Hydrogel wound dressing for monitoring wound microenvironment and preparation method and application thereof

Abstract

The application relates to a chiral hydrogel wound dressing for monitoring a wound microenvironment, a preparation method and application, and belongs to the field of biological materials. The preparation method of the hydrogel wound dressing comprises the following steps: A, adding an L-basic amino acid derivative into a polymer solution to be dissolved to form a mixed solution; B, heating the mixed solution, pouring the mixed solution into a mold after the mixed solution is clarified and standing for cooling, performing first cross-linking, and forming a pre-gel in the mold; C, immersing the formed pre-gel in a salt solution to perform second cross-linking, and obtaining the hydrogel wound dressing for monitoring a wound microenvironment after the cross-linking product is washed. The hydrogel wound dressing for monitoring a wound microenvironment has good biocompatibility, can effectively promote wound healing, and can monitor the pH value of a microenvironment near a wound in real time and indicate the healing condition of the wound.

Description

Technical Field

[0001] This invention relates to the field of biomaterials technology, specifically to a hydrogel wound dressing for monitoring the wound microenvironment, its preparation method, and its application. Background Technology

[0002] Medical wound dressings are medical materials used to cover sores, wounds, or other lesions. They create an ideal environment for wound healing by preventing and inhibiting the invasion of harmful microorganisms, absorbing wound exudate and toxic substances, and allowing gas exchange. Sodium alginate (SA) is a natural polymer material widely used in the development of biomedical materials.

[0003] Hydrogels, due to their physicochemical properties similar to the extracellular matrix, good biocompatibility, and ion transport capabilities, are widely used in the preparation of wound repair materials. However, most commercially available hydrogel dressings only possess antibacterial, bacteriostatic, and wound-healing-promoting properties, lacking an indication of wound infection and healing status. This makes it difficult for doctors and patients to directly obtain information about wound recovery in practical applications, causing significant inconvenience and even hindering wound healing. Furthermore, existing hydrogel dressings neglect the influence of gel chirality on biocompatibility.

[0004] CN 113509589A discloses a method for preparing and applying a biomimetic collagen wound dressing, but its gel cannot play a role in monitoring wound healing because the chiral gelling factor used to construct the gel dressing does not have properties that can change with the wound environment (such as color change, fluorescence intensity change, etc.). Summary of the Invention

[0005] Therefore, the purpose of this invention is to provide a hydrogel wound dressing for monitoring the wound microenvironment, its preparation method, and its application.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A method for preparing a chiral hydrogel wound dressing for monitoring the wound microenvironment includes the following steps:

[0008] A. L-basic amino acid derivatives dissolve in a polymer solution to form a mixture;

[0009] B. Heat the mixture and let it stand and cool after it becomes clear (to perform the first cross-linking of supramolecular helical fibers and long polymer chains) to form a pregel in the mold.

[0010] C. The pre-gel after molding is immersed in a salt solution for a second cross-linking (long-chain cross-linking of polymers). After washing the cross-linking product, a chiral hydrogel wound dressing for monitoring the wound microenvironment is obtained.

[0011] The second cross-linking of long polymer chains in step C can further improve the mechanical properties of the gel.

[0012] This invention endows dressings with fluorescent properties by employing chiral gelling factors composed of a central perylene ring with fluorescent characteristics, enabling them to respond according to pH. Changes in the dressing's fluorescence intensity reflect the healing status of the wound. Healthy, intact skin has a pH of 4.0–6.0, which is slightly acidic, while unhealed chronic wounds often have a pH in the alkaline range, ranging from 7.15 to 8.90, and some even reaching as high as 9.25. The L-basic amino acid derivative added in step A exhibits pH-dependent fluorescence intensity changes after heating and assembly.

[0013] In step A, the L-basic amino acid derivative has an aromatic ring as the central core and L-basic amino acids as symmetrical side chains.

[0014] In one embodiment of the present invention, the L-basic amino acid derivative has a perylene ring as the central core and L-basic amino acids as side chains.

[0015] The L-basic amino acid derivative is selected from L-histidine derivatives, L-lysine derivatives, or L-arginine derivatives.

[0016] The L-histidine derivative has a perylene ring as the central core, with 3,4,9,10-tetracarboxylic acid grafted onto L-histidine.

