materials (such as natural polymers or inorganic nanoparticles) to modulate hydrogel properties and subsequently fabricate hydrogel implants. However, this multi-component physical blending strategy often results in complex system compositions, significant batch-to-batch variations, and a tendency to induce phase separation or light scattering. It fails to fully leverage the inherent low adsorption and excellent biocompatibility of the PEG network, and also fails to fundamentally solve the rheological compatibility challenges of PEG in 3D printing. Therefore, a significant technological gap remains in this field, urgently requiring the development of a photocrosslinked PEG hydrogel system with a uniform structure, simplified composition, and the ability to simultaneously address precursor rheological compatibility issues and overcome the limitations of mechanical property trade-offs. Summary of the Invention

[0005] In view of the aforementioned deficiencies in the prior art, the technical problem to be solved by the present invention is that existing single-component polyethylene glycol hydrogel precursors have poor rheological properties, are difficult to adapt to advanced 3D printing processes, and have inherent defects in terms of hardness and toughness after photocrosslinking. The present invention provides a photocrosslinked polyethylene glycol hydrogel material, preparation method, and application. This hydrogel constructs a unique "physical-chemical" dual-modal crosslinking network by introducing vinyl-modal self-assembled short peptides into the chain ends of polyethylene glycol macromolecules. Its precursor system possesses highly sensitive and temperature-controllable reversible "sol-gel" transformation properties. After photocrosslinking, the nano-reinforced network structure formed by the self-assembly of short peptides achieves simultaneous improvement in material mechanics and toughness.

[0006] To achieve the above objectives, the present invention provides a photocrosslinked polyethylene glycol hydrogel material, comprising component A and component B, wherein component A is polyethylene glycol modified with a vinylated self-assembled tripeptide at a concentration of 5 wt% to 40 wt%; and component B is a photoinitiator at a concentration of 0.02 wt% to 1 wt%.

[0007] Components A and B are photocrosslinked in an aqueous medium to form a photocrosslinked polyethylene glycol hydrogel material.

[0008] Furthermore, the vinyllated self-assembled tripeptide-modified polyethylene glycol is selected from one of components A1 (X1X2) to A4 (X1X2):

[0009]

[0010] Component A1(X1X2)

[0011]

[0012] Component A2(X1X2)

[0013]

[0014] Component A3(X1X2)

[0015]

[0016] Component A4 (X1X2)

[0017] Where n is an integer between 20 and 500;

[0018] R is a vinylized self-assembled tripeptide, the specific structure of which is shown below:

[0019]

[0020] R1 and R2 are the side chain groups of amino acids X1 and X2 in the tripeptide sequence Fmoc-K(MA)-X1-X2, respectively.

[0021] Furthermore, the amino acids X1 and X2 used in R have the same configuration as Fmoc-K (MA), either L-type or D-type.

[0022] Furthermore, R1 and R2 are the side chain groups of amino acids X1 and X2 in the tripeptide sequence Fmoc-K(MA)-X1-X2, respectively, including one or more of the side chain groups of alanine, 2-aminobutyric acid, valine, leucine, isoleucine, phenylalanine, methionine or tryptophan.

[0023] Furthermore, component B includes one of components B1 to B4, specifically including

[0024]

[0025] Component B1

[0026]

[0027] Component B2

[0028]

[0029] Component B3

[0030]

[0031] Component B4.

[0032] Furthermore, the aqueous media used include pure water, physiological saline, pH buffer, cell culture medium and / or other salt solutions.

[0033] Furthermore, the mass concentration range of component A is 2wt% to 40wt%; the mass concentration range of component B is 0.01wt% to 1wt%.

[0034] In a preferred embodiment of the present invention, a method for preparing a photocrosslinked polyethylene glycol hydrogel material is provided, comprising the following steps:

[0035] By modifying the end groups of polyethylene glycol with vinylated self-assembling tripeptides, a polyethylene glycol molecule with photocrosslinking sites and self-assembly capabilities, namely component A, was obtained.

