An overheat temperature self-regulating intelligent fiber-based in-situ wound dressing and its preparation method and application

Abstract

The present invention discloses a self-regulating, intelligent fiber-based in-situ wound dressing, its preparation method, and application. The wound dressing is prepared by chemically grafting a thermosensitive polymer and a near-infrared-responsive polyethyleneimine onto a carboxylated cellulose nanofiber matrix to produce temperature / near-infrared and pH-responsive intelligent nanofibers, which are then composited with a photothermal agent responsive to near-infrared stimulation. The wound dressing exhibits gradient temperature responsiveness in two temperature ranges: 32-48°C and 48-52°C. It adapts to the shape of the wound, providing a physical barrier while releasing the photothermal agent in response to the wound's acidic microenvironment. Under near-infrared laser irradiation, the dressing performs in-situ photothermal therapy and can self-regulate back to 42-48°C when the photothermal temperature exceeds 48°C, protecting the wound tissue from overheating damage.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomass fiber modification, and in particular relates to an overheat temperature self-regulating intelligent fiber-based in-situ wound dressing, a preparation method thereof, and an application thereof. Background Art

[0002] The skin is the largest and most exposed organ of an organism and is extremely vulnerable to injury. Although most smaller skin defects heal within a few weeks without complications, large full-thickness skin defects or irregular wounds are exposed to the environment due to incomplete coverage or inability of traditional dressings to fully adhere to the wound bed. This makes the wound extremely susceptible to bacterial infection and even colonization to form bacterial biofilms, triggering inflammation and subsequently forming chronic wounds. In addition, the frequent use of antimicrobial drugs can lead to multidrug resistance in bacteria, and bacterial biofilms act as a physical barrier that protects bacteria from attacks by innate immune cells while preventing drugs from entering the wound bed, causing the drugs to lose their original therapeutic effects. Photothermal therapy (PTT) using near-infrared laser irradiation is an effective method for localized wound sterilization. However, the photothermal temperature during near-infrared laser irradiation is unstable and can easily cause overheating damage to wound tissue, causing secondary damage to the wound, thereby further delaying wound healing. Using a thermal imager to monitor photothermal temperature is currently a common method. However, when the photothermal temperature is detected to be too high, the temperature of the wound can only be reduced by adjusting the near-infrared laser power or turning off the near-infrared laser irradiation. The residual heat may still cause thermal damage to the wound tissue. It is impossible to cool the wound in time, and it will also consume more manpower and material resources to monitor the PTT photothermal temperature, which is not convenient for wound management. Summary of the Invention

[0003] To overcome the aforementioned issues with PTT therapy, the present invention provides a self-regulating, intelligent fiber-based in-situ wound dressing, its preparation method, and its application. This dressing can fully adapt to irregular wounds and form in situ at the wound bed, providing a physical barrier while simultaneously performing in-situ photothermal therapy under near-infrared light stimulation. When the photothermal temperature exceeds 48°C, it can automatically adjust back to 42-48°C, protecting wound tissue from overheating damage.

[0004] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0005] A method for preparing an overheat temperature self-regulating intelligent fiber-based in-situ wound dressing comprises the following steps:

[0006] S1. Preparation of near-infrared-responsive polyethyleneimine: Polyethyleneimine is prepared by amidation reaction with triethylenetetraminepentaacetic acid and near-infrared-responsive dopamine at high temperature in a stepwise reaction.

[0007] S2. Preparation of NIR- and pH-responsive smart nanofibers: Carboxylated cellulose nanofibers were prepared by amidation reaction with NIR-responsive polyethyleneimine at high temperature.

[0008] S3. Preparation of temperature-responsive smart nanofibers: Carboxylated cellulose nanofibers are prepared by esterification reaction with a thermosensitive polymer; the thermosensitive polymer is a triblock molecular structure of poloxamer F127, poloxamer F68, or poly-ε-caprolactone-poly-N-isopropylacrylamide-poly-ε-caprolactone;

[0009] S4. Preparation of an overheated temperature self-regulating intelligent fiber-based in situ wound dressing: The temperature-responsive intelligent nanofibers, near-infrared and pH-responsive intelligent nanofibers and a photothermal agent with near-infrared stimulus responsiveness are mixed and dispersed evenly to prepare an overheated temperature self-regulating intelligent fiber-based in situ wound dressing; the near-infrared stimulus responsive photothermal agent is indocyanine green which has the same near-infrared laser wavelength response as dopamine; the overheated temperature self-regulating intelligent fiber-based in situ wound dressing has gradient temperature responsiveness in two temperature ranges of 32-48°C and 48-52°C.