[0017] The preparation method of the L-histidine derivative includes the following steps:

[0018] 3,4,9,10-perylenetetracarboxylic dianhydride, L-histidine, and imidazole are heated to a high temperature, water (preferably deionized water) is added, the mixture is filtered, and the lower aqueous layer is acidified in a strong acid solution until the product is completely precipitated. The precipitate obtained by filtration is the L-histidine derivative. The strong acid solution is 2.0-2.5M hydrochloric acid. The heating temperature is 90-110℃, and the reaction time is 2-4 hours.

[0019] The mass ratio of 3,4,9,10-perylenetetracarboxylic acid dianhydride, L-histidine, and imidazole is 1:0.8-1:4-6.

[0020] The L-lysine derivative has a perylene ring as the central core, with 3,4,9,10-tetracarboxylic acid grafted onto L-lysine.

[0021] The preparation method of the L-lysine derivative includes the following steps:

[0022] 3,4,9,10-perylenetetracarboxylic dianhydride, L-lysine, and imidazole are reacted at high temperature. Water (preferably deionized water) is added, and the mixture is filtered. The lower aqueous layer is acidified in a strong acid solution until the product is completely precipitated. The precipitate obtained by filtration is the L-lysine derivative. The strong acid solution is 2.0-2.5M hydrochloric acid. The reaction temperature is 90-110℃, and the reaction time is 2-4 hours.

[0023] The mass ratio of the 3,4,9,10-perylenetetracarboxylic dianhydride, L-lysine, and imidazole is 1:0.75-0.95:4-6.

[0024] The L-arginine derivative has a perylene ring as the central core, with 3,4,9,10-tetracarboxylic acid grafted onto L-arginine.

[0025] The preparation method of the L-arginine derivative includes the following steps:

[0026] 3,4,9,10-Perylenetetracarboxylic acid dianhydride, L-arginine, and imidazole are heated to a high temperature to react. Water (preferably deionized water) is added, and the mixture is filtered. The lower aqueous layer is acidified in a strong acid solution until the product is completely precipitated. The precipitate obtained by filtration is the L-arginine derivative. The strong acid solution is 2.0-2.5M hydrochloric acid. The heating temperature is 90-110℃, and the reaction time is 2-4 hours.

[0027] The mass ratio of 3,4,9,10-perylenetetracarboxylic acid dianhydride, L-arginine, and imidazole is 1:0.9-1.12:4-6.

[0028] During the static cooling process in step B, the L-amino acid derivative building blocks stack up to form supramolecular helices under the drive of hydrogen bonding and π-π stacking interactions. Driven by hydrogen bonding with the building blocks, the long polymer chains undergo the first cross-linking with the supramolecular helical fibers, forming a pregel in the mold.

[0029] In step A, the polymer is selected from at least one of alginate and chitosan.

[0030] In step A, the concentration of the polymer in the mixture is 1-3% wt, and the concentration of the L-basic amino acid derivative is 5-10 mg / mL.

[0031] In step A, the dissolution temperature is 90-110℃.

[0032] In step B, the cooling temperature is 15-35℃.

[0033] In step C, the salt solution is a calcium salt solution (such as calcium chloride).

[0034] This application also provides a chiral hydrogel wound dressing for monitoring the wound microenvironment obtained by the above preparation method.

[0035] The present invention has the following beneficial effects:

[0036] 1. This invention uses L-basic amino acid derivatives, which can form micro / nanofibers with good biocompatibility and chiral helical structure. These fibers can promote the formation of microvessels and granulation tissue at the wound site, thereby accelerating wound healing. Compared with gels without amino acid side chains and chiral helical structure, this invention significantly promotes wound healing and shortens wound healing time. Compared with D-amino acid derivatives, it has higher healing efficiency.

[0037] 2. The polymers selected in this invention will not hydrolyze in the wound environment, and can maintain the helical structure formed by the L-amino acid derivatives without disintegrating during use.

[0038] 3. The chiral hydrogel dressing for monitoring the wound microenvironment prepared in this invention uses gel components with hydrophilic groups (such as carboxyl and hydroxyl groups in sodium alginate, and carboxyl groups in gelling agents), which solves the technical problem that traditional dressings are difficult to absorb wound exudate and ensure sufficient drainage. It achieves the beneficial effect of providing a slightly moist physiological environment for wound repair, which is conducive to the regeneration of wound epithelial cells and accelerates wound healing.

