Adhesive and application thereof

Abstract

The invention provides an adhesive and application thereof. Specifically, the adhesive provided by the invention is obtained by modifying gutta-percha and contains a polymer 1, 4-polyisoprene composed of a structural unit I and a structural unit II shown in the specification, and the weight ratio of the structural unit I to the structural unit II is (1-15): 1. The adhesive shows high adhesion strength, good dynamic adaptability, good subcutaneous tissue compatibility, cell biocompatibility and blood compatibility, has an active antibacterial function and tissue regeneration promoting capacity, has the potential of being used as a medical adhesive, and has the characteristics of no suture, no pain, no stimulation, good wound healing and no scar.

Description

Technical Field

[0001] The present invention relates to the field of biotechnology, in particular to an adhesive and application thereof. Background Art

[0002] In clinical practice, the problem of skin wound repair caused by trauma, surgery, burns, chronic ulcers, and other injuries is both common and complex. Failure to effectively and promptly seal wounds can easily lead to fluid loss, secondary infection, or tissue necrosis, which can delay healing and even induce systemic complications. Medical adhesives, such as cyanoacrylates, polyethylene glycol-based hydrogels, and fibrin glues, are widely used for wound closure. These materials physically isolate the wound from the outside environment, reducing the risk of infection and promoting healing to a certain extent. However, existing adhesives still have significant drawbacks: First, adhesion properties decrease dramatically in moist or dynamic wounds (such as those in joints), and mechanical stress or tissue fluid infiltration can easily lead to interfacial delamination. Second, the materials have limited functionality, such as insufficient antibacterial properties, lacking the ability to address the risk of infection in infectious wounds, and poor repair-promoting abilities. Currently, most medical adhesives only have an adhesive effect and have no practical effect on promoting wound healing or shortening healing time. Third, insufficient biocompatibility. For example, cyanoacrylate adhesives may trigger inflammatory reactions or hinder cell migration, affecting the regeneration of tissues and their appendages.

[0003] While natural polymers (such as chitosan and gelatin) possess certain biodegradability and low toxicity, their lack of mechanical strength and poor adhesion durability remain unresolved. Therefore, the development of a medical adhesive that combines high adhesion strength, dynamic adaptability, active antibacterial properties, and the ability to promote tissue regeneration is an urgent need in wound management. In particular, medical adhesives derived from natural ingredients derived from traditional Chinese medicine are still a niche topic, both domestically and internationally. Summary of the Invention

[0004] In response to the technical problems existing in the existing medical adhesives, the inventors modified Eucommia gum by high-temperature heating and found that the modified Eucommia gum has high adhesion strength and active antibacterial function, can promote skin tissue regeneration, and has the potential to become a medical adhesive, thus realizing the present invention.

[0005] In a first aspect of the present invention, an adhesive is provided. The adhesive is obtained by modifying eucommia gum and comprises a polymer 1,4-polyisoprene composed of structural unit I and structural unit II as shown below, wherein the weight ratio of structural unit I to structural unit II is 1-15:1:

[0006]

[0007] In a second aspect of the present invention, there is provided use of the adhesive according to the first aspect of the present invention as a medical adhesive.

[0008] The adhesive of the present invention has the following beneficial effects:

[0009] 1) High adhesion strength, can better adhere to the skin wound;

[0010] 2) Better dynamic adaptability, more suitable for dynamic skin wounds;

[0011] 3) It has active antibacterial function, which is more conducive to the healing of skin wounds;

[0012] 4) Can promote tissue regeneration;

[0013] 5) No cytotoxicity;

[0014] 6) It has good biocompatibility and meets the hemolysis rate standards for biomedical materials;

[0015] 7) It has the potential to be used as a medical adhesive;

[0016] 8) It has the characteristics of no sutures, no pain, no irritation, good wound healing and no scars. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the specific implementation or the description of the prior art.

[0018] Figure 1 The figures show the lap-shear tensile strength test results of adhesives 1-5 prepared according to the embodiments of the present invention.

[0019] Figure 2 The tensile strength test results of adhesives 1-5 prepared according to the embodiments of the present invention are shown.

[0020] Figure 3 The T-peel tensile load bearing results of adhesives 1-5 prepared according to examples of the present invention are shown.

[0021] Figure 4 The H-NMR spectrum and C-NMR spectrum of the adhesive 1 prepared according to an embodiment of the present invention are shown, wherein A is the H-NMR spectrum of the adhesive 1 and B is the C-NMR spectrum of the adhesive 1.

[0022] Figure 5 The cell viability results of L929 fibroblasts under different concentrations of the extract of adhesive 1 prepared according to an embodiment of the present invention are shown.

[0023] Figure 6The results of rabbit red blood cell hemolysis rate under different concentrations of the binder 1 leachate prepared according to the embodiment of the present invention are shown.

[0024] Figure 7 The graph shows the test results of the adhesive 1 prepared according to an embodiment of the present invention promoting the healing of linear skin wounds.

[0025] Figure 8 The graph shows the test results of the adhesive 1 prepared according to the embodiment of the present invention promoting the healing of exposed full-thickness wounds. DETAILED DESCRIPTION

[0026] Hereinafter, the present invention will be described in detail. It should be understood that the following description is only for illustration of the present invention and is not intended to limit the scope of the present invention. The scope of protection of the present invention shall be subject to the appended claims. In addition, those skilled in the art will understand that the technical solutions of the present invention may be modified without departing from the spirit and purpose of the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the subject matter of the present invention belongs. Before describing the present invention in detail, the following definitions are provided for a better understanding of the present invention.

