Block-type acellular dermal matrix powder-based skin graft material and method for manufacturing same

Abstract

The present invention relates to a block-type acellular dermal matrix powder-based skin graft material and a method for manufacturing same, wherein the block-type acellular dermal matrix powder-based skin graft material according to one aspect has excellent compressibility and restorability despite having a thicker thickness than a sheet-type skin graft material, thereby being able to be transplanted as is without a need for folding even in a deeply affected area, can helpfully be used for various indications regardless of the curvature, size, and shape of a wound site, has the effects of minimal incision, shortening hydration time, reducing patient pain, etc., and has excellent shape maintainability, thereby being able to stably maintain the shape even when hydrated by exudate from the affected area despite being manufactured on the basis of powder.

Description

Block-type acellular dermal matrix powder-based skin graft material and method for manufacturing the same

[0001] The present invention relates to a skin graft material based on block-type acellular dermal matrix powder and a method for manufacturing the same.

[0002] Recently, the number of patients requiring skin grafts for the treatment of skin tissue defects caused by various diseases, trauma, and other causes has been rapidly increasing. Methods for reconstructing these defects include autologous, allogeneic, and xenograft transplantation. While autologous transplantation is considered the optimal graft material due to its non-immunogenic nature, it suffers from limitations in donor volume, the need for additional surgery, and the associated pain and infection at the surgical site. Therefore, allogeneic skin grafts, processed from donated human cadavers, or xenogeneic skin grafts, processed from animal skin such as pigs or cows, are widely used as alternatives (Korean Patent Publication No. 10-2018-0028229). However, due to the significant shortage of human tissue donors in Korea, most of the raw tissue supply relies on imports. Furthermore, the inherent defects inherent in these raw materials often lead to significant product waste. Therefore, the supply of biomaterials for tissue regeneration is absolutely insufficient compared to the demand from patients, and it is necessary to find a systematic way to utilize the limited raw materials.

[0003] On the other hand, when using skin powder, there is an advantage in that discarded products can be utilized and molding through reprocessing is also easy, but since the three-dimensional structure of skin tissue derived from humans or animals is crushed and then reprocessed, there is an inherent problem in that it is difficult to maintain the shape when applied to the affected area and hydrated by exudates, and if external energy such as heat is treated or chemical additives are treated to solve this, the protein may be denatured, which may reduce the effect of inducing tissue regeneration, and cytotoxicity may be induced, which may reduce biocompatibility.

[0004] In addition, existing allogeneic or xenogeneic skin grafts are provided as acellular dermal matrices in which the epidermal layer is removed from skin tissue collected from humans or animals, cells that may cause immune rejection are removed, and the three-dimensional structure of the dermal layer is maintained. Most of them are provided in the form of sheets with a thickness of approximately 0.6 cm or less, similar to the collected dermal layer. However, these sheet types are used by folding the sheet when applied to a deeply damaged area, and therefore, there are limitations in their application depending on the affected area.

[0005] Therefore, there is a need for the development of a new type of skin graft material based on skin powder that is safe for the human body and has excellent shape retention properties, without concern for product deterioration, and can be applied to various affected areas without restriction.

[0006] One aspect is a block-type Acellular Dermal Matrix (ADM) powder-based skin graft material, which is reprocessed into a block shape by crushing and freeze-drying an ADM, wherein the skin graft material has an absolute value of a thickness change rate before and after compression of Equation 2 below of 60% or more.

[0007] [Formula 2]

[0008] Thickness change rate before and after compression (%) = [(thickness after hydration and compression with 50N (T p ) - Thickness after hydration (T h )) / Thickness after hydration (T h )] ×100

[0009] One aspect provides a method for producing a skin graft material based on an acellular dermal matrix powder, comprising the steps of: pulverizing a freeze-dried acellular dermal matrix to obtain an acellular dermal matrix powder; dispensing a powder solution obtained by mixing the obtained acellular dermal matrix powder with water into a block-shaped mold, followed by freeze-drying to recombinate; and further drying the recombined acellular dermal matrix.

[0010] One aspect provides a skin graft material based on an acellular dermal matrix powder manufactured by the above method.

[0011] One aspect is a block-type Acellular Dermal Matrix (ADM) powder-based skin graft material, which is reprocessed into a block shape by crushing and freeze-drying an ADM, wherein the skin graft material has an absolute value of a thickness change rate before and after compression of Equation 2 below of 60% or more.

[0012] [Formula 2]

[0013] Thickness change rate before and after compression (%) = [(thickness after hydration and compression with 50N (T p ) - Thickness after hydration (T h )) / Thickness after hydration (T h )] ×100

[0014] The term “acellular dermal matrix (ADM)” refers to skin tissue that maintains the three-dimensional structure of the dermal layer while substantially removing cells in the epidermis or dermis that may cause an immune rejection reaction in the patient after transplantation, and may be composed mainly of collagen and elastin. The acellular dermal matrix can be transplanted into defective skin tissue to provide a framework necessary for the influx of fibroblasts, nerve generation, and blood vessel regeneration. The term “substantially removed” as described above means substantially removed and “substantially does not contain”, and “substantially” may mean a state in which cells, etc. are removed by 90% or more, for example, 95% or more, 96% or more, 97% or more, 98% or more, or 99% or more, compared to the raw material.

[0015] The term “acellular dermal matrix powder (ADM powder)” refers to particles obtained by physically crushing acellular dermal matrix, which may be in the form of beads or linear particles.

[0016] The term "block type" may be used interchangeably with the terms "block shape" or "block-shaped" and refers to a thick product having a thickness of at least 1 cm. Here, the thickness refers to the thickness of the skin graft material in its original state upon opening, i.e., in a dry state without any hydration or other modifications.

[0017] The term "sheet type" may be used interchangeably with the term "sheet form" and refers to a product in the form of a thin plate having a thickness of approximately 0.02 cm to 0.6 cm. Here, the thickness refers to the thickness of the product when opened, i.e., the thickness of a dry skin graft material without any hydration or the like.

[0018] The term “thickness” refers to the axial length perpendicular to the bottom surface of the skin graft, which may be the thickness of the center of the skin graft.

[0019] The term “reprocessing” may be used interchangeably with the term “recombination” and refers to combining or processing the crushed material back into one single form.

[0020] The block-type ADM powder-based skin graft material according to the aspect may be a product obtained by crushing and freeze-drying an acellular dermal matrix and reprocessing it into a block form.

