Adhesive composite based on metal inorganic compounds for optimizing adhesion properties, process for its preparation and use

Abstract

The application discloses an adhesion compound based on metal inorganic compound for optimizing adhesion performance and a preparation method and application thereof, and belongs to the technical field of biological adhesives. The adhesion compound comprises an adhesion precursor, the adhesion precursor is composed of a protein-polyphenol composite hydrogel and a hydrogen bond breaking small molecule compound, and can perform network reconstruction containing beta-fold formation in an aqueous phase containing a metal inorganic compound; the metal inorganic compound has the following characteristics: (a) the solubility of itself and / or a hydrolysis product in water at 25 DEG C is less than 0.2 g / 100 mL; (b) the dissociation constant of a conjugate acid of an adapted anion is greater than 5; (c) the dissolution process produces one or more than one of water, gas or non-metallic precipitates. The application discloses for the first time that the release of metal cations is accurately adjusted by adapting metal inorganic compounds to directionally drive the network reconstruction of the adhesion precursor into a dense advanced structure, and the local metal ion concentration is avoided from being too high to produce stimulation to human tissues, the in-vivo adhesion performance is optimized, and the safe and durable soft and hard tissue bonding effect is achieved.

Description

Technical Field

[0001] This application belongs to the field of bio-based adhesive technology, and specifically relates to a highly safe and high-strength biomedical adhesive that is suitable for the human internal environment and can replace traditional sutures for the repair of internal organs, bone fixation and soft tissue healing. Specifically, it is an adhesive complex based on metal inorganic compounds with optimized adhesion properties, its preparation method and application. Background Technology

[0002] Adhesives are widely used in marine engineering, biomedicine, and automotive manufacturing. However, traditional commercial adhesives heavily rely on petroleum-based polymers such as epoxy resins, acrylates, and polyurethanes. When used in the biomedical field, the complex fluid media in the human body, including blood and tissue fluid, can easily cause traditional adhesives to fail due to interference with the hydration layer. Furthermore, the high biosafety requirements for use in the human body, coupled with the limited clinical application of traditional adhesives due to residual toxic crosslinking agents such as aldehydes, further complicate their use. Therefore, developing a bioadhesive that maintains high-strength adhesion in a water-rich physiological environment, possesses excellent biosafety, and is tolerated by the human body, and may even promote tissue regeneration, has become an urgent need in the fields of clinical medicine and biomaterials.

[0003] Currently, related fields have developed bio-based adhesives with excellent adhesion properties using polymers and polyphenols as raw materials. For example, patent technology with publication number CN 117323462 A discloses the preparation of an adhesive composite hydrogel by constructing an adhesive composite hydrogel using silk fibroin and tannic acid, and then mixing the adhesive composite hydrogel with urea or guanidine hydrochloride to obtain an adhesive hydrogel with excellent injection performance, effectively meeting the bio-adhesion needs of the biomedical field.

[0004] However, while existing bio-based adhesives such as those mentioned above have good safety, they generally suffer from insufficient adhesion performance (especially underwater adhesion strength, which is usually <1MPa), durability, and long-term stability when used in the complex dynamic mechanical environment of the human body. They cannot meet the requirements of harsh industrial environments such as long-term implantation, underwater operations, and aerospace. Summary of the Invention

[0005] This application discloses an adhesion complex based on metal inorganic compounds to optimize adhesion performance, its preparation method, and its application, effectively solving the technical problem that the adhesion performance, durability, and long-term stability of existing bio-based adhesives are generally insufficient.

[0006] To achieve the above objectives, the technical solution provided in this application is as follows:

[0007] The first aspect of this application provides an adhesion complex based on a metal-inorganic compound to optimize adhesion performance, comprising an adhesion precursor and a metal-inorganic compound in a mass ratio of 100:1 to 100; wherein the adhesion precursor is composed of a protein-polyphenol composite hydrogel and a hydrogen bond-breaking small molecule compound, and the adhesion precursor can undergo network reconstruction including β-sheet formation in an aqueous phase containing the metal-inorganic compound.

[0008] The metal inorganic compound has the following characteristics:

[0009] (a) The solubility of the substance itself and / or its hydrolysis products in water at 25°C is less than 0.2 g / 100 mL;

[0010] (b) The dissociation constant of the adapted anionic conjugate acid is greater than 5; and

[0011] (c) The dissolution process produces one or more of the following: water, gas or nonmetallic precipitate.

[0012] According to the disclosure of the first aspect, the metal inorganic compound is selected from oxides, sulfides, carbonates and silicates containing magnesium, calcium, strontium, barium, manganese, cobalt, copper and zinc.

[0013] According to the preferred disclosure of the first aspect, the protein component in the protein-polyphenol composite hydrogel is selected from at least one of silk fibroin, gelatin, collagen, keratin, soy textured protein, gluten, and fibroin;

[0014] The polyphenol component in the protein-polyphenol composite hydrogel is selected from at least one of tannic acid, dopamine, caffeic acid, tea polyphenols, and anthocyanins.

[0015] According to the preferred disclosure of the first aspect, the hydrogen bond-breaking small molecule compound is selected from at least one of urea, guanidine hydrochloride, and thiourea.

[0016] According to the disclosure of the first aspect, the mass ratio of the adhesion precursor to the metal inorganic compound is 100:10 to 100.

