Sequential bidirectional drainage-cooling integrated material with sandwich structure as well as preparation method and application of sequential bidirectional drainage-cooling integrated material

Abstract

The invention belongs to the technical field of fiber materials, and particularly relates to a sequential bidirectional drainage-cooling integrated material with a sandwich structure as well as a preparation method and application of the sequential bidirectional drainage-cooling integrated material. The material is composed of an upper hydrophobic antibacterial drainage layer capable of guiding liquid in one direction, a middle hydrophilic cooling layer and a lower hydrophobic antibacterial drainage layer capable of guiding liquid in one direction. According to the invention, the sequential bidirectional liquid guiding-cooling integrated material with a sandwich structure is successfully prepared through an electrohydrodynamic atomization technology; the liquid guiding performance of the upper hydrophobic antibacterial drainage layer and the lower hydrophobic antibacterial drainage layer is clearly observed by means of fluorescent dyeing in combination with a static contact angle measuring instrument. The material disclosed by the invention not only can guide away liquid between finger seams, chelidonium and abdominal folds, but also shows an obvious cooling effect, and the skin temperature can be reduced by 6.7 DEG C to the minimum extent. Meanwhile, vertical guide and separation of wound exudate are achieved, the excessive edema symptom of wound tissue is effectively relieved, and wound healing is achieved through antibiosis, anti-inflammation, vascularization promotion and collagen deposition promotion.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of fiber materials, and particularly relates to a sandwich-structured time-sequential bidirectional liquid-guiding and cooling integrated material and a preparation method and application thereof. BACKGROUND

[0002] Intertrigo is a superficial skin disease that often occurs in skin folds. Its onset is mainly the result of the combined action of many factors such as humid and warm environment and skin friction. In the folded area where the skin is in close contact with each other, sweat and heat are easy to accumulate and difficult to dissipate, and continuous friction between the skin promotes the increase of sweat secretion, and the local temperature continues to rise. Over time, the skin barrier function is damaged, and the wound and exudate create conditions for the growth of bacteria and fungi, and further cause infection. To promote rapid healing, the key lies in effectively handling a large amount of biological fluids such as sweat and exudate, reducing the skin temperature at the lesion site, and doing a good job in the prevention and control of microbial infection. At present, talcum powder and hydrophilic gauze are often used in clinical to absorb biological fluids such as sweat and exudate at the intertrigo site. However, the talcum powder particles are extremely small and can be easily inhaled into the human body during use, which poses a health risk. If it comes into contact with an open wound, it will also cause irritation and delay the healing process. The medical gauze has the problem of limited liquid absorption capacity and is difficult to absorb a large amount of biological fluids, and when the absorption reaches saturation, the liquid is easy to back seep under the skin friction and pressure, causing the intertrigo site to become wet again. Therefore, some researchers have proposed to prepare Janus structure materials with asymmetric wettability to guide away the biological fluids. However, this kind of material can only remove the fluid on one side of the skin, making the hydrophobic side dry, while the hydrophilic side is still wet due to direct contact with the hydrophilic layer, which is not conducive to the recovery of intertrigo. The treatment of intertrigo not only requires the management of biological fluids, but also the heat management. Hydrogel materials are often used for the treatment of surface skin conditions due to their heat absorption and cooling properties. In addition, some fillers with high thermal conductivity are added to the hydrogel, and this composite material shows better cooling effect on the skin surface. As mentioned above, the skin folds are narrow and closed, which hinders the evaporation of water in the hydrogel. Therefore, the heat dissipation performance of the hydrogel is limited in the skin folds. In recent years, radiation cooling materials have been used for heat management of body surface and wounds, but due to the narrow and closed nature of the intertrigo site, the material cannot effectively absorb visible light and cannot achieve radiation cooling. It is of great significance to develop new strategies to achieve effective overheat management in closed and narrow skin folds. Therefore, there is an urgent need to develop a material that can realize bidirectional liquid guidance and rapid cooling for the treatment of intertrigo. SUMMARY

[0003] The present application aims to provide a sandwich-structured time-sequential bidirectional liquid-guiding and cooling integrated material and a preparation method and application thereof in preventing and relieving intertrigo.

[0004] The implementation process of the present application is as follows:

[0005] A time-sequential bidirectional liquid-guiding and cooling integrated material with a sandwich structure is composed of an upper unidirectional liquid-guiding and hydrophobic antibacterial drainage layer, an intermediate hydrophilic cooling layer, and a lower unidirectional liquid-guiding and hydrophobic antibacterial drainage layer.

[0006] The preparation method of the time-sequential bidirectional liquid-guiding and cooling integrated material with a sandwich structure includes the following steps:

[0007] (1) Preparation of the intermediate hydrophilic cooling layer

[0008] Under stirring conditions, cooling substances and soluble hydrophilic polymer materials are added to a solvent to obtain a spinning solution; the spinning solution is subjected to electrospinning through an electrospinning device to obtain a nanofiber membrane; the nanofiber membrane is placed in glutaraldehyde vapor for crosslinking, and after drying, the intermediate hydrophilic cooling layer is obtained;

[0009] (2) Preparation of the upper unidirectional liquid-guiding and hydrophobic antibacterial drainage layer and the lower unidirectional liquid-guiding and hydrophobic antibacterial drainage layer

[0010] An antibacterial agent is added to a solvent and subjected to ultrasonic treatment, and then under stirring conditions, a soluble hydrophobic polymer material is added to obtain a hydrophobic antibacterial solution; the hydrophobic antibacterial solution is sprayed on the upper surface of the intermediate hydrophilic cooling layer through an electrostatic spraying device to obtain the upper unidirectional liquid-guiding and hydrophobic antibacterial drainage layer; the spraying step is repeated, and the hydrophobic antibacterial solution is sprayed on the lower surface of the intermediate hydrophilic cooling layer through the electrostatic spraying device to obtain the lower unidirectional liquid-guiding and hydrophobic antibacterial drainage layer, and finally the time-sequential bidirectional liquid-guiding and cooling integrated material with a sandwich structure is obtained.

[0011] Further, the preparation method of the upper unidirectional liquid-guiding and hydrophobic antibacterial drainage layer and the lower unidirectional liquid-guiding and hydrophobic antibacterial drainage layer in step (2) is replaced by:

[0012] The soluble hydrophobic polymer material and the antibacterial agent are dispersed or dissolved in a solvent to obtain a hydrophobic antibacterial solution; an electrospinning device is used to electrospun to prepare an octopus sucker-like nanofiber membrane with an array hole structure; the intermediate hydrophilic cooling layer is placed between the two layers of octopus sucker-like nanofiber membranes to form the time-sequential bidirectional liquid-guiding and cooling integrated material with a sandwich structure.

[0013] Further, in step (1), the soluble hydrophilic polymer material is selected from any one or a combination of several of chitosan, gelatin, collagen, polyacrylonitrile, cellulose acetate, polyvinyl alcohol, and polyvinylpyrrolidone; the solvent is selected from any one or a combination of several of hexafluoroisopropanol, glacial acetic acid, tetrahydrofuran, N,N-dimethylformamide, N,N-diethylacetamide, water, and ethanol; and the cooling substance is selected from one or a combination of several of ammonium salt, nitrate, or sugar alcohol compound.

[0014] Further, the ammonium salt is ammonium nitrate or ammonium chloride; the nitrate salt is potassium nitrate or sodium nitrate; the sugar alcohol compound is erythritol, xylitol, sorbitol, mannitol, lactitol or maltitol.

[0015] Further, in step (2), the soluble hydrophobic polymer material is selected from any one or combination of poly-epsilon-caprolactone, polyurethane, polylactic acid, polyglycolide, polysulfone, polymethyl methacrylate, polyvinyl butyral, polyvinylidene fluoride, and polystyrene; the solvent is selected from any one or combination of tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl pyrrolidone, dichloromethane, trichloromethane, hexafluoroisopropanol, and ethanol; the antibacterial agent is selected from any one or combination of metal silver particles, metal copper particles, curcumin, chitosan, and epsilon-polylysine hydrochloride, and the mass concentration of the soluble hydrophobic polymer material in the hydrophobic antibacterial solution is 0.1-1.0 g / mL.

