Medical multi-layer structure dressing

Abstract

The invention discloses a medical multi-layer structure dressing, and relates to the technical field of medical dressings, the medical multi-layer structure dressing comprises a surface protection layer, a functional layer and a wound contact layer, the functional layer is a fiber interlayer filled between the surface protection layer and the wound contact layer, the surface protection layer is made of super-hydrophobic fibers, and the wound contact layer is made of super-hydrophobic fibers. The functional layer is made of uniform fiber agglomerates formed by mixing chitosan fibers and fluff pulp with good water absorbability, the wound contact layer is made of a moisture-conducting material, the protective layer has a functional three-layer structure with the functions of bacteriostasis and liquid absorption, the protective layer can prevent bacteria in the external environment from invading, the functional layer can achieve the special functions of bacteriostasis and liquid absorption, and the wound contact layer is made of a moisture-conducting material. Meanwhile, the structure can enable bacterial toxins to stay in the inner layer of the dressing and prevent back infiltration of the bacterial toxins, an implemented sample has good active liquid absorption and antibacterial performance, and compared with the prior art, the liquid absorption performance of the implemented sample is remarkably improved, growth of bacteria can be effectively inhibited, and meanwhile the situation that the wound surface is further infected due to back infiltration of the bacterial toxins can be prevented.

Description

Technical Field

[0001] The invention relates to the technical field of medical dressings, and in particular to a medical multi-layer structure dressing. Background Art

[0002] Medical dressings can provide a good environment for wound healing by protecting wounds, absorbing wound exudate, and inhibiting the growth of wound bacteria. At the same time, in order to solve the problem of wound infection caused by bacteria, the previous generation of products are strong bacterial adhesion materials. By adhering to wound bacteria, the wound bacteria can be effectively removed after changing the dressing, thereby controlling wound infection and promoting wound healing. On the basis of the previous generation of technology, improving the liquid absorption performance, inhibiting bacterial growth, and preventing bacterial toxins from re-seeping and avoiding further infection of the wound are the directions for improving the performance of the dressing. Multilayer dressings are usually composed of layers with different functions. Through the selection of materials, various requirements for the use of dressings can be met and various conditions for promoting wound healing can be achieved. However, compared with traditional dressings, multilayer dressings are often thicker and are mostly made of non-woven fabrics. Their liquid absorption performance is poor, and they need to be post-processed by bonding, suturing and other means, which reduces the air permeability of the dressings and is not conducive to gas exchange in the wound environment. Therefore, it has become an urgent need to develop a dressing that meets the requirements of wound healing, can effectively absorb exudate, inhibit the growth of wound bacteria, prevent the back-infiltration of bacterial toxins, reduce the impact of biofilm on the wound surface, and is easy to process. Summary of the invention

[0003] Purpose of the invention: The technical problem to be solved by the present invention is to provide a medical multi-layer structure dressing, which solves the problems of poor liquid absorption performance, troublesome post-processing and poor air permeability of the existing multi-layer structure dressing.

[0004] Technical Solution

[0005] To solve the above problems, the technical solution provided by the present invention is:

[0006] A medical multi-layer structure dressing comprises a surface protection layer, a functional layer and a wound contact layer. The functional layer is a fiber interlayer filled between the surface protection layer and the wound contact layer. The material of the surface protection layer is super hydrophobic fiber. The functional layer is made of a uniform fiber mass formed by mixing chitosan fiber and fluff pulp with good water absorption. The material of the wound contact layer is a moisture conductive material.

[0007] Furthermore, the surface protection layer is made of polytetrafluoroethylene filaments.

[0008] Furthermore, the wound contact layer is made of profiled structural polyester filaments.

[0009] Furthermore, the fluff pulp having good water absorption is wood pulp.

[0010] Furthermore, the dressing is a double-layer tissue, the surface protection layer is the surface tissue, the wound contact layer is the inner tissue, the surface tissue is plain weave, the inner tissue is square plain, the warp and weft yarn arrangement ratio is 1:2, and the upper-lower connection method is adopted.

