A silk fiber-based anti-decubitus decompression pad and a preparation method thereof

Abstract

The application discloses a silk fiber-based anti-bedsores decompression pad and a preparation method thereof, which comprises a fabric layer in a concave shape, an aerogel layer and a fiber layer are arranged in the fabric layer from bottom to top, the total height of the aerogel layer and the fiber layer after being stacked is equal to the depth of the fabric layer, the fiber layer is prepared from drug-loaded hydrophobically modified sodium alginate fiber, and the aerogel layer is prepared from degummed silk-sodium alginate composite aerogel with a three-dimensional porous structure. The decompression pad has antibacterial and healing promotion effects, the silk fiber enhances the physical and mechanical properties of the aerogel layer, can greatly reduce external pressure, has excellent air permeation effect due to the through-hole structure in the interior, can fully and quickly absorb wound exudates, the sodium alginate-based material also provides a suitable microenvironment for cell growth, accelerates wound healing, and is suitable for the prevention and treatment of bedsores of patients who need to be in bed for a long time.

Description

Technical Field

[0001] This invention belongs to the field of anti-bedsore mattress technology, and in particular relates to a silk fiber-based anti-bedsore pressure-relieving mattress and its preparation method. Background Technology

[0002] Pressure ulcers are caused by prolonged pressure on a localized area of ​​the body, leading to continuous ischemia and hypoxia in the compressed tissues. This results in the accumulation of acidic metabolic products, causing cell degeneration and necrosis, which in turn forms blisters, ulcers, or gangrene on the cell surface. They typically occur in long-term bedridden individuals who are unable to adjust their position independently due to illness or disability. Non-breathable mattresses often exacerbate skin damage and hinder patient recovery. Currently, some hospitals still rely on nursing staff to periodically assist with turning patients, but this method is labor-intensive, ineffective in preventing pressure ulcers, and cumbersome. While commercially available automatic pressure ulcer-preventing turning beds allow patients to turn over, raise their backs, and flex and extend their legs, they are convenient to use but expensive, making them difficult to promote and apply in homes, communities, and small and medium-sized hospitals, thus hindering their widespread adoption.

[0003] Most anti-decubitus mattresses on the market are made of sponge or cotton. While they can reduce local pressure, they have poor breathability and heat dissipation, are prone to deformation after a period of use, and are not ideal in absorbing wound exudate. They require frequent replacement and cannot keep the skin dry for extended periods, which is detrimental to wound healing. Newly developed air-filled pressure-reducing mattresses, while ensuring good pressure distribution and shape stability, not only require charging but also generate noise during use. Furthermore, they require frequent checks of inflation, resulting in higher maintenance costs.

[0004] Alginate is a natural cellulose extracted from seaweed. When alginate materials come into contact with wound exudate, they form a soft gel, providing a moist environment for wound healing, relieving pain, promoting healing, and reducing scar formation. It also possesses the characteristics of being safe and non-toxic, highly absorbent, and hemostatic. The ion exchange reaction between sodium alginate and calcium ions can prepare a three-dimensional porous aerogel, which exhibits good elasticity and excellent breathability after absorbing water and swelling. However, wet sodium alginate composite aerogels are difficult to transport and store, while dry sodium alginate composite aerogels suffer from poor resilience and fragility. Therefore, researching a fiber-reinforced aerogel-type pressure-relief pad for preventing bedsores is of great significance. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a silk fiber-based pressure-reducing pad for preventing bedsores and its preparation method. It has antibacterial and healing-promoting effects. The silk fibers enhance the physical and mechanical properties of the aerogel layer, significantly reducing external pressure. Simultaneously, its internal porous structure provides excellent breathability and can effectively and quickly absorb wound exudate. The sodium alginate-based material also provides a suitable microenvironment for cell growth, accelerating wound healing. It is suitable for the prevention, treatment, and nursing care of bedsores in patients requiring long-term bed rest.

[0006] To address the problems in the existing technology, the technical solution adopted by this invention is as follows:

[0007] A silk fiber-based pressure-reducing pad for preventing bedsores includes a concave fabric layer. An aerogel layer and a fiber layer are disposed inside the concave fabric layer from bottom to top, and the height of the superimposed aerogel layer and fiber layer is equal to the depth of the fabric layer. The fiber layer is made of drug-loaded hydrophobic modified sodium alginate fiber, and the aerogel layer is made of degummed silk-sodium alginate composite aerogel with a three-dimensional porous structure.

[0008] Furthermore, the drug-loaded hydrophobically modified sodium alginate fiber is formed by loading tannic acid onto hydrophobically modified sodium alginate.

[0009] Furthermore, the degummed silk-sodium alginate composite aerogel is formed by uniformly dispersing silk in a blend system of sodium alginate and calcium ions.

[0010] Furthermore, the fiber layer has a thickness of 1-2 mm; the aerogel layer has a thickness of 0.3 ± 0.05 mm and a porosity of 50% to 90%.