[0028] Where a numerical range is provided, such as a concentration range, a percentage range, or a ratio range, it is understood that each intervening value, to the tenth of the unit of the lower limit, between the upper and lower limits of the range and any other stated or intervening values ​​in the stated range are encompassed within the subject matter unless the context clearly dictates otherwise. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges, and such embodiments are also encompassed within the subject matter, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also encompassed within the subject matter.

[0029] In the context of the present invention, many embodiments use the expressions "comprising", "including" or "consisting essentially / mainly of..." The expressions "comprising", "including" or "consisting essentially / mainly of..." can generally be understood as open-ended expressions, indicating that in addition to the various elements, components, assemblies, method steps, etc. specifically listed after the expression, other elements, components, assemblies, method steps, etc. are also included. In addition, in this document, the expressions "comprising", "including" or "consisting essentially / mainly of..." can also be understood as closed-ended expressions in some cases, indicating that only the various elements, components, assemblies, method steps specifically listed after the expression are included, and no other elements, components, assemblies, method steps are included. In this case, the expression is equivalent to the expression "consisting of..."

[0030] In a first aspect of the present invention, an adhesive is provided. The adhesive is obtained by modifying eucommia gum and comprises a polymer 1,4-polyisoprene composed of structural unit I and structural unit II as shown below, wherein the weight ratio of structural unit I to structural unit II is 1-15:1:

[0031]

[0032] Eucommia gum is a natural product extracted from the leaves, bark, and seed shells of the Eucommia ulmoides tree, primarily composed of trans-1,4-polyisoprene. Eucommia gum exhibits both rubber-plastic duality and shape memory properties, and exhibits pharmacological activities such as antibacterial and macrophage differentiation regulation. Eucommia gum is commonly found in the fresh leaves, bark, and seed shells of the Eucommia ulmoides tree and can improve the mechanical properties of plant tissues. However, eucommia gum extracted from the leaves, bark, and seed shells of the Eucommia ulmoides tree crystallizes at room temperature, transforming into a hard rubber and thus lacking adhesive properties. However, by modifying eucommia gum, it can be endowed with good adhesive properties at room temperature. Therefore, eucommia gum has the potential to be developed into a medical adhesive. For extraction methods of high-purity eucommia gum, reference can be made to Chinese Patent Application Publication No. CN108702930A, the entire contents of which are incorporated herein by reference.

[0033] As mentioned above, the present invention modifies Eucommia gum by high-temperature heating, and it is found that the modified Eucommia gum obtained thereby exhibits high adhesion strength, good dynamic adaptability, good subcutaneous tissue compatibility, cell biocompatibility and blood compatibility, has active antibacterial function and the ability to promote tissue regeneration, and has the potential to be used as a medical adhesive.

[0034] In a specific embodiment, the weight ratio of the structural unit I to the structural unit II can be, for example, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1 or 15:1, or a range consisting of any two of these values. The present inventors unexpectedly discovered that by heat-modifying natural eucommia gum to adjust the weight ratio of the structural unit I to the structural unit II to within the above range, the modified eucommia gum thus obtained has adhesive properties, while modified eucommia gum outside this ratio range does not have adhesive properties.

[0035] In a preferred embodiment, the weight ratio of the structural unit I to the structural unit II is 4-13:1, preferably 5-9:1, and more preferably 6-8:1.

[0036] In another embodiment, in the adhesive of the present invention, the polymer 1,4-polyisoprene has a degree of polymerization of 110-1400, for example, 110, 120, 130, 140, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300 or 1400, or a range consisting of any two values ​​therein.

[0037] It is understood that (average) degree of polymerization = (average) molecular weight of the polymer / molecular weight of the structural unit. The present inventors unexpectedly discovered that by heat-modifying natural eucommia gum to control the degree of polymerization of the polymer 1,4-polyisoprene within the above-mentioned range, the modified eucommia gum thus obtained has adhesive properties, while modified eucommia gum outside this ratio range does not have adhesive properties.

[0038] In a preferred embodiment, in the adhesive of the present invention, the degree of polymerization of the polymer 1,4-polyisoprene is 400-800.

[0039] In another specific embodiment, the eucommia gum is extracted from Eucommia ulmoides, a plant of the Eucommia family, and comprises trans-1,4-polyisoprene with a degree of polymerization of 1000-3500.

[0040] Preferably, the eucommia gum (raw material) contains at least 90% trans-1,4-polyisoprene, but preferably contains at least 96% trans-1,4-polyisoprene. The eucommia gum (raw material) can be obtained by any extraction method known in the art, such as organic solvent extraction, two-phase extraction, biomimetic enzyme extraction, etc.

[0041] In addition, as verified in the Examples section, when modifying eucommia gum in order to obtain a modified product with adhesive properties, it is necessary to pay special attention to the degree of polymerization of the high molecular compound trans-1,4-polyisoprene in the raw material eucommia gum. Only when the degree of polymerization of the high molecular compound trans-1,4-polyisoprene in eucommia gum is between 1000 and 3500 can it be effectively used as a raw material to prepare a product that can be used as an adhesive. If the degree of polymerization is too high or too low, an adhesive cannot be prepared. This discovery suggests that when implementing the method of the present invention, if the degree of polymerization of trans-1,4-polyisoprene contained in the raw material eucommia gum exceeds 3500, it can be considered to first reduce its degree of polymerization to within the above range by ultraviolet degradation, thermal degradation, electrochemical degradation, etc.