[0011] Furthermore, the hydrophobic material of the surface protection layer is 400D polytetrafluoroethylene filament.

[0012] Furthermore, the hydrophilic and moisture-conductive material of the wound contact layer is a 55D / 36f shaped polyester filament.

[0013] Furthermore, the fiber mass filler used as the functional layer is required to be 80±5 mg / 4 cm2 and 2.9±0.1 mm thick.

[0014] Furthermore, the average length of the chitosan fibers is 28 mm, and the average length of the fluff pulp composed of wood pulp fibers is 2-5 mm, wherein the content of the chitosan fibers in the mixed fiber mass is 30%, 50%, or 70%.

[0015] Beneficial Effects

[0016] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0017] The present invention has a functional three-layer structure with both antibacterial and liquid absorption properties. The protective layer can prevent the invasion of bacteria from the external environment, and the functional layer can achieve the special functions of antibacterial and liquid absorption. The chitosan surface presents a positive charge and has a strong binding force to electronegative bacteria and bacterial endotoxins. The hydrophobic polyester skin contact layer prevents the bacteria and bacterial toxins from seeping back. At the same time, the structure can make the bacteria and bacterial toxins adsorbed and separated from the wound surface remain in the inner layer of the dressing without secondary contamination of the wound surface. The sample implemented has good active liquid absorption and antibacterial properties. Compared with the previous generation of technology, the liquid absorption performance of the implemented sample is significantly improved, which can effectively inhibit the growth of bacteria and prevent the bacterial toxins from seeping back to further infect the wound surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a tissue diagram of a shaped dressing woven directly by weaving according to the present invention;

[0019] Figure 2 is a schematic diagram of a latitudinal cross section of a dressing of the present invention;

[0020] Figure 3 It is a three-dimensional simulation diagram of the fabric cross section of the present invention. DETAILED DESCRIPTION

[0021] In order to make the technical solution of the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Example 1

[0023] Combined with Figure 1-3 A medical multi-layer structure dressing, which consists of a three-layer structure, including a surface protection layer, a functional layer, and a wound contact layer. The functional layer is a fiber interlayer filled between the surface protection layer and the wound contact layer. The dressing can be directly formed by weaving and is easy to manufacture.

[0024] The material of the surface protection layer is hydrophobic and oleophobic fiber, and the surface protection layer is preferably made of polytetrafluoroethylene filaments.

[0025] The surface protective layer can protect the wound surface from contamination. Due to the super hydrophobic nature of polytetrafluoroethylene, pollutants such as moisture outside the wound surface have a larger contact angle when contacting the protective layer and will not penetrate into the dressing.

[0026] The functional layer is made of a uniform fiber mass formed by a mixture of chitosan fiber and fluff pulp with good water absorption. The fluff pulp with good water absorption is wood pulp. The chitosan fiber can make the dressing have the performance of inhibiting bacterial growth. Chitosan is positively charged and can strongly adsorb bacteria and bacterial blockage. The fluff pulp can effectively improve its liquid absorption performance. After the two are evenly mixed, multiple functions can be combined, so that it can effectively absorb wound exudate in the application environment while adhering to and combining bacteria and bacterial toxins, inhibiting the growth of bacteria in the exudate, thereby promoting wound healing.

[0027] The fiber layer mixed with chitosan and fluff pulp plays a role in absorbing exudate; fluff pulp has extremely high liquid absorption performance and can absorb a large amount of exudate. At the same time, bacteria will also be absorbed into this layer together with the exudate. Adding chitosan to this layer can inhibit the growth of bacteria.

[0028] The wound contact layer material is a moisture conductive material. The wound contact layer is composed of shaped polyester with moisture conductive function. The shaped polyester can accelerate the rate at which wound exudate enters the absorption layer through capillary effect; its hydrophobicity can also prevent the exudate in the chitosan and fluff pulp mixed fiber layer from seeping back into the wound.