[0011] Furthermore, the fiber layer and the aerogel layer are bonded together using sodium alginate.

[0012] Furthermore, the fabric layer is a uniform mesh fabric made of polyester warp-knitted and is connected to the fiber layer by stitching.

[0013] The preparation method of the above-mentioned silk fiber-based anti-bedsore pressure-relieving pad includes the following steps:

[0014] Step 1, Preparation of fiber layer: Diacetone acrylamide and sodium alginate solution are mixed, and potassium persulfate initiator is added to obtain hydrophobic modified sodium alginate solution. Tannic acid is added and stirred to obtain drug-loaded hydrophobic modified sodium alginate solution. Drug-loaded hydrophobic modified sodium alginate fiber is obtained by wet spinning and used as material to prepare fiber layer.

[0015] Step 2, Preparation of aerogel layer: After degumming, the silk is dispersed in sodium alginate solution, frozen to fix its shape after standing, and then freeze-dried. The resulting aerogel is then treated in calcium chloride solution, washed and freeze-dried to obtain a degummed silk-sodium alginate composite aerogel with a three-dimensional porous structure. This aerogel layer is prepared using this material.

[0016] Step 3: Connect the fiber layer and the aerogel layer together in an upper and lower order;

[0017] Step 4: Cover the outer surfaces of the fiber layer and aerogel layer with a fabric layer, leaving the upper surface of the fiber layer exposed, and finally connect and fix the fabric layer to the fiber layer.

[0018] Further, the preparation process of the drug-loaded hydrophobic modified sodium alginate solution in step 1 is as follows: a 10% (w / w) diacetone acrylamide solution and a 10 g / L sodium alginate solution are mixed at a mass ratio of 1:(1-5), and then a 0.2% (w / w) potassium persulfate initiator solution is added. The mixture is stirred at 90°C for 3-5 hours to obtain a hydrophobic modified sodium alginate solution. Then, 4%-10% (w / w) tannic acid is added to obtain a drug-loaded hydrophobic modified sodium alginate solution. The mass of tannic acid is relative to the mass of the hydrophobic modified sodium alginate solution, that is, it accounts for the total mass of the solution after tannic acid loading.

[0019] Further, the wet spinning preparation process described in step 1 is as follows: using a drug-loaded hydrophobically modified sodium alginate solution as the spinning solution, injecting a 0.1M CaCl2 solution into a water bath as a coagulation bath, adding 15% glycerol by mass to the spinning solution, extruding at a speed of 1 mL / min, drawing at a speed of 0 m / min to 0.4 m / min, and drying to constant weight to obtain drug-loaded hydrophobically modified sodium alginate fibers. Regarding the 0.1M calcium chloride, it refers to 0.1 mol / L. Different amounts of calcium chloride solution can be prepared, and 15% glycerol by mass can be added; the concentration can be controlled.

[0020] Further, the preparation process of the degummed silk-sodium alginate composite aerogel in step 2 is as follows: the silk is completely degummed in a sodium carbonate solution with a mass percentage of 0.2% at 98℃-100℃ and then dried. The obtained degummed silk is dispersed in a sodium alginate solution with a mass percentage of 1%-10% by ultrasonic assistance. The degummed silk accounts for 5%-12.5% ​​of the dry weight of sodium alginate. After standing for 12 hours, it is frozen for 12 hours to fix its shape. Then, it is freeze-dried for 24 hours. The obtained aerogel is taken out and placed in a calcium chloride solution with a mass percentage of 1%-5% for 5-10 minutes. After washing and freeze-drying, a degummed silk-sodium alginate composite aerogel with a three-dimensional porous structure is obtained.

[0021] Beneficial effects:

[0022] Compared with the prior art, the silk fiber-based anti-bedsore pressure-relieving pad and its preparation method of the present invention have the following advantages:

[0023] 1. The silk fiber-based anti-bedsore pressure-relieving pad of the present invention has a layered structure, wherein the fiber layer is a drug-loaded hydrophobic modified sodium alginate fiber layer, and the aerogel layer is a degummed silk-reinforced sodium alginate composite aerogel with a three-dimensional porous structure. The bio-based material has excellent biocompatibility and meets the necessary characteristics for biological applications. All components are non-irritating to the skin.

[0024] 2. The soft fabric structure of the fiber layer in this invention has excellent breathability and pressure-reducing effect. Loaded with natural antibacterial agents and protein depositing agents, tannic acid, it can directly contact the skin as an inner layer, effectively preventing infection and inflammation. This solves the problem that commercial alginate products do not have antibacterial effects, and the antibacterial effect is more stable and lasting. The hydrophobically modified sodium alginate is prepared into fibers, which increases its specific surface area in contact with pressure ulcer wounds, which is conducive to drug release. When in contact with human skin or wounds, it is non-allergenic and non-adhesive, which can protect pressure ulcer wounds from damage, improve the quality of wound care and treatment, and promote antibacterial healing.

