A strong and tough anti-swelling hydrogel with good biocompatibility and preparation method thereof

Abstract

The invention discloses a strong and tough anti-swelling hydrogel with good biocompatibility and a preparation method thereof, including using HEA as a monomer, MBAA as a cross-linking agent, and HPCK as a photoinitiator dissolved in DMSO, and after ultrasound, a PHEA precursor solution is obtained; (PVA-co-PE) is dissolved in DMSO by a heated and stirred method as a hydrophilic copolymer to mix and obtain (PVA-co-PE)-DMSO solution; (PVA-co-PE)-DMSO solution is mixed with a PHEA precursor solution, and after light curing for a period of time, it is then immersed in water to obtain PHEA-(PVA-co-PE) hydrogel with a micellar structure. The gelling process of the present invention is simple, and in the process of immersion, due to the hydrophobic interaction of the copolymer, a micellar structure can be self-assembled inside the hydrogel, and the swelling of the hydrophilic network is suppressed by hydrophobic interaction and the mechanical properties of the hydrogel are enhanced.

Description

Technical Field

[0001] The invention belongs to the field of hydrogel tissue engineering, and particularly relates to a strong, tough, and anti-swelling hydrogel with good biocompatibility and a preparation method thereof. Background Art

[0002] Hydrogels are highly hydrated polymer materials with a three-dimensional network structure that can absorb and retain large amounts of water. Hydrogels form and maintain a specific shape in water, characterized by high water content and controllable properties. Due to their unique properties, hydrogels have been widely used in numerous fields, such as tissue engineering, wound dressings, drug delivery, and cell culture.

[0003] However, traditional hydrogels generally have insufficient mechanical properties, especially when subjected to external forces, which can easily cause deformation or rupture. This defect seriously limits the application of hydrogels. To overcome this problem, researchers have developed a variety of methods to improve the mechanical properties of hydrogels, including double-network hydrogels, topological hydrogels, and nanostructured hydrogels.

[0004] In the above research on improving the mechanical properties of hydrogels, the following technical means have shown particular importance:

[0005] 1. Salting out: regulating the aggregation state of hydrogel polymer chains by ions, thereby significantly improving the mechanical properties of hydrogels;

[0006] 2. Polyelectrolyte toughening: Utilize the Hofmeister effect of polyelectrolytes to strengthen hydrogels and improve mechanical properties.

[0007] Although the above methods can improve the mechanical properties of hydrogels, they also bring about the problem of reduced anti-swelling ability, which causes the hydrogel to swell easily in a water environment. Especially when used in vivo, this swelling will significantly reduce the mechanical strength of the hydrogel and exert pressure on adjacent tissues, causing inflammation. To solve this problem, researchers currently use the following technologies:

[0008] 1. Multiple cross-linking: by increasing the cross-linking points to form a denser network structure, the anti-swelling ability of the hydrogel can be improved;

[0009] 2. Ion complexation: Utilize the interaction between ions to enhance the mechanical properties and stability of hydrogels.

[0010] However, these methods may have problems such as complex preparation processes or poor biocompatibility. Therefore, developing a hydrogel with simple preparation methods, good biocompatibility, strong toughness, and anti-swelling properties is one of the technical problems that technicians in this field urgently need to solve. Summary of the Invention

[0011] In response to the problems existing in the prior art, the present invention provides a strong and tough anti-swelling hydrogel with good biocompatibility and a preparation method thereof. The preparation of the strong and tough anti-swelling hydrogel is completed by utilizing the hydrophobic interaction of the copolymer, which not only has a simple process but also has good biocompatibility.