[0029] There are generally two ways to make the medical multilayer structure dressing. The first way is to make each layer separately and then combine the layers. The second way is to directly weave the multilayer structure dressing.

[0030] The first method is to make each layer separately and then fix each layer. The specific logic of the production process is: use each layer of material and weave the materials into cloth separately, preferably polytetrafluoroethylene filaments and asymmetric polyester filaments, and use various weaving methods to obtain polytetrafluoroethylene cloth and polyester cloth respectively. Mix chitosan and fluff pulp into a fiber layer (fiber functional interlayer), and then place the fiber functional interlayer between the two cloths. The multi-layer dressing is obtained by physical actions such as suturing and bonding.

[0031] The logic of the second production process of direct weaving is: direct weaving, directly using the following method of weaving double-layer fabrics: the fabric structure is a double-layer structure. When weaving, there are two independent systems of warp yarns and weft yarns, which form the upper and lower layers of the fabric on the same loom, called the surface layer and the inner layer.

[0032] In this implementation method, the fiber interlayer is filled between the outer and inner layers during weaving, that is, a dressing with a three-layer structure is formed, and the layers need to be connected to each other, such as the suturing and bonding methods mentioned in the first method. Here, the double-layer group is designed as a double-layer structure, and the inner and outer layers of the fabric can be connected by designing the junction point, and no other suturing treatment is required for the directly formed dressing. The warp and weft yarn arrangement ratio designed here is determined by the yarn density used, and the outer and inner structure design can also be adjusted in other ways.

[0033] The requirements for the second production method are: the dressing is a double-layer tissue, the surface protection layer is the surface tissue, the wound contact layer is the inner tissue, the surface tissue is plain weave, the inner tissue is square plain, the warp and weft yarn arrangement ratio is 1:2, and the top-down connection method is adopted. The surface warp and weft of the dressing are made of polytetrafluoroethylene filaments, and the inner warp and weft are peanut-shaped differential structure polyester filaments.

[0034] structure Figure 1 As shown, Figure 1 Schematic diagram of a multi-layered dressing obtained by direct weaving.

[0035] This figure is a fabric organization diagram of this implementation method, showing the interweaving rules of warp and weft yarns. The specific symbols have the following meanings:

[0036] The symbol represented by reference numeral 12 indicates a weft organization point; the symbol represented by reference numeral 14 indicates a warp organization point of the surface warp; the symbol represented by reference numeral 10 indicates a warp organization point of the inner warp; the symbol represented by reference numeral 11 is a heald lifting symbol, indicating that the surface warp must be lifted when weaving the inner weft, which is a special warp organization point; the symbol represented by reference numeral 13 is a junction point, indicating a cancellation point of the surface warp, indicating that the surface warp is not lifted when the inner weft is inserted, which is a special weft organization point;

[0037] Arabic numerals 1, 2, 3, etc. represent the outer longitude and outer latitude; Roman numerals Ⅰ, Ⅱ, Ⅲ, etc. represent the inner longitude and inner latitude.

[0038] The fiber mass filler used as the functional layer is required to be 80±5mg / 4cm 2 , thickness is 2.9±0.1mm.

[0039] The preparation process is:

[0040] 1. The chitosan fiber and the fluff pulp are opened by an opener respectively and then mixed evenly according to the ratio through a fiber blender to form a fiber mass as a functional layer.

[0041] 2. The double-layer fabric with polytetrafluoroethylene surface layer and polyester inner layer is woven to form a fabric with a hollow cloth pocket structure, that is, a double-layer fabric with a sandwich layer.

[0042] 3. Take a certain amount of mixed fiber balls and fill them into the double-layer fabric to form a fiber interlayer to obtain the multi-layer structure dressing.

[0043] The detailed preparation parameters and process details in this implementation method are:

[0044] 1. The chitosan fibers preferably have an average length of 28 mm; the fluff pulp is composed of wood pulp fibers with an average length of 2-5 mm; the specification of the polyester filaments is 55D / 36f; and the specification of the polytetrafluoroethylene filaments is 400D.