[0025] 3. The aerogel layer of this invention incorporates degummed silk fibers, enhancing the physical and mechanical properties of the aerogel and providing a healing-promoting effect. The aerogel layer is characterized by pressure reduction and high elasticity, which can greatly reduce external pressure and has a good dispersion effect on the human body, thereby significantly reducing the risk of pressure ulcers. At the same time, the aerogel layer can prevent external irritation, maintain a moist environment, and has good skin affinity. Its internal porous structure has excellent air permeability and can fully and quickly absorb wound exudate. The calcium ions in the aerogel can activate coagulation factors and have excellent coagulation properties. The sodium alginate-based material also provides a suitable microenvironment for cell growth and accelerates wound healing. It is suitable for the prevention, treatment, and nursing care of pressure ulcers in patients who need to be bedridden for a long time. Attached Figure Description

[0026] Figure 1 This is a side cross-sectional structural diagram of the silk fiber-based anti-bedsore pressure-relieving pad of the present invention, wherein 1-fiber layer, 2-aerogel layer, 3-fabric layer;

[0027] Figure 2 The porosity measurements are shown in Figures 1-4 and 1-3 of Comparative Examples.

[0028] Figure 3 The graphs show the water absorption rates of Examples 1-4 and Comparative Examples 1-3.

[0029] Figure 4 The graphs show the dry and wet fracture strength measurements of the aerogel layers in Examples 1-4 and Comparative Example 1.

[0030] Figure 5The graphs show the dry and wet elongation at break of the aerogel layers in Examples 1-4 and Comparative Example 1.

[0031] Figure 6 The graphs show the hemolysis rate determination of Examples 1-4 and Comparative Examples 1-3;

[0032] Figure 7 The graphs show the in vitro blood coagulation index (BCI) values ​​of Examples 1-4 and Comparative Examples 1-3.

[0033] Figure 8 The graphs show the free radical scavenging rates of the fiber layers in Examples 1, 5, 6, and 7.

[0034] Figure 9 The graphs show the inactivation rates of Escherichia coli and Staphylococcus aureus in Examples 1 and 5-7.

[0035] Figure 10 The graphs show the determination of the breaking strength and elongation at break of the fiber layers in Examples 1, 8-10. Detailed Implementation

[0036] The present invention will now be described in detail with reference to specific embodiments. The scope of protection of the present invention is not limited to the specific embodiments, but is defined by the claims.

[0037] Example 1

[0038] like Figure 1 As shown, a silk fiber-based pressure-reducing pad for preventing bedsores includes a concave fabric layer 3. An aerogel layer 2 and a fiber layer 1 are disposed inside the concave fabric layer 3 from bottom to top, and the combined height of the aerogel layer 2 and the fiber layer 1 is equal to the depth of the fabric layer 3. The fiber layer 1 is made of drug-loaded hydrophobically modified sodium alginate fiber, and the aerogel layer 2 is made of degummed silk-sodium alginate composite aerogel with a three-dimensional porous structure. The fabric layer 3 covers the outer surfaces of both the fiber layer 1 and the aerogel layer 2, excluding the upper surface of the fiber layer 1. Sodium alginate, a natural substance, is added between the fiber layer 1 and the aerogel layer 2, and the high viscosity of sodium alginate binds them together, eliminating the need for additional chemical adhesives. This design is environmentally friendly and beneficial to human health.

[0039] The preparation method of fiber layer 1 is as follows: 10 wt% diacetone acrylamide solution and 10 g / L sodium alginate solution are mixed at a mass ratio of 1:1, and then a 0.2 wt% potassium persulfate (K2S2O8) aqueous solution is prepared. 5 mL of this solution is added as an initiator, and the mixture is stirred at 90°C for 3 hours to obtain a hydrophobically modified sodium alginate solution. 10 wt% tannic acid is added to obtain a drug-loaded hydrophobically modified sodium alginate solution. Drug-loaded hydrophobically modified sodium alginate fibers are then obtained by wet spinning. The wet spinning method is as follows: the above drug-loaded hydrophobically modified sodium alginate solution is used as the spinning solution. A 0.1 M CaCl2 solution is injected into a water bath as a coagulation bath, and 15 wt% glycerol is added. The extrusion speed is 1 mL / min, the drawing speed is 0.1 m / min, and the mixture is dried to constant weight to obtain drug-loaded hydrophobically modified sodium alginate fibers. The thickness of fiber layer 1, made from drug-loaded hydrophobically modified sodium alginate fibers, is 1 mm.

[0040] The fibrous layer 1, as the inner layer, can directly contact the skin. It is loaded with natural antibacterial agents and protein depositors, such as tannic acid, which act as antibacterial and anti-inflammatory drugs, enabling rapid hemostasis and coagulation while also having a bactericidal effect.