[0036] Component A and component B were heated and completely dissolved in an aqueous medium to prepare a precursor solution for the hydrogel.

[0037] Cooling the precursor solution of the hot hydrogel to room temperature or below forms an intermediate physical gel cross-linked by the self-assembly of short peptides.

[0038] By irradiating the intermediate physical gel with a light source of a certain wavelength, a single-component photocrosslinked polyethylene glycol hydrogel material can be obtained.

[0039] Furthermore, the wavelength of the light source is set to 250 nm ~ 500 nm.

[0040] In another preferred embodiment of the present invention, an application of a photocrosslinked polyethylene glycol hydrogel material is provided, including the following applications:

[0041] Applications of extrusion 3D printing inks;

[0042] Applications of volumetric photopolymerization 3D printing inks;

[0043] Applications of preparing hydrogel microspheres via emulsion dispersion method;

[0044] Applications as a cell carrier;

[0045] Applications as controlled-release carriers for peptides, proteins, and small molecule drugs.

[0046] Technical effect

[0047] This invention provides a photocrosslinked polyethylene glycol (PEG) hydrogel material, its preparation method, and its application. It innovatively introduces vinylated self-assembled short peptides (SAPs) into the chain ends of polyethylene glycol (PEG) macromolecules, constructing a unique "physical-chemical" bimodal crosslinking network. Compared with existing technologies, it has the following technical advantages:

[0048] 1. The introduction of vinylated self-assembling short peptides endows the hydrogel system with highly sensitive and temperature-controllable reversible sol-gel properties before photochemical crosslinking. This property completely overturns the limitation of traditional PEG precursors, which only exhibit low-viscosity Newtonian fluid behavior, and endows them with rich and controllable processing rheological properties. Leveraging this rheological advantage, the hydrogel of this invention can achieve instantaneous shaping and self-support after extrusion in extrusion 3D printing, and also meet the stringent requirements of resisting resin flow and preventing sedimentation during volumetric photopolymerization 3D printing.

[0049] 2. By leveraging the ordered self-assembly of short peptides, this invention successfully constructed a nano-reinforced network structure within the hydrogel. This microstructure, with the short peptide self-assembly region as the rigid hard region and the highly hydrated PEG chains as the flexible soft region, endows the material with superior mechanical properties, achieving a simultaneous and significant improvement in tensile strength and tear toughness. This mechanism overcomes the bottleneck of traditional homogeneous PEG hydrogels, which struggle to simultaneously improve both strength and toughness.

[0050] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0051] Figure 1 This is the oscillation-temperature scan curve of the heating and cooling process of the hydrogel of formulation 3 in the embodiments of the present invention;

[0052] Figure 2 These are the small-angle X-ray scattering characterization results of the hydrogel of Formulation 1 in the embodiments of the present invention;

[0053] Figure 3 This is an example of the extrusion 3D printing process and printing effect diagram of the hydrogel of formulation 3 in this invention embodiment;

[0054] Figure 4 This is an example of how the hydrogel of Formula 3 in this invention is used to manufacture complex devices using volumetric 3D printing.

[0055] Figure 5 This is an image showing the effect of fabricating microspheres using hydrogels prepared from components A3 (AF) (30 wt%) and B1 (0.1 wt%) in an embodiment of the present invention.

[0056] Figure 6 This is a cell live / dead staining image on the surface of the hydrogel of formulation 3 in this embodiment of the invention;

[0057] Figure 7 These are the hydrogel release teriparatide kinetic curves of formulation 3 and control formulation 3 in the embodiments of the present invention. Detailed Implementation

[0058] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0059] In the following description, specific details, such as particular internal procedures and techniques, are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will appreciate that the invention may be practiced in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of the invention with unnecessary detail.