[0017] According to the disclosure of the first aspect, the adhesion precursor comprises a solution and a powder.

[0018] According to the disclosure of the first aspect, after the adhesive compound has been fully cured, the lap shear strength, as determined by ASTM F2255-24, is greater than 1 MPa.

[0019] The second aspect of this application also discloses a method for preparing the adhesion complex based on metal-inorganic compounds with optimized adhesion properties, comprising:

[0020] A protein-polyphenol composite hydrogel was mixed with a hydrogen bond-disrupting small molecule compound to prepare an adhesion precursor.

[0021] Furthermore, the adhesion precursor is mixed with a metal inorganic compound to form an adhesion complex.

[0022] The third aspect of this application also discloses the application of the adhesion complex based on metal inorganic compounds with optimized adhesion properties in biomedical bonding, tissue repair, bonding and repair of underwater structures, marine engineering, aerospace component assembly, automobile manufacturing, and electronic component packaging.

[0023] Compared with the prior art, the advantages or beneficial effects of this application include at least:

[0024] The adhesion complex provided in this application precisely regulates the release rate of metal cations by incorporating a suitable metal inorganic compound into an adhesion precursor composed of a protein-polyphenol composite hydrogel and hydrogen bond-breaking small molecule compounds. This allows the metal cations to directionally drive the dynamic equilibrium of the adhesion precursor to undergo network reconstruction involving β-sheet formation, generating a denser higher-order structure and achieving adhesion and curing. This significantly enhances the cohesive force of the cured adhesion complex, effectively generating an underwater lap shear strength of over 1 MPa. It also maintains excellent adhesion strength after long-term underwater immersion (over one year) and can withstand extreme temperature changes from -196 to 100°C and the erosion of organic solvents, ultimately exhibiting excellent underwater adhesion performance and stability. Simultaneously, it effectively avoids the violent exothermic reaction or drastic pH fluctuations, fundamentally solving the problem of traditional adhesives damaging human cells during curing. This makes it highly suitable for use in the human body. The adhesive compound has several advantages: 1) It can be used for the adhesion and repair of visceral tissues or nerves; 2) The curing process driven by the above-mentioned metal-inorganic compounds requires no external energy input, giving the adhesive compound excellent self-curing ability and effectively achieving a "zero-energy" self-curing process. This avoids the potential damage to human tissues caused by exogenous curing energy. Furthermore, all components of the adhesive compound are widely available, low-cost, and environmentally friendly, meeting the practical needs of green environmental protection, carbon neutrality, and a balance between "biosafety" and "functionality"; 3) This adhesive compound can directly replace traditional petroleum-based adhesives in high-value industrial fields with extremely stringent performance requirements, such as marine engineering, underwater repair, aerospace, automobile manufacturing, and precision electronic packaging; 4) This adhesive compound has good biocompatibility and component compatibility, and can be used as an implantable material for fracture fixation, sutureless closure of soft tissues, and drug-loaded sustained-release coatings, potentially meeting the high-end demand of non-surgical removal. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 The underwater steel-steel lap shear strength test results for adhesion complexes and compositions with different metal inorganic compounds;

[0027] Figure 2 Strain scanning rheomechanical diagram of the adhesion composite 20wt%MgO / STU before curing;

[0028] Figure 3 Injection force curves of x·wt%MgO / STU for STU adhesion precursor and adhesion complex before curing;

[0029] Figure 4 Strain scanning rheological diagram of the adhesion composite 20wt%MgO / STU after immersion and curing in water for 24 hours;

[0030] Figure 5 Scanning electron microscope images of the STU adhesion precursor and adhesion complex 20wt%MgO / STU after curing;

[0031] Figure 6 The diagram shows the protein secondary structure content of the STU adhesion precursor and adhesion complex 20wt%MgO / STU before and after curing.

[0032] Figure 7 Comparison of lap shear strength between STU adhesion precursor and adhesion complex x·wt%MgO / STU after 24 hours of underwater bonding;

[0033] Figure 8 The graph shows the variation of the lap shear strength of the adhesion composite 20wt%MgO / STU during long-term underwater immersion (1 day, 1 month, 6 months, 1 year).

[0034] Figure 9 Comparison of lap shear strength of the adhesion composite 20wt%MgO / STU after treatment at different temperatures (-196℃, 0℃, 25℃, 100℃) for 24 hours;

[0035] Figure 10 The underwater steel-steel lap shear strength test results for adhesion complexes and compositions containing calcium inorganic compounds;

[0036] Figure 11This is a comparison of the overlap shear strength of adhesion complexes prepared based on different proteins after being immersed in water for 24 hours and cured. Detailed Implementation

[0037] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments described in this application without creative effort are within the scope of protection of this application.

[0038] In the following description of this application, the term "and / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, B existing alone, and A and B existing simultaneously. Here, A and B can be singular or plural; the symbol " / " means "or".

[0039] In the following description of this application, the term "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions mean any combination of such items, including any combination of single or multiple items. For example, "at least one of A, B or C" or "at least one of A, B and C" can mean any one of A, B, and C, or A+B, or A+C, or B+C, or A+B+C, where A, B, and C can be single or multiple.

[0040] In the following description of this application, the order of the sequence numbers does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be specifically determined by its function and internal logic, and does not constitute any limitation on the execution process of this embodiment.