[0045] 2. Both chitosan fiber and fluff pulp are opened by a feeding machine, and the fibers are mixed and evenly mixed. The proportion of chitosan can be selected to be 30%, 50% or 70%. The higher the proportion of chitosan, the better the effect of inhibiting bacterial growth of the dressing, and the worse the corresponding liquid absorption capacity.

[0046] 3. The weaving method is machine weaving, and the structure is a double-layer structure. The surface structure is plain weave, using polyester filaments, and the lining structure is square weave, using polytetrafluoroethylene filaments. The warp and weft yarn arrangement ratio is 1:2, and the top-down connection method is adopted. The surface protection layer is the surface structure, and the wound contact layer is the lining structure.

[0047] 4. During weaving, the outer and inner layers of the double-layer fabric are connected by a joint point to form a sandwich cavity. The fiber sandwich is filled into the cavity of the fabric and the weaving is continued to sew the fiber sandwich together to form a three-layer dressing.

[0048] 5. The preferred loom model is the SGA598 semi-automatic proofing machine of Tongyuan Textile Machinery Co., Ltd.

[0049] Experimental Example 1

[0050] The material grades selected for the surface protection layer, functional layer and wound contact layer are as follows:

[0051] The hydrophobic material of the surface protection layer is 400D polytetrafluoroethylene filament.

[0052] The hydrophilic and moisture-conductive material used as the wound contact layer is an asymmetric polyester filament with a specification of 55D / 36f.

[0053] The average length of chitosan fiber is 28 mm, and the average length of fluff pulp composed of wood pulp fiber is 2-5 mm, wherein the content of chitosan fiber in the mixed fiber mass is 30%, 50%, and 70%, that is, the ratio of chitosan fiber to wood pulp fiber is 3:7, 5:5, and 7:3, respectively.

[0054] The comparative data of the three ratios of antibacterial rate, bacterial adhesion number per unit area, and exudate absorption per unit area are as follows:

[0055] At the same time, the medical multilayer structure dressings with three ratios were compared with the medical dressings made of acetyl modified cotton fabric and PMP fabric which are commonly used in the prior art.

[0056] The data is as follows:

[0057]

[0058] The test method for the inhibition rate is as follows: after the sample is sterilized, it is co-cultured with a certain concentration of bacteria in a liquid culture medium for 12 hours, and the difference in OD values ​​between the control group without sample culture for 12 hours and the experimental group with sample culture for 12 hours is measured to determine its antibacterial performance. Here, the inhibition rate = (1-OD value of the experimental group bacterial solution / OD value of the control group bacterial solution) * 100%.

[0059] Test method for the number of adherent Staphylococcus aureus:

[0060] First, establish a standard curve for detecting bacterial adhesion quantity by CCK-8 staining, the process is as follows:

[0061] The bacteria in the logarithmic growth phase were centrifuged (8000r / min, 5min) and washed three times with sterile water. The wound simulation fluid was used to redisperse to OD600 = 1.0 and then diluted 10 times to 8 concentration gradients (8 concentration gradients are about 10 9 , 10 8 , 10 7 , 10 6 , 10 5 , 10 4 , 10 3 , 10 2 CFU / mL), and the specific number of bacteria was determined by the plate count method. Take 900 μL of each concentration gradient bacterial solution and add it to a new centrifuge tube, mix it evenly with 100 μL of 10% CCK-8 solution, and incubate it in a biochemical incubator for 4 hours. After taking it out, transfer the upper solution to a 96-well plate, and measure the absorbance value of the solution at 450nm with an enzyme marker. Set 5 parallel samples for each group. Combined with the number of bacteria determined by the plate count method, establish a standard curve between the absorbance value of the CCK-8 staining method and the number of bacteria by the traditional plate count method.