[0016] Further, in step (1), the mass concentration of the soluble hydrophilic polymer material in the spinning solution is 0.02-0.19 g / mL.

[0017] Further, in step (1), the parameters of the electrospinning equipment are as follows: the collection device is an aluminum foil wrapped roller, the spinning voltage is 5-20 kv, the flow rate is 0.5-2.0 mL / h, and the spinning distance is 5-20 cm; in step (2), the parameters of the electrostatic spraying equipment are as follows: the voltage is 8-15 kV, the spraying distance is fixed at 3-5 cm, and the spraying flow rate is 1-2 mL / h.

[0018] Further, the soluble hydrophobic polymer material is selected from any one or combination of poly-epsilon-caprolactone, polyurethane, polylactic acid, polyglycolide, polysulfone, polymethyl methacrylate, polyvinyl butyral, polyvinylidene fluoride, and polystyrene; the solvent is selected from any one or combination of tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl pyrrolidone, dichloromethane, trichloromethane, hexafluoroisopropanol, and ethanol; the antibacterial agent is selected from any one or combination of metal silver particles, metal copper particles, curcumin, chitosan, and epsilon-polylysine hydrochloride, and the mass concentration of the soluble hydrophobic polymer material in the hydrophobic antibacterial solution is 0.1-1.0 g / mL; the parameters of the electrospinning equipment are as follows: the voltage is 5-20 kv, the flow rate is 0.5-2.0 mL / h, and the spinning distance is 5-20 cm.

[0019] The application of the time-sequential bidirectional liquid-guiding and cooling integrated material with a sandwich structure in preventing and relieving intertrigo, fever-reducing patches, emergency cooling for sports injuries, quick-drying cooling fabrics, and postoperative swelling and pain relief.

[0020] The design concept of the application: the time-sequential bidirectional liquid-guiding and cooling integrated material with a sandwich structure is successfully prepared by constructing an intermediate hydrophilic cooling layer (such as a soluble hydrophilic polymer material / cooling substance) and upper and lower pumping layers (soluble hydrophobic polymer material / antibacterial agent) through electrohydrodynamic atomization technology. The influence of the upper and lower hydrophobic antibacterial pumping layers on the liquid-guiding performance is studied. The influence of the composite amount of the cooling substance in the intermediate hydrophilic cooling layer on the cooling performance is explored. An in vitro model is established to evaluate the synergistic effect of the time-sequential bidirectional liquid-guiding and cooling integrated material with a sandwich structure on skin care for intertrigo. Repeated long-term wetting, heating, and friction can cause the destruction of the skin epidermal layer structure and form a bacterial infection wound. Therefore, a bacterial infection wound model in mice is further established to study the healing-promoting effect of the time-sequential bidirectional liquid-guiding and cooling integrated material with a sandwich structure on the bacterial infection wound of intertrigo. This idea is expected to provide a new solution for the wet and heat management of intertrigo. The time-sequential bidirectional liquid-guiding and cooling integrated material described in the application is also expected to be used in the fields of fever-reducing patches, emergency cooling for sports injuries, quick-drying cooling fabrics, postoperative swelling and pain relief, and the like.

[0021] The positive effects of the application:

[0022] (1) The time-sequential bidirectional liquid-guiding and cooling integrated material with a sandwich structure is successfully prepared by electrohydrodynamic atomization technology. When water drops from any pumping layer, the liquid drops are spontaneously and vertically guided into the intermediate cooling layer and do not backseep into the pumping layer. When water drops from the intermediate cooling layer, the liquid drops only spread horizontally in this layer. When water drops from the upper and lower pumping layers at the same time, the liquid drops are all vertically guided into the intermediate cooling layer, and do not backseep into the pumping layer as time goes on.

[0023] (2) By establishing an in vitro model to simulate the sweating process of the human body in a hot stimulation environment, the influence of the composite amount of the cooling substance in the intermediate hydrophilic cooling layer on the cooling performance is explored. It is found that the lower the lowest cooling temperature is, the higher the composite amount is, and the lowest cooling temperature reaches 6.5℃.

[0024] (3) The material described in the application not only can guide away the biological fluids from the interdigital space, elbow fossa, and abdominal creases, but also can show obvious cooling effect, which can reduce the skin temperature by 6.5℃. The experimental results show that the material can realize the vertical guidance of wound exudate, can effectively reduce the immersion condition around the wound, and can effectively relieve the excessive edema symptoms of the wound tissue. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 Preparation process and morphology characterization of the material of Example 1, wherein (a) preparation process; (b) photo; SEM images of (c) upper wicking layer, (d) middle temperature-reducing layer and (e) lower wicking layer of the material; (f) cross-sectional morphology of sandwich structure; (g) upper and middle layers, (h) middle hydrophilic layer and (i) middle and lower layers;

[0026] Figure 2 Composition and structure characterization of the material of Example 1, wherein (a-b) Mapping photos of upper and lower hydrophobic antibacterial wicking layers; (c) diameter statistics of polyacrylonitrile nanofibers; (d) porosity statistics; (e) FT-IR spectrum; (f) XRD diffraction patterns of each component; a) Ag NPs, b) PCL, c) Ag NPs+PCL, d) Xylitol, e) PAN, f) Xylitol+PAN, g) Ag NPs+PCL, h) sandwich structure material in figures (e) and (f);

[0027] Figure 3 Binding strength cycle test of the material of Example 1;

[0028] Figure 4 Liquid transport performance of the material of Example 1, wherein (a) process of water droplet dropping from the upper hydrophobic wicking layer into the middle temperature-reducing layer, accompanied by change of water contact angle; (b) process of water droplet dropping from the lower hydrophobic wicking layer into the middle temperature-reducing layer, accompanied by change of water contact angle;

[0029] Figure 5 Contact angle vs. time;

[0030] Figure 6 Fluorescence photos of unidirectional and bidirectional transport processes of liquid, wherein (a) liquid transport path in the double-layer material (upper layer+middle layer): from the upper wicking layer to the middle temperature-reducing layer, from the middle temperature-reducing layer to the upper wicking layer; (b) liquid transport path in the double-layer material (lower layer+middle layer): from the middle temperature-reducing layer to the lower wicking layer, from the lower wicking layer to the middle temperature-reducing layer. (c) liquid transport path in the three-layer material (upper layer+middle layer+lower layer): from the upper and lower wicking layers to the middle temperature-reducing layer at the same time;

[0031] Figure 7 Mechanism of unidirectional and bidirectional transport of liquid, wherein (a) liquid droplet dropping from the hydrophobic antibacterial wicking layer to the middle hydrophilic temperature-reducing layer, (b) force diagram of liquid droplet dropping from the middle hydrophilic temperature-reducing layer to the wicking layer;

[0032] Figure 8 Schematic diagram of temperature-reducing experiment;

[0033] Figure 9 For cooling effect, (a1) 0% xylitol, (a2) 5% xylitol, (a3) 10% xylitol and (a4) 20% xylitol on the infrared thermal imaging pictures of “sweating skin”; (b) data statistics;

[0034] Figure 10 For cooling mechanism, (a) SEM photos before and after dripping water; (b) schematic diagram of cooling mechanism;

[0035] Figure 11 For the time-dependent unidirectional fluid conduction and cooling function of the rat skin surface;

[0036] Figure 12 For the time-dependent unidirectional fluid conduction and cooling function of the rat skin wound surface;

[0037] Figure 13 For (a) BPRC materials were placed in the finger gap, elbow and abdominal fold for skin wrinkle moisture and heat management. (b, c) Changes in relative humidity of skin wrinkles before and after treatment with the material; (d, e) Changes in temperature of skin wrinkles before and after treatment with the material;

[0038] Figure 14 For in vitro cytotoxicity test;

[0039] Figure 15 For cell viability test after treatment with different fiber membranes;

[0040] Figure 16 For in vitro antibacterial activity of S. aureus, E. coli and C. albicans, (a) using the inhibition zone method and (b) plate counting method for evaluation and statistical analysis; (c-e) corresponding inhibition zone diameter; (f-h) corresponding colony count;

[0041] Figure 17 For wound healing effect and in vivo antibacterial performance, (a) representative images of wound healing and (b) simulated wound closure trajectory at different time points. (c) Wound healing rate of different treatment groups at different periods. (d, e) In vivo antibacterial activity of BPRC material at 7 days and 14 days;