[0041] The mechanism of action of fibrous layer 1 is as follows: ① Tannic acid contains many phenolic hydroxyl groups in its structure. The o-dihydroxyphenyl group preferentially chelates with iron ions, preventing bacteria from taking up iron ions from the surrounding environment and inhibiting their growth and reproduction; ② Tannic acid can interact with bacterial cell membranes and inhibit the formation of bacterial biofilms, thereby achieving its antibacterial effect by affecting membrane potential or increasing membrane permeability; ③ The electronegativity of sodium alginate itself can activate intrinsic coagulation and achieve procoagulant function.

[0042] The preparation method of aerogel layer 2 is as follows: Silk is degummed in a 0.2% sodium carbonate solution at 100℃ for 30 minutes and completely dried to obtain degummed silk. The degummed silk is then dispersed in a 3wt% sodium alginate solution using ultrasonic assistance, with the amount of degummed silk added being 10wt%, to obtain an aerogel precursor. After standing for 12 hours, it is frozen for 12 hours to fix its shape, followed by freeze-drying for 24 hours. The aerogel precursor is then removed and treated in a 1wt% calcium chloride solution for 5 minutes, washed, and freeze-dried to obtain the final degummed silk-sodium alginate composite aerogel with a three-dimensional porous structure. The aerogel layer 2, composed of degummed silk-reinforced sodium alginate composite aerogel, has a thickness of 0.3 mm and a porosity of 73.4%.

[0043] The pressure-reducing aerogel layer 2, serving as the intermediate layer, incorporates degummed silk fibers to enhance the aerogel's physical and mechanical properties, providing hemostatic and healing effects. It also improves the aerogel's strength and elasticity, resulting in excellent pressure dispersion and significantly reducing the risk of pressure ulcers. Furthermore, it effectively absorbs wound exudate while maintaining good breathability and withstanding external pressure from all directions, preventing external irritation and providing a good therapeutic effect for patients with pressure ulcers.

[0044] In this invention, the mechanism of action of the aerogel layer 2 is as follows: ① The aerogel has a high porosity, ensuring air permeability; ② Degummed silk fibers can enhance the intermolecular forces in the aerogel system, enhance the strength of the skeleton, and at the same time have excellent elasticity, which can disperse human body pressure; ③ Calcium ions can activate coagulation factors, and alginate aerogel has excellent coagulation properties, low cytotoxicity, and can promote fibroblast proliferation, thus having a synergistic effect.

[0045] Fabric layer 3 is made of polyester warp-knitted mesh fabric, which has good extensibility and uniformly distributed mesh holes on the surface, ensuring the breathability of the pressure-reducing pad. At the same time, it wraps around the fiber layer and aerogel functional layer, playing a role in abrasion protection and dirt resistance.

[0046] It should be noted that the sodium alginate on the upper surface of fiber layer 1 is hydrophobically modified, and it is non-sticky when in contact with human skin. However, when unmodified ordinary sodium alginate is added between the lower surface of fiber layer 1 and aerogel layer 2 as an adhesive, the sodium alginate exhibits high viscosity, bonding fiber layer 1 and aerogel layer 2 together.

[0047] The preparation method of the silk fiber-based anti-bedsore pressure-relieving pad of the present invention is as follows: fiber layer 1 and aerogel layer 2 are prepared according to the above method. The two are arranged in the order of fiber layer 1 on top and aerogel layer 2 on the bottom. The two are connected together by the high viscosity of sodium alginate without the need for additional chemical adhesives. Finally, fabric layer 3 covers the surface of fiber layer 1 and aerogel layer 2, leaving the upper surface of fiber layer 1 exposed. Fabric layer 3 and fiber layer 1 are then fixed by sewing.

[0048] The thickness and size of the fiber layer 1 and aerogel layer 2 of the silk fiber-based anti-bedsore pressure-relieving pad provided by the present invention can be selected according to actual needs, and the thickness of the fabric layer 3 can also be adjusted according to actual needs, making the cost of the anti-bedsore pressure-relieving pad provided by the present invention flexible and adjustable, and significantly improving the performance of the pad compared with the current pressure-relieving pads.

[0049] Example 2

[0050] The difference between the preparation method of the pressure-reducing pad in this embodiment and that in embodiment 1 is that, in the preparation method of aerogel layer 2, the amount of degummed silk added when preparing the aerogel precursor is 5wt%.

[0051] Example 3

[0052] The difference between the preparation process of the pressure-reducing pad in this embodiment and that in embodiment 1 is that, in the preparation method of aerogel layer 2, the amount of degummed silk added when preparing the aerogel precursor is 7.5 wt%.

[0053] Example 4

[0054] The difference between the preparation process of the pressure-reducing pad in this embodiment and that in embodiment 1 is that, in the preparation method of aerogel layer 2, the amount of degummed silk added when preparing the aerogel precursor is 12.5 wt%.

[0055] Example 5

[0056] The difference between the preparation process of the pressure-reducing pad in this embodiment and that in embodiment 1 is that, in the preparation method of fiber layer 1, the amount of tannic acid added is 4wt% when preparing the drug-loaded hydrophobic modified sodium alginate solution.

