Thermosensitive polymer hydrogel as well as preparation method and application thereof

Abstract

The invention discloses thermo-sensitive polymer hydrogel as well as a preparation method and application thereof, and the polymer hydrogel comprises a temperature response type polymer monomer, cement hydration product nanoparticles and an initiator. The polymer hydrogel disclosed by the invention has excellent compressive strength and biocompatibility, so that cells can well grow and adhere to the polymer hydrogel; the polymer hydrogel also has drug loading and rapid drug release properties, and lays a foundation for the gel as a wound dressing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biological materials, in particular to a temperature-sensitive polymer hydrogel and a preparation method and application thereof. BACKGROUND

[0002] Hydrogel is a kind of polymer material with three-dimensional cross-linked structure, which is characterized by high water content and excellent elasticity. Polymer hydrogel is often prepared by monomer polymerization or cross-linking reaction, and its physical and chemical properties can be adjusted by changing its composition, cross-linking degree and structure. This unique combination of properties makes them excellent biocompatible materials, which makes them very valuable in biomedical engineering. Poly-N-isopropylacrylamide (PNIPAM) is a thermosensitive raw material that makes hydrogel temperature sensitive. The lower critical solution temperature (LCST) of 32℃ is more suitable for human research, and has been studied for a large number of applications, including drug carriers, drug delivery, tissue engineering scaffolds, medical dressings and other fields. However, the poor mechanical properties of conventional hydrogels limit their application in high-load environments.

[0003] In recent years, researchers have been exploring ways to prepare high-strength polymer hydrogels to break through the mechanical performance limitations of traditional hydrogels. Among them, by combining nanoparticles with polymer hydrogel matrix to prepare nanocomposite hydrogels, the mechanical properties of polymer hydrogels can be significantly improved. However, the choice of nanoparticles is particularly important. The size and aggregation state of nanoparticles directly affect the performance of hydrogels. SUMMARY

[0004] The present application aims to solve at least one of the above technical problems in the prior art. To this end, the purpose of the present application is to provide a temperature-sensitive polymer hydrogel and a preparation method and application thereof.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present application is:

[0006] In a first aspect of the present application, a polymer hydrogel is provided, comprising a temperature-responsive polymer monomer, a cement hydration product nanoparticle and an initiator.

[0007] In the present application, the cement hydration product nanoparticles can provide physical crosslinking sites for the temperature-responsive polymer monomer to form a three-dimensional network of polymer materials, thereby significantly improving the strength and toughness of the polymer hydrogel; meanwhile, the nanoparticles with high specific surface area can form strong hydrogen bonds with the polymer molecular chains inside the hydrogel, enhancing the crosslinking effect and further improving the mechanical properties of the polymer hydrogel; the crosslinking network formed by the temperature-responsive polymer monomer has good biocompatibility, and the molecules thereof also have hydrophobic groups, which can maintain good morphology in a liquid environment without swelling, and can meet the requirements of cell adhesion and growth; the three-dimensional crosslinking network can also provide excellent drug loading and rapid drug release performance.

[0008] In some embodiments of the present application, the water content of the polymer hydrogel is 70wt%-90wt%.

[0009] In some embodiments of the present application, the temperature-responsive polymer monomer is crosslinked with the cement hydration product nanoparticles to form a three-dimensional network under the action of an initiator.

[0010] In some embodiments of the present application, the crosslinking includes physical crosslinking.

[0011] In some embodiments of the present application, the temperature-responsive polymer monomer includes at least one of N-isopropyl acrylamide, N,N-diethyl acrylamide, dimethylaminoethyl methacrylate, N-vinyl caprolactam, and oligomeric ethylene glycol monomethyl ether (meth)acrylate. In the present application, the polymer hydrogel formed by the above polymer monomers has temperature sensitivity, is greater than the lower critical solution temperature (LCST), does not swell in water, and can be used for drug loading and cell culture.

[0012] In some embodiments of the present application, the cement hydration product nanoparticles include calcium hydroxide nanoparticles.