[0012] In order to solve the above technical problems, the present invention is implemented through the following technical solutions:

[0013] A method for preparing a strong, tough, and anti-swelling hydrogel with good biocompatibility comprises the following steps:

[0014] Step 1) 2-hydroxyethyl acrylate (HEA) as a monomer, N,N'-methylenebisacrylamide (MBAA) as a crosslinker, and 1-hydroxycyclohexyl phenyl ketone (HPCK) as a photoinitiator are dissolved in a certain volume of dimethyl sulfoxide (DMSO) in a certain mass ratio, and ultrasonicated for a period of time to prepare a PHEA precursor solution;

[0015] step 2) dissolving a certain amount of poly(vinyl alcohol-co-ethylene) (PVA-co-PE) as a hydrophilic and hydrophobic copolymer in a certain amount of dimethyl sulfoxide (DMSO), and mixing for a period of time under certain temperature and stirring conditions to prepare a (PVA-co-PE)-DMSO solution with a specific mass fraction;

[0016] Step 3) A certain volume of the (PVA-co-PE)-DMSO solution prepared in step 2 is mixed with the PHEA precursor solution prepared in step 1. After photocuring for a period of time, the mixture is immersed in water to finally obtain a PHEA-(PVA-co-PE) hydrogel having a micellar structure. The obtained PHEA-(PVA-co-PE) hydrogel has good biocompatibility, strong toughness, and anti-swelling properties.

[0017] Furthermore, in step 1, the mass of 2-hydroxyethyl acrylate is 4 g, the mass of N,N'-methylenebisacrylamide is 40 mg, the mass of 1-hydroxycyclohexyl phenyl ketone is 10 mg, and the volume of dimethyl sulfoxide is 2.5 mL.

[0018] Furthermore, in step 1, the ultrasonication time is 5 minutes.

[0019] Furthermore, in step 2, the temperature when poly(vinyl alcohol-co-ethylene) and dimethyl sulfoxide are mixed is 150° C., the stirring speed is 300 rpm, and the stirring time is 2 h.

[0020] Furthermore, in step 2, the mass fraction of the prepared (PVA-co-PE)-DMSO solution is 20%.

[0021] Furthermore, in step 3, the volume of the (PVA-co-PE)-DMSO solution mixed with the PHEA precursor solution was 7.5 mL.

[0022] Furthermore, in step 3, the photocuring is performed by irradiating an ultraviolet lamp of a specific wavelength, so that the mixed solution of the (PVA-co-PE)-DMSO solution and the PHEA precursor solution forms a gel.

[0023] Furthermore, the wavelength of the ultraviolet light emitted by the ultraviolet lamp is 365nm.

[0024] Furthermore, in step 3, the light curing time is 1 minute.

[0025] A strong, tough, and anti-swelling hydrogel with good biocompatibility is prepared by adopting the preparation method of the strong, tough, and anti-swelling hydrogel with good biocompatibility. The prepared hydrogel has good biocompatibility and both strong, toughness, and anti-swelling properties.

[0026] The beneficial effects of the present invention are:

[0027] The present invention provides a method for simply preparing a hydrogel with excellent mechanical properties and good swelling resistance. The method introduces a hydrophilic and hydrophobic copolymer into the hydrogel and forms a gel through a rapid two-step process of light initiation and immersion. During the immersion process, due to the hydrophobic interaction of the copolymer, it will self-assemble into a micellar structure inside the hydrogel. The hydrophobic effect is used to inhibit the swelling of the hydrophilic network and enhance the mechanical properties of the hydrogel, thereby meeting different application requirements.

[0028] When the (PVA-co-PE) content in the hydrogel of the present invention reaches 15wt%, the strength of the hydrogel can reach 0.65MPa and the elongation at break reaches 320%. Compared with the hydrogel without adding (PVA-co-PE), the toughness of the hydrogel of the present invention is increased by 146 times, reaching 1.16MJ / m 3 , while the modulus reaches 0.25MPa.