[0010] Furthermore, the main operation of the preparation of near-infrared responsive polyethyleneimine in step S1 is: dispersing polyethyleneimine and triethylenetetraminepentaacetic acid in water at a mass ratio of 1 to 3:1, after ultrasonic treatment, reacting at 100°C for 10 to 12 hours, washing until the supernatant is neutral, freeze-drying the precipitate, and then dispersing it with dopamine in water at a mass ratio of 1:4, after ultrasonic treatment, reacting at 100°C for 10 to 12 hours, washing until the supernatant is neutral, and freeze-drying the precipitate to obtain near-infrared responsive polyethyleneimine.

[0011] Furthermore, the main operations for preparing the near-infrared and pH-responsive smart nanofibers in step S2 are: dispersing the near-infrared responsive polyethyleneimine and carboxylated cellulose nanofibers in water at a mass ratio of 2.5 to 4:1, ultrasonically treating them, reacting them at 100°C for 10 to 12 hours, and then centrifuging and precipitating them until the supernatant is neutral, and freeze-drying the precipitate to obtain near-infrared and pH-responsive smart nanofibers.

[0012] Furthermore, the specific operation of preparing the temperature-responsive smart nanofibers in step S3 is: dispersing the thermosensitive polymer and carboxylated cellulose nanofibers in water at a mass ratio of 3 to 8:1, then adding 4-dimethylaminopyridine and N-hydroxysuccinimide in sequence, continuously stirring for 8 to 10 hours, and then centrifuging and precipitating, and freeze-drying the precipitate to obtain temperature-responsive smart nanofibers.

[0013] Furthermore, the main operation of preparing the superheat temperature self-regulating intelligent fiber-based in situ wound dressing in step S4 is: dispersing the temperature-responsive intelligent nanofibers, near-infrared and pH-responsive intelligent nanofibers and indocyanine green in water at a mass ratio of 300:100:2-5 at a low temperature of 4-8°C, stirring for 2-3 hours, and preparing the superheat temperature self-regulating intelligent fiber-based in situ wound dressing.

[0014] The overheat temperature self-regulating intelligent fiber-based in situ wound dressing of the present invention has gradient temperature responsiveness in two temperature ranges of 32-48°C and 48-52°C. It is in a solution state at <32°C, in a gel state at 32-48°C, and returns to a flowable solution state at 48-52°C. The invention can be used to treat infected wounds, wherein the infected wounds are irregular wounds infected with Gram-negative Escherichia coli, Gram-positive Staphylococcus aureus or drug-resistant Staphylococcus aureus. The dressing is in a solution state at a temperature <32°C. When the dressing is dripped onto the infected wound, the dressing can fully adapt to the irregular wound and form a gel in situ under the stimulation of skin temperature (rising from <32°C to above 32°C), providing a physical barrier for the wound to prevent the invasion of external bacteria; the dressing can respond to the acidic microenvironment of the wound (pH stimulation) to release more of the loaded indocyanine green photothermal agent into the wound tissue, and under the stimulation of near-infrared 808nm laser, the dressing can rise to 42-48°C for photothermal treatment, thermally ablating bacteria and bacterial biofilms colonized in the wound tissue; when the photothermal temperature of the dressing is greater than 48°C, the dressing itself will be converted into a solution state, changing the distribution of the photothermal agent inside it, thereby affecting the photothermal effect, causing the photothermal temperature to drop to 42-48°C, and realizing temperature self-regulation.

[0015] The present invention has the following beneficial effects:

[0016] (1) The overheat temperature self-regulating intelligent fiber-based in situ wound dressing prepared by the present invention has near-infrared / pH / gradient temperature responsiveness, which enables the dressing to fully adapt to the shape of irregular wounds at low temperatures (>32°C), while providing a physical barrier for the wound and responding to the acidic microenvironment of the wound to release photothermal agents. In situ photothermal treatment is performed under the irradiation of near-infrared lasers, and the dressing can self-regulate back to 42-48°C when the photothermal temperature is >48°C, thereby protecting the wound tissue from overheating damage. This overcomes the defects of traditional dressings that cannot fully conform to irregular wound beds and that the excessively high photothermal temperature during PTT treatment is unavoidable and can burn the wound tissue.