[0021] The above skin graft material may be a product containing 1 to 5 wt% of moisture, obtained by dispensing and freeze-drying an acellular dermal matrix powder solution into a mold. The skin graft material may be recombined or formed through a mold casting method, and may be manufactured by dispensing a powder solution obtained by pulverizing an acellular dermal matrix into granules and mixing the powder with water into a block shape having a thickness of at least 1 cm, and then freeze-drying the powder solution. Accordingly, the skin graft material may have a shape manufactured by a mold. The skin graft material formed by recombining the granulated acellular dermal matrix may have a porous structure.

[0022] In one specific example, the acellular dermal matrix powder may be a powder obtained by crushing a freeze-dried sheet-type acellular dermal matrix, or may be used by crushing the remaining semi-finished product pieces after cutting the sheet-type acellular dermal matrix.

[0023] In one specific example, the acellular dermal matrix powder may have a particle size of 2,000 um or less.

[0024] In one specific example, the freeze-dried sheet-type acellular dermal matrix may have a moisture content of 3 to 10 wt%.

[0025] In one specific example, the acellular dermal matrix powder solution may have a concentration of 5 to 9% (w / w), for example, 5 to 8% (w / w), 5 to 7% (w / w), 5 to 6% (w / w), 6 to 9% (w / w), 6 to 8% (w / w), 6 to 7% (w / w), 7 to 9% (w / w), 7 to 8% (w / w), or 8 to 9% (w / w). If the concentration of the powder solution is too low, below the above range, it may be difficult to maintain the shape during hydration, and if it is too high, above the above range, it may be hard when transplanted into the body, causing an uncomfortable foreign body sensation, and the shape may be broken due to improper compression, and the porosity may be reduced, which may increase the time required for hydration.

[0026] In one specific example, the acellular dermal matrix may be of homologous or xenogeneic origin.

[0027] In one specific example, the skin graft material may be sterilized by irradiating it with electron beams.

[0028] In one specific example, the acellular dermal matrix powder solution may further comprise a bioactive substance, drug, or additive.

[0029] In one specific example, the skin graft may be cultured stem cells.

[0030] The block type ADM powder-based skin graft according to the aspect may have an absolute value of the thickness change rate before and after compression of the following formula 2 of 60% or more, for example, 65% or more, 70% or more, 75% or more, 60 to 90%, 60 to 80%, 60 to 75%, 65 to 90%, 65 to 85%, 65 to 80%, 65 to 75%, 70 to 90%, 70 to 85%, 70 to 80%, or 70 to 75%.

[0031] [Formula 2]

[0032] Thickness change rate before and after compression (%) = [(thickness after hydration and compression with 50N (T p ) - Thickness after hydration (T h )) / Thickness after hydration (T h )] ×100

[0033] In the above equation 2, the thickness after hydration is the central thickness measured 10 seconds after the skin graft is immersed in the tertiary purified water at room temperature for 3 minutes and then terminated, and the thickness after hydration and compression with 50 N is the central thickness measured 10 seconds after the skin graft is immersed in the tertiary purified water at room temperature for 3 minutes and then terminated, and the skin graft in a hydrated state is compressed in the thickness direction at room temperature until the force pressing the skin graft reaches 50 N and then maintained in that state for 10 seconds and then terminated.

[0034] The above change in thickness before and after compression may be measured by compressing a hydrated skin graft material by immersing the dry skin graft material in tertiary purified water at room temperature for 3 minutes to hydrate it, and then compressing it with a pressure of 50 N. At this time, the compression may be performed using a tensile and compression tester (manufacturer / model: LLOYD / LRX Plus).

[0035] Block-type skin grafts according to the aspect of the work may exhibit higher compressibility than sheet-type skin grafts, with an absolute value of 60% or more in thickness change rate before and after compression.

[0036] In one specific embodiment, the skin graft may have a thickness of 1 cm or more, for example, 1.3 cm or more, 1.5 cm or more, 1.7 cm or more, 1.9 cm or more, 2.1 cm or more, 2.2 cm or more, 2.3 cm or more, 2.4 cm or more, 2.5 cm or more, 2.6 cm or more, 2.7 cm or more, 2.8 cm or more, 2.9 cm or more, 3 cm or more, 3.1 cm or more, 3.2 cm or more, 1 cm to 50 cm, 1 cm to 40 cm, 1 cm to 30 cm, 1 cm to 20 cm, 1 cm to 15 cm, 1 cm to 12 cm, 1 cm to 10 cm, 1 cm to 8 cm, 1 cm to 6 cm, 1 cm to 4 cm, 1 cm to 3.5 cm, 1 cm to 3 cm, 1.3cm to 50cm, 1.3cm to 40cm, 1.3cm to 30cm, 1.3cm to 20cm, 1.3cm to 15cm, 1.3cm to 12cm, 1.3cm to 10cm, 1.3cm to 8cm, 1.3cm to 6cm, 1.3cm to 4cm, 1.3cm to 3.5cm, 1.3cm to 3cm, 1.5cm to 50cm, 1.5cm to 40cm, 1.5cm to 30cm, 1.5cm to 20cm, 1.5cm to 15cm, 1.5cm to 12cm, 1.5cm to 10cm, 1.5cm to 8cm, 1.5cm to 6cm, 1.5cm to 4cm, 1.5cm to 3.5cm, 1.5cm to 3cm, 1.7cm to 50cm, 1.7cm to 40cm, 1.7cm to 30cm, 1.7cm to 20cm, 1.7cm to 15cm, 1.7cm to 12cm, 1.7cm to 10cm, 1.7cm to 8cm, 1.7cm to 6cm, 1.7cm to 4cm, 1.7cm to 3.5cm, 1.7cm to 3cm, 2cm to 50cm, 2cm to 40cm, 2cm to 30cm, 2cm to 20cm, 2cm to 15cm, 2cm to 12cm, 2cm to 10cm, 2cm to 8cm, 2cm to 6cm, 2cm to 4cm, 2cm to 3.5cm, 2cm to 3cm, 22.5cm to 50cm, 2.5cm to 40cm, 2.5cm to 30cm, 2.5cm to 20cm, 2.5cm to 15cm, 2.5cm to 12cm, 2.5cm to 10cm, 2.5cm to 8cm, 2.5cm to 6cm, 2.5cm to 4cm, 2.5cm to 3.5cm, 2.5cm to 3cm, 2.7cm to 50cm, 2.7cm to 40cm, 2.7cm to 30cm, 2.7cm to 20cm, 2.7cm to 15cm, 2.7cm to 12cm, 2.7cm to 10cm, 2.7cm to 8cm, 2.7cm to 6cm, 2.7cm to 4cm, 2.7cm to 3.5cm, 2.7cm to 3cm, 2.8cm to 15cm, 2.8cm to 12cm, 2.8cm to 10cm, 2.8cm to 8cm, 2.8cm to 6cm, 2.8cm to 4cm, 2.8cm to 3.5cm, 2.8cm to 3cm, 3cm to 15cm, 3cm to 12cm, 3cm to 10cm, 3cm to It may be 8 cm, 3 cm to 6 cm, 3 cm to 4 cm, or 3 cm to 3.5 cm. The thickness may be the thickness in the initial state before hydration and the thickness in the dry state.