[0039] 4. The chiral hydrogel dressing for monitoring the wound microenvironment prepared in this invention uses a building material with good biocompatibility. The chiral fibers formed by it can mimic the inherent structure of the skin, support the proliferation and migration of skin cells, promote angiogenesis, and significantly improve the healing efficiency of skin damage. It has been widely used in the repair of ulcers, burns and other wounds, and has the beneficial effect of promoting wound repair.

[0040] 5. The chiral hydrogel dressing for monitoring the wound microenvironment prepared by this invention uses alkaline amino acid derivatives as gelling factors, endowing the gel dressing with positive charge similar to antibacterial peptides, which has antibacterial and anti-inflammatory effects, and achieves the beneficial effect of promoting wound healing.

[0041] 6. During the wound healing process, the pH value at the wound site changes. The hydrogel dressing prepared in this invention for monitoring the wound microenvironment contains a pH-responsive fluorescent supramolecular assembly (L-basic amino acid derivative), which can monitor the pH value in the wound microenvironment in real time. By using a chiral gel factor composed of a central perylene ring with fluorescent properties, the dressing is endowed with fluorescent properties, realizing the function of the change in the fluorescent intensity of the dressing reflecting the wound healing status. It is expected to be applied in fields such as intelligent indicative wound repair hydrogels.

[0042] 7. Most dressings containing antibiotics play a role in the sustained release of drugs, but the assembly in this invention always remains in the excipients and does not enter the biological body. At the same time, it has fluorescent properties and chiral structure that antibiotics do not have.

[0043] 8. During the heating process for preparing the gel, it is important not to overheat. The supramolecular molecules should be fully dissolved while the gel moisture should not be excessively evaporated, so as to ensure the formation of the gel interpenetrating network. Attached Figure Description

[0044] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0045] Figure 1 This is a macroscopic view of the chiral hydrogel dressing used for monitoring the wound microenvironment in Example 1.

[0046] Figure 2 SEM image of the chiral hydrogel wound dressing used to monitor the wound microenvironment in Example 1;

[0047] Figure 3 SEM image of the chiral hydrogel wound dressing used for monitoring the wound microenvironment in Example 2;

[0048] Figure 4 SEM image of the chiral hydrogel wound dressing used for monitoring the wound microenvironment in Example 3;

[0049] Figure 5 The graph shows the mechanical strength characterization of the gel in Example 1 using a flat plate rheometer.

[0050] Figure 6 The graph shows the mechanical strength characterization of the gel in Comparative Example 1 using a plate rheometer.

[0051] Figure 7 The graph shows the mechanical strength characterization of the gel in Comparative Example 2 using a plate rheometer.

[0052] Figure 8 The graph shows the mechanical strength characterization of the gel in Comparative Example 4 using a plate rheometer.

[0053] Figure 9 The graph shows the mechanical strength characterization of the gel in Comparative Example 6 using a plate rheometer.

[0054] Figure 10 The graph shows the mechanical strength characterization of the gel in Comparative Example 7 using a flat plate rheometer.

[0055] Figure 11 The healing efficiency of the gel dressings prepared in Examples 1, 2, 3, 3, 4, and 5 on diabetic wounds is shown in the figure.

[0056] Figure 12 The fluorescence intensity changes of the gel dressings prepared in Examples 1, 2, 3, 3, 4, and 5 on diabetic wounds 14 days later are shown. Detailed Implementation

[0057] The present invention will be described in detail below with reference to embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several adjustments and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0058] Example 1

[0059] This embodiment provides a method for preparing a chiral hydrogel wound dressing for monitoring the pH value of the wound microenvironment, including the following steps:

[0060] 1. Add 500 mg of 3,4,9,10-perylenetetracarboxylic acid dianhydride and 395 mg of L-histidine to 2 g of imidazole, stir and heat at 130 °C for 2 hours, stop heating, add 100 ml of deionized water, filter, take the lower aqueous layer and acidify with 2.0 M hydrochloric acid until the product is completely precipitated, filter, and the obtained precipitate is the L-histidine derivative;

[0061] The structure of the L-histidine derivative (with a perylene ring as the central core, and 3, 4, 9, 10 tetracarboxylic acids grafted with di-L-histidine) is shown in the following formula:

[0062]

[0063] Acid anhydrides and amino groups undergo a nucleophilic reaction. The free electron pair in the amino group attacks the acyl group in the acid anhydride, resulting in proton transfer, which lowers the energy barrier of the reaction. Finally, the product of the reaction between the acid anhydride and the amino group is formed: an amide.