[0042] In one embodiment, the adhesive is prepared by a method comprising the steps of heating the eucommia gum to 150° C.-320° C. and maintaining the temperature for 60-180 minutes.

[0043] Specifically, the eucommia gum can be heated to 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 245°C, 250°C, 255°C, 260°C, 265°C, 270°C, 275°C, 280°C, 285°C, 290°C, 295°C, 300°C, 310°C or 320°C, or a range consisting of any two of the values.

[0044] The present inventors have found through experiments that by modifying Eucommia gum within the temperature range, Eucommia gum can be formed into a modified product with adhesion properties, while if Eucommia gum is modified outside the temperature range, the resulting product does not have adhesion properties.

[0045] In a preferred embodiment, the heating temperature may be 160°C-300°C.

[0046] In a more preferred embodiment, the heating temperature may be 200°C-285°C.

[0047] In addition, the eucommia gum can be modified at the temperature for 60 minutes, 70 minutes, 80 minutes, 90 minutes, 100 minutes, 110 minutes, 120 minutes, 130 minutes, 140 minutes, 150 minutes, 160 minutes, 170 minutes or 180 minutes, or a range consisting of any two of these values.

[0048] The present inventors have found that by modifying eucommia gum within the temperature range and for the time period, the resulting modified product has adhesive properties, while a product with adhesive properties cannot be obtained if the modification time is too long or too short.

[0049] In a preferred embodiment, the holding time may be 90-150 minutes.

[0050] In a more preferred embodiment, the holding time may be 100-130 minutes.

[0051] In one embodiment, the adhesive has a lap-shear tensile bearing strength of at least 1 kPa, preferably at least 5 kPa, more preferably at least 10 kPa, as measured according to standard YY / T 0729.1-2009.

[0052] In one embodiment, the adhesive has a tensile bearing strength of at least 20 kPa, preferably at least 100 kPa, more preferably at least 150 kPa, as measured according to standard YY / T 0729.3-2009.

[0053] 11. In one embodiment, the adhesive has a 2 , preferably at least 40 J / m 2 , more preferably at least 60 J / m 2 The interface toughness is measured according to the YY / T 0729.2-2009 standard.

[0054] In one embodiment, the method further comprises filtering the modified eucommia gum through a 40-60 mesh sieve, such as a 50 mesh sieve, after stopping the heating.

[0055] In a second aspect of the present invention, there is provided use of the adhesive according to the first aspect of the present invention as a medical adhesive.

[0056] In one embodiment, the adhesive is used to bond open wounds on the skin.

[0057] In a preferred embodiment, the adhesive is used to promote the healing of linear skin wounds or promote the healing of exposed full-thickness wounds.

[0058] The adhesive of the present invention has the following beneficial effects:

[0059] 1) High adhesion strength, can better adhere to the skin wound;

[0060] 2) Better dynamic adaptability, more suitable for dynamic skin wounds;

[0061] 3) It has active antibacterial function, which is more conducive to the healing of skin wounds;

[0062] 4) It can promote tissue regeneration and accelerate the healing process;

[0063] 5) No cytotoxicity;

[0064] 6) It has good biocompatibility and meets the hemolysis rate standards for biomedical materials;

[0065] 7) When the adhesive is applied, surgical suturing of the wound is avoided, and the use process is painless and non-irritating;

[0066] 8) The surface of the healed skin is smooth and flat, without scars, and without damage to tissues such as skin appendages.

[0067] Example

[0068] The following examples illustrate the products, preparation methods, and related characterizations of the present invention. Unless otherwise specified, all experimental methods employed were conventional methods, and all test materials used in the following examples were purchased from conventional chemical reagent stores. % represents wt%, i.e., percentage by weight. Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which this invention pertains.

[0069] Preparation Example: Preparation of Adhesive

[0070] Preparation of Eucommia Gum:

[0071] The crushed Eucommia ulmoides seed shells were enzymatically hydrolyzed and then extracted with petroleum ether at 60°C for 3 hours. The extract was then poured into a beaker and 30% of the extract volume was added to 95% ethanol to precipitate Eucommia gum. The Eucommia gum was air-dried in a fume hood at room temperature to obtain the Eucommia gum product. Testing revealed that the trans-1,4-polyisoprene contained in the Eucommia gum product had a degree of polymerization of 5048 and a molecular weight of 34.33×10 4 g / mol.

[0072] The crushed Eucommia ulmoides seed shells were enzymatically hydrolyzed and then extracted with petroleum ether at 60°C for 3 hours. The extract was then poured into a beaker and 30% of the extract volume of 95% ethanol was added to the extract to precipitate Eucommia gum. The Eucommia gum was dried at room temperature in a fume hood and then irradiated under ultraviolet light for 24 hours to obtain the Eucommia gum product. Testing revealed that the trans-1,4-polyisoprene contained in the Eucommia gum product had a degree of polymerization of 3870 and a molecular weight of 26.32×10 4 g / mol.