[0037] In one specific embodiment, the skin graft material may have a density of 0.2 g / cm3 or less, for example, 0.18 g / cm3 or less, 0.15 g / cm3 or less, 0.13 g / cm3 or less, 0.11 g / cm3 or less, 0.1 g / cm3 or less, 0.09 g / cm3 or less, 0.08 g / cm3 or less, 0.07 g / cm3 or less, 0.06 g / cm3 or less, 0.05 g / cm3 or less, 0.01 g / cm3 to 0.2 g / cm3, 0.01 g / cm3 to 0.18 g / cm3, 0.01 g / cm3 to 0.15 g / cm3, 0.01 g / cm3 to 0.13 g / cm3, 0.01g / cm3 to 0.11g / cm3, 0.01g / cm3 to 0.1g / cm3, 0.01g / cm3 to 0.09g / cm3, 0.01g / cm3 to 0.08g / cm3, 0.03g / cm3 to 0.2g / cm3, 0.03g / cm3 to 0.18g / cm3, 0.03g / cm3 to 0.15g / cm3, 0.03g / cm3 to 0.13g / cm3, 0.03g / cm3 to 0.11g / cm3, 0.03g / cm3 to 0.09g / cm3, 0.03g / cm3 to 0.08g / cm3, It may be 0.05 g / cm3 to 0.2 g / cm3, 0.05 g / cm3 to 0.18 g / cm3, 0.05 g / cm3 to 0.15 g / cm3, 0.05 g / cm3 to 0.13 g / cm3, 0.05 g / cm3 to 0.11 g / cm3, 0.05 g / cm3 to 0.09 g / cm3, or 0.05 g / cm3 to 0.08 g / cm3.

[0038] In one specific example, the skin graft material may have an absolute value of a thickness change rate before and after compression and rehydration of Equation 3 below of 5% or less, for example, 4.5% or less, 4% or less, 3.5% or less, 3% or less, 2.5% or less, or 2% or less. It may be 1.5% or less, 1% or less, 0.01 to 5%, 0.01 to 4.5%, 0.01 to 4%, 0.01 to 3.5%, 0.01 to 3%, 0.01 to 3.5%, 0.01 to 3%, 0.01 to 2.5%, 0.01 to 2%, 0.01 to 1.5%, 0.01 to 1%, 1.5 to 5%, 1.5 to 4.5%, 1.5 to 4%, 1.5 to 3.5%, 1.5 to 3%, 1.5 to 3.5%, 1.5 to 3%, 1.5 to 2.5%, or 1.5 to 2%.

[0039] [Formula 3]

[0040] Thickness change before and after compression and rehydration (%) = [(Hydration, compression with 50 N, and thickness after rehydration (T r ) - Thickness after hydration (T h )) / Thickness after hydration (T h )] ×100

[0041] In the above equation 3, the thickness after hydration is the central thickness measured 10 seconds after the skin graft is immersed in tertiary purified water at room temperature for 3 minutes and then terminated, and the thickness after hydration, compression with 50 N, and rehydration is the central thickness measured 10 seconds after the skin graft is immersed in tertiary purified water at room temperature for 3 minutes and then terminated, and the hydrated skin graft is compressed in the thickness direction at room temperature until the force pressing the skin graft reaches 50 N and is maintained in that state for 10 seconds and then terminated, and the skin graft in the compressed state is immersed in tertiary purified water at room temperature for 30 seconds and then terminated.

[0042] The thickness change rate before and after compression and rehydration may be measured during a series of processes in which a hydrated skin graft material is immersed in tertiary purified water at room temperature for 3 minutes to hydrate a dry skin graft material, and then compression is performed with a pressure of 50 N and then the pressure is released to rehydrate the compressed skin graft material. The thickness change rate before and after compression and rehydration may be measured during this compression using a tensile and compression tester (manufacturer / model: LLOYD / LRX Plus).

[0043] The block-type skin graft material according to the daily aspect may exhibit excellent resilience because the absolute value of the thickness change rate before and after compression and rehydration is less than 5%, and thus, despite having a thick thickness, it is restored to a similar thickness as before compression through rehydration after compression.

[0044] In one specific example, the skin graft material may have an absolute value of a thickness change rate before and after hydration of Equation 1 below of 1 to 20%, for example, 1 to 15%, 1 to 12%, 1 to 10%, 1 to 8%, 1 to 6%, 2 to 15%, 2 to 12%, 2 to 10%, 2 to 8%, 2 to 6%, 5 to 15%, 5 to 12%, 5 to 10%, 5 to 8%, 5 to 6%, 8 to 15%, 8 to 12%, or 8 to 10%.

[0045] [Formula 1]

[0046] Change in thickness before and after hydration (%) = [(Thickness after hydration (T h )- Thickness before hydration (T d )) / Thickness before hydration (T d )] ×100

[0047] In the above equation 1, the thickness before hydration is the central thickness of the skin graft measured at room temperature, and the thickness after hydration is the central thickness measured 10 seconds after the skin graft is immersed in tertiary purified water at room temperature for 3 minutes.

[0048] The above change in thickness before and after hydration may be a measurement of the change in thickness before and after hydration of a hydrated skin graft material by immersing the dry skin graft material in purified water for 3 minutes at room temperature.

[0049]

[0050] Another aspect provides a method for producing a skin graft based on a block-type acellular dermal matrix powder, comprising the steps of: pulverizing a freeze-dried acellular dermal matrix to obtain an acellular dermal matrix powder; dispensing a powder solution obtained by mixing the obtained acellular dermal matrix powder with water into a block-shaped mold, followed by freeze-drying to recombinant; and further drying the recombined acellular dermal matrix. In the method, descriptions of common features with the aforementioned block-type acellular dermal matrix powder-based skin graft are omitted to avoid excessive complexity of the present specification.