[0057] Example 6

[0058] The difference between the preparation process of the pressure-reducing pad in this embodiment and that in embodiment 1 is that, in the preparation method of fiber layer 1, the amount of tannic acid added is 6wt% when preparing the drug-loaded hydrophobic modified sodium alginate solution.

[0059] Example 7

[0060] The difference between the preparation process of the pressure-reducing pad in this embodiment and that in embodiment 1 is that, in the preparation method of fiber layer 1, the amount of tannic acid added is 8 wt% when preparing the drug-loaded hydrophobic modified sodium alginate solution.

[0061] Example 8

[0062] The difference between the preparation process of the pressure-reducing pad in this embodiment and that in embodiment 1 is that, in the preparation method of fiber layer 1, there is no stretching during wet spinning of the drug-loaded hydrophobic modified sodium alginate solution.

[0063] Example 9

[0064] The difference between the preparation process of the pressure-reducing pad in this embodiment and that in embodiment 1 is that, in the preparation method of fiber layer 1, the stretching speed is 0.2 m / min when wet spinning the drug-loaded hydrophobic modified sodium alginate solution.

[0065] Example 10

[0066] The difference between the preparation process of the pressure-reducing pad in this embodiment and that in embodiment 1 is that, in the preparation method of fiber layer 1, the stretching speed is 0.3 m / min when wet spinning the drug-loaded hydrophobic modified sodium alginate solution.

[0067] Comparative Example 1

[0068] Unlike Example 1, the pressure-reducing pad in Comparative Example 1 does not have a fiber layer 1, and no silk reinforcement was added during the preparation of the aerogel layer 2. That is, the pressure-reducing pad is composed only of a warp-knitted uniform mesh fabric layer 3 covered by an aerogel layer 2 without silk reinforcement.

[0069] Comparative Example 2

[0070] Unlike Example 1, Comparative Example 1 pressure-reducing pad does not have fiber layer 1. In the preparation method of aerogel layer 2, the amount of degummed silk added when preparing the aerogel precursor is 10wt%. The pressure-reducing pad is composed only of aerogel layer 2 covering a warp-knitted uniform mesh fabric layer.

[0071] Comparative Example 3

[0072] Commercial disposable alginate dressing pressure relief pad, purchased from Kanglidi Medical Devices Flagship Store, specifically named Kanglidi Alginate Sterile Wound Dressing.

[0073] Performance Comparison

[0074] The examples and comparative examples were compared. Specific test subjects included porosity, water absorption, mechanical properties, hemolysis rate, in vitro blood coagulation index (BCI), free radical scavenging rate, and antibacterial properties. The specific test methods are as follows:

[0075] Porosity test:

[0076] Before testing, the sample was dried overnight in an oven and weighed (w0). It was then transferred to ethanol and kept there for 30 seconds. The sample was then removed from the ethanol and weighed (w1). The porosity was calculated using formula (1-1):

[0077]

[0078] P—density of ethanol, V0—volume of dry aerogel.

[0079] The porosity performance of Examples 1-4 was compared with that of Comparative Examples 1-3, and the results are as follows: Figure 2 As shown, compared with Comparative Example 1, the addition of silk fills some of the large pores of sodium alginate aerogel, and the porosity of the composite aerogel decreases slightly. However, it can still maintain a porosity of more than 73% when the content is 10wt%, which is close to that of commercial alginate materials with nonwoven fabric as the matrix. Therefore, it has good air permeability. At the same time, the high porosity is conducive to moisture evaporation, ensuring the air permeability effect.

[0080] Water absorption rate test:

[0081] Before testing, the sample (thickness 0.3±0.05mm; diameter 10mm) was dried overnight in an oven and weighed as w0. Then, the sample was immersed in PBS (pH=7.4) for 10 seconds. Finally, the SASF was removed from the PBS solution and allowed to stand on a standard sieve for 5 minutes until no more droplets fell; the weight was then recorded as w1. The water absorption rate was calculated using formula (1-2):

[0082]

[0083] All the above experiments were repeated 3 times, and the average value was calculated.

[0084] The water absorption performance of Examples 1-4 was compared with that of Comparative Examples 1-3, and the results are as follows: Figure 3 As shown, in the initial stage, due to the good hygroscopicity of silk itself, the water absorption rate of silk-reinforced sodium alginate aerogel increases with the increase of silk content.

[0085] Mechanical performance testing:

[0086] According to the national standard GB / T 1040-2006, aerogel was cut into 50×10mm test strips, and the thickness of the aerogel was measured using a thickness gauge. To simulate the moist state of the aerogel after absorbing wound exudate, the aerogel was moistened with a small spray bottle to achieve a moist but not water-permeable state. The dry and wet states correspond to different conditions during dressing transportation and packaging and application, respectively. The tensile mechanical properties of the aerogel in both dry and wet states were determined using an electronic tensile testing machine WDW-0.05, with the following parameters set: tensile speed 10mm / min, clamping distance 20mm. Tensile breaking strength σ b (kPa) is calculated using formula (1-3):

[0087]

[0088] F(N) — load at which the specimen breaks, b — sample width (mm), d — sample thickness (mm).