[0060] This invention provides a photocrosslinked polyethylene glycol hydrogel material, comprising component A and component B, wherein component A is polyethylene glycol modified with a vinylated self-assembled tripeptide, and component B is a photoinitiator; the ratio of component A to component B is set to **-**; component A and component B are photocrosslinked in an aqueous medium to form a photocrosslinked polyethylene glycol hydrogel material. The mass concentration range of component A is 2wt% to 40wt%; the mass concentration range of component B is 0.01wt% to 1wt%, preferably 10wt% to 30wt%, and more preferably 0.05wt% to 0.8wt%.

[0061] Furthermore, the vinyl-modified self-assembled tripeptide-modified polyethylene glycol is selected from one of components A1 (X1X2) to A4 (X1X2):

[0062]

[0063] Component A1(X1X2)

[0064]

[0065] Component A2(X1X2)

[0066]

[0067] Component A3(X1X2)

[0068]

[0069] Component A4 (X1X2)

[0070] Where n is an integer between 20 and 500;

[0071] R is a vinylized self-assembled tripeptide, the specific structure of which is shown below:

[0072]

[0073] In this context, R1 and R2 are the side chain groups of amino acids X1 and X2 in the tripeptide sequence Fmoc-K(MA)-X1-X2, respectively. The amino acids X1 and X2 used in R have the same configuration as Fmoc-K(MA), either L-type or D-type. R1 and R2 are the side chain groups of amino acids X1 and X2 in the tripeptide sequence Fmoc-K(MA)-X1-X2, including one or more of the following: alanine (A), 2-aminobutyric acid (U), valine (V), leucine (L), isoleucine (I), phenylalanine (F), methionine (M), or tryptophan (W).

[0074] Component B includes one of components B1 to B4, specifically including

[0075]

[0076] Component B1

[0077]

[0078] Component B2

[0079]

[0080] Component B3

[0081]

[0082] Component B4.

[0083] In this embodiment of the invention, B1 and B2 are preferred.

[0084] The aqueous media used in the embodiments of the present invention include pure water, physiological saline, pH buffer, cell culture medium and / or other salt solutions.

[0085] The preparation methods for components A1(X1X2) to A4(X1X2) are as follows:

[0086] First, ε-aminomethacrylate-treated 9-fluorenylmethoxycarbonyl (Fmoc) protected lysine (Fmoc-K(MA)) was prepared via the following synthetic route:

[0087]

[0088] Subsequently, using a standard Fmoc-based protected solid-phase synthesis method, the vinylized self-assembled tripeptide (Fmoc-K(MA)-X1-X2) in components A1(X1X2) to A4(X1X2) was synthesized, and the synthetic route is shown below:

[0089]

[0090] Finally, polymer materials of components A1(X1X2) to A4(X1X2) were obtained by liquid-phase coupling of amino-terminated polyethylene glycol (PEG-NH2) with Fmoc-K(MA)-X1-X2 in a condensing agent. The synthetic route is shown below:

[0091]

[0092] The following specific embodiments illustrate a photocrosslinked polyethylene glycol hydrogel material, its preparation method, and its application according to the present invention. Specifically, the side chain groups involved in the preparation of component A include alanine (A), 2-aminobutyric acid (U), valine (V), leucine (L), isoleucine (I), phenylalanine (F), methionine (M), or tryptophan (W).

[0093] Example 1: Preparation of component A3(FF) with n≈240, X1 being phenylalanine F, and X2 being phenylalanine F

[0094] (1) Synthesis of Fmoc-K(MA):

[0095] Fmoc-K(MA) was synthesized according to the existing published method (Advanced Materials, 2025, 37, e2503325).

[0096] (2) Solid-phase synthesis of Fmoc-K(MA)-FF tripeptide

[0097] Using royal jelly resin as a solid-phase support for peptide synthesis, Fmoc-K(MA)-FF tripeptide was prepared by solid-phase synthesis with standard Fmoc protection.