[0041] In the following description of this application, the numerical range should be understood to also specifically disclose each intermediate value between the upper and lower limits of the range. Any intermediate value within a stated range, as well as any other stated value or each smaller range between intermediate values ​​within a stated range, are also included in this embodiment, and the upper and lower limits of the smaller ranges may be independently included or excluded from the range.

[0042] Unless otherwise stated, the technical / scientific terms used in this application have the meanings commonly understood by one of ordinary skill in the art. While this application describes only preferred materials and methods, similar or equivalent methods and materials may be used in specific embodiments or test cases. All references to this application are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this application shall prevail.

[0043] To overcome the shortcomings of existing bio-based adhesives in terms of underwater adhesion performance, durability, and long-term stability, the first aspect of this application provides an adhesion complex based on a metal-inorganic compound to optimize adhesion performance. This adhesion complex comprises an adhesion precursor and a metal-inorganic compound in a mass ratio of 100:1 to 100. The adhesion precursor is composed of a protein-polyphenol composite hydrogel and a hydrogen bond-breaking small molecule compound, and the adhesion precursor can undergo network reconstruction involving β-sheet formation in an aqueous phase containing the metal-inorganic compound. The metal-inorganic compound possesses the following characteristics: (a) its own and / or hydrolysis products have a solubility of less than 0.2 g / 100 mL in water at 25°C; (b) its dissociation constant for adapting to anionic conjugate acids is greater than 5; and (c) the dissolution process produces one or more of the following: aqueous, gaseous, or non-metallic precipitates.

[0044] It should be noted that this application controls the release rate of metal ions by screening suitable anions for the inorganic metal compounds. Firstly, screening for appropriate solubility avoids excessively rapid dissolution of the inorganic metal compounds in the initial mixing stage with the adhesion precursor, which could lead to explosive release of metal ions. Secondly, screening for appropriate dissociation constants promotes further dissolution of the inorganic metal compounds in the weakly acidic environment of the adhesion precursor, generating gas, water, or non-metallic precipitates. This ensures a positive shift in the dissolution equilibrium for continuous release of metal ions. Based on the combined effect of these dissolution characteristics, the metal ions dynamically and holistically drive the adhesion precursor network to reconstruct a dense, higher-order structure for adhesion and solidification. Specifically, when the inorganic metal compound is easily hydrolyzed, the solubility of the hydrolysis products only needs to meet the requirements. For example, the hydrolysis products of MgS, MgO, CaS, and CaO (Mg(OH)2, Ca(OH)2) meet the solubility requirements.

[0045] It should be noted that the adhesion precursor described in this application is obtained by preparing a protein-polyphenol composite hydrogel from proteins and polyphenol compounds, and then mixing it with a hydrogen bond-breaking small molecule compound. This application does not specifically limit the preparation strategy of the protein-polyphenol composite hydrogel; any mature preparation technology known in the art can be used. Of course, in order to enable the adhesion precursor to undergo network reconstruction involving β-sheet formation in an aqueous phase containing the metal-inorganic compound, those skilled in the art should understand that the proteins in the protein-polyphenol composite hydrogel possess β-sheet potential.

[0046] This application's embodiments introduce a suitable metal-inorganic compound into the adhesion precursor composed of a protein-polyphenol composite hydrogel and a hydrogen bond-breaking small molecule compound to precisely regulate the release rate of metal cations. Firstly, this allows the metal cations to directionally drive the adhesion precursor to dynamically balance network reconstruction involving β-sheet formation, generating a dense, higher-order structure for adhesion and curing. This significantly enhances the cohesive force of the cured adhesion composite, effectively achieving an underwater lap shear strength exceeding 1 MPa. It also maintains excellent adhesion strength after long-term (over one year) immersion in water and can withstand extreme temperature changes from -196 to 100°C and the erosion of organic solvents. Ultimately, it exhibits excellent in vivo adhesion performance and stability, without swelling or rapid degradation in vivo. It can provide long-term, stable mechanical sealing for surgical incisions and / or fracture ends, while effectively avoiding the violent exothermic chemical reactions or drastic pH fluctuations, fundamentally solving the problem of cell damage during the curing process of traditional adhesives. First, it is highly suitable for adhesive repair of internal organs or nerves, effectively preventing postoperative complications. Second, the curing process driven by the above-mentioned metal-inorganic compounds requires no external energy input, giving the adhesive compound excellent self-curing ability and effectively achieving a "zero-energy" self-curing process. This avoids the potential damage to human tissues from external curing energy (such as ultraviolet or blue light). Furthermore, all components of the adhesive compound are widely available, low-cost, and environmentally friendly, meeting the practical needs of green environmental protection, carbon neutrality, and a balance between "biosafety" and "functionality." Third, this adhesive compound can directly replace traditional petroleum-based adhesives in high-value industrial fields with extremely stringent performance requirements, such as marine engineering, underwater repair, aerospace, automotive manufacturing, and precision electronic packaging. Fourth, this adhesive compound has good biocompatibility and component compatibility, and can be used as an implantable material for fracture fixation, sutureless closure of soft tissues, and drug-eluting sustained-release coatings, potentially meeting the high-end demand of non-surgical removal.