[0051] The method for manufacturing a skin graft material based on the above-mentioned acellular dermal matrix powder is described in detail step by step as follows.

[0052] First, the method may include a step of grinding a freeze-dried acellular dermal matrix to obtain an acellular dermal matrix powder, as illustrated in FIG. 2. The freeze-dried acellular dermal matrix may be a freeze-dried sheet-type acellular dermal matrix.

[0053] In the step (S300) of obtaining the above-mentioned acellular dermal matrix powder, the grinding may be performed using a grinder such as a cutting mill, a food processor, a mano grinder, or a freeze grinder, but preferably, a cutting mill may be used. In one specific example, the powder has a particle size of 2,000 um or less pulverized using a cutting mill, for example, 75 um to 2,000 um, 100 um to 2,000 um, 200 um to 2,000 um, 400 um to 2,000 um, 500 um to 2,000 um, 800 um to 2,000 um, 1,000 um to 2,000 um, 1,200 um to 2,000 um, 1,400 um to 2,000 um, 75 um to 1,800 um, 100 um to 1,800 um, 200 um to 1,800 um, 400 um to 1,800 um, 500 um to 1,800 um, 800 um to 1,800 um, 1,000 um to 1,800 um, 1,200 um to 1,800 um, 1,400 um to 1,800 um, 75 um to 1,500 um, 100 um to 1,500 um, 200 um to 1,500 um, 400 um to 1,500 um, 500 um to 1,500 um, 800 um to 1,500 um, 1,000 um to 1,500 um, 1,200 um to 1,500 um, 1,400 um to 1,500 um, 75 um to The powder may be 1,000 um, 100 um to 1,000 um, 200 um to 1,000 um, 400 um to 1,000 um, 500 um to 1,000 um, 800 um to 1,000 um, 75 um to 800 um, 100 um to 800 um, 200 um to 800 um, 400 um to 800 um, or 500 um to 800 um.If the particle size of the acellular dermal matrix powder is too large, exceeding the above range, the skin graft may easily crumble and lose its shape, which may cause a problem. If the particle size of the acellular dermal matrix powder is too small, which is less than the above range, the skin graft may be decomposed and disappear in the body by macrophages when transplanted into the body. The acellular dermal matrix is ​​pulverized into two forms, bead-shaped particles and linear particles, and the powder may include bead-shaped particles and / or linear particles. In this case, the linear particles may be entangled with each other to help form a three-dimensional structure, and in the case of the linear particles, the particle size may be measured based on the long axis.

[0054] The freeze-dried acellular dermal matrix may be a semi-finished product that can be used as a skin graft material on its own or can be manufactured into a skin graft material through an additional processing step, and may require rehydration before use because it is freeze-dried. Since the acellular dermal matrix powder may be derived from such a semi-finished product, it may be manufactured by utilizing pieces of semi-finished products that are nearing their expiration date or that are likely to be discarded due to defective components (S100, S200). The freeze-dried acellular dermal matrix may have a moisture content of 3 to 10 wt%, for example, 3 to 8 wt%, 3 to 6 wt%, 5 to 10 wt%, or 5 to 8 wt%. The freeze-dried acellular dermal matrix may be manufactured according to a conventional method, and may be manufactured according to the method illustrated in FIG. 5, for example.

[0055] Referring to FIG. 5, the freeze-dried acellular dermal matrix is ​​a freeze-dried sheet-type acellular dermal matrix, and can be manufactured by a method including the steps of: treating an epidermal removal solution on separated skin tissue to remove an epidermal layer; treating the skin tissue from which the epidermal layer has been removed with a cell removal solution to remove cells; treating the skin tissue from which the cells have been removed with a blood removal solution to remove blood; and treating the skin tissue from which the blood has been removed with a DNA removal solution to remove DNA.

[0056] In one specific example, the isolated skin tissue may be homologous skin tissue isolated from a human cadaver or xenogeneic skin tissue isolated from a mammal such as a cow, pig, guinea pig, or dog.

[0057] In one specific example, the epidermal removal solution used in the step (S2) of removing the epidermal layer may include a protein-decomposing enzyme, an ionic solution, or a combination thereof, and may be removed by separating the dermal layer from the dermal layer using forceps or the like after treating the epidermal removal solution. The protein-decomposing enzyme may be a neutral protein-decomposing enzyme such as dispase, thermolysin, or trypsin. The step (S2) of removing the epidermal layer may further include a step (S1) of thawing the separated skin tissue before the step (S2) of removing the epidermal layer, and the step (S3) of removing hair roots / fat / spots remaining in the dermal layer using forceps may further include after the step (S2) of removing the epidermal layer.

[0058] In one specific example, a surfactant may be used as the cell removal solution used in the step (S4) of removing the cells, and the surfactant may be, for example, sodium dodecyl sulfate (SDS), N-lauroyl sarcosine (NLS), deoxycholic acid (DA), sodium cholate, sodium deoxycholic acid, Triton X-100, Tween 20, Tween 40, Tween 60, Tween 80, Nonidet P-10 (NP-10), or Nonidet P-40 (NP-40). In addition, the cell removal solution may further include a HEPES solution, an EDTA solution, or a NaOH solution in addition to the surfactant.

[0059] In one specific example, the blood removal solution used in the step (S5) of removing blood may be hydrogen peroxide (H2O2), and for example, treatment may be performed at room temperature with H2O2 at a concentration of 0.001 to 10.0% (w / v) for 2 to 20 hours.

[0060] In one specific example, DNase may be used as the DNA removal solution used in the step (S6) of removing the DNA, and treatment may be performed with DNase at a concentration of 1 to 100 U / mL at room temperature for 2 to 20 hours.

[0061] After the step of removing the DNA (S6), a step of treating with a cryoprotectant (S7) and a step of freeze-drying (S8) may be further included. The cryoprotectant may be any cryoprotectant known to be used in the art, and for example, may be treated at room temperature for 90 minutes to 18 hours using D-PBS (without Ca, Mg), Mannitol, Sucrose, EDTA, Gentamicin, Penicillin, Streptomycin, Amphotericin, etc. The freeze-drying step (S8) may be for suppressing a decrease in the immune response of the graft and the growth of microorganisms that may occur due to moisture, and the moisture content after freeze-drying may be 3 to 10 wt%, for example, 3 to 8 wt%, 3 to 6 wt%, 5 to 10 wt%, or 5 to 8 wt%, based on the total weight of the freeze-dried acellular dermal matrix.