[0098] (3) Synthesis of component A3(FF)

[0099] 10 g of amino-terminated tetra-arm polyethylene glycol (Mn 40 kDa, amino content 1 mmol) was dissolved in 100 mL of N,N-dimethylformamide (DMF). 1.05 g of Fmoc-K(MA)-FF (1.5 mmol), 0.383 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (2 mmol), and 0.23 g of N-hydroxysuccinimide (2 mmol) were added sequentially to the system. After stirring at room temperature for 12 h, the reaction mixture was poured into 500 mL of diethyl ether and filtered to obtain the precipitate. The precipitate was washed twice with 200 mL of diethyl ether to obtain the A3(FF) fraction. The modification rate of the tripeptide was 3.68, determined by integrating the hydrogen signal of the vinyl group with the signal of the polyethylene glycol backbone.

[0100] Example 2: Preparation of component A3 (XF) where n≈240, X1 is one of A, U, M or V, and X2 is F.

[0101] Fmoc-K(MA) was prepared according to the method in Example 1 (1). Fmoc-K(MA)-F-X1 tripeptide was prepared using solid-phase synthesis method with standard Fmoc protection strategy, with royal jelly as the solid-phase support for polypeptide synthesis.

[0102] 10 g of amino-terminated tetra-arm polyethylene glycol (Mn 40 kDa, amino content 1 mmol) was dissolved in 100 mL of N,N-dimethylformamide (DMF). Fmoc-K(MA)-F-X1 (1.5 mmol), 0.383 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (2 mmol), and 0.23 g of N-hydroxysuccinimide (2 mmol) were added sequentially to the system. After stirring at room temperature for 12 h, the reaction mixture was poured into 500 mL of diethyl ether and filtered to obtain the precipitate. The precipitate was washed twice with 200 mL of diethyl ether to obtain fraction A3(XF). The modification range of the tripeptide in the above fraction was identified as 3.6–3.7 by 1H NMR spectroscopy.

[0103] Example 3: Preparation of component A2(FF) with n≈320, X1 being F and X2 being F

[0104] Fmoc-K(MA)-FF was obtained by referring to the steps of Example 1 (1) and (2).

[0105] 10 g of amino-terminated three-arm polyethylene glycol (Mn 40 kDa, amino content 0.75 mmol) was dissolved in 100 mL of N,N-dimethylformamide (DMF). 0.821 g of Fmoc-K(MA)-FF (1.125 mmol), 0.287 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (1.5 mmol), and 0.173 g of N-hydroxysuccinimide (1.5 mmol) were added sequentially to the system. After stirring at room temperature for 12 h, the reaction mixture was poured into 500 mL of diethyl ether and filtered to obtain the precipitate. The precipitate was washed twice with 200 mL of diethyl ether to obtain fraction A2(FF). The modification rate of the tripeptide was calculated to be 3.72 by 1H NMR spectroscopy.

[0106] Example 4: Preparation of component A4(AF) with n≈160, X1 being A, and X2 being F.

[0107] The Fmoc-K(MA)-FA tripeptide was prepared according to Example 2.

[0108] 10 g of amino-terminated six-arm polyethylene glycol (Mn 40 kDa, amino content 1.5 mmol) was dissolved in 100 mL of N,N-dimethylformamide (DMF). 2.21 g of Fmoc-K(MA)-FF (2.25 mmol), 0.58 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (3 mmol), and 0.35 g of N-hydroxysuccinimide (3 mmol) were added sequentially to the system. After stirring at room temperature for 12 h, the reaction mixture was poured into 500 mL of diethyl ether and filtered to obtain the precipitate. The precipitate was washed twice with 200 mL of diethyl ether to obtain fraction A4(AF). The modification rate of the tripeptide was calculated to be 3.46% by 1H NMR spectroscopy.

[0109] Example 5: Physical property characterization of polyethylene glycol hydrogels prepared from components A3 (FF) and B1

[0110] This embodiment uses the photocrosslinked PEG hydrogel formed by component A3(FF) and component B1 synthesized in Example 1 as an example to illustrate the gel preparation process and physical properties in detail.