[0047] In possible disclosed examples, the inorganic metal compounds described in this application are preferably oxides, sulfides, carbonates, and silicates containing magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), manganese (Mn), cobalt (Co), copper (Cu), and zinc (Zn). All of the above inorganic metal compounds possess suitable solubility characteristics, as detailed in Table 1.

[0048] Table 1: Solubility characteristics of preferred metal inorganic compounds

[0049]

[0050] Of course, the above-mentioned inorganic metal compounds are only some typical examples of achieving the technical effects of this application, and do not constitute a limitation on the inorganic metal compounds of this application. They can also be any other inorganic metal compounds that satisfy the dissolution kinetics, which will not be listed one by one in this article.

[0051] It should be noted that the oxides, sulfides, carbonates and silicates of magnesium (Mg) are selected as representatives for exemplary description in the embodiments of this application because the oxides, sulfides, carbonates and silicates of magnesium (Mg) are relatively common and inexpensive and readily available, which facilitates large-scale verification. However, this does not constitute any limitation on the scope of protection of this application. Other inorganic metal compounds that meet the above-mentioned dissolution characteristics fall within the scope of protection of this application, and will not be listed one by one in this application.

[0052] In possible public examples, the protein components of the protein-polyphenol composite hydrogel described in this application may be selected from silk fibroin, gelatin, collagen, keratin, soy textured protein, gluten, and fibroin, etc., and the polyphenol components may be selected from tannic acid, dopamine, caffeic acid, tea polyphenols, and anthocyanins, etc.; meanwhile, the hydrogen bond-breaking small molecule compounds may be selected from urea, guanidine hydrochloride, and thiourea, etc. Therefore, the adhesion precursors that may be selected in the embodiments of this application include silk fibroin-tannic acid-urea adhesion precursor, gelatin-tannic acid-urea adhesion precursor, silk fibroin-tannic acid-guanidine hydrochloride adhesion precursor, silk fibroin-caffeic acid-urea adhesion precursor, and gelatin-anthocyanin-urea adhesion precursor, etc. The silk fibroin-tannic acid-urea adhesion precursor is selected as a representative example in this application because its preparation is simple and easy to scale up for verification. However, this does not constitute any limitation on the scope of protection of this application. Any other adhesion precursor that conforms to the technical mechanism of this application falls within the scope of protection of this application, and will not be listed one by one in this application.

[0053] In possible public examples, the preferred mass ratio of the adhesion precursor to the inorganic metal compound in this application is 100:10 to 100 to improve the underwater overlap shear strength. Specifically, the embodiments of this application use mass ratios of 100:0.1, 100:1, 100:5, 100:10, 100:20, 100:40, 100:60, 100:80, and 100:100 as representative examples because these seven ratios cover the lower, middle, and upper limits of the aforementioned preferred range, comprehensively and intuitively verifying the technical effects within this ratio range, facilitating understanding by those skilled in the art. However, this does not constitute any limitation on the scope of protection of this application. Other ratios within the aforementioned range that achieve the same or similar technical effects are also acceptable, and will not be listed individually in this application.

[0054] In possible disclosed examples, the adhesion precursor of this application is preferably in solution or powder form. For example, when the STU adhesion precursor is in solution form, it can be formed by mixing SF (silk fibroin) solution and TA (tannic acid) solution and stirring at room temperature until an ST composite hydrogel is formed, and then mixing the ST composite hydrogel with urea powder and stirring at room temperature until a homogeneous viscous liquid of STU adhesion precursor is formed for direct use; when the STU adhesion precursor is in powder form, the formed viscous liquid adhesion precursor (STU) can be processed into powder form for later use, for example, after freeze-drying the viscous liquid of STU adhesion precursor, the freeze-dried block is successively ground and sieved to obtain a homogeneous STU adhesion precursor powder.

[0055] It should be noted that this application does not impose any special limitations on the concentration and mixing ratio of SF solution and TA solution, as long as the ST composite hydrogel can be formed. The example described in this application uses 10wt% SF solution and 10wt% TA solution as raw materials, mixed at a volume ratio of 1:4 to prepare the ST composite hydrogel, because the network structure of the ST composite hydrogel prepared at this concentration ratio is relatively the best, which can intuitively verify the technical effect after adding the metal inorganic compound, and is easy for those skilled in the art to understand. However, this does not constitute any limitation on the concentration and mixing ratio of SF solution and TA solution in this application. Other concentrations and mixing ratios that can achieve the same or similar technical effects are acceptable, and will not be listed individually in this application.

[0056] It should be noted that this application does not have a specific limitation on the mixing ratio of the ST composite hydrogel and urea powder. The goal is to achieve the regulation of the ST composite hydrogel network structure and form a modified hydrogel with target properties (e.g., adhesion, injectability, biocompatibility) through the introduction of urea. Those skilled in the art can flexibly adjust the ratio according to the performance requirements of actual application scenarios. In this application, the embodiment is described exemplarily with a urea powder to dried silk fibroin protein mass ratio of 2:3 because the adhesion precursor formed under this ratio can exhibit good injectability and can solidify upon contact with an aqueous environment to form an adhesion structure with good adhesion and support. This facilitates the understanding of the core technology by those skilled in the art, but it does not constitute any limitation on the scope of protection of this application. Any other ratio that can achieve the same or similar technical effects falls within the scope of protection of this application, and will not be listed individually here.