[0042] Figure 18 For H&E staining of regenerated tissue sections after treatment, (a) H&E staining images of 14-day tissue healing in each group; (b) Epidermal layer thickness at different periods after treatment in each group

[0043] Figure 19 For Masson staining of regenerated tissue sections after treatment, (a) Masson staining images of tissue healing at different periods in each group; (b) Collagen deposition rate in each group at 14 days after treatment

[0044] Figure 20 A schematic diagram of a spinning collection device with an array hole structure as described in Example 8;

[0045] Figure 21 A comparison chart of the liquid guiding performance of sandwich structure time-sequential bidirectional liquid guiding-cooling integrated materials prepared by the methods described in Example 1 and Example 8. DETAILED DESCRIPTION

[0046] Example 1

[0047] A preparation method of a sandwich structure time-sequential bidirectional liquid guiding-cooling integrated material, comprising the following steps:

[0048] (1) Preparation of an intermediate hydrophilic cooling layer

[0049] 0.07 g of xylitol and 0.7 g of polyacrylonitrile were added to 5 mL of N,N-dimethylformamide (DMF) solvent, continuously stirred at room temperature to achieve a uniform state to obtain a spinning solution; the spinning solution was transferred to a 10 mL syringe and placed on an electrospinning device, an aluminum foil wrapped drum was used as a collection device, the spinning voltage was 10 kv, the flow rate was 0.9 mL / h, the spinning distance was 6 cm, and the rotation speed of the collector was set to 300 r / min to obtain a nanofiber membrane, denoted as 10% xylitol; the nanofiber membrane was placed in a 50% glutaraldehyde vapor for crosslinking for 4 h, and after vacuum drying, an intermediate hydrophilic cooling layer was obtained.

[0050] (2) Preparation of an upper hydrophobic antibacterial drainage layer and a lower hydrophobic antibacterial drainage layer with unidirectional liquid guiding

[0051] 0.024 g of silver nanoparticles (AgNPs) was added to 5 mL of N-methylpyrrolidone (NMP) solvent and ultrasonically dispersed for 1 h, then 1 g of poly-ε-caprolactone was added under continuous stirring at room temperature to obtain a hydrophobic antibacterial solution; the hydrophobic antibacterial solution was transferred to a 10 mL syringe and sprayed on the upper surface of the intermediate hydrophilic cooling layer by an electrostatic spraying device to obtain an upper hydrophobic antibacterial drainage layer with unidirectional liquid guiding; the spraying step was repeated, and the hydrophobic antibacterial solution was sprayed on the lower surface of the intermediate hydrophilic cooling layer by the electrostatic spraying device to obtain a lower hydrophobic antibacterial drainage layer with unidirectional liquid guiding. The parameters of the electrostatic spraying device were as follows: voltage 12 kV, spraying distance fixed at 4 cm, and spraying flow rate 1.2 mL / h.

[0052] Comparative Example 1

[0053] The same method and parameters as in Example 1, except that no xylitol was added in step (1), and the obtained nanofiber membrane was denoted as 0% xylitol.

[0054] Comparative Example 2

[0055] The same method and parameters as in Example 1, except that the amount of xylitol added in step (1) was 0.035 g, and the resulting nanofiber membrane was labeled as 5% xylitol.

[0056] Comparative Example 3

[0057] The same method and parameters as in Example 1, except that the amount of xylitol added in step (1) was 0.14 g, and the resulting nanofiber membrane was labeled as 20% xylitol.

[0058] Example 2

[0059] A method for preparing a time-sequential bidirectional liquid-guiding and cooling integrated material with a sandwich structure, comprising the following steps:

[0060] (1) Preparation of an intermediate hydrophilic cooling layer

[0061] 0.05 g of sorbitol and 0.1 g of chitosan were added to 4 mL of a mixed solvent of hexafluoroisopropanol and 1 mL of glacial acetic acid, and continuously stirred at room temperature to achieve a uniform state to obtain a spinning solution; the spinning solution was transferred to a 10 mL syringe and placed on an electrospinning device, with an aluminum foil wrapped drum as a collection device, a spinning voltage of 20 kv, a flow rate of 2 mL / h, a spinning distance of 5 cm, and a collector speed set to 300 r / min, to obtain a nanofiber membrane; the nanofiber membrane was placed in a 1% glutaraldehyde vapor for crosslinking for 0.5 h, and then vacuum dried to obtain an intermediate hydrophilic cooling layer;

[0062] (2) Preparation of an upper hydrophobic antibacterial drainage layer and a lower hydrophobic antibacterial drainage layer for unidirectional liquid guidance

[0063] 0.005 g of copper nanoparticles (CuNPs) was added to 3 mL of a mixed solvent of tetrahydrofuran (THF) and 2 mL of N,N-dimethylacetamide, and ultrasonically dispersed for 0.5 h, followed by continuously stirring at room temperature, and 0.5 g of polyurethane was added to obtain a hydrophobic antibacterial solution; the hydrophobic antibacterial solution was transferred to a 10 mL syringe and sprayed on the upper surface of the intermediate hydrophilic cooling layer through an electrostatic spraying device to obtain an upper hydrophobic antibacterial drainage layer for unidirectional liquid guidance; the spraying step was repeated, and the hydrophobic antibacterial solution was sprayed on the lower surface of the intermediate hydrophilic cooling layer through the electrostatic spraying device to obtain a lower hydrophobic antibacterial drainage layer for unidirectional liquid guidance. The parameters of the electrostatic spraying device were: voltage 15 kV, spraying distance fixed at 3 cm, and spraying flow rate 2 mL / h.

[0064] Example 3

[0065] A preparation method of a time-sequential bidirectional liquid-guiding and cooling integrated material with a sandwich structure, comprising the following steps:

[0066] (1) Preparation of the intermediate hydrophilic cooling layer

[0067] 0.05 g of mannitol, 0.05 g of maltitol, 0.3 g of gelatin, and 0.2 g of collagen were added into 5 mL of N,N-dimethylacetamide solvent, continuously stirred at room temperature, and uniformly stirred to obtain a spinning solution; the spinning solution was transferred into a 10 mL syringe and placed on an electrospinning device for electrospinning, an aluminum foil wrapped drum was used as a collection device, the spinning voltage was 5 kv, the flow rate was 0.5 mL / h, the spinning distance was 10 cm, and the rotation speed of the collector was set to 300 r / min to obtain a nanofiber membrane; the nanofiber membrane was placed in 50% glutaraldehyde vapor for crosslinking for 3 h, and vacuum drying was performed to obtain the intermediate hydrophilic cooling layer;

[0068] (2) Preparation of the upper hydrophobic antibacterial drainage layer and the lower hydrophobic antibacterial drainage layer with unidirectional liquid guidance

[0069] 0.03 g of curcumin was added into 3 mL of a mixed solution of tetrahydrofuran and 2 mL of N,N-dimethylformamide, ultrasonic dispersion was performed for 2 h, then 5 g of polylactic acid was added under continuous stirring at room temperature to obtain a hydrophobic antibacterial solution; the hydrophobic antibacterial solution was transferred into a 10 mL syringe and sprayed on the upper surface of the intermediate hydrophilic cooling layer through an electrostatic spraying device to obtain the upper hydrophobic antibacterial drainage layer with unidirectional liquid guidance; the spraying step was repeated, the hydrophobic antibacterial solution was sprayed on the lower surface of the intermediate hydrophilic cooling layer through the electrostatic spraying device to obtain the lower hydrophobic antibacterial drainage layer with unidirectional liquid guidance. The parameters of the electrostatic spraying device were as follows: the voltage was 8 kV, the spraying distance was fixed at 5 cm, and the spraying flow rate was 1 mL / h.