[0073] The crushed Eucommia ulmoides seed shells were enzymatically treated and then extracted with petroleum ether at 60°C for 3 hours. The extract was then poured into a beaker and 30% of the extract volume of 95% ethanol was added to the extract to precipitate Eucommia gum. The Eucommia gum was dried at room temperature in a fume hood to obtain the Eucommia gum product. The dried Eucommia gum was transferred to a high-temperature furnace and heated at 150°C for 96 hours to obtain the final Eucommia gum product. Testing found that the degree of polymerization of trans-1,4-polyisoprene contained in the Eucommia gum product was 2544 and the molecular weight was 17.3×10 4 g / mol.

[0074] The crushed Eucommia ulmoides seed shells were enzymatically treated and then heated with petroleum ether at 60°C for extraction for 3 hours. The extract was then poured into a beaker, and 30% of the volume of the extract was added to 95% ethanol to precipitate Eucommia gum. The Eucommia gum was dried in a fume hood at room temperature to obtain the Eucommia gum product. 10g of Eucommia gum product was dissolved in 1000mL of toluene, and 50mg of titanium dioxide and 0.3g of hydrogen peroxide solution were added. The temperature was controlled at 25-40°C under a deuterium lamp or ultraviolet lamp and stirred for 4 hours. After the reaction solution was filtered to remove titanium dioxide, 30% of the volume of the reaction solution was added to 95% ethanol to precipitate Eucommia gum. The Eucommia gum was dried in a fume hood at room temperature to obtain the final Eucommia gum product. It was found that the degree of polymerization of trans-1,4-polyisoprene contained in the Eucommia gum product was 1159 and the molecular weight was 7.88×10 4 g / mol.

[0075] Adhesive preparation

[0076] Adhesive 1

[0077] (1) Weigh 50.0 g of Eucommia gum (polymerization degree 2544, molecular weight 17.3×10 4 g / mol) in a high temperature resistant glass flask.

[0078] (2) Place the high-temperature resistant glass flask containing Eucommia gum in a MF-1200C high-temperature box furnace (Anhui Beiyike Equipment Technology Co., Ltd.), set the heating program: 0-20 minutes, heat to 270℃, keep heating at 270℃ for 120 minutes, and then stop heating.

[0079] (3) Pour the eucommia gum after stopping heating into a 50-mesh (pore size 0.85 mm) pharmacopoeia sieve for filtration, and cool to below 40° C. to obtain adhesive 1.

[0080] Adhesive 2

[0081] Adhesive 2 was prepared in the same manner as Adhesive 1, except that the heating was maintained at 270° C. for 180 minutes.

[0082] Adhesive 3

[0083] Adhesive 3 was prepared in the same manner as Adhesive 1, except that the temperature was raised to 285° C. in the 0-20 minute range and maintained at 285° C. for 120 minutes.

[0084] Adhesive 4

[0085] (1) Weigh 50.0 g of Eucommia gum (polymerization degree 1159, molecular weight 7.88 × 10 4 g / mol, homemade) in a high-temperature resistant glass flask.

[0086] (2) The high-temperature resistant glass flask containing eucommia gum was placed in a MF-1200C high-temperature box furnace (Anhui Beiyike Equipment Technology Co., Ltd.), and the heating program was set: 0-20 minutes, heating to 200°C, and maintaining heating at 200°C for 120 minutes to obtain adhesive 4.

[0087] Adhesive 5

[0088] (1) Weigh 50.0 g of Eucommia gum (polymerization degree 1159, molecular weight 7.88 × 10 4 g / mol, homemade) in a high-temperature resistant glass flask.

[0089] (2) The high-temperature resistant glass flask containing eucommia gum was placed in a MF-1200C high-temperature box furnace (Anhui Beiyike Equipment Technology Co., Ltd.), and the heating program was set: 0-20 minutes, heating to 160°C, and maintaining heating at 160°C for 120 minutes to obtain adhesive 5.

[0090] Comparative Example 1

[0091] The preparation was carried out in the same manner as that of Adhesive 1, except that the temperature was raised to 330° C. from 0 to 20 minutes and kept at 330° C. for 60 minutes. The sample was charred and a semi-fluid adhesive could not be prepared.

[0092] Comparative Example 2

[0093] The preparation was carried out in the same manner as that of Adhesive 1, except that the temperature was raised to 120° C. from 0 to 10 minutes and the temperature was maintained at 120° C. for 240 minutes. The prepared sample had no fluidity and no adhesion.

[0094] Comparative Example 3

[0095] (1) Weigh 50.0 g of Eucommia gum (polymerization degree 5048, molecular weight 34.33 × 104 g / mol, homemade) in a high-temperature resistant glass flask.

[0096] (2) Place the high-temperature resistant glass flask containing Eucommia gum in a MF-1200C high-temperature box furnace (Anhui Beiyike Equipment Technology Co., Ltd.), set the heating program: 0-20 minutes, heat to 270℃, and keep heating at 270℃ for 120 minutes.

[0097] However, the product obtained by this preparation method cannot be used as an adhesive because it does not have adhesive properties.

[0098] Comparative Example 4

[0099] (1) Weigh 50.0 g of Eucommia gum (polymerization degree 3870, molecular weight 26.32 × 10 4 g / mol, homemade) in a high-temperature resistant glass flask.

[0100] (2) Place the high-temperature resistant glass flask containing Eucommia gum in a MF-1200C high-temperature box furnace (Anhui Beiyike Equipment Technology Co., Ltd.), set the heating program: 0-20 minutes, heat to 270℃, and keep heating at 270℃ for 120 minutes.

[0101] However, the product obtained by this preparation method cannot be used as an adhesive because it does not have adhesive properties.

