A hydrogel band-aid for bone repair, its preparation method and application

Abstract

The present invention belongs to the technical field of bone repair hydrogels, and discloses a hydrogel bandage for bone repair, its preparation method and application, which include the following steps: mixing a polyethylene glycol succinimide succinate solution with an alendronic acid solution, followed by dialysis and lyophilization to obtain alendronic acid-modified polyethylene glycol succinimide succinate; uniformly mixing the alendronic acid-modified polyethylene glycol succinimide succinate, polyphenols, metal ions and water in proportion, performing solid-liquid separation, and drying the solid to obtain a hydrogel. The preparation process of the present invention has the advantages of being simple and rapid, which not only simplifies the production process, but also enhances the abilities of bone regeneration, angiogenesis and immunomodulation.

Description

Technical Field

[0001] The present invention belongs to the technical field of bone repair hydrogels, and particularly relates to a hydrogel bandage for bone repair, its preparation method and application. Background Art

[0002] The statements herein merely provide background art related to the present invention and do not necessarily constitute prior art.

[0003] Osteoporosis is a common degenerative bone disease. Due to reduced bone density and damaged microstructure, the brittleness of bone and the susceptibility to fractures increase, especially in the elderly and postmenopausal women. Therefore, osteoporotic bone defects are challenging. Currently, the methods for treating osteoporotic fractures (such as bisphosphonates) are hindered by low bioavailability and insufficient bone immunomodulation, resulting in challenges in the recovery of osteoporotic fractures. To address these challenges, there is an urgent need for innovative materials that can not only support bone regeneration but also regulate the immune environment to promote healing.

[0004] Polyethylene glycol hydrogel bandages are an innovative material designed to cover bone defects, provide physical support, and promote bone tissue regeneration. These polyethylene glycol hydrogel bandages are highly tunable and reproducible, suitable for cross-linking and coupling with biomolecules (such as extracellular matrix mimetic peptides that promote cell adhesion and enzymatic degradation), and are considered a generally recognized as safe additive by the FDA. However, the ability of polyethylene glycol hydrogel bandages to promote bone growth and repair defects is often limited and cannot meet the complex biological requirements of bone regeneration, especially in severe or challenging cases. Summary of the Invention

[0005] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a hydrogel bandage for bone repair, its preparation method and application. The present invention provides a simple and controllable strategy for designing and manufacturing hydrogel bandages with bone repair ability. Compared with the traditional solution casting-evaporation method, the reported assembly strategy has the advantages of simple and rapid process, which not only simplifies the production process but also enhances the ability of bone regeneration, angiogenesis, and immunomodulation.

[0006] To achieve the above purpose, the present invention is realized through the following technical solutions:

[0007] In the first aspect, the present invention provides a preparation method of a hydrogel bandage for bone repair, including the following steps:

[0008] Mix a polyethylene glycol succinimide succinate solution with an alendronic acid solution, then dialyze and lyophilize to obtain alendronic acid-modified polyethylene glycol succinimide succinate;

[0009] Mix alendronic acid-modified polyethylene glycol succinimidyl succinate, polyphenol, metal ions and water in proportion and mix them evenly. Then, perform solid-liquid separation. Spread the solid obtained from the solid-liquid separation into a uniform thin layer. After drying, a hydrogel band-aid is obtained.

[0010] The function of polyethylene glycol succinimidyl succinate is to form a complex through the hydrogen bond interaction between polyethylene glycol and polyphenol; utilize the interaction between the succinimidyl succinate at the end of polyethylene glycol and alendronic acid to graft alendronic acid to the end of polyethylene glycol for the purpose of loading and sustained release of alendronic acid. Polyethylene glycol is the main body of the entire hydrogel band-aid.

[0011] The function of alendronic acid is that it is currently a drug for clinical treatment of osteoporosis, and alendronic acid is used to inhibit the activity of osteoclasts;

[0012] The functions of polyphenol are as follows: it has a hydrogen bond interaction with polyethylene glycol; it forms a metal-polyphenol network with metal ions; polyphenol also has the function of regulating the immune microenvironment.