[0089] The dry and wet fracture strength properties of the aerogel layer in Examples 1-4 and Comparative Example 1 were compared, and the results are as follows: Figure 4 As shown, compared with the fracture strength of 0.51±0.12MPa and 0.35±0.04MPa in dry and wet states of Comparative Example 1, the fracture strength of Example 1 in dry and wet states is 0.72±0.09MPa and 0.56±0.06MPa, respectively. The fracture strength in dry state increased by 41.18%, and the fracture strength in wet state increased by 60%.

[0090] The dry and wet elongation at break properties of the aerogel layers of Examples 1-4 and Comparative Example 1 were compared, and the results are as follows: Figure 5As shown, the elongation at break in Comparative Example 1 was only 6.33±0.32% in the dry state, but increased to 23.23±0.13% in the wet state. In contrast, the elongation at break in Example 1 was 13.49±0.33% in the dry state, an increase of 113.11%; and the elongation at break in the wet state was 52.79±0.37%, an increase of 127.25%.

[0091] marry Figure 4 and Figure 5 The results show that the addition of silk allows the fibers to be gradually and evenly distributed inside the aerogel, playing a skeletal role and becoming the main body that bears stress, thus ensuring that the silk fiber-based anti-bedsore pressure-relieving pad of the present invention has good mechanical properties.

[0092] Hemolysis rate test:

[0093] The hemolysis rate of the SASF composite aerogel was determined by co-culturing the PBS extract of the aerogel with rabbit erythrocytes (RBCs): samples were incubated in PBS buffer for 24 hours at 37°C. Then, they were incubated with diluted red blood cell suspension at V... RBCs V PBS RBCs were co-cultured at a ratio of 1:25 for 1 hour. The co-cultured suspension was then centrifuged at 1500 rpm for 10 minutes to obtain the supernatant. The absorbance of the supernatant was measured at 545 nm. Additionally, RBCs were co-cultured with deionized water and PBS buffer as negative and positive control groups, respectively. The hemolysis rate was calculated using formulas 1-4.

[0094]

[0095] OD s OD p and OD n The absorbance values ​​are those of the sample, positive control group, and negative control group supernatant, respectively.

[0096] The hemolysis rate performance of Examples 1-4 was compared with that of Comparative Examples 1-3, such as... Figure 6 As shown, an ideal hemostatic material should exhibit good blood compatibility and cause little or no hemolysis due to red blood cell rupture during use. The hemolysis rates of Examples 1-4 were significantly lower than those of Comparative Example 1, indicating that the addition of silk in this invention can effectively improve the blood compatibility of the composite aerogel.

[0097] In vitro blood coagulation index (BCI) test:

[0098] The sample (6 mm in diameter) was preheated in a constant temperature incubator for 10 minutes, and then co-cultured with 100 μL of fresh anticoagulated rabbit blood for 10 minutes. Subsequently, 1 mL of deionized water was added, and the sample was incubated in a shaker at 25 °C for 5 minutes. The absorbance of the mixed solution at 545 nm was recorded. Additionally, 100 μL of fresh anticoagulated rabbit blood and 1 mL of deionized water were incubated in a shaker under the same conditions for 5 minutes as a blank control group. The BCI value was calculated using formula 1-5.

[0099]

[0100] OD s —Absorbance of sample supernatant, OD c —Absorbance of the supernatant in the blank control group.

[0101] The coagulation index (BCI) values ​​of Examples 1-4 were compared with those of Comparative Examples 1-3, and the results are as follows: Figure 7 As shown, the BCI value is related to the absorbance of hemoglobin in the supernatant released from lysed, uncoagulated red blood cells. The higher the BCI value, the worse the coagulation effect. The BCI value of Comparative Example 1 was 23.89±2.16%, and the BCI value of Example 1 was 12.83±1.32%, indicating that the present invention has a good coagulation effect.

[0102] Free radical scavenging rate test:

[0103] A free radical scavenging test was conducted using 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) to confirm the wound dressing's ability to capture free radicals. A 0.1 mM initial solution of DPPH was prepared by dissolving DPPH in ethanol. Then, 50 mg of the sample was immersed in 3 mL of the DPPH solution and incubated in the dark at room temperature for 30 minutes. The supernatant was collected, and the absorbance at 517 nm was recorded using a UV-2600 spectrophotometer. The percentage of DPPH scavenging effect was calculated using Equation 1-6.

[0104]

[0105] The free radical scavenging rates of the fiber layers in Examples 1, 5, 6, and 7 were compared, such as... Figure 8 As shown, the introduction of tannic acid significantly improved the DPPH free radical scavenging activity of the fiber, i.e., its anti-free radical performance, and the higher the tannic acid content, the greater the antioxidant performance. The free radical scavenging activity of the fiber in Example 5 was 33.55±2.32%, while the free radical scavenging activity of the fiber in Example 1 reached 94.35±2.14%. Therefore, the present invention exhibits excellent free radical scavenging performance.