[0102] Experimental Example 1: Lap-shear tensile strength test of adhesive

[0103] Experimental materials: Adhesives 1-5, porcine fibrin adhesive (Harbin Hanbang Medical Technology Co., Ltd.).

[0104] Experimental instrument: TA-XTplusC universal testing machine: Xiamen Chaoji Instrument Equipment Co., Ltd.

[0105] According to the People's Republic of China Medical Industry Standard "Test Method for Tissue Adhesive Properties" YY / T0729.1-2009, the lap-shear tensile bearing strength of Adhesives 1-5 and porcine fibrin adhesive was measured. The specific steps are as follows:

[0106] Take 0.2g of adhesives 1-5 and porcine fibrin adhesive respectively and apply them evenly to the overlapping area of ​​the pig leather strips. The size of the overlapping area is 10mm long and 25mm wide. Bond the two pig leather strips of a pair of test fixtures together along the overlapping area. Apply a force of about 2N to the overlapping area or use a clamp to clamp the bonding area flatly until the overlapping area is tightly bonded (about 5min). Place the sample in the clamp of the testing machine so that the force direction is the long axis direction of the sample. The crosshead loads the sample to failure at a speed of 5mm / min, and records the overlap-shear tensile bearing strength. The temperature of the test environment is 30±1℃ and the relative humidity is 50±5%. The experimental results are as follows. Figure 1 shown.

[0107] Depend on Figure 1 As can be seen, the lap-shear tensile strengths of adhesives 1-5 are 10.94 kPa, 5.16 kPa, 2.21 kPa, 1.32 kPa, and 2.07 kPa, respectively, while the lap-shear tensile strength of the porcine fibrin adhesive is 5.89 kPa. This shows that the adhesives of the present invention exhibit relatively high lap-shear tensile strengths, with Adhesive 1 having the highest lap-shear tensile strength, indicating that it has the strongest maximum load-bearing capacity under parallel shear stress.

[0108] Experimental Example 2: Tensile Strength Test of Adhesive

[0109] Experimental materials: Adhesives 1-5, porcine fibrin adhesive (Harbin Hanbang Medical Technology Co., Ltd.).

[0110] Experimental instrument: TA-XTplusC universal testing machine: Xiamen Chaoji Instrument Equipment Co., Ltd.

[0111] According to the People's Republic of China Medical Industry Standard "Test Method for Tissue Adhesive Properties" YY / T0729.3-2009, the tensile bearing strength of Adhesives 1-5 and porcine fibrin adhesive was measured. The specific steps are as follows:

[0112] Take 0.2g of adhesives 1-5 and porcine fibrin adhesive respectively and apply them evenly to the overlapping area of ​​the pig leather strips. The size of the overlapping area is 25mm long and 25mm wide. Bond the two pig leather strip tissue surfaces of a pair of test fixtures together, paying attention to keeping the two fixtures aligned and the docking not misaligned. Apply a force of about 2N to the overlapping area or use a clamp to clamp the bonding area flatly until the overlapping area is tightly bonded (about 5min). Place the sample in the fixture of the testing machine, and the crosshead loads the sample at a speed of 2mm / min until it is destroyed. Record the maximum tensile strength. The temperature of the test environment is 30±1℃ and the relative humidity is 50±5%. The experimental results are as follows. Figure 2 shown.

[0113] Depend on Figure 2As can be seen, the tensile bearing strengths of adhesives 1-5 are 161.85 kPa, 107.43 kPa, 40.57 kPa, 30.20 kPa, and 19.47 kPa, respectively, while the tensile bearing strength of the porcine fibrin adhesive is 52.48 kPa. This shows that the adhesives of the present invention exhibit relatively high tensile bearing strengths, with adhesive 1 having the highest tensile bearing strength, indicating that it has a stronger maximum bearing capacity under parallel shear stress.

[0114] Experimental Example 3: T-peel tensile strength test of adhesive

[0115] Experimental materials: Adhesives 1-5, porcine fibrin adhesive (Harbin Hanbang Medical Technology Co., Ltd.).

[0116] Experimental instrument: TA-XTplusC universal testing machine: Xiamen Chaoji Instrument Equipment Co., Ltd.

[0117] According to the People's Republic of China Medical Industry Standard "Test Method for Tissue Adhesive Properties" YY / T0729.2-2009, the T-peel tensile strength of Adhesives 1-5 and porcine fibrin adhesive was measured. The specific steps are as follows:

[0118] Take 0.2g of adhesives 1-5 and porcine fibrin adhesive respectively and apply them evenly to the bonding area of ​​the pigskin strip. The size of the bonding area is 125mm long and 25mm wide. Place another uncoated sample on top of the glued sample, apply a force of about 5 to 10N to the overlapping area or use a clamp to clamp the bonding area flatly until the overlapping area is tightly bonded (about 5 minutes). Place the uncoated end of the sample in the clamp of the testing machine, and load the sample with the crosshead at a speed of 250mm / min. Record the maximum interface toughness. The temperature of the test environment is 30±1℃ and the relative humidity is 50±5%. The experimental results are as follows Figure 3 shown.