[0013] Loading metal: Alendronic acid can form a metal coordination bond with metal ions; polyphenol can form a metal-polyphenol network with metal. Utilizing these two interactions, metal ions can be effectively loaded in the hydrogel band-aid.

[0014] Different types of metal ions will produce significant biological effects under appropriate doses and controlled release, so they are very valuable in bone repair materials. Adding various metal ions (such as magnesium, calcium, strontium, zinc, copper and iron) at the optimal dose can significantly enhance the activity of osteoblasts, inhibit the function of osteoclasts, and promote angiogenesis. Therefore, the preparation of a polyethylene glycol hydrogel band-aid loaded with multiple metals is of great significance for the treatment of osteoporotic bone defects.

[0015] In some embodiments, the polyethylene glycol succinimidyl succinate is selected from one or a combination of methoxy polyethylene glycol succinimidyl succinate, di-arm polyethylene glycol succinimidyl succinate, tetra-arm polyethylene glycol succinimidyl succinate or octa-arm polyethylene glycol succinimidyl succinate.

[0016] Preferably, the polyethylene glycol succinimidyl succinate is octa-arm polyethylene glycol succinimidyl succinate.

[0017] In some embodiments, the molar ratio of polyethylene glycol succinimidyl succinate to alendronic acid is 1:1 - 5, preferably 1:2.

[0018] In some embodiments, after mixing polyphenol and metal ions, metal ion-polyphenol complex nanoparticles are formed;

[0019] Next, the metal ion-polyphenol complex nanoparticle dispersion is mixed evenly with the solution of alendronic acid-modified polyethylene glycol succinimide succinate, followed by solid-liquid separation. After drying the solid, the hydrogel is obtained.

[0020] Preferably, the molar ratio of the metal ion, polyphenol, and alendronic acid-modified polyethylene glycol succinimide succinate is 1.5 - 2.5:1:2 - 3, preferably 2:1:2.5.

[0021] In some embodiments, the polyphenol is selected from one or a combination of tannic acid, gallic acid, epigallocatechin gallate, catechin, or anthocyanin.

[0022] Preferably, the polyphenol is epigallocatechin gallate.

[0023] In some embodiments, the metal ion is selected from one or a combination of calcium ion, zinc ion, magnesium ion, or strontium ion.

[0024] Preferably, the metal ion is calcium ion and / or zinc ion.

[0025] In a second aspect, the present invention provides a hydrogel bandage for bone repair, which is prepared by the above preparation method.

[0026] In a third aspect, the present invention provides the application of the hydrogel bandage for bone repair in the treatment of osteoporotic bone defects.

[0027] The beneficial effects obtained by one or more of the above embodiments of the present invention are as follows:

[0028] (1) The preparation method of the present invention is simple and easy to implement. By utilizing the coordination between metal and polyphenol and the coordination between metal and alendronic acid, a flexible and multifunctional metal-polyethylene glycol hydrogel bandage is obtained. The present invention provides a general method for rapidly preparing hydrogel bandages loaded with multiple metal ions and having excellent performance.

[0029] (2) The hydrogel bandage obtained by the preparation method of the present invention has excellent stretchability (150%) and can achieve the slow release of multiple metal ions.

[0030] (3) The hydrogel bandage obtained by the preparation method of the present invention has high biocompatibility (95%) with mouse mononuclear macrophages and mouse bone marrow mesenchymal stem cells, and has high osteogenic promotion performance, osteoclast inhibition performance, and the ability to regulate the immune microenvironment. It can be used as a therapeutic bandage to accelerate the repair of bone defect sites. The present invention provides a simple and controllable strategy for the engineering design of multifunctional bone repair hydrogel bandages loaded with multiple metals, and has broad application prospects in the fields of osteoporotic bone defects and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings forming a part of this invention are used to provide a further understanding of the invention. The schematic embodiments of the invention and their descriptions are used to explain the invention and do not unduly limit the invention.