[0064] 2. Weigh 1g of sodium alginate and dissolve it completely in 100ml of water to form a sodium alginate solution;

[0065] 3. Weigh 500 mg of the L-histidine derivative prepared in step 1 and disperse it in the sodium alginate aqueous solution prepared in step 2. Stir for 2 hours to disperse it evenly and form a sodium alginate dispersion of the L-histidine derivative.

[0066] 4. Heat the sodium alginate dispersion of the L-histidine derivative obtained in step 3 to 90°C. After the solution becomes clear, pour it into a mold at 20°C and let it stand and cool for 0.5 hours. The helical fibers assembled by the L-histidine derivative will undergo the first cross-linking with sodium alginate to form a pregel.

[0067] 5. The pre-gel after molding is soaked in 0.1M calcium chloride solution for 12 hours. The supramolecular helical fibers formed by L-histidine derivatives undergo a second cross-linking with the pre-gel formed by sodium alginate, thereby improving the mechanical strength of the gel.

[0068] 6. The gel product after two cross-linkings is washed with water more than twice; the hydrogel wound dressing with the function of monitoring the pH value of the wound microenvironment is obtained. Its macroscopic image is shown in Formula 1 below, and its SEM image is shown in Formula 2 below.

[0069] In this embodiment, the pregel prepared by forming an interpenetrating network between supramolecular helical fibers formed from L-histidine derivatives and sodium alginate, and the resulting gel after secondary crosslinking, showed a storage modulus of 37479 Pa through rheological characterization. Figure 5 The prepared gel was placed in an acidic environment (pH=6) and the fluorescence signal was compared with that in a neutral environment (pH=7). It was found that the fluorescence intensity was significantly enhanced in the acidic environment.

[0070] Example 2

[0071] This embodiment provides a method for preparing a chiral hydrogel wound dressing for monitoring the pH value of the wound microenvironment, including the following steps:

[0072] 1. Add 500 mg of 3,4,9,10-perylenetetracarboxylic acid dianhydride and 450 mg of L-lysine to 2 g of imidazole, stir and heat at 130 °C for 2 hours, stop heating, add 100 ml of deionized water, filter, take the lower aqueous layer and acidify with 2.5 M hydrochloric acid until the product is completely precipitated, filter, and the obtained precipitate is the L-lysine derivative;

[0073] The structure of the L-lysine derivative (with a perylene ring as the central core, and 3, 4, 9, 10 tetracarboxylic acids grafted onto di-L-lysine) is shown in the following formula:

[0074]

[0075] Acid anhydrides and amino groups undergo a nucleophilic reaction. The free electron pair in the amino group attacks the acyl group in the acid anhydride, resulting in proton transfer, which lowers the energy barrier of the reaction. Finally, the product of the reaction between the acid anhydride and the amino group is formed: an amide.

[0076] 2. Weigh 1g of chitosan and dissolve it completely in 100ml of water containing 1% acetic acid to form a chitosan solution;

[0077] 3. Weigh 500 mg of the L-lysine derivative from step 1 and disperse it in the chitosan aqueous solution obtained in step 2. Stir for 3 hours to disperse it evenly and form a chitosan dispersion of the L-lysine derivative.

[0078] 4. Heat the chitosan dispersion of the L-lysine derivative obtained in step 3 to 100°C. After the solution becomes clear, pour it into a mold at 20°C and let it stand and cool for 0.5 hours. The helical fibers assembled by the L-lysine derivative will undergo the first cross-linking with the chitosan to form a pregel.

[0079] 5. The pregel after molding is soaked in 0.1M sodium hydroxide solution for 12 hours. The supramolecular helical fibers formed by L-lysine derivatives undergo a second cross-linking with the pregel formed by chitosan, thereby improving the mechanical strength of the gel.

[0080] 6. The gel product after two cross-linking processes is washed with water at least twice to obtain the hydrogel wound dressing with the function of monitoring the pH value of the wound microenvironment. The SEM image is shown in Formula 3 below.

[0081] In this embodiment, a pregel was prepared by forming an interpenetrating network between supramolecular helical fibers formed from L-lysine derivatives and chitosan. The mechanical strength of the gel obtained after secondary crosslinking was characterized by rheological analysis, showing a storage modulus of 28983 Pa. The prepared gel was placed in an acidic environment (pH=6) and the fluorescence signal was compared with that in a neutral environment (pH=7). It was found that the fluorescence intensity was significantly enhanced in the acidic environment.