[0119] Depend on Figure 3 It can be seen that the interface toughness of adhesives 1-5 is 62.65 J / m 2 40.16J / m 2 , 20.21J / m 2 、17.37J / m 2 、18.10J / m 2 The interfacial toughness of porcine fibrin adhesive is 23.81 J / m 2 It can be seen that the adhesives of the present invention exhibit relatively high interfacial toughness, among which Adhesive 1 has the highest interfacial toughness, indicating that it has a stronger anti-delamination ability at the interface with the pig skin tissue.

[0120] Experimental Example 4: Nuclear Magnetic Proton Spectroscopy and Carbon Spectroscopy of Adhesives

[0121] Experimental materials: Adhesives 1-5; deuterated chloroform (Sypleus (Beijing) Technology Co., Ltd.).

[0122] Experimental instruments: JNM-ECZ600R / S1 nuclear magnetic resonance spectrometer (JEOL Ltd.); SQP 1 / 100,000 balance (Sartorius Scientific Instruments (Beijing) Co., Ltd.).

[0123] Accurately weigh 20 mg of adhesive 1 and place it in a test tube. Add 0.5 mL of deuterated chloroform to completely dissolve the adhesive 1. Transfer the solution to an NMR tube and place it in an NMR spectrometer to detect the hydrogen and carbon spectra of the adhesive 1. The results are as follows: Figure 4 shown.

[0124] Depend on Figure 4 It can be seen that the main component of Adhesive 1 is a polymer 1,4-polyisoprene composed of structural units derived from trans-1,4-isoprene and structural units derived from cis-1,4-isoprene, wherein the weight ratio of the structural units derived from trans-1,4-isoprene to the structural units derived from cis-1,4-isoprene is 7.73:1.

[0125] In addition, the methods for determining H-NMR and C-NMR spectra of adhesives 2-5 were the same as those for adhesive 1, and their main component was also a polymer 1,4-polyisoprene composed of structural units derived from trans-1,4-isoprene and structural units derived from cis-1,4-isoprene, wherein the weight ratios of the structural units derived from trans-1,4-isoprene and the structural units derived from cis-1,4-isoprene were 6:1, 4:1, 13:1, and 11:1, respectively.

[0126] Experimental Example 5: Gel chromatography detection of adhesives

[0127] Experimental materials: Adhesives 1-5; tetrahydrofuran (TEDIA, USA); KF804L gel chromatography column (Showa Denko K.K., Japan); narrow distribution polystyrene (TOSOH, Japan).

[0128] Experimental instruments: LC20 high performance liquid chromatograph (Shimadzu Corporation, Japan); RID-20 differential refractive index detector (Shimadzu Corporation, Japan); SQP 1 / 100,000 balance (Sartorius Scientific Instruments (Beijing) Co., Ltd.).

[0129] Accurately weigh 10 mg of Adhesive 1 into a 10 mL volumetric flask. Add 5 mL of tetrahydrofuran to completely dissolve Adhesive 1. Continue adding tetrahydrofuran dropwise to the mark on the volumetric flask. Accurately pipette 10 μL of Adhesive 1 sample solution onto a spectrophotometer. Using a polystyrene standard curve, calculate the molecular weight of the polymer 1,4-polyisoprene (comprising structural units derived from trans-1,4-isoprene and structural units derived from cis-1,4-isoprene) in Adhesive 1 to be 4.41 × 10 4 g / mol, and the degree of polymerization is 648.

[0130] The molecular weight and degree of polymerization of adhesives 2-5 were determined in the same manner as for adhesive 1. The molecular weight and degree of polymerization of the polymer 1,4-polyisoprene (having structural units derived from trans-1,4-isoprene and structural units derived from cis-1,4-isoprene) contained therein are shown in Table 1.

[0131] Table 1

[0132] Sample name Molecular weight (g / mol) Degree of polymerization Adhesive 1 <![CDATA[4.41×10 4 ]]> 648 Adhesive 2 <![CDATA[3.87×10 4 ]]> 569 Adhesive 3 <![CDATA[3.30×10 4 ]]> 485 Adhesive 4 <![CDATA[3.07×10 4 ]]> 451 Adhesive 5 3.51 x 10 4 ]]> 516

[0133] Experimental Example 5: In vitro cytotoxicity test of adhesive

[0134] Experimental cells: L929 fibroblasts, purchased from Xiamen Yimo Biotechnology Co., Ltd.

[0135] Experimental materials: Adhesive 1, DMEM high glucose medium (Beijing Solebold Technology Co., Ltd.), fetal bovine serum (Gibco), MTT kit (Beijing Solebold Technology Co., Ltd.)

[0136] Experimental instrument: 1510 full wavelength microplate reader, purchased from Thermo Fisher Scientific (China) Co., Ltd.

[0137] According to the "In vitro cytotoxicity test" standard for biological evaluation of medical devices GB / T 16886.5-2017, the in vitro cytocompatibility of adhesive 1 was evaluated. The specific steps are as follows:

[0138] According to the extraction condition guidance in GB / T 16886.5-2017, "In Vitro Cytotoxicity Tests for Biological Evaluation of Medical Devices," and considering the low polarity of Adhesive 1, complete culture medium containing 10% (v / v) fetal bovine serum and 1% (v / v) bispecific antibody was selected as the extraction medium. 200 mg of Adhesive 1 was placed in a Petri dish, 10 mL of complete culture medium was added, and the mixture was incubated in a sterile incubator for 24 hours. After filtering the extract through a 0.22 μm sterile filter, the extract was diluted with complete culture medium to obtain adhesive extracts with concentrations of 20, 10, 5, 2, and 1 mg / mL, respectively.