[0111] Accurately weigh a certain mass of component A3 (FF) and component B1, heat and dissolve them in pure water. After cooling to room temperature, the hydrogel precursor forms a self-assembled physical gel. The physical gel is then irradiated with a 405 nm LED light source to prepare the photocrosslinked polyethylene glycol hydrogel described in this invention. Specific formulations are detailed in Table 1.

[0112] Table 1

[0113]

[0114] This embodiment uses a rotational rheometer (TA Instruments, DHR-2) with a temperature control system to characterize the rheological properties of the self-assembled physical gels formed by the above formulations before light exposure. The rheological test conditions were set as follows: constant strain 1%, test frequency 1 Hz, test temperature range 20 ℃ ~ 85 ℃, and heating / cooling rate 10 ℃ / min. During the test, the hydrogel precursors of formulations 1-3 were placed in a heated state between flat rotors, and the system continuously recorded the changes in the storage modulus (G') and loss modulus (G'') of the system with temperature. The gel-sol transition temperature during the heating and cooling processes of each formulation was 73 ℃ ~ 76 ℃. Simultaneously, as... Figure 1 As shown, continuous temperature-controlled cycling tests were conducted using formulation 3 as an example, demonstrating that this physical gel system has a rapid "gel-sol" transition process.

[0115] The hydrogel precursor solution prepared in this embodiment can achieve the assembly and disassembly of the physical network under purely thermodynamic driving. This unique temperature-sensitive rheological property overcomes the shortcomings of traditional PEG aqueous solutions, such as low viscosity and lack of support, and endows the hydrogel precursor with richer processing rheology. This makes the material of this invention perfectly adaptable to extrusion 3D printing (achieving physical self-support after extrusion cooling) and volumetric photopolymerization 3D printing (providing the anti-settling network required for resin molding process).

[0116] Furthermore, this embodiment characterizes the mechanical properties of the photocrosslinked polyethylene glycol hydrogels prepared by formulations 1-3. First, the hydrogel precursor was injected into a mechanical testing sample mold while heated. After cooling to room temperature, a 405 nm LED (30 mW / cm²) was used for the test. 2 The physical gel was irradiated with a light source for 40 seconds to obtain a mechanical test sample.

[0117] To demonstrate that the polyethylene glycol hydrogel of this invention possesses enhanced mechanical properties, this embodiment designed and synthesized a control component A3 with similar photocrosslinking sites to component A3(FF) but without self-assembly properties, the structure of which is shown below:

[0118]

[0119] The control group was divided into A3 structural formulas.

[0120] The preparation method is as follows: 10 g of amino-terminated tetra-arm polyethylene glycol (Mn 40 kDa, amino content 1 mmol) was dissolved in 100 mL of N,N-dimethylformamide (DMF). 0.65 g of Fmoc-K(MA)-FF (1.5 mmol), 0.383 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (2 mmol), and 0.23 g of N-hydroxysuccinimide (2 mmol) were added sequentially to the system. After stirring at room temperature for 12 h, the reaction system was poured into 500 mL of diethyl ether, and the precipitate was obtained by filtration. The precipitate was washed twice with 200 mL of diethyl ether to finally obtain the control group A3.

[0121] Specifically, refer to Table 2 to prepare tensile test samples of the same size control hydrogel.

[0122] Table 2

[0123]

[0124] The stress-strain curves of the hydrogel mechanical test samples prepared in this embodiment were obtained using a universal force measuring machine (Instron 5969, 200 N sensor) to calculate the elastic modulus, tensile strength, and fracture toughness of the hydrogels. The attached figures show the stress-strain curves of the hydrogels from formulations 1-3 and controls 1-3, and the specific data are summarized in Table 3. The test results show that the mechanical properties (modulus, strength, and toughness) of the photocrosslinked polyethylene glycol hydrogels constructed in this invention are significantly better than those of the control gels with the same mass concentration.