[0082] Example 3

[0083] This embodiment provides a method for preparing a chiral hydrogel wound dressing for monitoring the pH value of the wound microenvironment, including the following steps:

[0084] 1. Add 500 mg of 3,4,9,10-perylenetetracarboxylic acid dianhydride and 500 mg of L-arginine to 2 g of imidazole, stir and heat at 130 °C for 2 hours, stop heating, add 100 ml of deionized water, filter, take the lower aqueous layer and acidify with 2.5 M hydrochloric acid until the product is completely precipitated, filter, and the obtained precipitate is the L-arginine derivative;

[0085] The structure of the L-arginine derivative (with a perylene ring as the central core, and 3, 4, 9, 10 tetracarboxylic acids grafted with di-L-arginine) is shown in the following formula:

[0086]

[0087] Acid anhydrides and amino groups undergo a nucleophilic reaction. The free electron pair in the amino group attacks the acyl group in the acid anhydride, resulting in proton transfer, which lowers the energy barrier of the reaction. Finally, the product of the reaction between the acid anhydride and the amino group is formed: an amide.

[0088] 2. Weigh 2g of sodium hyaluronate and dissolve it completely in 100ml of water to form a sodium hyaluronate solution;

[0089] 3. Weigh 500 mg of the L-arginine derivative prepared in step 1 and disperse it in the sodium hyaluronate aqueous solution obtained in step 2. Stir for 2 hours to disperse it evenly and form a sodium hyaluronate dispersion of L-arginine derivative.

[0090] 4. The sodium hyaluronate dispersion of the L-arginine derivative obtained in step 3 is heated to 110°C. After the solution clarifies, it is poured into a mold at 20°C and allowed to cool for 0.5 hours. This allows the helical fibers assembled from the L-arginine derivative to undergo their first cross-linking with the sodium hyaluronate, forming a gel. This yields the hydrogel wound dressing with the function of monitoring the pH value of the wound microenvironment. The SEM image is shown in Formula 4 below.

[0091] In this embodiment, a pregel was prepared by forming an interpenetrating network between supramolecular helical fibers formed from L-arginine derivatives and sodium hyaluronate. The mechanical strength of the resulting gel after secondary crosslinking was characterized by a storage modulus of 28387 Pa, as shown by rheological characterization. The prepared gel was placed in an acidic environment at pH 6, and the fluorescence signal was compared with that in a neutral environment. It was found that the fluorescence intensity was significantly enhanced in the acidic environment.

[0092] Comparative Example 1

[0093] This comparative example provides a method for preparing a hydrogel wound dressing. The specific steps are basically the same as those in Example 1, except that sodium alginate is not added.

[0094] 1. Weigh 500 mg of L-amino acid derivative (with a perylene ring as the central core, and 3,4,9,10 tetracarboxylic acids grafted onto di-L-histidine);

[0095] Acid anhydrides and amino groups undergo a nucleophilic reaction. The free electron pair in the amino group attacks the acyl group in the acid anhydride, resulting in proton transfer, which lowers the energy barrier of the reaction. Finally, the product of the reaction between the acid anhydride and the amino group is formed: an amide.

[0096] 2. Disperse the L-amino acid derivative from step 1 in 100 ml of deionized water;

[0097] 3. Heat the deionized aqueous dispersion of the L-amino acid derivative obtained in step 2 to 90°C. After the solution becomes clear, pour it into a mold at 20°C and let it stand and cool until the L-amino acid derivative self-assembles to form a pregel.

[0098] 4. Soak the formed pregel in a 0.1M calcium chloride solution for 12 hours;

[0099] 5. The gel product after treatment with calcium chloride solution should be washed with water two or more times.

[0100] Since the fibers formed by L-amino acid derivatives do not cross-link with calcium ions, the resulting gel dressing is solely a product of the self-assembly of L-amino acid derivatives. In this comparative example, the storage modulus of the gel formed by the self-assembly of L-amino acid derivatives is 9007 Pa. Figure 6 The mechanical strength (storage modulus 37479 Pa) of the gel obtained by secondary crosslinking in Example 1 is much lower than that of the gel obtained by secondary crosslinking in Example 1. This gel is extremely fragile and cannot be used as a wound dressing.

[0101] Comparative Example 2

[0102] This comparative example provides a method for preparing a gel wound dressing that undergoes only one crosslinking process. The specific steps are basically the same as in Example 1, with the only difference being:

[0103] Step 5 is to soak the formed pregel in a 0.1M potassium chloride solution for 12 hours.