[0062]

[0063] In addition, the method may include a step of dispensing a powder solution obtained by mixing the obtained acellular dermal matrix powder with water into a block-shaped mold, and then freeze-drying and recombining, as shown in FIG. 2.

[0064] This step is to reassemble the pulverized acellular dermal matrix into a matrix and shape it.

[0065] Specifically, the step (S400) of mixing the obtained acellular dermal matrix powder with water is a step of rehydrating to a desired concentration, and the content ratio of the powder and water can be adjusted according to the physical properties such as hardness or the degree of biodegradability required for each indication within a range that can maintain the shape when implanted in the affected area.

[0066] In addition, the step (S500) of dispensing the powder solution into a block-shaped mold is a step of dispensing the powder solution into a block-shaped mold and molding it, and if the mold is manufactured in a block type with a thickness of at least 1 cm, it can be manufactured patient-specifically according to the desired area / thickness / shape without any specific restrictions, and since it can be reprocessed into various areas / thicknesses / shapes, it can be utilized without restrictions for various indications regardless of the curvature, size, and shape of the wound site.

[0067] In addition, the step of recombining by freeze-drying (S600) may be to freeze-dry so that the moisture content is 3 to 10 wt%, for example, 3 to 8 wt%, 3 to 6 wt%, 5 to 10 wt%, or 5 to 8 wt%, based on the total weight of the recombinant acellular dermal matrix that has been freeze-dried, and if necessary, freezing and freeze-drying may be performed in advance.

[0068]

[0069] Additionally, the method may include a step of further drying the recombinant acellular dermal matrix, as illustrated in FIG. 2.

[0070] The above additional drying step (S700) may be drying for 24 hours or more while maintaining a constant humidity, for example, drying for 24 hours to 4 days, 24 hours to 3 days, 24 hours to 2 days, 30 hours to 4 days, 30 hours to 3 days, 30 hours to 2 days, 36 hours to 4 days, 36 hours to 3 days, 36 hours to 2 days, or 1 day to 3 days. If the drying time is too long, exceeding the above range, economic efficiency may be reduced, and if the drying time is too short, less than the above range, moisture may not be sufficiently removed. The above additional drying is drying using a humidity-controllable dryer, and the humidity-controllable dryer refers to a device that absorbs moisture of a sample while maintaining a constant humidity, such as a desiccator, a thermo-hygrostat, a humidity-controlling dehumidifier, and a chamber. The above additional drying step (S700) may be performed by additionally drying the recombinant acellular dermal matrix so that the moisture content is 1 to 5 wt%, for example, 1 to 4 wt%, 1 to 3 wt%, 1 to 2 wt%, 2 to 5 wt%, 2 to 4 wt%, 2 to 3 wt%, or 3 to 5 wt%, based on the total weight of the recombinant acellular dermal matrix that has undergone additional drying.

[0071]

[0072] After the above-mentioned additional drying step (S800), a sterilization step may be performed to prevent the growth of microorganisms, etc., and as a sterilization method, a conventional sterilization method such as irradiating with an electron beam (E-beam) or using ethylene oxide gas may be used. Specifically, a step (S800) of sterilizing by irradiating with an electron beam of 10 to 30 kGy, for example, 20 to 30 kGy or 23 to 27 kGy, may be performed.

[0073]

[0074] Additionally, the method may further include a step of adding a bioactive substance, drug, or additive, as illustrated in FIG. 3, to improve the functionality of the skin graft.

[0075] The above-mentioned physiologically active substance may refer to a substance that can regulate the growth and function of cells, or a substance that induces differentiation of cells into tissues or differentiation into other cells. For example, the above-mentioned physiologically active substance may be an exosome, or a growth factor such as transforming growth factor-beta (TGF-β), fibroblast growth factor (FGF), bone morphogenic protein (BMP), vascular endothelial growth factor (VEGF), or insulin-like growth factor (IGF).

[0076] The above medications may be pharmaceutical anesthetics, topical / local hemostatic agents, lidocaine, etc. that help relieve pain.

[0077] The additive may be at least one selected from the group consisting of a viscosity-increasing agent, a substance promoting cell adhesion, a natural or synthetic polymer, an antioxidant, and a substance inhibiting cell death. The viscosity-increasing agent may be added to adjust the mechanical properties of the bone graft material, and may be, for example, hyaluronic acid or dextran, but is not limited thereto. The substance promoting cell adhesion may be, for example, a product using a blood coagulant such as fibrin glue, but is not limited thereto. The natural or synthetic polymer may be added to enhance mechanical properties, and may be, for example, collagen, atelocollagen, elastin, gelatin, hydroxyapatite, or the like of heterologous or homologous origin. The antioxidant may be, but is not limited to, a chelating agent such as, for example, erythorbic acid, dibutylhydroxytoluene, butylhydroxyanisole, α-tocopherol, tocopherol acetate, L-ascorbic acid and its salts, L-ascorbic acid palmitate, L-ascorbic acid stearate, sodium bisulfite, sodium sulfite, triamyl gallic acid, propyl gallic acid or sodium ethylenediaminetetraacetate (EDTA), sodium pyrophosphate, sodium metaphosphate, etc. The substance that inhibits the above cell death (e.g., necrosis, apoptosis, or autophagy) may be, but is not limited to, one or more selected from, for example, a small molecule, an antibody, a peptide, a peptibody, an anti-TNF substance, a substance that inhibits the activity of interleukins, a substance that inhibits the activity of interferons, a substance that inhibits the activity of GCSF (granulocyte colony-stimulating factor), a substance that inhibits the activity of macrophage inflammatory proteins, a substance that inhibits the activity of MMPs (matrix metalloproteinases), a substance that inhibits the activity of caspases, a substance that inhibits the activity of MAPK / JNK signaling cascades, a substance that inhibits the activity of Src kinases, a substance that inhibits the activity of JAKs (Janus kinases), or a combination thereof.