[0057] It should be noted that this application does not specifically limit the specific strategies and parameters for processing the viscous liquid adhesion precursor into adhesion precursor powder, as long as a uniform adhesion precursor powder can be prepared. Specifically, when the adhesion precursor is in solution form, the adhesion performance is optimized using a liquid method, i.e., directly mixing the adhesion precursor solution with the metal inorganic compound powder; when the adhesion precursor is in powder form, the adhesion performance is optimized using a powder method, i.e., first physically dry-mixing the adhesion precursor powder with the metal inorganic compound powder, and then activating it with water or an aqueous solution before use.

[0058] In a second aspect, embodiments of this application also provide a method for preparing the adhesion composite with optimized adhesion properties based on metal-inorganic compounds as described above, which includes the following steps:

[0059] An adhesion precursor is prepared by mixing a protein-polyphenol composite hydrogel with a hydrogen bond-breaking small molecule compound; and the adhesion precursor is mixed with a metal inorganic compound to form an adhesion complex.

[0060] It should be noted that the entire preparation process of this application does not use any organic solvents, and relies entirely on the exothermic efficiency of the metal ion source compound to achieve structural solidification. It has the advantages of simple operation, low energy consumption and environmental friendliness, and is suitable for large-scale preparation and field application.

[0061] In a third aspect, embodiments of this application also provide the application of the adhesion complex based on metal inorganic compounds to optimize adhesion performance, specifically the use of the adhesion complex in biomedical bonding, soft tissue repair, bone tissue fixation, bonding and repair of underwater structures, marine engineering, aerospace component assembly, automobile manufacturing, and electronic component packaging.

[0062] The technical solution of this application will be further described below with reference to specific embodiments.

[0063] Example 1

[0064] This example provides an adhesion composite 20wt%MgO / STU with optimized adhesion properties based on a metal-inorganic compound, which is prepared through the following steps:

[0065] S1: Add 10g of tannic acid (TA) powder to 90g of deionized water and stir to dissolve for 1 hour to form a 10wt% TA solution;

[0066] S2: 120g of natural silkworm cocoons were soaked in 10L of 0.02M Na2CO3 solution and boiled for 1 hour. The cocoons were removed, the liquid was discarded, and the soaking and boiling process was repeated three times to obtain degummed silk fibroin fibers. The silk fibroin fibers were washed five times with deionized water and then dried in an oven at 45℃ for 48 hours. The dried silk fibroin fibers were then dissolved in 100mL of 9.3M LiBr solution at 60℃ to form a silk fibroin (SF) solution. The silk fibroin (SF) solution was dialyzed with deionized water for three days (dialysis bag molecular weight 1.4×10⁻⁶). 4 Da), and 15wt% PEG solution were reverse dialyzed for 24h to obtain 10wt% SF solution, wherein the PEG solution was prepared by 300g of 2×10⁻⁶ ppm PEG solution. 4 Da's PEG powder was added to 1700g of deionized water and stirred for 2 hours to form a solution.

[0067] S3: Mix the SF solution and the TA solution at a volume ratio of 1:4 and stir until an ST composite hydrogel is formed. Then mix the ST composite hydrogel with urea powder and stir until a uniform viscous liquid of STU adhesion precursor is formed. The mass ratio of urea powder to dried silk protein is 2:3.

[0068] S4: Add magnesium oxide (MgO) powder equivalent to 20 wt% of its mass to the viscous liquid of the STU adhesion precursor to obtain the adhesion composite 20 wt% MgO / STU.

[0069] Example 2

[0070] This example provides an adhesion composite of 20wt% MgS / STU with optimized adhesion properties based on a metal-inorganic compound. The only difference between this composite and Example 1 is:

[0071] Adding magnesium sulfide (MgS) powder at 20 wt% of its mass to the viscous liquid of the STU adhesion precursor yields the adhesion composite 20 wt% MgS / STU.

[0072] Example 3

[0073] This example provides an adhesion composite 20wt% MgCO3 / STU with optimized adhesion properties based on a metal-inorganic compound. The only difference between this composite and Example 1 is:

[0074] Adding magnesium carbonate (MgCO3) powder at 20 wt% of its mass to the viscous liquid of the STU adhesion precursor yields the adhesion composite 20 wt% MgCO3 / STU.

[0075] Example 4

[0076] This example provides an adhesion composite 20wt%MgSiO3 / STU with optimized adhesion properties based on a metal-inorganic compound. The only difference between this composite and Example 1 is:

[0077] Adding magnesium silicate (MgSiO3) powder at 20 wt% of its mass to the viscous liquid of the STU adhesion precursor yields the adhesion composite 20 wt% MgSiO3 / STU.

[0078] To illustrate the effect of the adhesion complexes prepared in Examples 1-4 above, this application also provides comparative examples 1-9 of metal salts that do not meet the dissolution characteristics, using magnesium as an example.

[0079] Comparative Example 1

[0080] This example provides a 20wt% MgSO4 / STU composition, which differs from Example 1 only in that:

[0081] Adding magnesium sulfate (MgSO4) powder at 20 wt% of its mass to the viscous liquid of the STU adhesion precursor yields a 20 wt% MgSO4 / STU composition.

[0082] Comparative Example 2

[0083] This example provides a 20wt% MgF2 / STU composition, which differs from Example 1 only in that:

[0084] Adding magnesium fluoride (MgF2) at 20 wt% of its mass to the viscous liquid of the STU adhesion precursor yields a 20 wt% MgF2 / STU composition.