[0029] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the invention and to implement it according to the contents of the description, the following preferred embodiments of the present invention are described in detail with reference to the accompanying drawings. The specific implementation methods of the present invention are given in detail by the following embodiments and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0031] Figure 1 This is a flow chart of the method for preparing the strong, tough, and anti-swelling hydrogel with good biocompatibility of the present invention;

[0032] Figure 2 This is an SEM image of the PHEA-15% (PVA-co-PE) hydrogel after soaking in water in Test Example 1 of the present invention;

[0033] Figure 3 : These are the stress-strain curves of PHEA hydrogel, PHEA-5% (PVA-co-PE) hydrogel, PHEA-10% (PVA-co-PE) hydrogel, and PHEA-15% (PVA-co-PE) hydrogel in Test Example 2 of the present invention;

[0034] Figure 4 Figures showing the swelling of PHEA hydrogel, PHEA-5% (PVA-co-PE) hydrogel, PHEA-10% (PVA-co-PE) hydrogel, and PHEA-15% (PVA-co-PE) hydrogel during the immersion process in Test Example 3 of the present invention, as well as the swelling rate and water content results.

[0035] Figure 5 This is a graph showing the results of detecting the viability of 3T3 cells using the CCK8 method in Test Example 4 of the present invention;

[0036] Figure 6 This is a graph showing the swelling results of PHEA-15% (PVA-co-PE)-Bi hydrogel under mouse skin in Test Example 5 of the present invention;

[0037] Figure 7 This is a tissue section of the PHEA-15% (PVA-co-PE)-Bi hydrogel implanted subcutaneously in mice in Test Example 6 of the present invention. DETAILED DESCRIPTION

[0038] The following will be described in detail with reference to the accompanying drawings to better understand the purpose, features and advantages of the invention. It should be understood that the embodiments shown in the accompanying drawings are not intended to limit the scope of the invention, but are only intended to illustrate the essential spirit of the technical solution of the invention.

[0039] In the following description, for the purpose of illustrating the various disclosed embodiments, certain specific details are set forth in order to provide a thorough understanding of the various disclosed embodiments. However, those skilled in the relevant art will recognize that the embodiments may be practiced without one or more of these specific details. In other cases, well-known devices, structures, and techniques associated with this application may not be shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

[0040] Unless the context requires otherwise, throughout the specification and claims, the word "comprise" and variations such as "include" and "have" should be construed in an open, inclusive sense, that is, should be interpreted to mean "including, but not limited to."

[0041] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any manner in one or more embodiments.

[0042] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. It should be noted that the term "or" is generally employed in its sense including "and / or" unless the context clearly dictates otherwise.

[0043] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. Unless otherwise specified, the reagents and materials used in the present invention are commercially available.

[0044] The present invention provides a strong, tough, and anti-swelling hydrogel with good biocompatibility. The hydrogel is mainly composed of a monomer: 2-hydroxyethyl acrylate (HEA), a hydrophilic and hydrophobic copolymer: poly(vinyl alcohol-co-ethylene) (PVA-co-PE), a cross-linker: N,N'-methylenebisacrylamide (MBAA), and a photoinitiator: 1-hydroxycyclohexyl phenyl ketone (HPCK).

[0045] See also Figure 1 As shown, the present invention also provides a method for preparing such a strong and anti-swelling hydrogel with good biocompatibility, which specifically comprises the following steps:

[0046] Step 1) HEA, MBAA and HPCK are dissolved in a certain volume of dimethyl sulfoxide (DMSO) in a certain mass ratio, and a PHEA precursor solution is prepared after ultrasonication for a period of time;

[0047] Step 2) dissolving a certain amount of (PVA-co-PE) in a certain amount of dimethyl sulfoxide (DMSO) and mixing the mixture for a period of time at a certain temperature and stirring speed to prepare a (PVA-co-PE)-DMSO solution with a specific mass fraction;

[0048] Step 3) A certain volume of the (PVA-co-PE)-DMSO solution prepared in step 2 is mixed with the PHEA precursor solution prepared in step 1. After photocuring for a period of time, the mixture is immersed in water to finally obtain a PHEA-(PVA-co-PE) hydrogel having a micellar structure. The obtained PHEA-(PVA-co-PE) hydrogel has good biocompatibility, strong toughness, and anti-swelling properties.

[0049] The preparation method, structure and performance of the hydrogel of the present invention are described in detail below through the following embodiments and test examples.