[0106] Antibacterial performance test:

[0107] (1) Preparation of experimental materials

[0108] The antimicrobial properties of fiber samples were evaluated in accordance with AATCC 100-2012, "Evaluation Methods for Antimicrobial Textiles". Two bacteria (purchased from Shanghai Xiejiu Co., Ltd.) were selected as test species: Staphylococcus aureus (ATCC-6538) among Gram-positive bacteria and Escherichia coli (ATCC-8099) among Gram-negative bacteria.

[0109] Prepare S. aureus culture medium (TSB: 15 g / L tryptone; 5 g / L sodium chloride; 5 g / L soybean peptone), and add 15 g / L agar powder to the TSB culture medium to prepare TSA medium.

[0110] E. coli culture medium was prepared (LB: 10 g / L tryptone; 5 g / L yeast extract powder; 10 g / L NaCl), and LA medium was prepared by adding 15 g / L agar powder to the LB culture medium. All culture media were autoclaved.

[0111] (2) Cultivation of bacterial culture

[0112] Take 0.1 mL of the pre-activated bacterial culture stored in the refrigerator and place it into a 10 mL centrifuge tube. Then add 8 mL of the corresponding culture medium prepared in the previous step, and incubate in a constant temperature shaker for 10 hours until the bacteria reach the appropriate concentration of 10⁻⁶. 7 -10 8 CFU / mL, meaning the absorbance at 600 nm measured using a UV spectrophotometer is 0.35-0.45. If the absorbance is too low, continue culturing, extending the culturing time appropriately; if the absorbance is too high, dilute the bacterial suspension with TSB or LB. Then, take 3 mL of the bacterial suspension and centrifuge for 10 minutes at 1000 rpm. After centrifugation, discard the supernatant to obtain bacterial colonies. Add an equal volume of PBS phosphate buffer, and use a vortex mixer to resuspend the bacteria and disperse them evenly to obtain the original bacterial suspension used in the antibacterial experiment.

[0113] (3) Oscillation antibacterial method

[0114] The antibacterial activity of drug-loaded fibers against Staphylococcus aureus and Escherichia coli was studied using the plate count method. 15 mg of fiber sample was placed in a pre-sterilized centrifuge tube, and 900 μL of PBS (pH 7.4) solution was added. Then, 100 μL of the original bacterial culture was added to the tube. After inoculation, all tubes were incubated at 37°C and 100 rpm for 24 hours. Each tube was then serially diluted 6 times with PBS solution at a 1:10 ratio. 10 μL of each diluted culture was dropped onto a 6×6 grid plate containing TSA (S. aureus) or LA (E. coli) medium. All inoculated plates were incubated overnight at 37°C. Centrifuge tubes containing only the original bacterial culture served as a blank control group to assess bacterial viability. All experiments were performed in triplicate. Bacterial viability was calculated using formulas 1-7.

[0115]

[0116] The inactivation rates of E. coli and S. aureus were compared in Examples 1 and 5-7, and the results are as follows: Figure 9 As shown, commercial alginate and original aerogel have no antibacterial ability due to the lack of loading of highly effective antibacterial agents. However, the addition of tannic acid in the fiber layer of this invention has a strong inhibitory effect on E. coli and S. aureus, showing significantly superior antibacterial efficiency.

[0117] The breaking strength and breaking elongation of the fiber layers in Examples 1 and 8-10 were compared, and the results are as follows: Figure 10 As shown, the breaking elongation of the fiber decreases with increasing drawing speed, while significantly improving the fiber's breaking strength. The breaking elongation of the fiber is 12.36 ± 1.01% when drawn at 0.3 m / min. Considering the mechanical performance of the fiber under different drawing speeds, a drawing speed of 0.1 m / min is optimal for preparing fiber layer materials.

[0118] Based on the above analysis, it can be seen that the composition of Example 1 is the most effective.

[0119] In summary, the pressure-reducing pad of the present invention possesses both the good biocompatibility of natural bio-based materials with the human body and meets the physical and mechanical properties of modern pressure-reducing pads. It is also multifunctional, simultaneously achieving a complex balance of good and stable physical protection, maintaining a moist healing environment, excellent antibacterial and hemostatic properties, and breathability and comfort. Furthermore, it can be used as a drug delivery system to promote wound healing and exert a synergistic effect. It is suitable for use in the modern biomedical field, particularly in the treatment and care of burns, scalds, and pressure ulcers. It can also be applied to the treatment and care of pressure ulcers in patients with hemiplegia, paraplegia, fractures, advanced cancer, and other patients requiring long-term bed rest.

[0120] The embodiments of the present invention have been described in detail above, but the content is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should fall within the patent coverage of the present invention.