[0013] In some embodiments of the present application, the cement hydration product nanoparticles are formed by a hydration reaction of cement nanoparticles; the hydration reaction is carried out under the action of mechanical external force and at low temperature; the time of the hydration reaction is 5-15min, such as 8-12min; the temperature of the low temperature is -2-5℃, such as 0-2℃; the mechanical external force includes ultrasonic, stirring or a combination thereof; the frequency of the ultrasonic is 30-50Hz; the stirring rate is 800-1200rpm.

[0014] In some embodiments of the present application, the mass ratio of the temperature-responsive polymer monomer to the cement nanoparticles is 100:(1.3-3.0).

[0015] In the present application, too little cement dosage leads to a decrease in cement hydration product nanoparticles, and a decrease in the crosslinking sites of the provided material, resulting in a decrease in the compressive strength of the polymer hydrogel.

[0016] In some embodiments of the present application, the average particle size of the cement nanoparticles is 1-10 nm, such as 4-7 nm, 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, or 10 nm. In the present application, the fineness of the cement nanoparticles affects the hydration reaction rate, and a smaller average particle size of the cement nanoparticles can promote the rapid generation of hydration product nanoparticles.

[0017] In some embodiments of the present application, the cement nanoparticles include cement nanoparticles of Portland cement; the Portland cement includes at least one of fast-hardening Portland cement, ordinary Portland cement, slag Portland cement, pozzolanic Portland cement, fly ash Portland cement, or composite Portland cement.

[0018] In the present application, Portland cement can release calcium hydroxide nanoparticles, which can provide crosslinking sites for temperature-responsive polymer monomers.

[0019] In some embodiments of the present application, the strength grade of the Portland cement is 42.5, 42.5R, 52.5, 52.5R, 62.5, or 62.5R. The strength grade of cement refers to the minimum compressive strength achieved after 28 days of curing under standard conditions.

[0020] In some embodiments of the present application, the Portland cement includes at least one of Portland cement of 52.5, 52.5R, 62.5, or 62.5R; P·I 52.5R Portland cement, P·II 52.5R Portland cement in GB 175-2020; idt EN 197-1:2000 Type I-52.5R Portland cement; CEM I 52.5R cement in EN 197-1; Type III Portland cement in ASTM C150.

[0021] In the present application, the content of tricalcium silicate in the above-mentioned fast-hardening Portland cement is more than 55%, such as 55-70%, and the main doping of non-active admixtures such as limestone powder can quickly generate more calcium hydroxide nanoparticles during the hydration reaction, and almost no calcium hydroxide nanoparticles are consumed during the hydration process.

[0022] In some embodiments of the present invention, the initiator includes at least one of persulfate initiators, azo initiators, or peroxide initiators; more preferably, the initiator is selected from persulfate initiators; even more preferably, the initiator includes at least one of ammonium persulfate, sodium persulfate, or potassium persulfate.

[0023] In some embodiments of the present invention, the initiator is 0.1 to 0.5% of the mass of the temperature-responsive polymer monomer.

[0024] In some embodiments of the present invention, the polymer hydrogel further includes a co-initiator and water.

[0025] In some embodiments of the present invention, the co-initiator is selected from amine co-initiators; more preferably, the co-initiator includes at least one of tetramethylethylenediamine, tetraethylethylenediamine, triethanolamine or triisopropanolamine; such as tetramethylethylenediamine, tetraethylethylenediamine or combinations thereof.

[0026] In some embodiments of the present invention, the mass of the co-initiator is 0.7 to 1.8% of the temperature-responsive polymer monomer.

[0027] In some embodiments of the present invention, the mass ratio of water to temperature-responsive polymer monomer is (6-9):1.

[0028] A second aspect of the present invention provides a method for preparing the polymer hydrogel, comprising the following steps:

[0029] The polymer hydrogel is prepared by hydrating the components of the polymer hydrogel and then polymerizing them.

[0030] In some embodiments of the present invention, the preparation method of the polymer hydrogel includes the following steps:

[0031] The polymer hydrogel is prepared by subjecting temperature-responsive polymer monomers, initiators, co-initiators, cement nanoparticles, and water to a hydration reaction under mechanical force and low temperature conditions, followed by a polymerization reaction at elevated temperature.