[0139] L929 fibroblasts were cultured at a rate of 1×104 The cells were inoculated at a density of 100 μL / well in a 96-well plate, with 100 μL inoculated into each well, and incubated in a constant temperature incubator for 24 hours. After the cells adhered, 100 μL of the adhesive 1 solution at the above concentration was added to the 96-well plate, with 6 replicates in each group. A negative control group (L929 cells + complete culture medium) and a reference group (complete culture medium containing only the extract) were also set up and incubated in a constant temperature incubator for 24 hours. Then, 20 μL of MTT reagent was added to each well, and after incubation in the incubator for 3 hours, the liquid in the well was removed, and dimethyl sulfoxide was added to dissolve the purple crystals. After 10 minutes, the absorbance at a wavelength of 570 nm was measured with a microplate reader. The cell activity was calculated according to the following formula:

[0140] Cell activity = (As-Ab) / (Ac-Ab) × 100%

[0141] In the above formula, As represents the absorbance of the experimental group, Ab represents the absorbance of the reference group, and Ac represents the absorbance of the control group.

[0142] The results are shown in Figure 5 .Depend on Figure 5 It can be seen that the cell survival rate of adhesive 1 in the extract concentration range of 1-20 mg / mL is higher than 85%, and different extract concentrations have almost no effect on the cell survival rate, which shows that the adhesive of the present invention has good cell compatibility and high safety, and can be used as a medical adhesive.

[0143] Experimental Example 6: Rabbit red blood cell hemolysis rate test of adhesive

[0144] Experimental materials: Adhesive 1; physiological saline (Sichuan Kelun Pharmaceutical Co., Ltd.)

[0145] Experimental instrument: 1510 full wavelength microplate reader, purchased from Thermo Fisher Scientific (China) Co., Ltd.

[0146] According to the "In vitro cytotoxicity test" standard for biological evaluation of medical devices GB / T 16886.5-2017, the in vitro cytocompatibility of adhesive 1 was evaluated. The specific steps are as follows:

[0147] 2.5 mL of a 2% rabbit erythrocyte suspension was placed in a 10 mL centrifuge tube. 2.5 mL of the adhesive extract prepared in Experimental Example 5 (20, 10, 5, 2, and 1 mg / mL) was added, along with 2.5 mL of normal saline and distilled water, respectively, to form the reference and control groups. After incubation in a 37°C incubator for 3 hours, the tubes were centrifuged at 1500 rpm for 5 minutes. The supernatant was collected and the absorbance of each group was measured at 540 nm. The hemolysis rate was calculated according to the following formula:

[0148] Hemolysis rate = (As-Ab) / (Ac-Ab) × 100%

[0149] In the above formula, As represents the absorbance of the experimental group, Ab represents the absorbance of the reference group, and Ac represents the absorbance of the control group.

[0150] The results are shown in Figure 6 .Depend on Figure 6 It can be seen that the hemolysis rate of adhesive 1 in the extract concentration range of 1-20 mg / mL is less than 5%. When the concentration of the adhesive extract is 1-5 mg / mL, the hemolysis rate is even less than 1%, indicating that the adhesive of the present invention has good blood compatibility and high safety, and can be used as a medical adhesive.

[0151] Experimental Example 7: In vivo biodegradability test of adhesive

[0152] Experimental materials: Adhesive 1

[0153] The in vivo biocompatibility and biodegradability of adhesive 1 were evaluated using a rat subcutaneous implantation model.

[0154] Experimental procedure: After 3 days of adaptive feeding, 12 SD male rats (180-200g) were anesthetized by intraperitoneal injection of 1% sodium pentobarbital (5mL / kg), and a 2cm linear skin wound was established on the back (3.5cm away from the ear in a straight line). After 0.3g of adhesive 1 was implanted subcutaneously, the wound was sutured with surgical thread. A skin wound was established in the same position in the blank control group, and no implantation treatment was performed. After treatment, the rats were housed in a single cage and fed freely. The wounds of the rats were photographed and recorded on days 0, 7, 14, and 28, and 3 rats were anesthetized and sacrificed on days 7, 14, and 28, and the implanted adhesive 1 was taken out and weighed to calculate the degradation rate. The results are shown in Table 2.

[0155] Skin tissue (3×3 cm) from the wound was taken for pathological staining to analyze the biocompatibility of adhesive 1 with rat subcutaneous tissue. The results are shown in Table 3.

[0156] Table 2

[0157] Time (days) Degradation rate (%) 7 6.09±1.63 14 12.99±1.67 28 37.85±2.92 56 59.00±8.90

[0158] Table 3

[0159]

[0160] As shown in Table 2, the degradation rate of Adhesive 1 after 56 days of application was as high as 59.00%, indicating that the adhesive of the present invention has good in vivo biodegradability. In addition, through observation of the surrounding tissues, no tissue necrosis, inflammatory lesions, etc. were found, which also indicates that this product has good biosafety.

[0161] As shown in Table 3, the adhesive of the present invention has good in vivo biocompatibility.

[0162] Experimental Example 8: Testing of Adhesives to Promote Linear Skin Wound Healing

[0163] Experimental materials: Adhesive 1; surgical sutures (Shanghai Pudong Jinhuan Medical Supplies Co., Ltd.), Ankejing adhesive (Harbin Hanbang Medical Technology Co., Ltd.); Kangpaite adhesive (Beijing Kangpaite Medical Equipment Co., Ltd.)