Claims

1. A method for preparing a silk fiber-based anti-decubitus decompression pad, characterized by, The silk fiber-based anti-decubitus pad includes a concave fabric layer (3), and the concave interior of the fabric layer (3) is provided with an aerogel layer (2) and a fiber layer (1) from bottom to top. The preparation method of the silk fiber-based anti-decubitus pad includes the following steps: Step 1, Preparation of fiber layer (1): Diacetone acrylamide and sodium alginate solution are mixed, and potassium persulfate initiator is added to obtain hydrophobically modified sodium alginate solution. Tannic acid is added and stirred to obtain drug-loaded hydrophobically modified sodium alginate solution. Drug-loaded hydrophobically modified sodium alginate fiber is obtained by wet spinning. Fiber layer (1) is prepared using this fiber as the material. The preparation process of the drug-loaded hydrophobically modified sodium alginate solution is as follows: 10% diacetone acrylamide solution and 10 g / L sodium alginate solution are mixed at a mass ratio of 1:(1~5). Then, 0.2% potassium persulfate initiator solution is added. The mixture is stirred at 90 °C for 3~5 hours to obtain hydrophobically modified sodium alginate solution. Then, 4%-10% potassium persulfate initiator solution is added. A drug-loaded hydrophobic modified sodium alginate solution was obtained by adding % tannic acid; the wet spinning process is as follows: using the drug-loaded hydrophobic modified sodium alginate solution as the spinning solution, injecting a 0.1 M CaCl2 solution into a water tank as a coagulation bath, adding 15% glycerol by mass to the spinning solution, extruding at a speed of 1 mL / min, drawing at a speed of 0 m / min ~ 0.4 m / min, and drying to constant weight to obtain drug-loaded hydrophobic modified sodium alginate fiber; Step 2, Preparation of aerogel layer (2): After degumming, the silk is dispersed in sodium alginate solution, frozen to fix its shape after standing, and then freeze-dried. The resulting aerogel is placed in calcium chloride solution for treatment, washed and freeze-dried to obtain a degummed silk-sodium alginate composite aerogel with a three-dimensional porous structure. The aerogel layer (2) is prepared using this as the material. Step 3: Connect the fiber layer (1) and the aerogel layer (2) into one piece in an upper and lower order; Step 4: Cover the outer surfaces of the fiber layer (1) and the aerogel layer (2) with a fabric layer (3), leaving the upper surface of the fiber layer exposed, and finally connect and fix the fabric layer (3) to the fiber layer (1).

2. The method of claim 1, wherein the method is characterized by the steps of: The height of the superimposed silk fiber-based anti-bedsore pressure pad aerogel layer (2) and fiber layer (1) is equal to the depth of the fabric layer (3); the fiber layer (1) is made of drug-loaded hydrophobic modified sodium alginate fiber, and the aerogel layer (2) is made of degummed silk-sodium alginate composite aerogel with a three-dimensional porous structure.

3. The method for preparing a silk fiber-based pressure-relief pad for preventing bedsores according to claim 1, characterized in that, The drug-loaded hydrophobically modified sodium alginate fiber is formed by loading tannic acid onto hydrophobically modified sodium alginate.

4. The method for preparing a silk fiber-based pressure-relief pad for preventing bedsores according to claim 1, characterized in that, The degummed silk-sodium alginate composite aerogel is formed by uniformly dispersing degummed silk in a blend system of sodium alginate and calcium ions.

5. A method for preparing a silk fiber-based pressure-relief pad according to claim 1, characterized in that, The fiber layer (1) has a thickness of 1~2 mm; the aerogel layer (2) has a thickness of 0.3±0.05 mm and a porosity of 50%~90%.

6. The method for preparing a silk fiber-based pressure-relief pad for preventing bedsores according to claim 1, characterized in that, The fiber layer (1) and the aerogel layer (2) are bonded together with sodium alginate.

7. The method for preparing a silk fiber-based pressure-relief pad for preventing bedsores according to claim 1, characterized in that, The fabric layer (3) is a uniform mesh fabric made of polyester warp knitting, which is connected to the fiber layer (1) by stitching.

8. The method for preparing a silk fiber-based pressure-relief pad for preventing bedsores according to claim 1, characterized in that, The preparation process of the degummed silk-sodium alginate composite aerogel in step 2 is as follows: the silk is completely degummed in a sodium carbonate solution of 0.2% by mass at 98 ℃-100 ℃ and then dried. The obtained degummed silk is dispersed in a sodium alginate solution of 1%-10% by mass using ultrasonic assistance. The degummed silk accounts for 5%-12.5% ​​of the dry weight of sodium alginate. After standing for 12 hours, it is frozen for 12 hours to fix its shape. Then, it is freeze-dried for 24 hours. The obtained aerogel is taken out and placed in a calcium chloride solution of 1%~5% by mass for 5~10 minutes. After washing and freeze-drying, a degummed silk-sodium alginate composite aerogel with a three-dimensional porous structure is obtained.

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