[0032] Figure 1 It is a flowchart for the preparation method and application of the hydrogel band-aid for bone repair in Example 1 of the present invention;

[0033] Figure 2 It is a macroscopic photograph of the preparation process of the hydrogel band-aid for bone repair in the embodiments of the present invention. Among them, a is the PZnE hydrogel; b is the PCaE hydrogel; c is the PZnCaE hydrogel;

[0034] Figure 3 It is an SEM image of the hydrogel band-aid for bone repair containing different metal ions in the present invention. Among them, a is the PZnE hydrogel; b is the PCaE hydrogel; c is the PZnCaE hydrogel;

[0035] Figure 4 It is the tensile mechanical property curve and statistical chart of the tensile mechanical properties of the hydrogel band-aid with different metal ions in the present invention. Among them, a is the tensile property curve; b is the tensile strength quantitative diagram; c is the fracture toughness quantitative diagram;

[0036] Figure 5 It is the metal ion release curve of the hydrogel band-aid with different metal ions in the present invention. Among them, a is the zinc ion release curve; b is the calcium ion release curve;

[0037] Figure 6 It is the biocompatibility of the hydrogel band-aid with different metal ions in the present invention. Among them, a is the survival rate of RAW 264.7 cells; b is the survival rate of BMMSC cells; c is the survival rate of HUVEC cells;

[0038] Figure 7 It is the osteogenic property of the hydrogel band-aid with different metal ions in the present invention. Among them, a is the detection of the osteogenic ability of different types of multi-metal bone repair hydrogels by real-time fluorescence quantitative PCR technology; b is the detection result of the alkaline phosphatase (ALP) activity assay kit; c is the detection result of the alizarin red (ARS) activity assay kit;

[0039] Figure 8 It is the osteoclast property of the hydrogel band-aid with different metal ions in the present invention. Among them, a is the detection diagram of tartrate-resistant acid phosphatase activity; b is the quantitative diagram of tartrate-resistant acid phosphatase activity detection;

[0040] Figure 9The angiogenesis performance of the hydrogel band-aids with different metal ions of the present invention. Among them, a is the cell migration ability diagram of the hydrogel band-aids with different metal ions, and the scales of each diagram in a are the same; b is the angiogenesis diagram of the hydrogel band-aids with different metal ions, and the scales of each diagram in b are the same;

[0041] Figure 10 The immunomodulatory performance of the hydrogel band-aids with different metal ions of the present invention. Among them, a is the flow cytometry diagram; b is the quantitative data of M1-type cells; c is the quantitative data of M2-type cells;

[0042] Figure 11 Shows the treatment effect of the hydrogel band-aid for bone repair in Example 1 of the present invention on osteoporotic bone defects in mice. Among them, a is the control group; b is the hydrogel band-aid group containing calcium ions; c is the hydrogel band-aid group containing zinc ions; d is the hydrogel band-aid group containing calcium ions and zinc ions;

[0043] Figure 12 Shows the schematic diagram of using the hydrogel band-aid to treat osteoporotic bone defects in mice in the examples of the present invention. Detailed implementation mode

[0044] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0045] The present invention will be further described below in conjunction with examples.

[0046] Example 1

[0047] A preparation method of a hydrogel band-aid for bone repair, comprising the following steps:

[0048] (1) Accurately weigh 1.6 g of sodium hydroxide in 20 mL of ultrapure water, and ultrasonicate for 3 min at 25 °C to obtain a dissolved sodium hydroxide solution. Accurately weigh 2 g of alendronic acid in 10 mL of PBS, and add the sodium hydroxide solution to adjust the pH value of the solution to 7.4 to obtain a dissolved alendronic acid solution;

[0049] Accurately weigh 1 g of octa-arm polyethylene glycol succinimidyl succinate in 10 mL of PBS, and ultrasonicate for 5 min at 25 °C to obtain a dissolved octa-arm polyethylene glycol succinimidyl succinate solution;

[0050] After mixing the above octa-arm polyethylene glycol succinimidyl succinate solution and alendronic acid solution, stir at 25 °C for 4 h, dialyze for 48 h, and then lyophilize to obtain alendronic acid-modified polyethylene glycol.

[0051] (2) Weigh accurately 30 mg of epigallocatechin gallate in 10 mL of PBS, and ultrasonically dissolve it for 5 min at 25 °C to obtain a well-dissolved epigallocatechin gallate solution with a concentration of 3 mg / mL.