[0125] Table 3

[0126]

[0127] In this invention, the macromonomers of the constructed hydrogel undergo self-assembly in water, forming self-assembled structural domains. Subsequently, photo-triggered covalent crosslinking locks these self-assembled domains. Due to the abundant non-covalent interactions within these domains, they can effectively withstand the stress transmitted by the polyethylene glycol chains, ultimately enhancing the macroscopic mechanical properties of the hydrogel. To verify this microstructural characteristic, the hydrogel of formulation 3 was characterized by small-angle X-ray scattering. The results (as shown in...) Figure 2 As shown in the figure, the gel micronetwork structure contains a periodically arranged ordered structure with a characteristic size of 19.5 nm, confirming this micronetwork feature.

[0128] Example 6: Physical property characterization of hydrogels prepared from components A3 (X1F) and B1

[0129] Hydrogels were prepared using components A3(XF) (30wt% solid content) and B1 (0.3wt%) prepared in Example 2, respectively. The rheological properties of the physical gels before photocrosslinking were measured using a rotational rheometer; stress-strain curves of the hydrogels were obtained using a universal force measuring machine, and data such as elastic modulus, tensile stress, and tear toughness were calculated. The results are shown in Table 4.

[0130] Table 4

[0131]

[0132] The characterization results show that the photocrosslinked hydrogel constructed in this invention can regulate the processing rheology of the hydrogel precursor through amino acid sequences, and the gel-sol transition temperature can be adjusted within the range of 42 ℃ - 95 ℃. Its mechanical properties are superior to those of the non-self-assembled control gel (Control 3), confirming the universality of this enhancement and toughening mechanism.

[0133] Example 7: Application of photocrosslinked polyethylene glycol hydrogel as extrusion 3D printing ink

[0134] The hydrogel precursor solution of Formulation 3 prepared in Example 5 was loaded into the printing barrel of an extrusion 3D printer equipped with a temperature control system. The barrel temperature was maintained at 70 °C to keep the polyethylene glycol hydrogel in an extrudable state. The temperature of the printing stage was controlled within the range of room temperature, 20 °C to 25 °C. Under these conditions, the hydrogel extruded from the barrel could solidify rapidly due to cooling, forming physical gel fibers. After extrusion, it was cured by irradiation with a 405 nm light source, finally obtaining a porous 3D printed gel scaffold (such as...). Figure 3 (As shown). The printing results show that the rapid temperature-response physical gelation of the photocrosslinked polyethylene glycol hydrogel constructed in this invention before light irradiation can rapidly solidify the polyethylene glycol gel precursor into hydrogel extruded fibers, avoiding fiber deformation caused by factors such as slow solidification speed and the continued fluidity after extrusion.

[0135] Example 8: Application of photocrosslinked polyethylene glycol hydrogel as volumetric 3D printing ink

[0136] Volumetric 3D printing (VP) is a novel 3D printing technology that has emerged in recent years. It overcomes the inherent bottlenecks of traditional layer-by-layer printing, such as slow manufacturing speed and rough surface texture of printed samples. However, VP places stringent requirements on the rheological properties and light transmittance of the ink. It requires good light transmittance while maintaining high viscosity or a gel state during light exposure, and the ability to quickly clean uncured areas after printing. Currently, apart from methacrylamide gel hydrogels, no commercially available inks are used in this field. The photocrosslinked polyethylene glycol hydrogel constructed in this invention exhibits good light transmittance and controllable gel-sol transition properties, making it suitable as a VP ink. Specific application examples are as follows:

[0137] First, different 3D printing models were constructed and imported into the VP printer (EFL, BP96) system for exposure slicing modeling. Then, the hydrogel precursor solution of Formula 3 prepared in Example 5 was added to the printing sample vial in a high-temperature sol state and cooled to room temperature to form a physical gel. Next, a volumetric light field projection device was used for overall exposure, and the printing quality was controlled by adjusting parameters such as illumination time, light intensity, and sample cell rotation speed. After printing, the sample vial was placed in a heating bath and heated above the transition temperature. Unreacted ink was then ultrasonically cleaned to obtain the target printed device. The printed device was then subjected to a second exposure to enhance stability. The printing results are shown (e.g., Figure 4 As shown in the figure, the photocrosslinked polyethylene glycol hydrogel constructed by the present invention can be fully adapted to the VP processing mode to manufacture printed devices with complex structures.