[0032] In some embodiments of the present invention, the preparation method of the polymer hydrogel includes the following steps:

[0033] Cement nanoparticles are slowly added to an aqueous solution containing temperature-responsive polymer monomers, initiators, and co-initiators under mechanical external force and low temperature conditions to continue the hydration reaction, followed by a polymerization reaction to obtain the polymer hydrogel.

[0034] In some embodiments of the present invention, the polymerization reaction is carried out immediately after the hydration reaction.

[0035] In this invention, temperature-responsive polymer monomers such as NIPAM are difficult to polymerize, and oxygen easily inhibits the polymerization of free radicals. Therefore, after ultrasonic stirring, the mixture is immediately poured into a mold for vacuum operation to minimize contact with oxygen.

[0036] In some embodiments of the present invention, the reaction temperature of the polymerization reaction is 18–35°C, such as 20–30°C; and the reaction time is 6–10 h.

[0037] In some embodiments of the present invention, the polymerization reaction is carried out under vacuum conditions.

[0038] A third aspect of the present invention provides a hydrogel dressing comprising the aforementioned polymer hydrogel.

[0039] In some embodiments of the present invention, the polymer hydrogel is also loaded with an active drug.

[0040] In some embodiments of the present invention, the loading of the active drug in the polymer hydrogel is 50-150 mg / g, such as 60-120 mg / g, 70-100 mg / g, 80 mg / g, 90 mg / g, etc.

[0041] In some embodiments of the present invention, the active pharmaceutical ingredient includes anti-inflammatory drugs, analgesics, anesthetics, anticoagulants, antivirals, or antibiotics.

[0042] In this invention, the aforementioned active pharmaceutical ingredient is required to be released rapidly in order to exert its effects as quickly as possible.

[0043] In some embodiments of the present invention, the antibiotic includes at least one of vancomycin (Van), amikacin (Ami), gentamicin (Gen), doripenem (Dor), kanamycin (Kan), daptomycin (Dap), amoxicillin (Amo), streptomycin (Str), levofloxacin (Lev), ciprofloxacin (Cip), azithromycin (Azi), doxycycline (Dox), metronidazole (Met), linezolid (Lin), tetracycline (Tet), triclosan (Tri), rifampin (Rif), or norfloxacin (Nor).

[0044] In some embodiments of the present invention, the analgesic drug includes at least one of lidocaine, prilocaine, and bupivacaine.

[0045] The beneficial effects of this invention are:

[0046] The polymer hydrogel of this invention has excellent compressive strength and biocompatibility, enabling cells to grow and attach well on the polymer hydrogel; the polymer hydrogel also has drug loading and rapid drug release properties, laying the foundation for the use of the gel as a wound dressing. Attached Figure Description

[0047] Figure 1 This is a SEM image of the polymer hydrogel from Example 1 of the present invention.

[0048] Figure 2 The following are the compression test results of the polymer hydrogel in Example 1 of the present invention, wherein (A) is a picture of the polymer hydrogel before compression; (B) is a picture of the polymer hydrogel after compression of 7500N; and (C) is the compression resistance curve.

[0049] Figure 3 The results of polymer hydrogel cell culture in Example 1 of this invention are shown.

[0050] Figure 4 The results of the drug loading and release test of the polymer hydrogel in Example 1 of the present invention are shown; where (A) is the drug loading amount; and (B) is the drug release amount. Detailed Implementation

[0051] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials, reagents, or apparatus used in the embodiments and comparative examples are all available from conventional commercial sources or can be obtained by existing technical methods. Unless otherwise specified, the test or experimental methods are conventional methods in the art.

[0052] Raw materials and reagents:

[0053] Rapid-hardening Portland cement: 52.5R and 42.5 rapid-hardening Portland cement produced by Macau Cement Co., Ltd.;

[0054] N-Isopropylacrylamide was purchased from Shanghai TCI Company;

[0055] Ammonium persulfate: Shanghai Aladdin Reagent Co., Ltd.;

[0056] Tetramethylethylenediamine: Shanghai Aladdin Reagent Company.

[0057] Example 1

[0058] This embodiment prepares a polymer hydrogel, and the specific process is as follows:

[0059] The polymer hydrogel is composed of: 10g N-isopropylacrylamide, 60g water, 0.045g ammonium persulfate, 100μL tetramethylethylenediamine, and 0.15g 52.5R rapid-hardening silicate cement.