[0062] The process of the Staphylococcus aureus adhesion test is as follows:

[0063] Cut the sample to be tested into 3cm×3cm samples and put them into a 50mL centrifuge tube for later use. Take the Staphylococcus aureus liquid in the logarithmic growth phase into a centrifuge tube, use a high-speed centrifuge to centrifuge for 5min at 8000r / min, wash it with sterile water for 3 times, pour out the supernatant, add the wound simulation liquid, measure its absorbance at 600nm with an ultraviolet spectrophotometer, and dilute it with the wound simulation liquid to a bacterial suspension with OD600=0.1. Add 5mL of bacterial suspension to each 50mL centrifuge tube containing each sample to be tested, add 20mL of wound simulation liquid, seal it, and place it in a 37℃ biochemical incubator for static culture. After 12 hours of incubation, the sample membrane with bacteria adhered was taken out, rinsed with sterile water 3 times, placed in a new 10mL centrifuge tube, 2mL of 10% CCK-8 solution (PBS dilution) was added, and the centrifuge tube was placed in a biochemical incubator for 4 hours. After taking it out, the upper solution was transferred to a 96-well plate, and the absorbance value of the solution at 450nm was measured with an enzyme marker. The high and low light values ​​can reflect the number of adhered bacteria. Five parallel samples were set for each group, and the mean ± standard deviation of the optical density measured in each group was calculated using SPSS16.0.

[0064] The number of bacteria adhered to the dressing to be tested was calculated using a standard curve between the absorbance value of the CCK-8 staining method and the number of bacteria by the traditional plate counting method.

[0065] It can be seen from the experimental results that, for Staphylococcus aureus and Escherichia coli, the multi-layer structure dressing has excellent antibacterial properties that the PMP melt-spun fabric dressing and the acetyl-modified cotton fabric dressing do not have, and the higher the proportion of the corresponding chitosan fiber, the better the antibacterial performance. In addition, the wound dressing of the PMP melt-spun fabric is a fully hydrophobic structure made of a single layer of hydrophobic material, and the acetyl-modified cotton fabric does not have the liquid absorption function, so they are not liquid-absorbent. The multi-layer structure dressing of the present application has liquid absorption and can absorb tissue fluid deep in the wound. The higher the proportion of the corresponding wood pulp fiber, the better the liquid absorption. At the same time, the multi-layer structure dressing has stronger bacterial adhesion performance than the PMP melt-spun fabric dressing and the acetyl-modified cotton fabric dressing, and the higher the proportion of the corresponding chitosan fiber, the better the bacterial adhesion performance.

[0066] Since the antibacterial and liquid absorption functions are relatively balanced in the ratio of chitosan fiber to wood pulp fiber of 5:5, this ratio is used as the ratio for large-scale use. At the same time, a medical multilayer structure dressing made of chitosan fiber to wood pulp fiber in a ratio of 5:5 is used as an experimental example for subsequent experiments.

[0067] The prepared materials are made into finished dressings using the above-mentioned preparation process.

[0068] Comparative experiment of different materials used in wound contact layer:

[0069] Test method for wound exudate absorption: Place the prepared wound exudate simulation liquid in a round culture dish, place the wound dressing with the wound contact layer facing downward on the culture dish containing the wound exudate simulation liquid, and press the wound dressing to contact the wound exudate simulation liquid for 30 minutes, then take it out and weigh it. The weight before contact with the exudate is recorded as m1, and the weight after contact with the exudate is recorded as m2. The calculation method for the wound exudate absorption is: absorption amount = m2-m1.

[0070] The parameter of liquid aspiration volume is used to serve the subsequent test of liquid aspiration speed, so it is no longer listed in the data table.

[0071] Test method for liquid absorption speed: place an excess of wound exudate simulation liquid in a round culture dish, place the wound dressing with the wound contact layer facing downward on the culture dish containing wound exudate simulation liquid, and press the wound dressing to contact with the wound exudate simulation liquid for 1 minute, then take it out and weigh it. The weight before contact with exudate is recorded as m1, and the weight after contact with exudate is recorded as m2. The area of ​​the wound dressing is S, and the calculation method of the wound exudate absorption is: liquid absorption speed = (m2-m1) / S.