[0078]

[0079] In addition, the method may further include a step of seeding and culturing cells on the manufactured skin graft, as illustrated in FIG. 4, in order to produce a skin graft as a cell therapy agent. The cells may include cells to be cultured within an acellular dermal matrix-based structure, cells to be differentiated into tissues or other cells, or cells to be used for tissue regeneration. For example, the cells may be stem cells, osteoblasts, fibroblasts, chondrocytes, etc., and the stem cells may be bone marrow-derived mesenchymal stem cells, umbilical cord-derived mesenchymal stem cells, or adipose-derived stem cells.

[0080] The above cells are 1 x 10 5 1 x 10 7 cells / ml, 3 x 10 5 1 x 10 7 cells / ml, 5 x 10 5 1 x 10 7 cells / ml, 1 x 10 6 1 x 10 7 cells / ml, 2 x 10 6 1 x 10 7 cells / ml, 1 x 10 5 5 x 10 6 cells / ml, 3 x 10 5 5 x 10 6 cells / ml, 5 x 10 5 5 x 10 6 cells / ml, 1 x 10 6 5 x 10 6 cells / ml, 2 x 106 5 x 10 6 cells / ml, 1 x 10 5 3 x 10 6 cells / ml, 3 x 10 5 3 x 10 6 cells / ml, 5 x 10 5 3 x 10 6 cells / ml, 1 x 10 6 3 x 10 6 cells / ml, 2 x 10 6 3 x 10 6 It may be included as cells / ml.

[0081]

[0082] Another aspect provides a skin graft material based on a block-type acellular dermal matrix powder manufactured by the above method. More specifically, a block-type skin graft material based on acellular dermal matrix powder is provided, in which a powder solution obtained by mixing acellular dermal matrix powder with water is dispensed into a block-shaped mold, followed by freeze-drying to reassemble the powder solution, and then further dried and then electron beam irradiated to enhance shape retention. In the skin graft material, common components such as the acellular dermal matrix and the acellular dermal matrix powder are as described above. The skin graft material can be used as a biomaterial for tissue repair due to a wound, and can be usefully utilized as a biomaterial for damaged tissue repair in various indications such as enophthalmos and breast reconstruction following breast cancer treatment.

[0083] The block-type acellular dermal matrix powder-based skin graft material according to the aspect has a thicker thickness than the sheet type, but has excellent compressibility and resilience, so that it can be transplanted as is without folding even to a deeply damaged area, and can be usefully used for various indications regardless of the curvature, size, and shape of the wound area, and has the effects of minimal incision, shortening the hydration time, and reducing patient pain, and has excellent shape retention, so that it can stably maintain its shape even when hydrated by exudate from the affected area despite being manufactured on a powder basis.

[0084] FIG. 1 schematically illustrates a method for manufacturing a block-type acellular dermal matrix powder-based skin graft material according to one embodiment.

[0085] FIG. 2 is a flowchart illustrating a method for manufacturing a block-type acellular dermal matrix powder-based skin graft according to one embodiment.

[0086] FIG. 3 is a flowchart exemplifying a method for manufacturing a block-type acellular dermal matrix powder-based skin graft material further comprising a bioactive substance, drug, or additive according to one embodiment.

[0087] FIG. 4 is a flowchart exemplifying a method for manufacturing a skin graft material based on a cell-cultured block-type acellular dermal matrix powder according to one embodiment.

[0088] Figure 5 is a flow chart exemplifying a method for manufacturing a freeze-dried sheet-type acellular dermal matrix.

[0089] Figure 6 is a photograph of a cell-free dermal matrix powder that was crushed into particles of 2,000 μm or less by using a cutting mill to crush a cell-free dermal matrix in a freeze-dried sheet type.

[0090] FIG. 7 is a photograph of the appearance of a block-type acellular dermal matrix powder-based skin graft material manufactured in various areas / thicknesses / shapes according to one embodiment.

[0091] FIG. 8 is a photograph comparing the appearance of a block-type acellular dermal matrix powder-based skin graft material before and after hydration according to one embodiment with a sheet-type acellular dermal matrix skin graft material of a comparative example.

[0092] FIG. 9 is a result of evaluating the influence of the concentration of the powder solution on the shape retention of a skin graft material in manufacturing a block-type acellular dermal matrix powder-based skin graft material according to one embodiment.

[0093] FIG. 10 is a result of evaluating the effect on the shape retention of a skin graft material depending on the presence or absence of electron beam irradiation in manufacturing a block-type acellular dermal matrix powder-based skin graft material according to one embodiment.

[0094] The present invention will be described in more detail below through examples. However, these examples are intended to exemplify the present invention and the scope of the present invention is not limited to these examples.

[0095]

[0096] Examples 1-15. Preparation of block-type ADM powder-based skin graft material

[0097] 1.1. Preparation of sheet-type acellular dermal matrix (ADM)

[0098] Human cadaveric skin tissue obtained from a tissue bank was stored in a refrigerator until completely thawed. The thawed skin tissue was removed, washed with a tissue rinse solution, and then incubated in an epidermal stripping solution at an active temperature for 14–32 hours. The epidermis was peeled from the dermis using forceps. Hair roots, fat, and moles remaining in the dermis were removed, and the epidermal stripping solution was washed with a tissue rinse solution. The dermis from which the epidermis had been stripped was then stirred with a cell removal solution at room temperature for 14–32 hours to remove intradermal cells and then washed with a tissue rinse solution. To remove blood, the tissue was stirred with a H2O2 solution at room temperature for 14–32 hours and then washed with a tissue rinse solution. Subsequently, the tissue was removed by stirring with a DNase solution at room temperature for 14–32 hours to remove DNA, and then treated with an enzyme stop solution at room temperature for 30–180 minutes to inactivate the enzyme. The enzyme stopping solution was removed, and the solution was treated with a phosphate buffer solution, which is a cryoprotectant solution, for a minimum of 90 minutes and a maximum of 18 hours, followed by freeze-drying to produce a freeze-dried sheet-type acellular dermal matrix having a moisture content of 3 to 10 wt%.

[0099] 1.2. Preparation of block-type ADM powder-based skin graft material

[0100] The freeze-dried sheet acellular dermal matrix prepared in 1.1 above was cut into pieces smaller than a certain size. The cut acellular dermal matrix was ground using a grinder and sieved to obtain an acellular dermal matrix powder containing a mixture of bead-shaped particles and linear particles smaller than a certain size. Figure 6 is a photograph of the freeze-dried acellular dermal matrix ground using a grinder into particles smaller than a certain size.