[0138] Example 9: Application of photocrosslinked polyethylene glycol hydrogel in the preparation of gel microspheres

[0139] Hydrogel microspheres are widely used as cell and drug delivery carriers in the biomedical field, and are mainly prepared on a large scale via emulsion dispersion. The photocrosslinked polyethylene glycol hydrogel constructed in this invention provides a convenient and efficient method for the batch preparation of stable hydrogel microspheres.

[0140] The specific procedure for preparing hydrogel microspheres using 30 wt% components A3(AF) and B1 is described below: First, 100 mL of mineral oil containing 1 wt% SPAN80 was prepared and heated to 55 °C. Then, 5 mL of the hydrogel thermal precursor solution was slowly added dropwise to the mineral oil, stirred for 10 min, and then cooled to room temperature to allow physical cross-linking to occur within the microspheres. Further, the prepared hydrogel microspheres were collected by centrifugation, and then washed with petroleum ether and diethyl ether sequentially. Finally, the collected hydrogel microspheres were irradiated with light to obtain a batch of hydrogel microspheres. Preparation results (e.g.) Figure 5 As shown in the figure, the obtained microspheres have good sphericity and integrity, and their particle size range is [value missing]. They can be further used as cell microcarriers, protein / drug sustained-release particles, or injectable microsphere systems.

[0141] Example 10: Application of photocrosslinked polyethylene glycol hydrogel as a cell carrier

[0142] 100 mg of acrylic acid-modified RGD cell adhesion peptide was added to the hydrogel thermal precursor solution in Formulation 3 of Example 5. While still hot, the precursor solution was applied to the surface of the cell culture plate wells, and then cooled to form a physical gel. Subsequently, the physical gel was irradiated with light to form a covalent hydrogel.

[0143] L929 cell suspension was dropwise added to the surface of a hydrogel. Cells were cultured under standard cell culture conditions (37 °C, 5% CO2). After 24 h of culture, cell adhesion and survival on the hydrogel surface were characterized using live / dead staining and fluorescence microscopy. Characterization results (e.g.) Figure 6 As shown in the figure, L929 cells adhered to the surface of the hydrogel constructed in this invention 24 h after inoculation, and no dead cell positive staining results were found, confirming the good compatibility of the polyethylene glycol hydrogel constructed in this invention, which can be used for cell culture and loading applications.

[0144] Example 11: Application of photocrosslinked polyethylene glycol hydrogel as a drug controlled-release carrier

[0145] The polyethylene glycol hydrogel network constructed in this invention contains self-assembly domains, exhibiting partial hydrophobicity and supramolecular interaction characteristics. Therefore, it can interact with drug molecules to control the drug release rate. This invention further discloses the application of hydrogels as drug delivery carriers, using the hydrogel of formulation 3 prepared in Example 5 as an example to illustrate its drug release application:

[0146] A 20 μL block hydrogel was prepared and immersed in a solution containing FITC-labeled teriparatide (FITC-PTH) for saturated adsorption. After adsorption reached equilibrium for 24 h, the initial drug concentration in the drug solution and the drug concentration after immersion in the gel were measured using a fluorescence spectrophotometer to calculate the drug loading in the gel. Subsequently, the hydrogel was immersed in physiological saline and released by shaking at 37 °C. The physiological saline was changed daily, and the amount of drug released in the saline was measured daily using a microplate reader to obtain the release curve. The release kinetics were also compared with those of the hydrogel prepared with control formulation 3.