[0017] (2) The present invention prepares temperature / near-infrared and pH-responsive smart nanofibers by chemically grafting a thermosensitive polymer and near-infrared responsive polyethyleneimine onto a carboxylated cellulose nanofiber matrix. The temperature-responsive smart nanofibers and the near-infrared and pH-responsive smart nanofibers can form an interwoven network structure. Temperature stimulation can cause the molecular chains of the temperature-responsive smart nanofibers to shrink or stretch, thereby driving the network structure of the entire dressing to undergo two reconstructions at 32-52°C, thereby achieving in-situ formation of the dressing on the wound bed and self-regulation of overheating temperature during PTT treatment. pH stimulation can cause the dressing to release more photothermal agent. The photothermal agent release rate of the dressing at pH = 3 is 86.5-92.7%, while the photothermal agent release rate at pH = 7 is 50.3-65.9%. DETAILED DESCRIPTION

[0018] Example 1

[0019] S1. Preparation of near-infrared responsive polyethyleneimine: 1 g of polyethyleneimine and 1 g of triethylenetetraminepentaacetic acid were dispersed in 35 mL of water, ultrasonicated for 10 min, reacted at 100°C with stirring for 10 h, washed until the supernatant was neutral, and freeze-dried the precipitate to obtain polyethyleneimine with a terminal carboxyl group; 1 g of polyethyleneimine with a terminal carboxyl group and 4 g of dopamine were dispersed in 35 mL of water, ultrasonicated for 10 min, reacted at 100°C with stirring for 10 h, washed until the supernatant was neutral, and freeze-dried the precipitate to obtain near-infrared responsive polyethyleneimine.

[0020] S2. Preparation of near-infrared and pH-responsive smart nanofibers: 2.5 g of near-infrared responsive polyethyleneimine and 1 g of carboxylated cellulose nanofibers were uniformly dispersed in 200 mL of water, ultrasonically treated for 15 min, and then reacted at 100°C with stirring for 10 h. The mixture was centrifuged and precipitated until the supernatant was neutral. The precipitate was freeze-dried to obtain near-infrared and pH-responsive smart nanofibers.

[0021] S3. Preparation of temperature-responsive smart nanofibers: 8 g of poloxamer F68 and 1 g of carboxylated cellulose nanofibers were dispersed in 30 mL of water, and then 50 mg of 4-dimethylaminopyridine and 1 g of N-hydroxysuccinimide were added in sequence. The mixture was reacted at room temperature with stirring for 8 h, and then centrifuged and precipitated. The precipitate was freeze-dried to obtain temperature-responsive smart nanofibers.

[0022] S4. Preparation of superheated temperature self-regulating smart fiber-based in situ wound dressing: 3 g of temperature-responsive smart nanofibers, 1 g of near-infrared and pH-responsive smart nanofibers, and 20 mg of indocyanine green were dispersed in 20 mL of water and stirred at 4 °C for 2 h to prepare superheated temperature self-regulating smart fiber-based in situ wound dressing.

[0023] Example 2

[0024] S1. Preparation of near-infrared responsive polyethyleneimine: 2 g of polyethyleneimine and 1 g of triethylenetetraminepentaacetic acid were dispersed in 45 mL of water, ultrasonicated for 10 min, reacted at 100 °C with stirring for 11 h, washed until the supernatant was neutral, and freeze-dried the precipitate to obtain polyethyleneimine with terminal carboxyl groups; 1 g of polyethyleneimine with terminal carboxyl groups and 4 g of dopamine were dispersed in 35 mL of water, ultrasonicated for 10 min, reacted at 100 °C with stirring for 11 h, washed until the supernatant was neutral, and freeze-dried the precipitate to obtain near-infrared responsive polyethyleneimine.

[0025] S2. Preparation of near-infrared and pH-responsive smart nanofibers: 3 g of near-infrared responsive polyethyleneimine and 1 g of carboxylated cellulose nanofibers were uniformly dispersed in 250 mL of water, ultrasonically treated for 15 min, and then reacted at 100°C with stirring for 11 h. The mixture was centrifuged and precipitated until the supernatant was neutral. The precipitate was freeze-dried to obtain near-infrared and pH-responsive smart nanofibers.