[0104] Since potassium ions cannot undergo ionic cross-linking with sodium alginate, the resulting gel dressing is merely a one-time cross-linked product of helical fibers formed by the self-assembly of sodium alginate and L-amino acid derivatives (with a perylene ring as the central core and 3,4,9,10 tetracarboxylic acids grafted with di-L-histidine). In this comparative example, the storage modulus of the gel formed by the one-time cross-linking of helical fibers formed by the self-assembly of L-amino acid derivatives and sodium alginate is 2633 Pa. Figure 7 The mechanical strength (storage modulus 37479 Pa) of this gel is far less than that of the gel obtained by secondary crosslinking in Example 1. This gel is extremely prone to breakage during actual use and cannot be used as a wound dressing.

[0105] Comparative Example 3

[0106] This comparative example provides a method for preparing a hydrogel wound dressing. The specific steps are basically the same as those in Example 1, except that the heating process in step 3 is omitted.

[0107] Because no heating-cooling process was involved, the L-amino acid derivatives (with a perylene ring as the central core and 3,4,9,10 tetracarboxylic acids grafted with di-L-histidine) in the system did not self-assemble to form helical fibers and subsequently an interpenetrating network with the polymer chains. Therefore, the resulting gel dressing was merely a physical mixture of L-amino acid derivatives and sodium alginate with secondary cross-linking. In this comparative example, the prepared gel was placed in an acidic environment at pH 6, and the fluorescence signal was compared with that in a neutral environment. It was found that the fluorescence intensity in the acidic environment did not change significantly and could not indicate changes in the wound microenvironment.

[0108] Comparative Example 4

[0109] This comparative example provides a method for preparing a hydrogel wound dressing. The specific steps are basically the same as in Example 1, except that the L-histidine derivative (with a perylene ring as the central core, and 3,4,9,10 tetracarboxylic acids grafted onto di-L-histidine) is replaced with a D-histidine derivative (with a perylene ring as the central core, and 3,4,9,10 tetracarboxylic acids grafted onto di-D-histidine). The anhydride and amino group undergo a nucleophilic reaction. The free electron pair in the amino group attacks the acyl group in the anhydride, resulting in proton transfer, thereby reducing the energy barrier of the reaction. Finally, the product of the reaction between the anhydride and the amino group is formed: an amide.

[0110] Because a gelling agent with the opposite chirality to that used in the examples was used, the resulting gel dressing has chiral microhelical fibers with the opposite chirality to those used in the examples. In this comparative example, the gel storage modulus of the helical fibers self-assembled from the D-histidine derivative and secondary cross-linked with sodium alginate is 27901 Pa. Figure 8 The mechanical strength (storage modulus 37479 Pa) of the gel dressing constructed with L-histidine derivatives in Example 1 is less than that of the gel dressing in Example 1.

[0111] Comparative Example 5

[0112] This comparative example provides a method for preparing a hydrogel wound dressing. The specific steps are basically the same as in Example 1, except that the L-histidine derivative is replaced with an L-phenylalanine derivative (with a perylene ring as the central core, and 3,4,9,10 tetracarboxylic acids grafted onto di-L-phenylalanine), the structure of which is shown in the following formula:

[0113]

[0114] Acid anhydrides and amino groups undergo a nucleophilic reaction. The free electron pair in the amino group attacks the acyl group in the acid anhydride, resulting in proton transfer, which lowers the energy barrier of the reaction. Finally, the product of the reaction between the acid anhydride and the amino group is formed: an amide.

[0115] In this comparative example, the prepared gel was placed in an acidic environment with pH=6 and the fluorescence signal was compared with that in a neutral environment. It was found that the fluorescence intensity in the acidic environment did not change significantly and could not indicate changes in the wound microenvironment.

[0116] Comparative Example 6

[0117] The difference from Example 1 is that, in step 4, the sodium alginate dispersion of the L-histidine derivative obtained in step 3 is heated to 75°C.

[0118] At this temperature, the amino acid derivatives cannot completely dissolve and assemble. In this comparative example, the storage modulus of the gel formed by the self-assembly of the L-histidine derivative and secondary cross-linking with sodium alginate was 3490 Pa. Figure 9The mechanical strength (storage modulus 37479 Pa) of the gel dressing constructed with L-histidine derivatives in Example 1 is much lower than that of the gel dressing in Example 1. This gel is extremely prone to breakage during actual use and cannot be used as a wound dressing.