[0085] Comparative Example 3

[0086] This example provides an STU-Mg3(PO4)2 composition, which differs from Example 1 only in that:

[0087] Adding magnesium phosphate (Mg3(PO4)2) at 20 wt% of its mass to the viscous liquid of the STU adhesion precursor yields the STU-Mg3(PO4)2 composition.

[0088] Comparative Example 4

[0089] This example provides an STU-Mg3(BO3)2 composition, which differs from Example 1 only in that:

[0090] Adding magnesium borate (Mg3(BO3)2) at 20 wt% of its mass to the viscous liquid of the STU adhesion precursor yields the STU-Mg3(BO3)2 composition.

[0091] Comparative Example 5

[0092] This example provides an STU-MgCl2 composition, which differs from Example 1 only in that:

[0093] Adding magnesium chloride (MgCl2) at 20 wt% of its mass to the viscous liquid of the STU adhesion precursor yields the STU-MgCl2 composition.

[0094] Comparative Example 6

[0095] This example provides an STU-MgBr2 composition, which differs from Example 1 only in that:

[0096] Adding magnesium bromide (MgBr2) at 20 wt% of its mass to the viscous liquid of the STU adhesion precursor yields the STU-MgBr2 composition.

[0097] Comparative Example 7

[0098] This example provides an STU-MgI2 composition, which differs from Example 1 only in that:

[0099] Adding magnesium iodide (MgI2) at 20 wt% of its mass to the viscous liquid of the STU adhesion precursor yields the STU-MgI2 composition.

[0100] Comparative Example 8

[0101] This example provides an STU-Mg(NO3)2 composition, which differs from Example 1 only in that:

[0102] Adding magnesium nitrate (Mg(NO3)2) at 20 wt% of its mass to the viscous liquid of the STU adhesion precursor yields the STU-Mg(NO3)2 composition.

[0103] The solubility characteristics of the inorganic metal compounds in the above comparative examples are shown in Table 2.

[0104] Table 2: Solubility characteristics of inorganic metal compounds in the comparative examples

[0105]

[0106] Test Example 1

[0107] Following the ASTM F2255 standard method for testing lap shear strength, the adhesive composites and compositions prepared in the above examples and comparative examples were coated between two stainless steel sheets (adhesive area 2.5 cm²). After curing underwater for 24 hours, the lap shear strength was tested using a universal testing machine. The results were as follows: Figure 1 As shown. Among them, Figure 1The results of underwater steel-to-steel lap shear strength tests for various adhesion compounds and compositions are presented.

[0108] according to Figure 1 As can be seen, the adhesion strength of the adhesion complexes prepared in Examples 1-4 all reached above 1 MPa, especially the adhesion strength of the STU-MgSiO3 adhesion complex, which reached the highest at 5.2 MPa. In contrast, the compositions provided in Comparative Examples 1-8 did not reach an adhesion strength of 1 MPa due to mismatched solubility characteristics. Therefore, only by adding a metal-inorganic compound that meets specific solubility characteristics can an adhesion complex with high adhesion performance be obtained.

[0109] Test Example 2

[0110] This test example uses magnesium oxide (MgO) as an example to verify and analyze the composite amount range of metal inorganic compounds. Specifically, 0 wt%, 0.1 wt%, 1 wt%, 5 wt%, 10 wt%, 20 wt%, 40 wt%, 60 wt%, 80 wt%, and 100 wt% of MgO were added to the viscous liquid of the STU adhesion precursor to prepare adhesion composites x·wt%MgO / STU. The structural properties of each adhesion composite x·wt%MgO / STU (x=0, 0.1, 1, 5, 10, 20, 40, 60, 80, and 100) were then tested.

[0111] 2.1 Characterization of mechanical properties before curing

[0112] The strain scanning test was performed on the 20wt% MgO / STU adhesive composite material using a rheometer to monitor the changes in its storage modulus (G') and loss modulus (G'') with strain. The results are as follows: Figure 2 As shown.

[0113] according to Figure 2 It can be seen that the adhesion composite 20wt%MgO / STU before curing exhibits a loss modulus (G'') greater than the storage modulus (G'), indicating that the adhesion composite 20wt%MgO / STU is a viscous fluid with good flowability and injectability.

[0114] 2.2 Injectability Testing

[0115] Each adhesion complex (x·wt%MgO / STU) was loaded into a standard syringe, and its injection force was tested using a texture analyzer or a universal testing machine. The results were as follows: Figure 3 As shown.

[0116] according to Figure 3 It can be seen that as the amount of MgO composite increases, the initial injection force gradually increases, but it is still within the appropriate injection force range, thus indicating that the adhesion composite prepared in this application has good injectability.

[0117] 2.3 Characterization of mechanical properties after curing

[0118] After the adhesion composite (20 wt% MgO / STU) was immersed in an underwater environment and cured for 24 hours, strain scanning tests were performed using a rheometer. The results were as follows: Figure 4 As shown.

[0119] according to Figure 4 It can be seen that the cured adhesion composite 20wt%MgO / STU all exhibit the characteristic that the storage modulus (G') is greater than the loss modulus (G''), indicating that the fluid dynamic adhesion composite 20wt%MgO / STU has been transformed into an elastic solid and successfully cured.