[0026] S3. Preparation of temperature-responsive smart nanofibers: 5 g of poloxamer F127 and 1 g of carboxylated cellulose nanofibers were dispersed in 30 mL of water, and then 40 mg of 4-dimethylaminopyridine and 3 g of N-hydroxysuccinimide were added in sequence. The mixture was reacted at room temperature with stirring for 9 h, and then centrifuged and precipitated. The precipitate was freeze-dried to obtain temperature-responsive smart nanofibers.

[0027] S4. Preparation of superheated temperature self-regulating smart fiber-based in situ wound dressing: 3 g of temperature-responsive smart nanofibers, 1 g of near-infrared and pH-responsive smart nanofibers, and 30 mg of indocyanine green were dispersed in 20 mL of water and stirred at 6°C for 2.5 h to prepare superheated temperature self-regulating smart fiber-based in situ wound dressing.

[0028] Example 3

[0029] S1. Preparation of near-infrared responsive polyethyleneimine: 3 g of polyethyleneimine and 1 g of triethylenetetraminepentaacetic acid were dispersed in 60 mL of water, ultrasonicated for 10 min, reacted at 100 °C with stirring for 12 h, washed until the supernatant was neutral, and freeze-dried the precipitate to obtain polyethyleneimine with terminal carboxyl groups; 1 g of polyethyleneimine with terminal carboxyl groups and 4 g of dopamine were dispersed in 35 mL of water, ultrasonicated for 10 min, reacted at 100 °C with stirring for 12 h, washed until the supernatant was neutral, and freeze-dried the precipitate to obtain near-infrared responsive polyethyleneimine.

[0030] S2. Preparation of near-infrared and pH-responsive smart nanofibers: 4 g of near-infrared responsive polyethyleneimine and 1 g of carboxylated cellulose nanofibers were uniformly dispersed in 300 mL of water, ultrasonically treated for 15 min, and then reacted at 100°C with stirring for 12 h. The mixture was centrifuged and precipitated until the supernatant was neutral. The precipitate was freeze-dried to obtain near-infrared and pH-responsive smart nanofibers.

[0031] S3. Preparation of temperature-responsive smart nanofibers: 3 g of poly(ε-caprolactone)-poly(N-isopropylacrylamide)-poly(ε-caprolactone) and 1 g of carboxylated cellulose nanofibers were dispersed in 30 mL of water, and then 30 mg of 4-dimethylaminopyridine and 5 g of N-hydroxysuccinimide were added in sequence. The mixture was reacted at room temperature with stirring for 10 h, and then centrifuged and precipitated. The precipitate was freeze-dried to obtain temperature-responsive smart nanofibers.

[0032] S4. Preparation of superheated temperature self-regulating smart fiber-based in situ wound dressing: 3 g of temperature-responsive smart nanofibers, 1 g of near-infrared and pH-responsive smart nanofibers, and 50 mg of indocyanine green were dispersed in 20 mL of water and stirred at 8°C for 3 h to prepare superheated temperature self-regulating smart fiber-based in situ wound dressing.

[0033] Performance test of the superheat temperature self-regulating intelligent fiber-based in situ wound dressing prepared in Examples 1, 2, and 3

[0034] ① The overheat temperature self-regulating intelligent fiber-based in situ wound dressings prepared in Examples 1, 2, and 3 were tested for indocyanine green release performance. The test results showed that they had higher indocyanine green release capacity at acidic pH. The indocyanine green release rates at pH = 3 were 86.5%, 90.4%, and 92.7%, respectively, and the indocyanine green release rates at pH = 7 were 50.3%, 58.8%, and 65.9%, respectively.

[0035] ② The overheated temperature self-regulating intelligent fiber-based in situ wound dressings prepared in Examples 1, 2, and 3 were tested for gradient temperature stimulus response performance. The test results all showed good gradient temperature stimulus response performance. The dressings were in a solution state at <32°C and could be continuously heated to 32-48°C under near-infrared light stimulation. At this time, the dressings turned into a gel state. When the temperature continued to rise to 48-52°C, the dressings turned back into a flowable solution state.

[0036] ③ The overheated temperature self-regulating intelligent fiber-based in situ wound dressings prepared in Examples 1, 2, and 3 were subjected to antibacterial and anti-infection tests. The test results all showed good antibacterial properties, with antibacterial rates of more than 99% against Gram-negative Escherichia coli, Gram-positive Staphylococcus aureus, and drug-resistant Staphylococcus aureus. The in vivo anti-infection test results showed that the dressings could be completely applied to the wounds of mice and achieved anti-infection effects under the stimulation of near-infrared lasers. After 14 days of treatment, the healing rate of infected wounds in mice was 99%, while that of the control group was only 73.6%. When the photothermal temperature was >48°C, the dressing could self-adjust back to 42-48°C, protecting the wound tissue from overheating damage.