[0060] Preparation method of polymer hydrogel:

[0061] Under ice bath conditions, nitrogen gas was introduced into a three-necked flask, and water (0–2°C) and N-isopropylacrylamide were added sequentially. After the N-isopropylacrylamide was completely dissolved, ammonium persulfate and tetramethylethylenediamine were added. Silicate cement was slowly added to the flask along the walls under ultrasonic and mechanical stirring, a process that lasted approximately 30 seconds. Stirring was then continued stably at 40 kHz ultrasonication and 1000 rpm mechanical stirring for 10 minutes. While stirring, the solution in the beaker was quickly dispensed into 50 mm × 30 mm × 30 mm glass molds. The molds containing the reaction solution were then rapidly transferred to a vacuum oven and vacuumed at room temperature for 6–8 hours to obtain the polymer hydrogel.

[0062] SEM image of the polymer hydrogel prepared in Example 1 is shown below. Figure 1 As shown.

[0063] It can be seen that the polymer hydrogel has pores of uniform size and regularly arranged inside, proving that CNS has successfully prepared a temperature-sensitive polymer hydrogel with a three-dimensional network as a crosslinking agent.

[0064] Example 2

[0065] This embodiment prepares a polymer hydrogel, and the specific process is as follows:

[0066] The polymer hydrogel is composed of: 10g N-isopropylacrylamide, 60g water, 0.045g ammonium persulfate, 100μL tetramethylethylenediamine, and 0.1g 52.5R rapid-hardening silicate cement.

[0067] The preparation method of the polymer hydrogel was carried out in accordance with Example 1.

[0068] Example 3

[0069] This embodiment prepares a polymer hydrogel, and the specific process is as follows:

[0070] The polymer hydrogel is composed of: 10g N-isopropylacrylamide, 60g water, 0.045g ammonium persulfate, 100μL tetramethylethylenediamine, and 0.15g 42.5 rapid-hardening silicate cement.

[0071] The preparation method of the polymer hydrogel was carried out in accordance with Example 1.

[0072] Comparative Example 1

[0073] A polymer hydrogel was prepared in this comparative example, and the specific process is as follows:

[0074] The polymer hydrogel is composed of: 10g N-isopropylacrylamide, 60g water, 0.045g ammonium persulfate, 100μL tetramethylethylenediamine, and 0.35g N,N-methylenebisacrylamide.

[0075] Preparation method of polymer hydrogel:

[0076] Under ice bath conditions, nitrogen gas was introduced into a three-necked flask, and water (0–2 °C) and N-isopropylacrylamide were added sequentially. After the N-isopropylacrylamide was completely dissolved, ammonium persulfate and tetramethylethylenediamine were added. Under ultrasonic and mechanical stirring, N,N-methylenebisacrylamide was added to the flask, and the mixture was continuously sonicated at 40 kHz and mechanically stirred at 1000 rpm for 10 min. While stirring, the solution in the beaker was quickly dispensed into 50 mm × 30 mm × 30 mm glass molds, and the molds containing the reaction solution were quickly transferred to a vacuum oven and vacuumed at room temperature for 6–8 h to obtain the polymer hydrogel.

[0077] Experimental Example 1

[0078] This experiment demonstrates the compression test of a polymer hydrogel. Specifically, an MTS machine was used to perform the compression test on the polymer hydrogel. The test sample, measuring 25mm × 28mm × 30mm, was laid out on a compression plate for testing. The test temperature was room temperature (25℃) and humidity was 75%. The compression speed was 2mm / min.

[0079] Figure 2 The results of the compression test of the polymer hydrogel in Example 1 are shown, where (A) is a picture of the polymer hydrogel before compression; (B) is a picture of the polymer hydrogel after compression of 7500N; and (C) is the compression resistance curve.