[0070] Example 4

[0071] A preparation method of a time-sequential bidirectional liquid-guiding and cooling integrated material with a sandwich structure, comprising the following steps:

[0072] (1) Preparation of the intermediate hydrophilic cooling layer

[0073] 0.1 g of ammonium nitrate, 0.05 g of ammonium chloride, and 0.95 g of polyvinyl alcohol were added into 5 mL of water, continuously stirred at room temperature, and uniformly stirred to obtain a spinning solution; the spinning solution was transferred into a 10 mL syringe and placed on an electrospinning device for electrospinning, an aluminum foil wrapped drum was used as a collection device, the spinning voltage was 15 kv, the flow rate was 2 mL / h, the spinning distance was 20 cm, and the rotation speed of the collector was set to 300 r / min to obtain a nanofiber membrane; the nanofiber membrane was placed in 50% glutaraldehyde vapor for crosslinking for 5 h, and vacuum drying was performed to obtain the intermediate hydrophilic cooling layer.

[0074] Preparation of the upper hydrophobic antibacterial drainage layer of unidirectional liquid conduction and the lower hydrophobic antibacterial drainage layer of unidirectional liquid conduction

[0075] 0.01 g of chitosan was added to 5 mL of tetrahydrofuran solvent and ultrasonic dispersed for 2 h, then 1.5 g of polyglycolide, 1 g of polyvinylidene fluoride were added at room temperature under continuous stirring to obtain a hydrophobic antibacterial liquid; the hydrophobic antibacterial liquid was transferred to a 10 mL syringe and sprayed on the upper surface of the middle hydrophilic cooling layer by an electrostatic spraying device to obtain the upper hydrophobic antibacterial drainage layer of unidirectional liquid conduction; the spraying step was repeated, and the hydrophobic antibacterial liquid was sprayed on the lower surface of the middle hydrophilic cooling layer by the electrostatic spraying device to obtain the lower hydrophobic antibacterial drainage layer of unidirectional liquid conduction. The parameters of the electrostatic spraying device are: voltage of 10 kV, spraying distance fixed at 3 cm, and spraying flow rate of 2 mL / h.

[0076] Example 5

[0077] A preparation method of a time-sequential bidirectional liquid conduction-cooling integrated material with a sandwich structure, comprising the following steps:

[0078] (1) Preparation of the middle hydrophilic cooling layer

[0079] 0.05 g of lactitol, 0.04 g of erythritol, and 0.7 g of cellulose acetate were added to 5 mL of tetrahydrofuran solvent and stirred continuously at room temperature until a uniform state was obtained to obtain a spinning solution; the spinning solution was transferred to a 10 mL syringe and placed on an electrospinning device for electrospinning, with an aluminum foil wrapped drum as a collection device, a spinning voltage of 20 kv, a flow rate of 1 mL / h, a spinning distance of 10 cm, and a collector speed of 300 r / min to obtain a nanofiber membrane; the nanofiber membrane was placed in a 30% glutaraldehyde vapor for crosslinking for 3 h, and then vacuum dried to obtain the middle hydrophilic cooling layer.

[0080] (2) Preparation of the upper hydrophobic antibacterial drainage layer of unidirectional liquid conduction and the lower hydrophobic antibacterial drainage layer of unidirectional liquid conduction

[0081] Add 0.024 g of ε-polylysine hydrochloride to a mixed solvent of 4 mL of N,N-dimethylacetamide and 1 mL of hexafluoroisopropanol, ultrasonic dispersion for 1 h, then add 1.2 g of polysulfone, 0.5 g of polystyrene at room temperature under continuous stirring to obtain a hydrophobic antibacterial liquid; transfer the hydrophobic antibacterial liquid to a 10 mL syringe, spray it on the upper surface of the middle hydrophilic cooling layer through an electrostatic spraying device to obtain an upper hydrophobic antibacterial drainage layer with unidirectional liquid conduction; repeat the spraying step, and spray the hydrophobic antibacterial liquid on the lower surface of the middle hydrophilic cooling layer through the electrostatic spraying device to obtain a lower hydrophobic antibacterial drainage layer with unidirectional liquid conduction. The parameters of the electrostatic spraying device are: voltage 15 kV, spraying distance fixed at 4 cm, and spraying flow rate 1.2 mL / h.

[0082] Example 6

[0083] A preparation method of a time-sequential bidirectional liquid conduction-cooling integrated material with a sandwich structure, comprising the following steps:

[0084] (1) Preparation of a middle hydrophilic cooling layer

[0085] Add 0.03 g of potassium nitrate, 0.1 g of sodium nitrate, and 0.9 g of polyvinylpyrrolidone to 5 mL of ethanol solvent, continuously stir at room temperature to obtain a spinning solution; transfer the spinning solution to a 10 mL syringe and place it on an electrospinning device for electrospinning, use an aluminum foil wrapped drum as a collection device, the spinning voltage is 8 kv, the flow rate is 0.9 mL / h, the spinning distance is 15 cm, and the rotation speed of the collector is set to 300 r / min to obtain a nanofiber membrane; place the nanofiber membrane in a 50% glutaraldehyde vapor for crosslinking for 4 h, and then vacuum dry to obtain a middle hydrophilic cooling layer.

[0086] (2) Preparation of an upper hydrophobic antibacterial drainage layer with unidirectional liquid conduction and a lower hydrophobic antibacterial drainage layer with unidirectional liquid conduction

[0087] Add 0.03 g of silver nanoparticles (AgNPs) to a mixed solvent of 4 mL of dichloromethane and 1 mL of trichloromethane, ultrasonic dispersion for 1 h, then add 2 g of polymethyl methacrylate at room temperature under continuous stirring to obtain a hydrophobic antibacterial liquid; transfer the hydrophobic antibacterial liquid to a 10 mL syringe, spray it on the upper surface of the middle hydrophilic cooling layer through an electrostatic spraying device to obtain an upper hydrophobic antibacterial drainage layer with unidirectional liquid conduction; repeat the spraying step, and spray the hydrophobic antibacterial liquid on the lower surface of the middle hydrophilic cooling layer through the electrostatic spraying device to obtain a lower hydrophobic antibacterial drainage layer with unidirectional liquid conduction. The parameters of the electrostatic spraying device are: voltage 12 kV, spraying distance fixed at 4 cm, and spraying flow rate 1.2 mL / h.

[0088] Example 7

[0089] The preparation method of this embodiment is the same as that of Example 1, except that the poly-ε-caprolactone in step (2) is replaced by polyvinyl butyral, and the solvent N-methyl pyrrolidone is replaced by ethanol.

[0090] Example 8

[0091] The preparation method of the sandwich structure time sequence bidirectional liquid guiding and cooling integrated material described in this embodiment is the same as that of step (1) of Example 1, except that step (2) is as follows:

[0092] 0.024 g of silver nanoparticles (AgNPs) and 1 g of poly-ε-caprolactone were dispersed in 5 mL of N-methyl pyrrolidone (NMP) solvent, and stirred at room temperature for 12 h until uniformly dispersed to obtain a hydrophobic antibacterial solution; the above solution was transferred to a glass syringe, and a spinning collection device with an array of circular holes (see Figure 20 ) was used to electrospun to obtain an octopus sucker-like nanofiber membrane; the hole diameter-hole spacing parameters of the metal plate were 0.7-1.0 mm; the electrospinning parameters were as follows: the voltage was 7.4 kV, the flow rate was 0.5 mL / h, the spinning distance was 10 cm, and the deposition time was 12 min. The middle hydrophilic cooling layer was placed between the two octopus sucker-like nanofiber membranes to form a sandwich structure time sequence bidirectional liquid guiding and cooling integrated material.

[0093] Example 9

[0094] The preparation method of this embodiment is the same as that of steps (1) and (2) of Example 8, except that 0.024 g of silver nanoparticles (AgNPs) is replaced by 0.005 g of copper nanoparticles (CuNPs); 5 mL of N-methyl pyrrolidone (NMP) solvent is replaced by a mixed solvent of 3 mL of tetrahydrofuran (THF) and 2 mL of N,N-dimethylacetamide; 1 g of poly-ε-caprolactone is replaced by 0.5 g of polyurethane; and the electrospinning parameters are as follows: the voltage is 5 kV, the flow rate is 0.5 mL / h, the spinning distance is 5 cm, and the deposition time is 15 min.

[0095] Example 10

[0096] The preparation method of this embodiment is the same as that of steps (1) and (2) of Example 8, except that 0.024 g of silver nanoparticles (AgNPs) is replaced by 0.03 g of curcumin; 5 mL of N-methyl pyrrolidone (NMP) solvent is replaced by a mixed solution of 3 mL of tetrahydrofuran and 2 mL of N,N-dimethylformamide; and 1 g of poly-ε-caprolactone is replaced by 5 g of polylactic acid; and the electrospinning parameters are as follows: the voltage is 20 kV, the flow rate is 2.0 mL / h, the spinning distance is 20 cm, and the deposition time is 12 min.