[0164] A rat linear skin incision model was used to evaluate the promoting effect of adhesive 1 on the healing of rat linear skin incisions. The specific steps are as follows:

[0165] After 15 SD male rats (180-200g) were adaptively fed for 3 days, the back hair was removed 12h before modeling, and after anesthesia with intraperitoneal injection of 1% sodium pentobarbital (5mL / kg), a 1.5cm linear skin wound was established on both sides of the back (3.5cm away from the ear in a straight line), with a depth of skin thickness. The rats after modeling were randomly divided into 5 groups, with 3 rats in each group, and the wounds of each group of rats were treated as follows: no treatment (blank control group), suture surgery (surgical suture group), application of Ankejing adhesive (positive control group), application of Kangpaite adhesive (positive control group), application of adhesive 1 (experimental group). After treatment, the rats were raised in a single cage and fed freely. After anesthesia of the rats on the 7th day, skin tissue (3×3cm) at the wound was taken for pathological staining analysis. The results are shown in Table 4 and Figure 7 shown.

[0166] Table 4

[0167]

[0168] From Table 4 and Figure 7 It can be seen that the adhesive 1 of the present invention can promote the healing of linear skin wounds, and its healing effect on linear skin wounds is better than that of surgical sutures, Compat adhesives and Ankejing adhesives currently commonly used in clinical practice.

[0169] Experimental Example 9: Testing of Adhesives to Promote Healing of Exposed Full-Thickness Wounds

[0170] Experimental materials: Adhesive 1; Alginate dressing (Minnesota Mining and Manufacturing Company).

[0171] A rat exposed full-thickness wound model was used to evaluate the promoting effect of Adhesive 1 on wound healing in rats exposed full-thickness wounds. The specific steps are as follows:

[0172] 27 SD male rats (180-200g) were shaved of their back hair 12 hours before modeling. After anesthesia with intraperitoneal injection of 1% sodium pentobarbital (5mL / kg), the back skin was disinfected with iodine tincture, and a skin biopsy puncture with a diameter of 10mm was used to establish a tissue defect model on both sides of the rat's back (3.5cm away from the ear in a straight line). The diameter of the skin defect on the rat's back is 10mm, and the depth is the thickness of the skin. After modeling, the rats were randomly divided into 3 groups, with 9 rats in each group, and the wounds of each group of rats were treated as follows: no treatment (blank control group), alginate dressing (positive control group), and adhesive 1 (experimental group). After anesthesia on the 12th day, the rats were anesthetized and the skin tissue (3×3cm) at the wound was taken for pathological staining analysis. The results are shown in Tables 5 and Figure 8 shown.

[0173] Table 5

[0174]

[0175] From Table 5 and Figure 8 It can be seen that the adhesive of the present invention can promote the healing of exposed full-thickness wounds, and the healing effect on exposed full-thickness wounds is better than that of the alginate dressing commonly used in clinical practice.

[0176] It should be noted that the terms used in the description of the present invention are intended only to describe specific embodiments and are not intended to limit the present invention. The above summary of the invention and the detailed description below are intended only to illustrate the present invention and are not intended to limit the present invention in any way. Without departing from the spirit and purpose of the present invention, the scope of the present invention is determined by the appended claims.

Claims

1. An adhesive obtained by modifying eucommia gum, comprising a polymer 1,4-polyisoprene composed of structural unit I and structural unit II as shown below, wherein the weight ratio of structural unit I to structural unit II is 1-15:1:

2. The adhesive according to claim 1, wherein The weight ratio of the structural unit I to the structural unit II is 4-13:1, preferably 5-9:1, and more preferably 6-8:

1.

3. The adhesive according to claim 1 or 2, wherein The degree of polymerization of the polymer 1,4-polyisoprene is 110-1400, preferably 400-800.

4. The adhesive according to any one of claims 1 to 3, wherein The eucommia gum is extracted from Eucommia ulmoides, a plant of the Eucommia family, and contains trans-1,4-polyisoprene with a degree of polymerization of 1000-3500.

5. The adhesive according to any one of claims 1 to 4, wherein The adhesive is prepared by a method comprising the steps of heating the eucommia gum to a temperature of 150-320°C, preferably 160-300°C, more preferably 200-285°C, and maintaining the temperature for 60-180 minutes, preferably 90-150 minutes, more preferably 100-130 minutes.

6. The adhesive according to any one of claims 1 to 5, wherein The adhesive has a lap-shear tensile bearing strength of at least 1 kPa, preferably at least 5 kPa, more preferably at least 10 kPa, as measured in accordance with standard YY / T 0729.1-2009.

7. The adhesive according to any one of claims 1 to 6, wherein The adhesive has a tensile bearing strength of at least 20 kPa, preferably at least 100 kPa, more preferably at least 150 kPa, as measured in accordance with standard YY / T 0729.3-2009.

8. The adhesive according to any one of claims 1 to 7, wherein The adhesive has a strength of at least 15 J / m 2 , preferably at least 40 J / m 2 , more preferably at least 60 J / m 2 The interface toughness is measured according to the YY / T 0729.2-2009 standard.

9. Use of the adhesive according to any one of claims 1 to 8 as a medical adhesive.

10. The use according to claim 9, wherein The adhesive is used to bond open wounds on the skin; preferably, the adhesive is used to promote the healing of linear skin wounds or promote the healing of exposed full-thickness wounds.

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