Claims

1. A method for preparing an overheat temperature self-regulating intelligent fiber-based in-situ wound dressing, characterized in that: The method comprises the following preparation steps: S1. Preparation of near-infrared-responsive polyethyleneimine: Polyethyleneimine is prepared by amidation reaction with triethylenetetraminepentaacetic acid and near-infrared-responsive dopamine at high temperature in a stepwise reaction. S2. Preparation of NIR- and pH-responsive smart nanofibers: Carboxylated cellulose nanofibers were prepared by amidation reaction with NIR-responsive polyethyleneimine at high temperature. S3. Preparation of temperature-responsive smart nanofibers: Carboxylated cellulose nanofibers are prepared by esterification reaction with a thermosensitive polymer; the thermosensitive polymer is a triblock molecular structure of poloxamer F127, poloxamer F68, or poly-ε-caprolactone-poly-N-isopropylacrylamide-poly-ε-caprolactone; S4. Preparation of an overheated temperature self-regulating intelligent fiber-based in situ wound dressing: The temperature-responsive intelligent nanofibers, near-infrared and pH-responsive intelligent nanofibers and a photothermal agent with near-infrared stimulus responsiveness are mixed and dispersed uniformly to prepare an overheated temperature self-regulating intelligent fiber-based in situ wound dressing; the near-infrared stimulus responsive photothermal agent is indocyanine green which has the same near-infrared laser wavelength response as dopamine; the overheated temperature self-regulating intelligent fiber-based in situ wound dressing has gradient temperature responsiveness in two temperature ranges of 32-48°C and 48-52°C.

2. The preparation method according to claim 1, characterized in that The main operations for preparing the near-infrared responsive polyethyleneimine in step S1 are as follows: polyethyleneimine and triethylenetetraminepentaacetic acid are dispersed in water at a mass ratio of 1 to 3:1, and after ultrasonic treatment, reacted at 100°C for 10 to 12 hours, washed until the supernatant is neutral, and freeze-dried the precipitate. The mixture is then dispersed in water with dopamine at a mass ratio of 1:4, and after ultrasonic treatment, reacted at 100°C for 10 to 12 hours, washed until the supernatant is neutral, and freeze-dried to obtain the near-infrared responsive polyethyleneimine.

3. The preparation method according to claim 1, characterized in that The main operations for preparing the near-infrared and pH-responsive smart nanofibers in step S2 are: dispersing near-infrared-responsive polyethyleneimine and carboxylated cellulose nanofibers in water at a mass ratio of 2.5-4:1, ultrasonically treating the mixture, reacting the mixture at 100° C. for 10-12 hours, and then centrifuging the mixture until the supernatant is neutral, and freeze-drying the precipitate to obtain near-infrared and pH-responsive smart nanofibers.

4. The preparation method according to claim 1, characterized in that The specific operation of preparing the temperature-responsive smart nanofibers in step S3 is as follows: dispersing the thermosensitive polymer and carboxylated cellulose nanofibers in water at a mass ratio of 3 to 8:1, then adding 4-dimethylaminopyridine and N-hydroxysuccinimide in sequence, continuously stirring for 8 to 10 hours, and then centrifuging and precipitating, and freeze-drying the precipitate to obtain the temperature-responsive smart nanofibers.

5. The preparation method according to claim 1, characterized in that The main operation of preparing the superheat temperature self-regulating intelligent fiber-based in situ wound dressing in step S4 is: dispersing the temperature-responsive intelligent nanofibers, near-infrared and pH-responsive intelligent nanofibers and indocyanine green in water at a mass ratio of 300:100:2~5 at a low temperature of 4~8°C, stirring for 2~3 hours, and preparing the superheat temperature self-regulating intelligent fiber-based in situ wound dressing.

6. The superheat temperature self-regulating intelligent fiber-based in situ wound dressing prepared by the preparation method according to any one of claims 1 to 5, wherein the wound dressing is in a solution state at <32°C, in a gel state at 32-48°C, and returns to a flowable solution state at 48-52°C.

7. Use of the superheat temperature self-regulating intelligent fiber-based in-situ wound dressing prepared by the preparation method according to any one of claims 1 to 5 for preparing an infectious wound dressing.