[0101] The obtained acellular dermal matrix powder was added to distilled water and mixed in a mixer for 10 to 15 minutes to prepare powder solutions at different concentrations (5% (w / w), 7% (w / w), 9% (w / w)). The mixed acellular dermal matrix powder solution was dispensed into molds with a certain thickness and shape to form blocks, and then freeze-dried. Afterwards, the skin graft was further dried for more than 24 hours while maintaining a constant humidity using a humidity-controllable desiccator. The additional drying was performed so that the residual moisture content of the skin graft was 1 to 5 wt%. Afterwards, it was transferred to a moisture-blocking pouch, sealed, and stored after electron beam sterilization (25 kGy).

[0102] A total of 15 block-type skin graft samples were prepared using the above method, 5 using a 5% (w / w) acellular dermal matrix powder solution (Examples 1 to 5), 5 using a 7% (w / w) acellular dermal matrix powder solution (Examples 6 to 10), and 5 using a 9% (w / w) acellular dermal matrix powder solution (Examples 11 to 15).

[0103]

[0104] Comparative Examples 1-5. Manufacturing of sheet-type ADM skin graft material

[0105] A total of five sheet-type skin graft samples were manufactured using the same method as in Example 1.1 above.

[0106]

[0107] Experimental Example 1. Evaluation of the physical properties of manufactured skin graft materials

[0108] 1.1. Measurement of density and thickness change rate

[0109] The density and thickness change rate of the skin grafts manufactured in Examples 1 to 15 were measured and compared with those of Comparative Examples 1 to 5. All measurements were performed at room temperature, and the equipment and solutions used for the measurements are as follows:

[0110] Thickness: Thickness measuring instrument (Manufacturer / Model: MITUTOYO / (0~12.7) mm, 0.01 mm)

[0111] Weight: Electric indicating scale (Manufacturer / Model: CAS / XB6200HX)

[0112] Length: Inner / Outer Caliper (Manufacturer / Model: MITUTOYO / (0~300) mm, 0.02 mm)

[0113] Compression with 50 N force: Tensile and compression tester (Manufacturer / Model: LLOYD / LRX Plus)

[0114] Hydration and Rehydration: 3rd Purified Water

[0115] [Formula 1]

[0116] Change in thickness before and after hydration (%) = [(Thickness after hydration (T h ) - Thickness before hydration (T d )) / Thickness before hydration (T d )] ×100

[0117] (In the above equation 1, the thickness before hydration is the thickness of the central part of the sample measured at room temperature, and the thickness after hydration is the thickness of the central part measured 10 seconds after the sample is immersed in tertiary purified water at room temperature for 3 minutes and then terminated.)

[0118] [Formula 2]

[0119] Thickness change rate before and after compression (%) = [(thickness after hydration and compression with 50N (T p ) - Thickness after hydration (T h )) / Thickness after hydration (T h )] ×100

[0120] (In the above equation 2, the thickness after hydration is the central thickness measured 10 seconds after the sample is immersed in tertiary purified water at room temperature for 3 minutes and then terminated, and the thickness after hydration and pressing with 50 N is the central thickness measured 10 seconds after the sample is immersed in tertiary purified water at room temperature for 3 minutes and then terminated, and the sample in a hydrated state is compressed in the thickness direction at room temperature until the force pressing the sample reaches 50 N and then maintained in that state for 10 seconds and then terminated.)

[0121] [Formula 3]

[0122] Thickness change before and after compression and rehydration (%) = [(Hydration, compression with 50 N, and thickness after rehydration (T r ) - Thickness after hydration (T h )) / Thickness after hydration (T h )] ×100

[0123] (In the above formula 3, the thickness after hydration is the central thickness measured 10 seconds after the sample is immersed in tertiary purified water at room temperature for 3 minutes and then terminated, and the thickness after hydration, compression with 50 N, and rehydration is the central thickness measured 10 seconds after the sample is immersed in tertiary purified water at room temperature for 3 minutes and then terminated, and the sample in a hydrated state is compressed in the thickness direction at room temperature until the force pressing the sample reaches 50 N and then maintained in that state for 10 seconds and then terminated, and the skin graft in a compressed state is immersed in tertiary purified water at room temperature for 30 seconds and then terminated.)

[0124] The results are shown in Table 1 below.

[0125] No. Before hydration (dry state) After hydration (hydrated state) After hydration Compression (50 N) (compression state) After hydration Compression Rehydration (rehydrated state after decompression) Thickness (T d )(cm)Density (g / cm3)Thickness (T h )(cm) Thickness change rate before and after hydration (%) Thickness (T p )(cm) Thickness change rate before and after compression (%) Thickness (Tr)(cm) Thickness change rate (%) before and after compression and rehydration Comparative example 10.5690.3760.5740.8790.539-6.0980.573-0.174 Comparative example 20.5700.3760.5832.2810.549-5.8320.571-2.058 Comparative example 30.5830.3640.577-1.0290.562-2.6000.575-0.347 Comparative example 40.5040.340.498-1.1900.477-4.2170.484-2.811 Comparative example 50.3810.3180.3943.4120.375-4.8220.387-1.777Average0.5210.3550.5250.8700.500-4.7140.518-1.433Example 13.0070.0672.826-6.0190.585-79.2992.816-0.354Example 23.0400.0612.841-6.5460.521-81.6612.701-4.928Example 33.1740.0592.966-6.5530.592-80.0402.889-2.596Example 43.0220.0622.820-6.6840.580-79.4332.718-3.617Example 52.9420.0672.674-9.1090.694-74.0462.649-0.935Average3.0370.0632.825-6.9820.594-78.8962.755-2.486Example 62.8840.0762.499-13.3500.656-73.7492.456-1.721Example 72.8500.0792.652-6.9470.658-75.1892.618-1.282Example 82.8900.0812.527-12.5610.627-75.1882.512-0.594Example 92.8880.0742.593-10.2150.693-73.2742.505-3.394Example 102.8960.0792.683-7.3550.656-75.5502.655-1.044Average 2.8820.0782.591-10.0850.658-74.5902.549-1.607Example 112.9050.1062.813-3.1670.938-66.6552.807-0.213Example 122.8140.1022.747-2.3810.905-67.0552.739-0.291Example 132.9210.1042.873-1.6430.919-68.0132.772-3.515Example 142.7290.1052.669-2.1990.966-63.8072.658-0.412Example 152.8290.1022.750-2.7930.838-69.5272.747-0.109Average 2.8400.1042.770-2.4360.913-67.0112.745-0.908.