[0097] Example 11

[0098] The preparation method of this embodiment is the same as steps (1) and (2) of Example 8, except that: 0.024g of silver nanoparticles (AgNPs) is replaced with 0.01g of chitosan; 5mL of N-methylpyrrolidone (NMP) solvent is replaced with 5mL of tetrahydrofuran solvent; 1g of poly(ε-caprolactone) is replaced with 1.5g of poly(ethylene lactide) and 1g of polyvinylidene fluoride; the electrospinning parameters are as follows: voltage is 15kV, flow rate is 1.0mL / h, spinning distance is 15cm, and deposition time is 12min.

[0099] Example 12

[0100] The preparation method of this embodiment is the same as steps (1) and (2) of Example 8, except that: 0.024 g of silver nanoparticles (AgNPs) is replaced with 0.024 g of ε-polylysine hydrochloride; 5 mL of N-methylpyrrolidone (NMP) solvent is replaced with a mixed solvent of 4 mL of N,N-dimethylacetamide and 1 mL of hexafluoroisopropanol; 1 g of polyε-caprolactone is replaced with 1.2 g of polysulfone and 0.5 g of polystyrene; the electrospinning parameters are as follows: voltage is 12 kV, flow rate is 1.5 mL / h, spinning distance is 15 cm, and deposition time is 12 min.

[0101] Example 13

[0102] The preparation method of this embodiment is the same as that of Example 8, except that: in step (2), poly(ε-caprolactone) is replaced with polyvinyl butyral, and the solvent N-methylpyrrolidone is replaced with ethanol.

[0103] Example 14

[0104] The preparation method of this embodiment is the same as that of Example 8, except that: in step (2), poly(ε-caprolactone) is replaced with 2g of polymethyl methacrylate, and the solvent N-methylpyrrolidone is replaced with a mixed solvent of 4mL dichloromethane and 1mL trichloromethane.

[0105] Characterization and performance testing:

[0106] (1) Structural and compositional characterization

[0107] Taking Example 1 as an example, this invention utilizes electrohydrodynamic atomization technology to obtain a time-sequential bidirectional liquid guiding and cooling integrated material with a sandwich structure. Figure 1 a). For example Figure 1 As shown in b, the results indicate that this material can be fabricated over large areas. Figure 1As shown in FIGS. 1c and 1e, the surfaces of the upper and lower hydrophobic antibacterial drainage layers both present porous structures, which are caused by the low volatility of the solvent of the spinning solution. In the early stage, there is almost no solvent evaporation on the intermediate hydrophilic cooling layer, but as time goes on, the solvent gradually evaporates and causes phase separation, forming a porous surface. As shown in FIG. 1d, the hydrophilic cooling layer presents a smooth nanofiber morphology, which is composed of fibers with diameters ranging from 420 to 620 nm. Figure 1 Figure 2 c) As shown in FIG. 1c, the material is composed of the upper hydrophobic antibacterial drainage layer with unidirectional liquid guidance, the intermediate hydrophilic cooling layer, and the lower hydrophobic antibacterial drainage layer with unidirectional liquid guidance. Figure 1 f-1i. In addition, as shown in FIGS. 1f-1i, the material is composed of the upper hydrophobic antibacterial drainage layer with unidirectional liquid guidance, the intermediate hydrophilic cooling layer, and the lower hydrophobic antibacterial drainage layer with unidirectional liquid guidance. Figure 2 a-b. As shown in FIGS. 1a-b, AgNPs (red) are uniformly distributed on the surfaces of the upper and lower hydrophobic antibacterial drainage layers. Figure 2 e FT-IR spectrum. The characteristic peak at 3348 cm-1 is the stretching vibration peak of -OH group, indicating the presence of xylitol in the material. The characteristic peak at 2240 cm-1 is the stretching vibration peak of -C=N group, indicating the presence of polyacrylonitrile in the material. The characteristic peak at 1729 cm-1 is the stretching vibration peak of C=O, which is closely related to the molecular structure of poly-ε-caprolactone. The characteristic peak at 1300-1500 cm-1 is Ag-O bond, which indicates the presence of AgNPs in the material. -1 -1 -1 -1 Figure 2 f. XRD also confirms the composition of its structure. The peak at 16.72° indicates the crystal structure characteristics of polyacrylonitrile; the crystallization peak of poly-ε-caprolactone appears at 21.53°; when the crystallization peak is at 38.18°, it is one of the most significant characteristic peaks of AgNPs in XRD, corresponding to the (111) crystal plane in the face-centered cubic crystal structure of silver. The combination of XRD and FT-IR characterization results proves the successful preparation of the time-sequential bidirectional liquid-guiding and cooling integrated material with sandwich structure (denoted as BPRC). In the pathological state of intertrigo, the skin is long-term exposed to a frequently rubbing environment, which puts a rigorous wear resistance requirement on the practical material applied to this part. The structure of the skin fold area of the human body is highly complex and diverse in form, and is always in a dynamic change process in daily activities. The present application simulates the actual rubbing scene of the skin fold. As shown in FIG. 1g, the BPRC was placed in the hand to perform folding and rubbing operation, and after 100 repeated rubbings, the three-layer structure of the BPRC was still tightly combined without delamination, and the surface integrity was good, showing excellent wear resistance. Figure 3

[0108] (2) Directional liquid guiding performance research

[0109] ​​​​​​Taking the material prepared in Example 1 as an example, in order to further explore the bidirectional transport path of droplets on the material, 10 μL droplets were taken and dropped onto the upper hydrophobic antibacterial drainage layer ( Figure 4 a) and the lower hydrophobic antibacterial drainage layer ( Figure 4 (b) Droplets successfully passed through the upper hydrophobic antibacterial drainage layer in 1.25 s, while the lower hydrophobic antibacterial drainage layer was dry. Due to gravity, droplets successfully passed through the lower hydrophobic antibacterial drainage layer in 1.53 s, while the upper hydrophobic antibacterial drainage layer was dry. This phenomenon indicates that both the upper and lower hydrophobic antibacterial drainage layers of the material have the ability to rapidly conduct liquids. Furthermore, the droplet transport path of the upper and lower hydrophobic antibacterial drainage layers was studied using a contact angle measuring system. After 0.5 s, all droplets were completely guided away, and the contact angle of the droplets gradually decreased over time. Figure 5 To observe the transport behavior of the liquid in the BPRC, the upper and lower hydrophobic antibacterial drainage layers were stained with 1% curcumin (green) to enhance contrast, and the droplets were stained with Rhodamine B (red). The liquid transport process was recorded using a static contact angle meter under ultraviolet light irradiation. Figure 6 In layer a, red droplets can be rapidly guided from the upper drainage layer to the intermediate cooling layer within 1.19 seconds. Over time, the upper hydrophobic antibacterial drainage layer remains green. Red droplets can spontaneously transport to the intermediate hydrophilic cooling layer in 0.12 seconds and then diffuse laterally within that layer. Figure 6 In layer b, when the red droplet is transported from the intermediate hydrophilic cooling layer to the lower drainage layer, it diffuses rapidly and spontaneously within 0.21 seconds without penetrating the lower hydrophobic antibacterial drainage layer. When the droplet is transported from the lower hydrophobic antibacterial drainage layer to the intermediate hydrophilic cooling layer, it takes 1.45 seconds for the droplet to be completely guided away due to gravity. Figure 6 As shown in section c, when droplets are simultaneously added to the upper and lower hydrophobic antibacterial drainage layers of the sample, the droplets are successfully guided to the middle hydrophilic cooling layer within 0.53 s and 1.21 s, respectively. Further analysis of the droplet transport mechanism in the sandwich-structured BPRC is needed. Figure 7 Studies have shown that for hydrophobic porous surfaces, the wetting behavior of liquids on these surfaces conforms to the Wenzel-Kathy model. When a droplet contacts the hydrophobic porous layer, the liquid is transported along the porous channels under hydrostatic pressure (Fg). Because the hydrophobic layer is very thin, the liquid can easily penetrate the thin hydrophobic layer completely and contact the hydrophilic layer, and this occurs when Fg is greater than the hydrophobic force (Fr). Furthermore, under the action of capillary force (Fw), the liquid rapidly diffuses in the hydrophilic layer, thus achieving liquid transport from the hydrophobic layer to the hydrophilic layer. In this study, due to the sandwich structure of the material, the wettability gradient between the upper hydrophobic layer and the middle hydrophilic layer drives the unidirectional transport of the liquid, while the wettability gradient between the lower hydrophobic layer and the middle hydrophilic layer also drives the unidirectional transport of the liquid, giving this material unique bidirectional liquid-transfer properties.