[0050] Example 1

[0051] Preparation of PHEA hydrogel:

[0052] First, 4 g of HEA, 40 mg of MBAA, and 10 mg of HPCK were dissolved in 10 mL of DMSO, and after ultrasonication for 5 min, 10 mL of PHEA precursor solution was prepared.

[0053] Then, 10 mL of the PHEA precursor solution was irradiated under an ultraviolet lamp with a wavelength of 365 nm (irradiation time 1 min) to form a PHEA gel, which was then immersed in water.

[0054] Example 2

[0055] Preparation of PHEA-5% (PVA-co-PE) hydrogel:

[0056] First, 4 g of HEA, 40 mg of MBAA, and 10 mg of HPCK were dissolved in 7.5 mL of DMSO, and after ultrasonication for 5 min, 7.5 mL of PHEA precursor solution was prepared.

[0057] Then, 20 g of (PVA-co-PE) was placed in 80 g of DMSO, a magnet was added, and the mixture was stirred for 2 h under a magnetic heating stirrer (temperature 150°C, speed 300 rpm) to prepare a (PVA-co-PE)-DMSO solution with a mass fraction of 20%.

[0058] Finally, 2.5 mL of 20% (PVA-co-PE)-DMSO solution was measured and mixed with 7.5 mL of PHEA precursor solution. The mixture was irradiated under a UV lamp with a wavelength of 365 nm (irradiation time 1 min) to form a PHEA-5% (PVA-co-PE) hydrogel, which was then immersed in water.

[0059] Example 3

[0060] Preparation of PHEA-10% (PVA-co-PE) hydrogel:

[0061] First, 4 g of HEA, 40 mg of MBAA, and 10 mg of HPCK were dissolved in 5 mL of DMSO, and after ultrasonication for 5 min, 5 mL of PHEA precursor solution was prepared.

[0062] Then, 20 g of (PVA-co-PE) was placed in 80 g of DMSO, a magnet was added, and the mixture was stirred for 2 h under a magnetic heating stirrer (temperature 150°C, speed 300 rpm) to prepare a (PVA-co-PE)-DMSO solution with a mass fraction of 20%.

[0063] Finally, 5 mL of 20% (PVA-co-PE)-DMSO solution was measured and mixed with 5 mL of PHEA precursor solution. The mixture was irradiated under a UV lamp with a wavelength of 365 nm (irradiation time 1 min) to form a PHEA-10% (PVA-co-PE) hydrogel, which was then immersed in water.

[0064] Example 4

[0065] Preparation of PHEA-15% (PVA-co-PE) hydrogel:

[0066] First, 4 g of HEA, 40 mg of MBAA, and 10 mg of HPCK were dissolved in 2.5 mL of DMSO, and after ultrasonication for 5 min, 2.5 mL of PHEA precursor solution was prepared.

[0067] Then, 20 g of (PVA-co-PE) was placed in 80 g of DMSO, a magnet was added, and the mixture was stirred for 2 h under a magnetic heating stirrer (temperature 150°C, speed 300 rpm) to prepare a (PVA-co-PE)-DMSO solution with a mass fraction of 20%.

[0068] Finally, 7.5 mL of 20% (PVA-co-PE)-DMSO solution was measured and mixed with 2.5 mL of PHEA precursor solution. The mixture was irradiated under a UV lamp with a wavelength of 365 nm (irradiation time 1 min) to form a PHEA-15% (PVA-co-PE) hydrogel, which was then immersed in water.

[0069] Example 5

[0070] Preparation of PHEA-15% (PVA-co-PE)-Bi hydrogel:

[0071] First, 4 g of HEA, 40 mg of MBAA, and 10 mg of HPCK were dissolved in 2.5 mL of DMSO, and 0.5 g of Bi was uniformly dispersed therein using ultrasound. After ultrasound for 5 minutes, 2.5 mL of PHEA-Bi precursor solution was prepared.

[0072] Then, 20 g of (PVA-co-PE) was placed in 80 g of DMSO, a magnet was added, and the mixture was stirred for 2 h under a magnetic heating stirrer (temperature 150°C, speed 300 rpm) to prepare a (PVA-co-PE)-DMSO solution with a mass fraction of 20%.