[0052] Weigh accurately 50 mg of zinc nitrate hexahydrate in 10 mL of ultrapure water, and ultrasonically dissolve it for 3 min at 25 °C to obtain a zinc nitrate hexahydrate solution with a zinc nitrate concentration of 5 mg / mL.

[0053] After mixing 1 mL of the epigallocatechin gallate solution with 1 mL of the zinc nitrate hexahydrate solution, EGCG-Zn nanoparticles are obtained.

[0054] (3) Weigh accurately 250 mg of alendronic acid-modified polyethylene glycol in 10 mL of PBS, and ultrasonically dissolve it for 3 min at 25 °C to obtain a well-dissolved alendronic acid-modified polyethylene glycol solution with a concentration of 25 mg / mL. Mix 0.5 mL of the alendronic acid-modified polyethylene glycol solution with 1 mL of the EGCG-Zn nanoparticles, and centrifuge at 500 rcf for 3 min. After removing the supernatant, collect the precipitate.

[0055] (4) Spread the precipitate evenly on a glass Petri dish with a diameter of 2 cm to form a uniform thin layer. After drying, a self-supporting hydrogel bandage can be obtained, as shown in Figure 1 and Figure 2 as shown in a of

[0056] Example 2

[0057] A preparation method of a hydrogel bandage for bone repair, which is different from Example 1 in that the concentration of alendronic acid-modified polyethylene glycol is changed from 25 mg / mL to 50 mg / mL.

[0058] Example 3

[0059] A preparation method of a hydrogel bandage for bone repair, which is different from Example 1 in that the concentration of epigallocatechin gallate is changed from 3 mg / mL to 5 mg / mL.

[0060] Example 4

[0061] A preparation method of a hydrogel bandage for bone repair, which is different from Example 1 in that the concentration of zinc nitrate hexahydrate is changed from 5 mg / mL to 10 mg / mL.

[0062] Example 5

[0063] A preparation method of a hydrogel band-aid for bone repair, which is different from Example 1 in that the centrifugation speed is changed from 500 rcf to 3000 rcf.

[0064] Example 6

[0065] A preparation method of a hydrogel band-aid for bone repair, which is different from Example 1 in that the centrifugation time is changed from 3 min to 10 min.

[0066] Example 7

[0067] A preparation method of a hydrogel band-aid for bone repair, which is different from Example 1 in that the metal ion is changed from zinc nitrate hexahydrate to anhydrous calcium chloride with a concentration of 5 mg / mL. The prepared hydrogel is shown in Figure 2 b below.

[0068] Example 8

[0069] A preparation method of a hydrogel band-aid for bone repair, which is different from Example 1 in that the metal ion is changed from zinc nitrate hexahydrate to a mixed solution of anhydrous calcium chloride and zinc nitrate hexahydrate, the concentration of zinc nitrate hexahydrate is 2.5 mg / mL, and the concentration of anhydrous calcium chloride is 2.5 mg / mL. The prepared hydrogel is shown in Figure 2 c below.

[0070] Experimental Example 1: Performance detection of a hydrogel band-aid loaded with metal and with controllable release

[0071] (1) SEM test

[0072] The morphological characterization was carried out on the hydrogel band-aids for bone repair prepared in Example 1, Example 7 and Example 8. It can be seen from Figure 3 a, b and c below that the thickness of the hydrogel band-aid is uniform on the micron scale and has a dense microstructure.

[0073] (2) Mechanical property test

[0074] The mechanical properties of the hydrogel band-aids for bone repair obtained in the examples were quantitatively tested for tensile properties. As shown in Figure 4 a, b and c below, where PZnE is the hydrogel band-aid prepared in Example 1 and contains zinc ions; PCaE is the hydrogel band-aid prepared in Example 7 and contains calcium ions; PZnCaE is the hydrogel band-aid prepared in Example 8 and contains calcium ions and zinc ions.

[0075] When the hydrogel band-aid contains calcium ions and zinc ions, the tensile strength of the PZnCaE hydrogel band-aid reaches the maximum, which can reach 530 kPa.