[0120] 2.4 Morphological characterization before and after curing

[0121] After the adhesion composite (20 wt% MgO / STU) was immersed in an underwater environment for 24 hours and cured, it was freeze-dried and sputter-coated with gold. The microstructure was then observed using a scanning electron microscope. The results were as follows: Figure 5 As shown.

[0122] according to Figure 5 It can be seen that, compared with the porous structure of the STU adhesion precursor, the network structure of the adhesion composite 20wt%MgO / STU with added MgO becomes denser, indicating that the addition of MgO effectively promotes the directional transformation of the porous structure of the STU adhesion precursor into a denser advanced structure, which is consistent with the improvement of its mechanical properties.

[0123] 2.5 Characterization of secondary structure before and after curing

[0124] After the adhesion complex (20 wt% MgO / STU) was immersed in an underwater environment for 24 hours to cure, the secondary structure content of silk fibroin was determined by circular dichroism (CD) chromatography. The results were as follows: Figure 6 As shown.

[0125] according to Figure 6 It can be seen that, compared with the STU adhesion precursor, the β-sheet content of the adhesion complex with added MgO (20wt% MgO / STU) is significantly increased, confirming that the addition of MgO effectively drives the directional transformation of protein secondary structure and that the solubility properties of MgO can effectively drive the directional transformation of protein secondary structure.

[0126] 2.6 Adhesion strength test of adhesion composites with different MgO addition amounts x·wt%MgO / STU (x=0, 0.1, 1, 5, 10, 20, 40, 60, 80 and 100)

[0127] According to the ASTM F2255 standard method for testing lap shear strength, an adhesion compound with different concentrations of MgO (x·wt%MgO / STU, x=0, 0.1, 1, 5, 10, 20, 40, 60, 80, and 100) was coated between two stainless steel sheets (adhesion area 2.5 cm²). After curing underwater for 24 hours, the lap shear strength was tested using a universal testing machine. The results were as follows: Figure 7 As shown.

[0128] according to Figure 7 It can be seen that as the concentration of magnesium oxide increases, the adhesion strength of the adhesion complex increases significantly, reaching the maximum value at a concentration of 80 wt%, and the adhesion strength decreases slightly at a concentration of 100 wt%.

[0129] 2.7 Durability Testing

[0130] After the adhesion composite 20wt% MgO / STU was immersed in an underwater environment and cured for 24 hours, it was then immersed in an underwater environment for extended periods (1 day, 1 month, 6 months, and 1 year). The remaining lap shear strength was tested at different time points, and the results were as follows: Figure 8 As shown.

[0131] according to Figure 8 It is evident that the adhesion strength of the 20wt%MgO / STU adhesion composite remains almost unchanged after long-term immersion, indicating that the adhesion composite prepared in this application possesses excellent long-term stability.

[0132] 2.8 Temperature stability test

[0133] After the adhesion composite 20wt% MgO / STU was immersed in an underwater environment and cured for 24 hours, its lap shear strength was tested after being kept at different temperatures (-196℃, 0℃, 25℃, 100℃) for 24 hours and then restored to room temperature. The results were as follows: Figure 9 As shown.

[0134] according to Figure 9 It can be seen that the adhesion strength of the 20wt%MgO / STU adhesion composite remains almost unchanged after extreme temperature treatment, proving that the adhesion performance of the adhesion composite prepared in this application has excellent stability over a wide temperature range.

[0135] Test Example 3

[0136] To verify the universality of the adhesion complex based on metal-inorganic compounds that optimizes adhesion performance, this application also provides Examples 5-8 and Comparative Examples 10-11.

[0137] Example 5

[0138] This example provides an adhesion composite 20wt%CaCO3 / STU with optimized adhesion properties based on a metal-inorganic compound. The only difference between this composite and Example 1 is:

[0139] Adding calcium carbonate (CaCO3) at 20 wt% of its mass to the viscous liquid of the STU adhesion precursor yields the adhesion complex 20 wt% CaCO3 / STU.

[0140] Comparative Example 10

[0141] This example provides a 20wt% Ca3(PO4)2 / STU composition, which differs from Example 1 only in that:

[0142] Adding 20 wt% of tricalcium phosphate (Ca3(PO4)2) to the viscous liquid of the STU adhesion precursor yields a 20 wt% Ca3(PO4)2 / STU composition.

[0143] Comparative Example 11

[0144] This example provides a 20wt% CaCl2 / STU composition, which differs from Example 1 only in that:

[0145] Adding calcium chloride (CaCl2) at 20 wt% of its mass to the viscous liquid of the STU adhesion precursor yields a 20 wt% CaCl2 / STU composition.

[0146] According to the ASTM F2255 standard method for testing lap shear strength, adhesive composites of 20wt% CaO2 / STU, 20wt% Ca3(PO4)2 / STU, and 20wt% CaCl / STU were respectively coated between two stainless steel sheets (adhesive area 2.5 cm²). After curing in an underwater environment for 24 hours, the lap shear strength was tested using a universal testing machine. The results were as follows: Figure 10 As shown.