[0073] Finally, 7.5 mL of 20% (PVA-co-PE)-DMSO solution was mixed with 2.5 mL of PHEA-Bi precursor solution and irradiated under a UV lamp with a wavelength of 365 nm (irradiation time 1 min) to form PHEA-15% (PVA-co-PE)-Bi hydrogel, which was then immersed in water.

[0074] Test Example 1

[0075] Observe the micelle structure inside the hydrogel after soaking in water:

[0076] The cross-sectional morphologies of the PHEA hydrogel prepared in Example 1 and the PHEA-15% (PVA-co-PE) hydrogel prepared in Example 4 were photographed using a cold field emission scanning electron microscope (Hitachi S-4700).

[0077] See also Figure 2 As shown, the images taken showed that compared with PHEA hydrogel ( Figure 2 a), after soaking in water, micelle structures formed by self-assembly of hydrophilic and hydrophobic copolymers were formed inside the PHEA-15% (PVA-co-PE) hydrogel ( Figure 2 b).

[0078] Test Example 2

[0079] Mechanical testing:

[0080] An electronic universal testing machine was used to perform tensile tests on the PHEA hydrogel, PHEA-5% (PVA-co-PE) hydrogel, PHEA-10% (PVA-co-PE) hydrogel, and PHEA-15% (PVA-co-PE) hydrogel prepared in Examples 1-4.

[0081] See also Figure 3 As shown in Figure 3, the test results show that after adding (PVA-co-PE), the strength (a), toughness and elastic modulus (b) of the hydrogel are significantly improved.

[0082] Test Example 3

[0083] Swelling behavior test and water content test:

[0084] The PHEA hydrogel, PHEA-5% (PVA-co-PE) hydrogel, PHEA-10% (PVA-co-PE) hydrogel, and PHEA-15% (PVA-co-PE) hydrogel prepared in Examples 1-4 were immersed in water for 6 h, 12 h, 24 h, and 48 h to test the swelling rate, and the water content of the hydrogel at swelling equilibrium was tested.

[0085] See also Figure 4 As shown in Figure 3, the test results show that as the content of the hydrophilic and hydrophobic copolymers increases, the anti-swelling ability of the hydrogel becomes stronger (a, b) and the water content becomes smaller (c).

[0086] Test Example 4

[0087] In vitro biocompatibility testing:

[0088] First, the PHEA-15% (PVA-co-PE) hydrogel prepared in Example 4 was sterilized with 75% ethanol for 3 hours and then immersed in sterilized PBS for 12 hours (replaced every 4 hours). Then, the hydrogel treated as above was immersed in DMEM culture medium for 24 hours to obtain an leaching solution, which was diluted with culture medium to obtain a 50% leaching solution. 3T3 cells were cultured at 5×10 cells per well. 3 Cells were seeded into 96-well plates at a density of 100 μL and incubated at 37°C and 5% CO2 for 12 hours. The cells adhered to the plate. The culture medium was then replaced with different hydrogel extracts. After 24 and 48 hours of incubation, 100 μL of blank culture medium (containing 10 μL of CCK-8 reagent) was added to each well and incubated at 37°C for an additional 30 minutes. Absorbance was measured at 450 nm using a microplate reader to calculate cell viability.

[0089] See also Figure 5 As shown in the figure, it can be found from the test results that PHEA-15% (PVA-co-PE) hydrogel has good cell compatibility.

[0090] Test Example 5

[0091] In vivo anti-swelling phase test:

[0092] The PHEA-15% (PVA-co-PE)-Bi hydrogel prepared in Example 5 was formed into 5 mm diameter discs, soaked in 75% ethanol for 3 hours, then soaked in PBS for 12 hours, and then implanted subcutaneously in mice. The hydrogel's swelling in the mice was monitored using a small animal SPECT-CT imaging system on days 0, 10, 20, and 30.