[0076] (3)Metal ion sustained release test

[0077] Take 5 mg of the PZnCaE hydrogel bandage prepared in Example 8 and place it in a centrifuge tube containing 10 mL of PBS buffer solution (10 mM, pH 6.5). Take out 0.1 mL of the dialysis solution every day on the 0th, 2nd, 4th, 6th, 8th, 10th, 15th, 20th, and 25th days of soaking, and then add 0.1 mL of fresh buffer solution. After the sampling is completed, use ICP-MS to quantitatively analyze the released zinc ions and calcium ions, and plot the metal ion release curve. The metal ion release curve is as shown in Figure 5 shown, where Figure 5 a is the zinc ion release curve and b is the calcium ion release curve in. Under physiological pH conditions, the PZnCaE hydrogel bandage can continuously and stably release metal ions for about 30 days, which is very beneficial for bone repair and regeneration applications.

[0078] (4)Biocompatibility test

[0079] Characterize the biocompatibility of the metal-polyethylene glycol hydrogel bandage on mouse mononuclear macrophages (RAW 264.7) and mouse bone marrow mesenchymal stem cells (BMMSCs) through a cell proliferation and cytotoxicity detection kit (CCK-8, purchased from Beyotime Biotechnology Co., Ltd.).

[0080] Select a 96-well cell culture plate, inoculate 5000 cells in each well, and after culturing overnight, the PZnE hydrogel bandage prepared in Example 1, the PCaE hydrogel bandage prepared in Example 7, and the PZnCaE hydrogel bandage prepared in Example 8 are respectively soaked in cell culture medium, and the concentration of the hydrogel bandage is 5 mg / mL. After soaking for 24 hours, take out the supernatant, which is the hydrogel bandage extract. Add 100 μL of the three types of hydrogel bandage extracts to the cells and continue to culture for 72 h. After the culture is completed, add 10 μL of CCK-8 solution to each well, and after acting for 4 h, use an enzyme-linked immunosorbent assay (ELISA) reader to detect the absorbance, and the excitation wavelength is 480 nm. The biocompatibility curve is as shown in Figure 6 shown, where a is the survival rate of RAW 264.7 cells; b is the survival rate of BMMSC cells; c is the survival rate of HUVEC cells; it can be seen that the metal-polyethylene glycol hydrogel bandages with different metal ions can all well maintain the growth of cells, and the cell survival rate can reach more than 95%.

[0081] (5)Osteogenic performance test

[0082] To study the potential application as a bone repair band-aid, the osteogenic properties of the PZnE hydrogel band-aid obtained in Example 1, the PCaE hydrogel band-aid obtained in Example 7, and the PZnCaE hydrogel band-aid obtained in Example 8 were characterized, as shown in Figure 7 .

[0083] The PZnE hydrogel band-aid prepared in Example 1, the PCaE hydrogel band-aid prepared in Example 7, and the PZnCaE hydrogel band-aid prepared in Example 8 were respectively immersed in cell culture medium, and the concentration of the hydrogel band-aid was 5 mg / mL. After soaking for 24 hours, the supernatant was taken out, which was the hydrogel band-aid extract. A 24-well cell culture plate was selected, and 50,000 mouse bone marrow mesenchymal stem cells (BMMSCs) were inoculated in each well. After culturing overnight, 500 μL of the extracts of the three types of hydrogel band-aids were respectively added to the cells and cultured for another 10 days. After the culture was completed, the protein level in the cells was detected by real-time fluorescence quantitative PCR technology. And the effects of different hydrogel extracts on the osteogenic ability of cells were detected by using an alkaline phosphatase (ALP, purchased from Beijing Solarbio Science & Technology Co., Ltd.) activity assay kit and an alizarin red S (ARS, purchased from Beijing Solarbio Science & Technology Co., Ltd.) activity assay kit.