[0110] (3) Cooling performance

[0111] To further investigate the effect of xylitol content on cooling performance, 0% xylitol, 5% xylitol, 10% xylitol, and 20% xylitol were selected, and the same weight of fiber film was taken for subsequent experiments. During the experiment, the physiological situation of human sweat glands sweating outward was simulated, and the above four groups of intermediate hydrophilic cooling layers were placed between two layers of continuously "sweating skin" (water-filled gel sponge). Because the gel sponge has a rich pore structure inside, it can realize the discharge of water, so as to simulate the secretion process of human sweat. According to relevant reports, the sweat secretion rate of human under thermal stimulation can reach 0.42 μL / min / cm 2 The commercial gel sponge used in this experiment has a specification of 2x2 cm 2 . After comprehensive consideration, the outflow rate was set to 1.7 μL / min. Subsequently, the entire experimental composition was placed on a hot stage with a constant temperature of 40°C to simulate the state of the human body under high temperature thermal stimulation. During the experiment, according to the fixed time node, the infrared thermal imager was used to measure the temperature of the upper and lower layers of the sponge ( Figure 8 ).

[0112] The following results were obtained from the experiment: as shown in Figure 9 a, the 0% xylitol group had no cooling effect ( Figure 9 a1. The 5% xylitol group decreased by 0.6°C at 5 minutes ( Figure 9 a2), and the cooling amplitude was relatively small. The temperature of the 10% xylitol group ( Figure 9 a3) and the 20% xylitol group ( Figure 9 a4) decreased by 5.5°C and 6.5°C respectively ( Figure 9 b) as shown in Figure 10As shown in FIG. 8, after cutting 0% xylitol, 5% xylitol, 10% xylitol, 20% xylitol into 5x5 cm squares, respectively, distilled water was dropped on them and they were allowed to dry naturally, followed by SEM observation. For 0% xylitol, no solid material was precipitated between the fibers regardless of the amount of water added, and it always appeared as smooth fibers. When xylitol was added to the polyacrylonitrile solution for electrospinning, the solid material precipitated between the fibers became more obvious as the amount of xylitol complex increased. This material is xylitol that dissolves and precipitates upon contact with water. In addition, as the amount of distilled water added increased, the amount of solid material between the fibers in each group also increased, and the dissolved xylitol could recrystallize, allowing for repeated cooling. In summary, BPRC achieves rapid cooling through its unique structure and composition design. The present application uniformly loads xylitol molecules into hydrophilic nanofibers. The reason for choosing hydrophilic nanofibers as the carrier material for xylitol is that the specific surface area of nanofibers is large and the porosity is high, allowing xylitol molecules to interact with water molecules for a long time. In simple terms, xylitol on the surface of the fibers can quickly interact directly with water, helping to cool rapidly, while xylitol embedded inside the fibers can slowly interact with water, making the cooling process more sustainable. Previous SEM results confirm that xylitol can dissolve and be released from nanofibers. This indicates that when xylitol-loaded nanofibers come into contact with water, the xylitol molecules on the surface of the nanofibers will quickly dissolve in the water. The process of xylitol dissolution is actually the process of breaking the intramolecular hydrogen bonds of xylitol, and new intermolecular hydrogen bonds are formed between the xylitol molecules and the water molecules Figure 10b) The breaking of intramolecular hydrogen bonds in xylitol requires energy absorption from the surrounding environment, while the formation of intermolecular hydrogen bonds is a process of energy release. During the dissolution of xylitol, the energy absorbed by the breaking of old hydrogen bonds is greater than the energy released by the formation of new hydrogen bonds. Therefore, the overall process of xylitol dissolution is an endothermic process. As the complex of xylitol increases, the content of xylitol molecules deposited on the surface of nanofibers increases accordingly, which in turn leads to a greater cooling amplitude. Overall, thanks to the endothermic dissolution properties of xylitol molecules and the structural properties and hydrophilicity of the nanofiber carrier, this xylitol-loaded nanofiber film exhibits a rapid, sustained and controllable cooling effect. It is worth noting that the dissolved xylitol can stably exist in the middle hydrophilic layer without spreading to the skin on both sides. This is because, as previously confirmed, the hydrophobic layers on both sides of the sandwich structure material have directional liquid conductivity. This allows liquid to be transported from the hydrophobic layers on both sides to the middle hydrophilic layer, and the liquid entering the hydrophilic layer cannot penetrate the hydrophobic layer in the opposite direction. Therefore, even if some xylitol has dissolved out of the middle hydrophilic fiber film layer, it does not flow out with the liquid penetrating the hydrophobic layer on both sides, but only stably exists in the middle hydrophilic layer. Interestingly, when the middle hydrophilic layer is completely dry, xylitol can again absorb heat when in contact with water, thus achieving repeated cooling.

[0113] (4) Time-dependent bidirectional liquid drainage and cooling performance of animal / human experiments

[0114] Since the upper and lower layers of the BPRC material exhibit bidirectional liquid drainage characteristics, and the middle hydrophilic layer containing xylitol exhibits a unique water-triggered cooling effect, we subsequently investigated the time-dependent bidirectional liquid drainage and rapid cooling effect. We first verified the effectiveness of wet heat management on the surface of normal rat skin ( Figure 11 ) and rat wounds ( Figure 12 ) respectively. The results showed that, compared with the large blue marks left by the blank control group and commercial materials, the BPRC material left a small blue area on the skin surface, with a temperature drop of 6°C from 33.4°C to 27.4°C. And the BPRC group completely absorbed the blue liquid added to the wound, leaving no blue stains around it. The temperature of this group dropped by 5.4°C from 37.0°C to 31.6°C. These results indicate that the material can effectively drain water and cool rapidly. We also tested the effectiveness on the skin folds of volunteers, including the gap between the fingers, the elbow and the abdomen ( Figure 13a) Prior to this, we first tested the material's biosafety and found that no red spots or extensive edema were noted on the animal's skin. The red spots and edema reactions on the test site skin were evaluated as grade 0. The aforementioned results show that this sandwich structure vertical liquid drainage material has excellent safety and does not cause allergic reactions to the user's skin. As for the gap between the fingers, after the material is processed, the relative humidity of the fingers decreases from 20% to 15.4% Figure 13 b) In addition, the local temperature decreased from 33.9°C to 28.3°C in 5 minutes Figure 13 c) Similar results were also found in the treatment of elbow and abdominal skin folds Figure 13 d and e) Due to the moisture and heat management of the skin folds, the volunteers felt dry, cool and comfortable, thus promoting skin health.

[0115] (5) In vitro cytotoxicity and antibacterial activity studies

[0116] Process of in vitro cytotoxicity experiment: CCK-8 method was used to study the biocompatibility of the sample using mouse fibroblasts (L929) as the object. The blank control group (Blank control) did not use any material, one group placed the commercial hydrophilic material (Commercial), and the experimental group was the material of Example 1 (BPRC). Mouse fibroblasts (L929) were inoculated into 96-well plates at a density of 1x10 6 cells / L, and then the 96-well plates were placed in a cell incubator at 37°C for 24h. Subsequently, the CCK-8 method was used to detect the proliferation of mouse fibroblasts (L929), and the samples were gently washed with PBS, then 100μL of 10% CCK-8 reagent was added to each well. After incubation at 37°C, 5% CO2, and protected from light for 2h, the absorbance of each group was detected at 450nm wavelength using a microplate reader. The cells cultured for 24h were stained using a live / dead cell staining kit, and the cell state of all groups was observed by fluorescence inverted microscope. As shown in Figure 14 , after 24h of culture, it was found that there were very few dead cells (red) in all groups, and none of the groups showed cytotoxicity to L929 cells (green). This is consistent with the detection results of the CCK-8 method Figure 15 ).