[0072] The test method of re-seepage is as follows: the wound contact layer of the wound dressing saturated with wound exudate is pressed in contact with dry filter paper for one minute, and the weight of the dressing before and after is weighed. The weight before contact with dry filter paper is recorded as m3, and the weight after contact with dry filter paper is recorded as m4. The area of ​​the wound dressing is S, and the calculation method of the re-seepage of wound exudate is: re-seepage rate = (m3-m4) / S.

[0073] The comparative examples tested were: a wound contact layer made of conventional polyester fiber and a wound contact layer made of ordinary cotton fabric.

[0074] The experimental data are as follows:

[0075]

[0076]

[0077] The liquid absorption rate and the re-infiltration rate are the liquid absorption and re-infiltration per unit area. The actual area used in the test is 4cm 2 , and further infer the amount of liquid absorption and re-infiltration per unit area.

[0078] Through the above experimental results, it can be observed that both the special-shaped polyester fiber and the conventional polyester fiber have a certain degree of hydrophobicity and can have a good anti-rewet effect; however, due to its hydrophobic characteristics, the liquid absorption speed will also decrease. Based on the capillary effect of the special-shaped fiber, the liquid absorption rate of the special-shaped cross-section fiber will be greater than that of the conventional polyester fiber. When the wound contact layer is ordinary cotton fabric, the cotton fabric has high hydrophilicity, so the liquid absorption rate is fast, but it does not have the anti-rewet effect.

[0079] Therefore, the wound contact layer of the present application has an excellent liquid absorption performance while having the effect of preventing back seepage, and the properties are more balanced, so it can better treat the wound.

[0080] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A medical multi-layered dressing, characterized in that: It includes a surface protection layer, a functional layer and a wound contact layer. The functional layer is a fiber interlayer filled between the surface protection layer and the wound contact layer. The material of the surface protective layer is super hydrophobic fiber. The functional layer is made of a uniform fiber mass formed by mixing chitosan fibers with fluff pulp with good water absorption. The wound contact layer material is a moisture conductive material.

2. A medical multi-layered dressing according to claim 1, characterized in that: The surface protection layer is made of polytetrafluoroethylene filaments.

3. The medical multi-layered dressing according to claim 1, characterized in that: The wound contact layer is made of profiled structured polyester filaments.

4. The medical multi-layered dressing according to claim 1, characterized in that: Fluff pulp with good water absorption is wood pulp.

5. The medical multi-layered dressing according to claim 1, characterized in that: The surface protection layer and the wound contact layer are respectively made of cloth and then fixed into shape after being woven separately. The functional layer is placed between the two cloths, and the surface protection layer and the wound contact layer are fixed.

6. The medical multi-layered dressing according to claim 1, characterized in that: Directly woven into shape, it adopts a double-layer structure with the surface protection layer being the surface structure and the wound contact layer being the inner structure. The surface structure is plain weave and the inner structure is square weave. The warp and weft yarn arrangement ratio is 1:2, and the top-to-bottom connection method is adopted.

7. The medical multi-layered dressing according to claim 2, characterized in that: The hydrophobic material of the surface protection layer is 400D polytetrafluoroethylene filament.

8. The medical multi-layered dressing according to claim 3, characterized in that: The hydrophilic and moisture-conductive material of the wound contact layer is a 55D / 36f shaped polyester filament.

9. The medical multi-layered dressing according to claim 1, characterized in that: The fiber mass filler used as the functional layer is required to be 80±5mg / 4cm 2 , thickness is 2.9±0.1mm.

10. The medical multi-layered dressing according to claim 3, characterized in that: The average length of chitosan fiber is 28mm, and the average length of fluff pulp composed of wood pulp fiber is 2-5mm, wherein the content of chitosan fiber in the mixed fiber mass is 30%, 50% or 70%.

Images