[0084] As Figure 7 shown in a, on the 10th day of osteogenic induction, the expression of osteogenesis-related proteins such as human type I collagen, osteopontin, runt-related transcription factor 2, and bone morphogenetic protein 2 in BMMSCs of the calcium ion-containing group increased significantly. As Figure 7 shown in b and c, the alkaline phosphatase staining on the 14th day of culturing BMMSCs and the alizarin red S staining on the 21st day showed that the alkaline phosphatase activity and calcium deposition of BMMSCs cultured in the PCaE and PZnCaE groups increased significantly. Compared with the PZnE group and the control group, the PCaE group and the PZnCaE group would slowly release Ca ions during the degradation process and promote osteogenic differentiation through the phosphatidylinositol 3-kinase (PI3K) signaling pathway.

[0085] (6)Osteoclast performance test

[0086] To study the potential application as a bone repair band-aid, the osteoclast properties of the PZnE hydrogel band-aid obtained in Example 1, the PCaE hydrogel band-aid obtained in Example 7, and the PZnCaE hydrogel band-aid obtained in Example 8 were characterized ( Figure 8 ).

[0087] The PZnE hydrogel band-aid prepared in Example 1, the PCaE hydrogel band-aid prepared in Example 7, and the PZnCaE hydrogel band-aid prepared in Example 8 were respectively immersed in cell culture medium, and the concentration of the hydrogel band-aid was 5 mg / mL. After soaking for 24 hours, the supernatant was taken out, which was the hydrogel band-aid extract. A 24-well cell culture plate was selected, and 50,000 mouse bone marrow mesenchymal stem cells (BMMSCs) were inoculated into each well. After culturing overnight, 500 μL of the extracts of the three types of hydrogel band-aids were added to the cells and cultured for another 7 days. After the culture was completed, a tartrate-resistant acid phosphatase (TRAP, purchased from Beijing Solarbio Science & Technology Co., Ltd.) activity assay kit was used to detect the effect of different hydrogel extracts on the osteoclast ability of the cells. The results showed that on the 7th day of osteoclast induction, except for the control group, the TRAP staining results of other experimental groups did not show obvious osteoclast formation (as shown in Figure 8 a). Quantitative analysis further confirmed that with the slow release of ALN, the osteoclast differentiation in the PZnE group, PCaE group, and PZnCaE group was significantly inhibited (as shown in Figure 8 b). Therefore, the bone repair hydrogel band-aid can achieve the balanced regulation of osteoblasts and osteoclasts.

[0088] (7) Angiogenesis performance test

[0089] The hydrogel band-aid can promote angiogenesis and induce cell migration. The cell migration experiment was carried out on the PZnE hydrogel band-aid obtained in Example 1, the PCaE hydrogel band-aid obtained in Example 7, and the PZnCaE hydrogel band-aid obtained in Example 8 using human umbilical vein endothelial cells (HUVECs) to evaluate the migration ability of different metal hydrogel band-aids on HUVECs.

[0090] The PZnE hydrogel band-aid prepared in Example 1, the PCaE hydrogel band-aid prepared in Example 7, and the PZnCaE hydrogel band-aid prepared in Example 8 were respectively immersed in cell culture medium, and the concentration of the hydrogel band-aid was 5 mg / mL. After soaking for 24 hours, the supernatant was taken out, which was the hydrogel band-aid extract. A 12-well cell culture plate was selected, and 100,000 HUVECs were inoculated into each well. After culturing overnight, a sterile 200 μL pipette tip was used to make a scratch perpendicular to the well plate, and then washed three times with PBS to make the scratch area free of floating cells. 1 mL of the extracts of the three types of hydrogel band-aids were added to the cells and cultured for another 24 days. After the culture was completed, an inverted fluorescence microscope was used to observe the cell migration results. The results are as shown in Figure 9 a. Compared with the control group, PZnE group, and PCaE group, the PZnCaE group had the strongest migration ability.

[0091] Subsequently, angiogenesis experiments were conducted on the surface of the matrix gel to evaluate the effects of different metal hydrogel band-aids on angiogenesis. A 48-well cell culture plate was selected. After inoculating 200 μL of matrix gel into each well and culturing for 30 minutes at 37 °C, 100,000 HUVECs were further inoculated into each well and cultured for 4 hours. After the culture, the results of cell angiogenesis were observed using an inverted fluorescence microscope. The number of junctions and tube lengths in the PZnCaE group increased significantly, and it had the strongest in vitro tube formation ability (as shown in b of Figure 9 ). Therefore, the hydrogel band-aid can promote cell migration, improve angiogenesis ability, and is beneficial to promoting fracture healing.