[0080] It can be seen that the gel size was 30mm long before compression and became 25mm after compression, with some deformation in shape, proving that the polymer hydrogel has a certain compressive strength. The compressive strength of the polymer hydrogel prepared in Example 1 is about 16MPa, while the strength of the ordinary gel in Comparative Example 1 is 0.1-1MPa. This shows that the release of nanoparticles from cement significantly enhances the mechanical properties of the hydrogel. The compressive strengths of the polymer hydrogels in Examples 2 and 3 are about 13MPa and 10MPa, respectively.

[0081] Experimental Example 2

[0082] This experimental example uses polymer hydrogels for cell culture experiments. The specific process is as follows:

[0083] The polymer hydrogel was soaked in culture medium for 48 hours to wash away unpolymerized monomers. The polymer hydrogel sample was placed in a six-well plate, and human umbilical vein endothelial cells (HUVECs) were cultured on its surface. 20,000 HUVECs were placed in each well. After culturing at 37°C for 48 hours, the cells were stained with Calcein-AM / PI staining agent and observed under a DMi-8 fluorescence microscope to observe cell viability and adhesion to the gel. During microscope use, the 37°C culture medium solution needed to be continuously replenished to maintain cell nutrients and gel morphology.

[0084] Figure 3 The results of polymer hydrogel cell culture in Example 1 are shown. Green represents viable cells, and red represents dead cells.

[0085] As can be seen from the figure, more than 99% of the cells survived, with only a few cells dying, indicating that the hydrogel reinforced with cement-released nanoparticles has good biocompatibility and can be applied to the field of bioengineering.

[0086] Experimental Example 3

[0087] This experimental example uses polymer hydrogels for drug loading and release experiments. The specific process is as follows:

[0088] Drug loading and release of the polymer hydrogel were tested using amoxicillin: 0.25 g of the polymer hydrogel was immersed in a 2 mg / mL amoxicillin solution and incubated at 25°C for 2, 4, 6, and 8 hours for drug loading. The drug-loaded gel was then placed in 50 mL of PBS solution, and the drug loading and release were calculated based on the absorbance of the UV absorbance. The results are as follows: Figure 4 As shown.

[0089] As shown in the figure, after 8 hours of drug loading, the drug loading capacity can reach 18.48 mg. Amoxicillin can be released rapidly in a short time, with about 80% of the amoxicillin being released within 30 minutes, demonstrating the good drug loading and release capacity of the polymer hydrogel and showing good potential for medical applications.

[0090] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A polymer hydrogel, characterized in that: This includes temperature-responsive polymer monomers, cement hydration product nanoparticles, and initiators.

2. The polymer hydrogel according to claim 1, characterized in that: The temperature-responsive polymer monomers, under the action of an initiator, crosslink with cement hydration product nanoparticles to form a three-dimensional network.

3. The polymer hydrogel according to claim 1, characterized in that: The cement hydration product nanoparticles are formed by the hydration reaction of cement nanoparticles; preferably, the cement hydration product nanoparticles include calcium hydroxide nanoparticles.

4. The polymer hydrogel according to claim 3, characterized in that: The mass ratio of the temperature-responsive polymer monomer to cement nanoparticles is 100:(1.3-3.0).

5. The polymer hydrogel according to claim 3, characterized in that: The average particle size of the cement nanoparticles is 1–10 nm.

6. The polymer hydrogel according to claim 3, characterized in that: The cement nanoparticles include silicate cement nanoparticles; preferably, the silicate cement includes at least one of 52.5, 52.5R, 62.5 or 62.5R silicate cement.

7. The polymer hydrogel according to claim 1, characterized in that: The temperature-responsive polymer monomer includes at least one of N-isopropylacrylamide, N,N-diethylacrylamide, dimethylaminoethyl methacrylate, N-vinylcaprolactam, and oligoethylene glycol monomethyl ether (meth)acrylate.

8. A method for preparing the polymer hydrogel according to any one of claims 1 to 7, characterized in that: Includes the following steps: The polymer hydrogel is prepared by hydrating the components of the polymer hydrogel and then polymerizing them.

9. A hydrogel dressing, characterized in that: Includes the polymer hydrogel according to any one of claims 1 to 7.

10. The hydrogel dressing according to claim 9, characterized in that: The polymer hydrogel is also loaded with an active drug; preferably, the loading of the active drug in the polymer hydrogel is 50-150 mg / g.

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