[0119] Comparative Example 7

[0120] The difference from Example 1 is that, in step 4, the sodium alginate dispersion of the L-histidine derivative obtained in step 3 is heated to 120°C.

[0121] At this temperature, the solution undergoes violent vaporization, resulting in the loss of a large amount of solvent. In this comparative example, the storage modulus of the gel formed by the self-assembly of L-histidine derivatives and secondary cross-linking with sodium alginate is 7684 Pa. Figure 10 The mechanical strength (storage modulus 37479 Pa) of the gel dressing constructed with L-histidine derivatives in Example 1 is much lower than that of the gel dressing in Example 1. This gel is extremely prone to breakage during actual use and cannot be used as a wound dressing.

[0122] Comparative Example 8

[0123] The only difference from Example 1 is that the L-histidine derivative (with a perylene ring as the central core, and 3,4,9,10 tetracarboxylic acids grafted onto di-L-histidine) is replaced with a histamine derivative (with a perylene ring as the central core, and 3,4,9,10 tetracarboxylic acids grafted onto dihistamine), the structure of which is shown in the following formula:

[0124]

[0125] Acid anhydrides and amino groups undergo a nucleophilic reaction. The free electron pair in the amino group attacks the acyl group in the acid anhydride, resulting in proton transfer, which lowers the energy barrier of the reaction. Finally, the product of the reaction between the acid anhydride and the amino group is formed: an amide.

[0126] In this comparative example, the prepared gel was placed in an acidic environment with pH=6 and the fluorescence signal was compared with that in a neutral environment. It was found that the fluorescence intensity in the acidic environment did not change significantly and could not indicate changes in the wound microenvironment.

[0127] Performance test example: verification of wound healing effect

[0128] Diabetic wounds were modeled on the backs of mice, and hydrogel wound dressings prepared in Examples 1-3 and Comparative Examples 3-5 were applied to the wounds. Mice without treatment served as blank controls. The healing rate was statistically analyzed after fourteen days. The healing rate was calculated by comparing the wound area with the initial wound area. The fluorescence intensity was calculated by using a three-dimensional fluorescence imaging system (PerkinElmer IVISSpectrum) and software (Living Image 4.5). The average value of the initial intensity was considered as 100%.

[0129] The results are shown in Table 1 and... Figure 11 and Figure 12 Show:

[0130] Experimental Group 1 (Example 1) 96％ 128％ Experimental Group 2 (Example 2) 92％ 122％ Experimental Group 3 (Example 2) 94％ 113％ Experimental group 4 (Comparative example 3) 75％ 102％ Experimental group 5 (Comparative example 4) 74％ 110％ Experimental group 6 (Comparative example 5) 87％ 103％ Experimental group 7 (blank control) 37％ -

[0131] In Example 1 (Experimental Group 1), the wounds treated with the gel dressing for monitoring the pH value of the wound microenvironment, which was prepared based on L-histidine derivatives (with perylene ring as the central core and 3,4,9,10 tetracarboxylic acids grafted onto di-L-histidine) and sodium alginate and calcium ions through secondary cross-linking, healed faster, with a healing rate of 96% after 14 days. Furthermore, the fluorescence intensity of the dressing increased to 128% of its original value after 14 days.

[0132] In Example 2 (Experimental Group 2), the wound treated with a gel dressing for monitoring the pH value of the wound microenvironment, which was prepared based on L-lysine derivatives (with perylene ring as the central core and 3,4,9,10 tetracarboxylic acids grafted onto di-L-lysine) and chitosan and sodium hydroxide through secondary cross-linking, achieved a healing rate of 92% after 14 days. Furthermore, the fluorescence intensity of the dressing increased to 122% of its original value after 14 days.

[0133] In Example 3 (Experimental Group 3), the wound treated with a gel dressing for monitoring the pH value of the wound microenvironment, which was prepared by cross-linking L-arginine derivative (with perylene ring as the central core and 3,4,9,10 tetracarboxylic acid grafted onto di-L-arginine) and hyaluronic acid, achieved a healing rate of 94% after 14 days, and the fluorescence intensity of the dressing increased to 113% of the original after 14 days.