[0092] (8) Immunomodulatory performance test

[0093] Regulating the polarization state of macrophages and inducing their transformation from the M1 phenotype to the M2 phenotype is crucial for promoting angiogenesis and bone repair. The hydrogel band-aids obtained in Example 1, Example 8, and Example 9 can effectively regulate the immune microenvironment and promote macrophage polarization. Flow cytometry was used to detect the surface markers of macrophage polarization, as shown in a of Figure 10 . The proportion of M1 macrophages in the PZnE, PCaE, and PZnCaE groups decreased significantly, as shown in b of Figure 10 , while the proportion of M2 macrophages increased significantly, as shown in c of Figure 10 . This indicates that the hydrogel band-aid containing EGCG can effectively regulate the transformation of macrophages from the M1 phenotype to the M2 phenotype, provide a more favorable immune microenvironment, and thus contribute to enhancing bone repair at the fracture site in osteoporosis patients.

[0094] (9) Treatment of osteoporotic bone defects in rats with hydrogel band-aids for bone repair

[0095] To further demonstrate the bone defect treatment potential of the hydrogel band-aids obtained in Example 1, Example 8, and Example 9, the effect of the hydrogel band-aid on treating skull defects in osteoporotic rats was also studied.

[0096] Different types of hydrogel band-aids were implanted into circular defects with a diameter of 8 mm on the skulls of rats, as shown in Figure 12 . The results of micro-computed tomography (micro-CT) are shown in Figure 11 . The defects in the control group were obvious at the fourth week after surgery, and only a small amount of new bone formed near the fracture ends, as shown in a of Figure 11 . Compared with other groups, the PZnE group and the PCaE group showed a trend of bone repair, as shown in b and c of Figure 11 , and the PZnCaE group had the smallest defect area. At the 8th week after surgery, the defect areas of all groups except the control group decreased. Compared with other groups, the PZnCaE group had a better bone repair effect, as shown inFigure 11 as shown in d in the Chinese version.

[0097] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a hydrogel band-aid for bone repair, characterized in that: The steps include: The polyethylene glycol succinimidyl succinate solution and the alendronic acid solution are mixed, dialyzed, and freeze-dried to obtain alendronic acid-modified polyethylene glycol succinimidyl succinate; After the polyphenols are mixed with metal ions, metal ion-polyphenol complex nanoparticles are formed; Then, the metal ion-polyphenol complex nanoparticle dispersion and the alendronic acid-modified polyethylene glycol succinimidyl succinate solution are uniformly mixed, the solid and the liquid are separated, and the solid is dried to obtain a hydrogel; The molar ratio of metal ions, polyphenols and alendronic acid-modified polyethylene glycol succinimidyl succinate is 1.5-2.5:1:2-3; The polyphenol is selected from one or a combination of tannic acid, gallic acid, epigallocatechin gallate, catechin or anthocyanin.

2. The method for preparing a hydrogel band-aid for bone repair according to claim 1, characterized in that: The polyethylene glycol succinimidyl succinate is selected from one of methoxy polyethylene glycol succinimidyl succinate, two-arm polyethylene glycol succinimidyl succinate, four-arm polyethylene glycol succinimidyl succinate or eight-arm polyethylene glycol succinimidyl succinate or a combination thereof.

3. The method for preparing a hydrogel band-aid for bone repair according to claim 1, characterized in that: The molar ratio of polyethylene glycol succinimidyl succinate to alendronic acid is 1:1-5.

4. The method for preparing a hydrogel band-aid for bone repair according to claim 1, characterized in that: The metal ion is selected from one or a combination of calcium ion, zinc ion, magnesium ion or strontium ion.

5. A hydrogel bandage for bone repair, characterized in that: Prepared by the preparation method described in any one of claims 1 to 4.

6. Use of the hydrogel band-aid for bone repair according to claim 5 in the preparation of a drug for treating osteoporotic bone defects.

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