[0147] according to Figure 10 It is evident that the 20wt%CaCO3 / STU adhesion composite also achieves a significant enhancement of adhesion performance, with adhesion strengths far exceeding 1MPa; while the adhesion strengths of the 20wt%Ca3(PO4)2 / STU composition and the 20wt%CaCl2 / STU composition are not significantly enhanced, meaning their adhesion strengths remain below 1MPa. This indicates that the metal ions contained in the inorganic metal compounds added in this application are not limited to magnesium, but can also be calcium, strontium, barium, manganese, cobalt, copper, zinc, etc.

[0148] Example 6

[0149] This example provides an adhesion composite 20wt%MgO / GTU with optimized adhesion properties based on metal-inorganic compounds, which differs from Example 1 only in that:

[0150] GTU was prepared by replacing silk fibroin with gelatin during the STU preparation process in Example 1. Adding 20 wt% magnesium oxide (MgO) to the viscous liquid of the GTU adhesion precursor yielded the adhesion complex 20 wt% MgO / GTU.

[0151] Example 7

[0152] This example provides an adhesion composite material of 20wt% MgO / KTU with optimized adhesion properties based on a metal-inorganic compound. The only difference between this composite and Example 1 is:

[0153] KTU was prepared by replacing silk fibroin with keratin during the STU preparation process in Example 1. Adding 20 wt% magnesium oxide (MgO) to the viscous liquid of the KTU adhesion precursor yields the adhesion complex 20 wt% MgO / KTU.

[0154] Example 8

[0155] This example provides an adhesion composite of 20wt% MgO / WTU with optimized adhesion properties based on a metal-inorganic compound. The only difference between this composite and Example 1 is that:

[0156] WTU was prepared by replacing silk fibroin with gluten during the STU preparation process in Example 1. Adding 20 wt% magnesium oxide (MgO) to the viscous liquid of the WTU adhesion precursor yielded the adhesion complex 20 wt% MgO / WTU.

[0157] According to the ASTM F2255 standard method for testing lap shear strength, adhesive composites of 20wt% MgO / STU, 20wt% MgO / GTU, 20wt% MgO / KTU, and 20wt% MgO / WTU were applied between two stainless steel sheets (bonding area 2.5 cm²). After curing underwater for 24 hours, the lap shear strength was tested using a universal testing machine. The results were as follows: Figure 11 As shown.

[0158] according to Figure 11It is evident that the adhesion complexes 20wt%MgO / GTU, 20wt%MgO / KTU, and 20wt%MgO / WTU can also achieve a significant enhancement of adhesion performance, with adhesion strengths all far exceeding 1MPa. This enhancement effect is similar to that of the STU adhesion precursor prepared using silk fibroin, indicating that the protein in the adhesion precursor of this application is not limited to silk fibroin, but can also be gelatin, collagen, keratin, soy textured protein, gluten, and fibrin, etc.

[0159] The various embodiments in this application are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0160] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of this application.

Claims

1. An adhesive composite based on metal-inorganic compounds to optimize adhesion properties, characterized in that, The mixture comprises an adhesion precursor and a metal-inorganic compound in a mass ratio of 100:1 to 100; wherein the adhesion precursor is composed of a protein-polyphenol composite hydrogel and a hydrogen bond-breaking small molecule compound, and the adhesion precursor can undergo network reconstruction involving β-sheet formation in an aqueous phase containing the metal-inorganic compound. The metal inorganic compound has the following characteristics: (a) The solubility of the substance itself and / or its hydrolysis products in water at 25°C is less than 0.2 g / 100 mL; (b) The dissociation constant of the anionic conjugate acid is greater than 5; (c) The dissolution process produces one or more of the following: water, gas or nonmetallic precipitate.

2. The adhesion compound according to claim 1, characterized in that, The inorganic metal compound is selected from oxides, sulfides, carbonates and silicates containing magnesium, calcium, strontium, barium, manganese, cobalt, copper and zinc.

3. The adhesion compound according to claim 1, characterized in that, The protein component in the protein-polyphenol composite hydrogel is selected from at least one of silk fibroin, gelatin, collagen, keratin, soy textured protein, gluten, and fibroin. The polyphenol component in the protein-polyphenol composite hydrogel is selected from at least one of tannic acid, dopamine, caffeic acid, tea polyphenols, and anthocyanins.

4. The adhesion compound according to claim 3, characterized in that, The hydrogen bond-breaking small molecule compound is selected from at least one of urea, guanidine hydrochloride, and thiourea.

5. The adhesion compound according to claim 4, characterized in that, The mass ratio of the adhesion precursor to the metal inorganic compound is 100:10~100.

6. The adhesion compound according to claim 1, characterized in that, The adhesion precursor comprises a solution and a powder.

7. The adhesion compound according to claim 1, characterized in that, After the adhesive compound has fully cured, the lap shear strength, as measured by ASTM F2255-24, is greater than 1 MPa.

8. A method for preparing an adhesion composite based on optimized adhesion properties using a metal-inorganic compound according to any one of claims 1 to 8, characterized in that, Include: A protein-polyphenol composite hydrogel was mixed with a hydrogen bond-disrupting small molecule compound to prepare an adhesion precursor. Furthermore, the adhesion precursor is mixed with a metal inorganic compound to form an adhesion complex.

9. The adhesion complex based on the optimized adhesion properties of a metal-inorganic compound according to any one of claims 1 to 8 is used in applications including biomedical bonding, soft tissue repair, bone tissue fixation, bonding and repair of underwater structures, marine engineering, aerospace component assembly, automobile manufacturing, and electronic component packaging.

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