[0134] In Comparative Example 3 (Experimental Group 4), the wound healing rate of the gel dressing prepared by physical mixing of L-histidine derivative (with perylene ring as the central core and 3,4,9,10 tetracarboxylic acid grafted with di-L-histidine) and sodium alginate secondary cross-linking gel reached 75% after 14 days, and the fluorescence intensity of the gel did not change significantly during the process.

[0135] In Comparative Example 4 (Experimental Group 5), the wound healing rate of the gel dressing prepared based on D-histidine derivative (with perylene ring as the central core and 3,4,9,10 tetracarboxylic acids grafted with di-D-histidine) and sodium alginate and calcium ions after secondary cross-linking reached 74% after 14 days, and the fluorescence intensity of the dressing increased to 110% of the original after 14 days.

[0136] In Comparative Example 5 (Experimental Group 6), the wound healing rate of the gel dressing prepared by secondary cross-linking of L-phenylalanine derivative (with perylene ring as the central core and 3,4,9,10 tetracarboxylic acid grafted onto di-L-phenylalanine) with sodium alginate and calcium ions reached 94% after 14 days, and the fluorescence intensity of the gel did not change significantly during the process.

[0137] Group 7 served as the control group. The wound healing rate of the untreated wounds was 37% after 14 days.

[0138] Animal experiments confirmed that the chiral hydrogel dressings with repair function prepared in Examples 1-3 and Comparative Examples 3-5 improved the wound healing speed after treatment, and Examples 1 and Comparative Examples 5 healed faster. Examples 1-3 and Comparative Examples 4 can indicate the wound healing status in real time.

[0139] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A method for preparing a chiral hydrogel wound dressing for monitoring the wound microenvironment, characterized in that, Includes the following steps: A. L-basic amino acid derivatives dissolve in a polymer solution to form a mixture; B. Heat the mixture, and after the mixture becomes clear, let it stand and cool to carry out the first cross-linking and form a pregel. C. The pre-gel after molding is soaked in a salt solution for a second cross-linking. The cross-linking product is washed to obtain the chiral hydrogel wound dressing for monitoring the wound microenvironment. In step A, the L-basic amino acid derivative is selected from L-histidine derivatives, L-lysine derivatives, or L-arginine derivatives; The L-histidine derivative has a perylene ring as its central core, with 3,4,9,10-tetracarboxylic acid grafted onto L-histidine. Its preparation method is as follows: 3,4,9,10-perylenetetracarboxylic dianhydride, L-histidine, and imidazole are heated to react at high temperature. Water is added, and the mixture is filtered. The lower aqueous layer is acidified in a strong acid solution until the product is completely precipitated. The precipitate obtained by filtration is the L-histidine derivative. The strong acid solution is 2.0-2.5M hydrochloric acid. The heating temperature is 90-110℃, and the reaction time is 2-4 hours. The L-lysine derivative is prepared by grafting L-lysine with a perylene ring as the central core and 3,4,9,10-tetracarboxylic acid. The preparation method is as follows: 3,4,9,10-perylenetetracarboxylic acid dianhydride, L-lysine, and imidazole were heated to react at high temperature. Water was added, and the mixture was filtered. The lower aqueous layer was acidified in a strong acid solution until the product was completely precipitated. The precipitate obtained by filtration was the L-lysine derivative. The strong acid solution was 2.0-2.5M hydrochloric acid. The heating temperature was 90-110℃, and the reaction time was 2-4 hours. The L-arginine derivative has a perylene ring as the central core, with 3,4,9,10-tetracarboxylic acid grafted onto L-arginine; its preparation method is as follows: 3,4,9,10-perylenetetracarboxylic acid dianhydride, L-arginine, and imidazole were heated to react at high temperature. Water was added, and the mixture was filtered. The lower aqueous layer was acidified in a strong acid solution until the product was completely precipitated. The precipitate obtained by filtration was the L-arginine derivative. The strong acid solution was 2.0-2.5M hydrochloric acid. The heating temperature was 90-110℃, and the reaction time was 2-4 hours. In step B, the heating temperature is 90-110℃; the polymer is selected from at least one of alginate and chitosan; In step C, the salt solution is a calcium salt solution.

2. The preparation method according to claim 1, characterized in that, In step A, the concentration of the polymer in the mixture is 1%-3%wt, and the concentration of the L-basic amino acid derivative is 5-10mg / mL.

3. The preparation method according to claim 1, characterized in that, In step B, the cooling temperature is 15-35℃.

4. A chiral hydrogel wound dressing for monitoring the wound microenvironment prepared by the method according to any one of claims 1-3.

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