[0117] Antibacterial performance in vitro: The antibacterial performance in vitro was explored by the spread plate method using S. aureus, E. coli and C. albicans. The blank group was not treated, the control group was commercial, and the experimental group was sandwich structure antibacterial nanofiber membrane (BPRC). S. aureus (about 1×10 9 CFU / mL), E. coli (about 1×10 11 CFU / mL) and C. albicans (about 1×10 11 CFU / mL) were pre-cultured overnight in TSB medium, LB medium and SDA medium, respectively. 1 mL of bacterial solution was diluted 1000 times and then cultured with different treated sample culture solutions at 37°C, 170 rpm for 24 h. The bacteria solution after co-culture was gradiently diluted, and 100 μL was taken and cultured on blood plates for 18 h. The colonies on the blood plates were photographed and counted.

[0118] The antibacterial performance in vitro was explored by the spread plate method using S. aureus, E. coli and C. albicans. The blank group was not treated, the control group was commercial, and the experimental group was sandwich structure antibacterial nanofiber membrane (BPRC). S. aureus (about 1×10 9 CFU / mL), E. coli (about 1×10 11 CFU / mL) and C. albicans (about 1×10 11 CFU / mL) were pre-cultured overnight in TSB medium, LB medium and SDA medium, respectively. 1 mL of bacterial solution was diluted 1000 times and then cultured with different treated sample culture solutions at 37°C, 170 rpm for 24 h. The bacteria solution after co-culture was gradiently diluted, and 100 μL was taken and cultured on blood plates for 18 h. The colonies on the blood plates were photographed and counted. Figure 16 a) and spread plate method ( Figure 16 b) were used to study the antibacterial performance of Blank, Commercial and BPRC against S. aureus, E. coli and C. albicans. As shown in Figure 17As shown in c-e, BPRC showed excellent bactericidal effect on all three bacterial strains. Blank and Commercial had no antibacterial activity against S. aureus, E. coli and C. albicans. BPRC showed the best antibacterial activity against S. aureus, E. coli and C. albicans. In addition, it was found that after BPRC treatment, the colony images of S. aureus, E. coli and C. albicans showed a decrease in the number of colonies Figure 16 f-h).

[0119] (6) In vivo healing-promoting performance research

[0120] In intertrigo, excessive moisture and overheated microenvironment can destroy the epithelial layer, making the skin folds into open wounds, and even leading to infected wounds. In addition, the friction and shear of this special wrinkled skin always exacerbate the formation of wounds. In view of this, in order to explore the healing effect of BPRC material on bacterial infected wounds, a mouse skin wound model infected with S. aureus was constructed.

[0121] Bacterial infected wound healing research: Mice (C57BL / 6) were injected with 1% isopropyl barbiturate for anesthesia in vivo. Subsequently, the hair on the back of the mouse was completely shaved, and the remaining hair was further cleaned with depilatory cream. Then, a biopsy punch was used to create a defect wound with a diameter of Φ = 10 mm on the back of the mouse, and 100 μL of 3 x 10 9 CFU / mL of S. aureus bacterial solution was added to the wound to establish a bacterial infection model. Without any treatment as Blank control, Commercial as control group and BPRC as experimental group, the samples were placed on the wound, and the wound healing was observed: at different time nodes (0, 1, 4, 7, 10 and 14 days) after the operation, the healing state of the wound in each group was observed, and the photographs were recorded, the wound diameter was measured, the average size of the wound in each group and the healing time were calculated, and the wound healing rate was calculated according to the following formula. Wound healing rate = (S0-S X ) / S0x100%, wherein S X is the wound area size on the Xth day (0, 1, 4, 7, 10 and 14 days), and S0 is the initial area size of the wound.

[0122] In vivo antibacterial property: On the 7th and 14th day after the operation, the exudate from the wound of different samples was collected using a sterile cotton swab, which was placed in the culture medium and incubated at 37°C for 4h. The bacterial solution was diluted and plated, and the number of colonies on the plate was counted.

[0123] Histological analysis: To evaluate the skin regeneration during the wound healing process, histological analysis was performed on the healed wounds. Regenerated skins were collected on day 7 and day 14 for each group. The skin tissues were processed by rinsing with normal saline, followed by fixation in a fixative solution (4% paraformaldehyde solution) for 48 h. The tissues were then dehydrated using ethanol to remove water, and the dehydrated tissue samples were embedded in paraffin. The tissues were cut into sections of 5 pm thickness. Hematoxylin and eosin (H&E) staining and Masson’s trichrome staining were performed to analyze the inflammatory response, the process of epithelialization, and the collagen deposition in the wound tissues of each experimental group. Three different locations were randomly selected from all sections, and the samples were observed, analyzed, and photographed under a microscope at different magnifications. Image J was used to calculate the thickness of the epidermal layer, the thickness of the dermal layer, the number of hair follicles, and the collagen density. Each experiment and data were performed at least three times independently, and each test was performed on at least three samples for statistical analysis. The quantitative data were expressed as the mean ± standard deviation, and statistical analysis was performed using GraphPad software. p < 0.05 was considered statistically significant, marked as *; p < 0.01 was marked as **; p < 0.001 was marked as ***; and p < 0.0001 was marked as ****.

[0124] As Figure 17 a clearly shows that the wound healing conditions are different on day 0, 1, 4, 7, and 14 after treatment with different materials. It can be observed that the wound area of each group gradually decreases over time Figure 17 b). On day 1 after the operation, the blank group still showed the largest wound area and redness; while the BPRC group showed the smallest wound. On day 4, the wound healing rate of the blank control group was 16.82%, while that of the Commercial group was 15.12%. In contrast, the wound healing rate of BPRC was 27.40%. On day 7, the wound healing rate of the blank control group was 79.23%, and that of BPRC was 91.76%. On day 14, although the wounds of each group were basically healed, no obvious scab was observed in the BPRC group. This suggests that the material can shorten the wound healing time and effectively prevent the formation of scar tissue. As shown in Figure 17 c, the bacteria were extracted from the wound on day 7 and day 14, and the in vivo antibacterial effect was statistically analyzed using the plate counting method, which revealed that the antibacterial performance of the BPRC group was much higher than that of the other groups Figure 17 d and e). To further evaluate the histological changes during healing, H&E and Masson’s trichrome staining were performed on the wound tissues. Reepithelialization is a key step in wound healing. To evaluate the reepithelialization process, the growth of newly formed epithelium was analyzed by H&E staining Figure 18a). The epidermis thickness layer of the wound site was collected on day 4, 7 and 14 Figure 18 b). On day 4, the blank control group was 50.63 pm, the Commercial group was 45.62 pm, and the BPRC group was 104.91 pm. On day 7, the blank control group was 86.35 pm, the Commercial group was 89.43 pm, and the BPRC group was 171.47 pm. On day 14, the blank control group was 74.52 pm, the Commercial group was 82.14 pm, and the BPRC group was 36.73 pm. Compared with the control group, the BPRC group had the most complete and uniform epidermis layer on day 14, and the epidermis layer first thickened and then thinned, showing a good healing trend. This indicates that the epidermis cells are metabolized faster, accelerating the repair of the damaged skin surface, thereby resisting further damage from external stimulating factors. In addition, during the wound healing process, as the reconstruction of the dermis and epidermis layers of the wound site occurs, the changes in the extracellular matrix components provide support for the growth and development of hair follicles, promoting the growth and development of hair follicles, thereby effectively promoting wound healing. As a key component of the extracellular matrix, collagen is mainly synthesized by fibroblasts, and the synthesis and deposition of collagen protein is another important indicator of wound healing. Therefore, the new tissue at the wound site was collected on day 14 for Masson staining. As shown in FIG. 8A, the BPRC group showed more dense and organized collagen deposition, while the other groups had fewer collagen fibers deposited. The positive rate of collagen fibers in the BPRC group was 72.91% (FIG. 8B), which was significantly higher than the blank (37.83%) and Commercial groups (35.27%). The results show that BPRC can promote the formation of collagen protein. Cells can perceive the surrounding environment and adjust their own functions through interaction with collagen protein, gradually restoring the structure and function of the wound tissue to normal, thereby effectively accelerating wound healing. Figure 19 a. As shown in FIG. 8A, the BPRC group showed more dense and organized collagen deposition, while the other groups had fewer collagen fibers deposited. The positive rate of collagen fibers in the BPRC group was 72.91% (FIG. 8B), which was significantly higher than the blank (37.83%) and Commercial groups (35.27%). The results show that BPRC can promote the formation of collagen protein. Cells can perceive the surrounding environment and adjust their own functions through interaction with collagen protein, gradually restoring the structure and function of the wound tissue to normal, thereby effectively accelerating wound healing. Figure 19 b. As shown in FIG. 8A, the BPRC group showed more dense and organized collagen deposition, while the other groups had fewer collagen fibers deposited. The positive rate of collagen fibers in the BPRC group was 72.91% (FIG. 8B), which was significantly higher than the blank (37.83%) and Commercial groups (35.27%). The results show that BPRC can promote the formation of collagen protein. Cells can perceive the surrounding environment and adjust their own functions through interaction with collagen protein, gradually restoring the structure and function of the wound tissue to normal, thereby effectively accelerating wound healing.