[0147] Release test results (such as) Figure 7 As shown in the figure, the fluorescently labeled teriparatide can be smoothly released from the hydrogel constructed in this invention, with no significant burst release. In contrast, the control hydrogel exhibits a clear burst release, with rapid drug release and poor sustained-release effect. This difference is likely due to the interaction between the peptide and its self-assembling domains.

[0148] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A photocrosslinked polyethylene glycol hydrogel material, characterized in that, It includes component A and component B, wherein component A is polyethylene glycol modified with a vinylated self-assembled tripeptide at a concentration of 5 wt% to 40 wt%; and component B is a photoinitiator at a concentration of 0.02 wt% to 1 wt%. Components A and B are photocrosslinked in an aqueous medium to form the photocrosslinked polyethylene glycol hydrogel material.

2. The photocrosslinked polyethylene glycol hydrogel material as described in claim 1, characterized in that, The vinylated self-assembled tripeptide-modified polyethylene glycol is selected from one of components A1 (X1X2) to A4 (X1X2): ， Component A1(X1X2) ， Component A2(X1X2) ， Component A3(X1X2) ， Component A4 (X1X2) Where n is an integer between 20 and 500; R is a vinylized self-assembled tripeptide, the specific structure of which is shown below: ， R1 and R2 are the side chain groups of amino acids X1 and X2 in the tripeptide sequence Fmoc-K(MA)-X1-X2, respectively.

3. The photocrosslinked polyethylene glycol hydrogel material as described in claim 2, characterized in that, The amino acids X1 and X2 used in R have the same configuration as Fmoc-K (MA), either L-type or D-type.

4. The photocrosslinked polyethylene glycol hydrogel material as described in claim 2, characterized in that, R1 and R2 are the side chain groups of amino acids X1 and X2 in the tripeptide sequence Fmoc-K(MA)-X1-X2, respectively, including one or more of the side chain groups of alanine, 2-aminobutyric acid, valine, leucine, isoleucine, phenylalanine, methionine or tryptophan.

5. The photocrosslinked polyethylene glycol hydrogel material as described in claim 1, characterized in that, Component B includes one of components B1 to B4, specifically including ， Component B1 ， Component B2 ， Component B3 ， Component B4.

6. The photocrosslinked polyethylene glycol hydrogel material as described in claim 1, characterized in that, The aqueous media used include pure water, physiological saline, pH buffer, cell culture medium and / or other salt solutions.

7. The photocrosslinked polyethylene glycol hydrogel material as described in claim 1, characterized in that, The mass concentration range of component A is 2wt% to 40wt%; the mass concentration range of component B is 0.01wt% to 1wt%.

8. A method for preparing a photocrosslinked polyethylene glycol hydrogel material as described in any one of claims 1-7, characterized in that, Includes the following steps: By modifying the end groups of polyethylene glycol with vinylated self-assembling tripeptides, a polyethylene glycol molecule with photocrosslinking sites and self-assembly capabilities, namely component A, was obtained. Component A and component B were heated and completely dissolved in an aqueous medium to prepare a precursor solution for the hydrogel. Cooling the precursor solution of the hot hydrogel to room temperature or below forms an intermediate physical gel cross-linked by the self-assembly of short peptides. By irradiating the intermediate physical gel with a light source of a certain wavelength, a single-component photocrosslinked polyethylene glycol hydrogel material can be obtained.

9. The preparation method according to claim 8, characterized in that, The wavelength of the light source is set to 250 nm ~ 500 nm.

10. The application of a photocrosslinked polyethylene glycol hydrogel material as described in any one of claims 1-7, characterized in that, Applications include the following: Applications of extrusion 3D printing inks; Applications of volumetric photopolymerization 3D printing inks; Applications of preparing hydrogel microspheres via emulsion dispersion method; Applications as a cell carrier; Applications as controlled-release carriers for peptides, proteins, and small molecule drugs.

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