[0093] See also Figure 6 As shown in the figure, it can be found from the test results that after being implanted subcutaneously in mice, the diameter of the PHEA-15% (PVA-co-PE)-Bi hydrogel did not change, indicating that the gel has good anti-swelling ability in vivo.

[0094] Test Example 6

[0095] In vivo biocompatibility testing:

[0096] Based on Test Example 5, HE staining of mouse skin tissue sections was performed after 30 days of subcutaneous hydrogel implantation.

[0097] See also Figure 7 As shown, the test results showed that compared with the blank group (a), after gel implantation (b), the skin cell morphology did not change, and the surface hydrogel had good compatibility in the body.

[0098] In summary, the present invention prepares PHEA-(PVA-co-PE) tough hydrogel by rapid photoinitiated polymerization. By adjusting the content of (PVA-co-PE), the mechanical properties of the hydrogel can be controlled to meet different application requirements. When the (PVA-co-PE) content reaches 15wt%, the strength of the hydrogel can reach 0.65MPa and the elongation at break reaches 320%. Compared with the hydrogel without (PVA-co-PE), the toughness is increased by 146 times, reaching 1.16MJ / m 3 , while the modulus reaches 0.25MPa.

[0099] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a strong and anti-swelling hydrogel with good biocompatibility, characterized in that: The following steps are involved: Step 1) 2-hydroxyethyl acrylate as a monomer, N,N'-methylenebisacrylamide as a crosslinker, and 1-hydroxycyclohexyl phenyl ketone as a photoinitiator are dissolved in a certain volume of dimethyl sulfoxide in a certain mass ratio, and ultrasonicated for a period of time to prepare a PHEA precursor solution; Weigh 4 g of 2-hydroxyethyl acrylate, 40 mg of N,N'-methylenebisacrylamide, 10 mg of 1-hydroxycyclohexyl phenyl ketone, and 2.5 mL of dimethyl sulfoxide; Step 2) dissolving a certain amount of poly(vinyl alcohol-co-ethylene) as a hydrophilic and hydrophobic copolymer in a certain amount of dimethyl sulfoxide, and mixing the mixture for a certain period of time at a certain temperature and stirring speed to prepare a 20% (PVA-co-PE)-DMSO solution; Step 3) 7.5 mL of the (PVA-co-PE)-DMSO solution prepared in Step 2 was mixed with the PHEA precursor solution prepared in Step 1. After photocuring for a period of time, the mixture was immersed in water to finally obtain a PHEA-(PVA-co-PE) hydrogel with a micellar structure. The obtained PHEA-(PVA-co-PE) hydrogel has good biocompatibility, strong toughness, and anti-swelling properties.

2. The method for preparing a strong and anti-swelling hydrogel with good biocompatibility according to claim 1, characterized in that: In step 1, the ultrasonication time is 5 min.

3. The method for preparing a strong and anti-swelling hydrogel with good biocompatibility according to claim 1, characterized in that: In step 2, the temperature when poly(vinyl alcohol-co-ethylene) and dimethyl sulfoxide are mixed is 150° C., the stirring speed is 300 rpm, and the stirring time is 2 h.

4. The method for preparing a strong and anti-swelling hydrogel with good biocompatibility according to claim 1, characterized in that: In step 3, the photocuring is performed by irradiating an ultraviolet lamp with a specific wavelength, so that the mixed solution of the (PVA-co-PE)-DMSO solution and the PHEA precursor solution forms a gel.

5. The method for preparing a strong and anti-swelling hydrogel with good biocompatibility according to claim 4, characterized in that: The wavelength of the ultraviolet light emitted by the ultraviolet lamp is 365nm.

6. The method for preparing a strong and anti-swelling hydrogel with good biocompatibility according to claim 1, characterized in that: In step 3, the light curing time is 1 minute.

7. A strong and anti-swelling hydrogel with good biocompatibility, characterized in that: The hydrogel is prepared by the method for preparing a strong, tough and anti-swelling hydrogel with good biocompatibility as described in any one of claims 1 to 6.

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