[0125] (7) Comparison of the liquid guiding performance of sandwich structure time sequence bidirectional liquid guiding-cooling integrated materials prepared by the methods described in Example 1 and Example 8

[0126] The simulated biological liquid was dropped on the upper and lower surfaces of the materials prepared in Example 1 and Example 8. The material of Example 1 can quickly bidirectionally drain these simulated liquids, with a drainage speed of up to 9.90 pL / s, and the material of Example 8 can drain at a speed of up to 5.6 pL / s, as shown in FIG. 9. Figure 21 .

Claims

1. A time-sequential bidirectional liquid guiding and cooling integrated material with a sandwich structure, characterized in that: It consists of an upper hydrophobic antibacterial drainage layer with unidirectional liquid flow, a middle hydrophilic cooling layer, and a lower hydrophobic antibacterial drainage layer with unidirectional liquid flow.

2. The method for preparing the time-sequential bidirectional liquid guiding and cooling integrated material with a sandwich structure as described in claim 1, characterized in that, Includes the following steps: (1) Preparation of the intermediate hydrophilic cooling layer Under stirring conditions, cooling substances and soluble hydrophilic polymers are added to a solvent to obtain a spinning solution; the spinning solution is electrospun using an electrospinning device to obtain a nanofiber membrane; the nanofiber membrane is cross-linked in glutaraldehyde vapor and dried to obtain an intermediate hydrophilic cooling layer. (2) Preparation of the upper hydrophobic antibacterial drainage layer and the lower hydrophobic antibacterial drainage layer of the unidirectional fluid guiding layer An antibacterial agent is added to a solvent and sonicated. Then, under stirring conditions, a soluble hydrophobic polymer material is added to obtain a hydrophobic antibacterial liquid. The hydrophobic antibacterial liquid is sprayed onto the upper surface of the intermediate hydrophilic cooling layer using an electrostatic spraying device to obtain a unidirectional liquid-guiding upper hydrophobic antibacterial drainage layer. The spraying steps are repeated to spray the hydrophobic antibacterial liquid onto the lower surface of the intermediate hydrophilic cooling layer using an electrostatic spraying device to obtain a unidirectional liquid-guiding lower hydrophobic antibacterial drainage layer. Finally, a time-sequential bidirectional liquid-guiding and cooling integrated material with a sandwich structure is obtained.

3. The method for preparing the time-sequential bidirectional liquid guiding and cooling integrated material with a sandwich structure according to claim 2, characterized in that, The preparation method of the unidirectional liquid guiding upper hydrophobic antibacterial drainage layer and the unidirectional liquid guiding lower hydrophobic antibacterial drainage layer in step (2) is replaced by: A hydrophobic antibacterial liquid is obtained by dispersing or dissolving soluble hydrophobic polymer materials and antibacterial agents in a solvent; an octopus-like sucker nanofiber membrane is prepared by electrospinning using a spinning collection device with an array pore structure and an electrospinning device; an intermediate hydrophilic cooling layer is placed between two layers of octopus-like sucker nanofiber membranes to form a time-sequential bidirectional liquid guiding and cooling integrated material with a sandwich structure.

4. The preparation method of the time-sequential bidirectional liquid guiding and cooling integrated material with a sandwich structure according to claim 2, characterized in that: In step (1), the soluble hydrophilic polymer material is selected from chitosan, gelatin, collagen, polyacrylonitrile, cellulose acetate, polyvinyl alcohol, and polyvinylpyrrolidone, or any combination thereof; the solvent is selected from hexafluoroisopropanol, glacial acetic acid, tetrahydrofuran, N,N-dimethylformamide, N,N-diethylacetamide, water, and ethanol, or any combination thereof; and the cooling substance is selected from ammonium salts, nitrates, or sugar alcohols, or any combination thereof.

5. The method for preparing the time-sequential bidirectional liquid guiding and cooling integrated material with a sandwich structure according to claim 4, characterized in that: The ammonium salt is ammonium nitrate or ammonium chloride; the nitrate is potassium nitrate or sodium nitrate; the sugar alcohol is erythritol, xylitol, sorbitol, mannitol, lactitol or maltitol.

6. The method for preparing the time-sequential bidirectional liquid guiding and cooling integrated material with a sandwich structure according to claim 2, characterized in that: In step (2), the soluble hydrophobic polymer material is selected from any one or a combination of poly(ε-caprolactone), polyurethane, polylactic acid, poly(ethylene lactide), polysulfone, polymethyl methacrylate, polyvinyl butyral, polyvinylidene fluoride, and polystyrene; the solvent is selected from any one or a combination of tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dichloromethane, chloroform, hexafluoroisopropanol, and ethanol; the antibacterial agent is selected from any one or a combination of silver particles, copper particles, curcumin, chitosan, and ε-polylysine hydrochloride; and the mass concentration of the soluble hydrophobic polymer material in the hydrophobic antibacterial solution is 0.1–1.0 g / mL.

7. The method for preparing the time-sequential bidirectional liquid guiding and cooling integrated material with a sandwich structure according to claim 2, characterized in that: In step (1), the mass concentration of the soluble hydrophilic polymer material in the spinning solution is 0.02 to 0.19 g / mL.

8. The method for preparing the time-sequential bidirectional liquid guiding and cooling integrated material with a sandwich structure according to claim 2, characterized in that: In step (1), the parameters of the electrospinning equipment are: using an aluminum foil-wrapped roller as a collection device, a spinning voltage of 5kV to 20kV, a flow rate of 0.5 to 2.0mL / h, and a spinning distance of 5 to 20cm; in step (2), the parameters of the electrostatic spraying equipment are: a voltage of 8 to 15kV, a spraying distance fixed at 3 to 5cm, and a spraying flow rate of 1 to 2mL / h.

9. The method for preparing the time-sequential bidirectional liquid guiding and cooling integrated material with a sandwich structure according to claim 3, characterized in that: The soluble hydrophobic polymer material is selected from any one or a combination of several of the following: poly(ε-caprolactone), polyurethane, polylactic acid, poly(ethylene lactide), polysulfone, polymethyl methacrylate, polyvinyl butyral, polyvinylidene fluoride, and polystyrene; the solvent is selected from any one or a combination of several of the following: tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dichloromethane, chloroform, hexafluoroisopropanol, and ethanol; the antibacterial agent is selected from any one or a combination of several of the following: metallic silver particles, metallic copper particles, curcumin, chitosan, and ε-polylysine hydrochloride; the mass concentration of the soluble hydrophobic polymer material in the hydrophobic antibacterial solution is 0.1–1.0 g / mL; the parameters of the electrospinning equipment are: voltage of 5 kV–20 kV, flow rate of 0.5–2.0 ml / h, and spinning distance of 5–20 cm.

10. The application of the sequential bidirectional liquid-cooling integrated material with sandwich structure as described in claim 1 in the fields of prevention and relief of intertrigo, fever-reducing patches, emergency cooling for sports injuries, quick-drying cooling fabrics, and postoperative swelling and pain relief.

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