[0126] As a result, as shown in Table 1 above, Examples 1 to 15, which are block-type acellular dermal matrix powder-based skin grafts, were about 5 to 6 times thicker in a dry state than Comparative Examples 1 to 5, which are sheet-type acellular dermal matrix skin grafts, and the density was about 1 / 5 times lower for Examples 1 to 5 at a concentration of 5%, about 1 / 4 times lower for Examples 6 to 10 at a concentration of 7%, and about 1 / 3 times lower for Examples 11 to 15 at a concentration of 9%. In addition, in the case of Comparative Examples 1 to 5, the change rate of thickness before and after compression in the hydrated state was within about 5%, but in Examples 1 to 15, the change rate of thickness before and after compression in the hydrated state was large at about 65% or more, and in particular, in the case of Examples 1 to 5, the change rate of thickness before and after compression in the hydrated state was very large at about 74% or more, confirming that compression was possible at a level similar to that of Comparative Examples 1 to 5. In addition, the change rate of thickness before and after compression and rehydration of Examples 1 to 15 and Comparative Examples 1 to 5 were all within 5%, confirming that they were restored to almost the same thickness as before compression. That is, it was confirmed that the block-type skin graft of the Examples had better compressibility and resilience properties than the sheet-type Comparative Examples. The block-type skin graft of the Examples can provide various advantages over the sheet-type skin graft due to its higher compressibility and ability to return to the pre-compression state when rehydrated after compression.

[0127] First, the block-type skin graft of the embodiment can achieve a similar thickness to a sheet-type skin graft when compressed, so it can act with a similar thickness to a sheet-type skin graft in a shallow damaged area, and in a deep damaged area, it can be compressed and transplanted to the damaged area, and when hydrated, it restores to a similar thickness before compression and fills the volume, so it can be applied to various damaged areas regardless of the depth of the damaged area. In particular, in cases where the damaged area is deep and the required thickness is high in the damaged area, the sheet-type skin graft has no choice but to perform a suture to fold the sheet and fix it in that state before transplanting it to the damaged area. In this case, the circulation of nutrients necessary for cell migration, attachment, and proliferation after transplantation may not be smooth. In addition, when a high-density sheet type is folded and transplanted, the patient may feel a foreign body sensation or discomfort due to the edge. In addition, soft tissue reconstruction using tissue transplantation is accompanied by radiation therapy that can cause tissue contraction. When a high-density sheet type is folded and transplanted, the innermost tissue is likely to become very hard, which results in the need to take it out again because it does not biodegrade for a long time, which is a fundamental limitation. On the other hand, the block-type skin graft of the embodiment can be transplanted as is at the desired thickness without the need for folding, so nutrient circulation can be smooth, the possibility of uneven engraftment or uneven tissue regeneration is low, and the patient feels much less discomfort, and the effect of radiation energy can be reduced.

[0128] In addition, it would be ideal for a skin graft to be injected through a minimal incision when transplanting it into the affected area. However, a sheet-type skin graft, such as the comparative example, has a high density, so the length of the incision site must be large when injected into the affected area. On the other hand, the block-type skin graft of the embodiment has a low density, so it can be injected into the affected area by compressing it, thereby minimizing the incision site. In addition, if it is transplanted after compressing, the volume can be filled again by body fluid and blood, so it can function as a minimal incision skin graft.

[0129] In addition, in terms of the patient's usability, the sheet type skin graft material has a hardness that can cause a foreign body sensation inside when transplanted to the affected area due to its high density, but the block type of the embodiment has a low density sponge shape and does not cause a foreign body sensation, so the usability can be improved.

[0130] In addition, compared to sheet-type skin grafts, a larger defect volume can be treated using the same weight of skin powder, and because it has a low density and thus has a large internal porosity, the hydration time before product use, which takes more than 10 minutes in sheet-type skin grafts, can be shortened to less than 2 minutes.

[0131]

[0132] Experimental Example 2. Evaluation of shape retention according to powder solution concentration

[0133] In order to evaluate the effect of the concentration of the acellular dermal matrix powder solution on the shape retention of the skin graft material manufactured by the method according to one embodiment, the degradation rates of the skin graft materials manufactured by varying the concentration of the powder solution to 5% (w / w), 7% (w / w), and 9% (w / w) were compared and evaluated.

[0134] Specifically, the initial weight of the skin graft sample manufactured after final sterilization, i.e., the dry weight, was measured, and then placed in a sterile specimen container and hydrated with phosphate buffered saline (PBS) at 1x concentration / 200 mL volume. Thereafter, the sample was stirred at 100 rpm at 37°C for 72 hours using a constant temperature stirrer. After removing the sample from the sterile specimen container, the remaining clumped portion was re-dried excluding the detached portion, and the weight of the re-dried sample was measured to confirm the shape retention according to hydration. The degradation rate was measured according to Equation 4 below.

[0135] [Formula 4]

[0136] Decomposition rate (%) = [(dry weight before hydration (G d ) - Re-assembled weight after disassembly test (G) h )) / Dry weight before hydration (G) d )] ×100

[0137] FIG. 9 is a result of evaluating the influence of the concentration of the powder solution on the shape retention of a skin graft material in manufacturing a block-type acellular dermal matrix powder-based skin graft material according to one embodiment.

[0138] As a result, as shown in Fig. 9, it was confirmed that all 5 to 9% (w / w) skin grafts exhibited excellent shape retention. This means that the block-type acellular dermal matrix powder-based skin graft according to one embodiment can stably maintain its shape even when hydrated by exudate from the affected area, even though it was manufactured on a powder basis.

[0139]

[0140] Experimental Example 3. Evaluation of shape retention according to the presence or absence of electron beam irradiation.

[0141] In order to evaluate the effect of electron beam irradiation on the shape retention of skin grafts manufactured by the method according to one embodiment, the concentration of the powder solution was changed to 5% (w / w), 7% (w / w), and 9% (w / w), and the decomposition rate of skin grafts manufactured by changing the presence or absence of electron beam (25 kGy) irradiation was compared and evaluated in the same manner as in Experimental Example 2.

[0142] FIG. 10 is a result of evaluating the effect on the shape retention of a skin graft material depending on the presence or absence of electron beam irradiation in manufacturing a block-type acellular dermal matrix powder-based skin graft material according to one embodiment.

[0143] As a result, as shown in Fig. 10, it was confirmed that the shape retention of the electron beam irradiated group was significantly improved compared to the electron beam non-irradiated group.

Claims

1. A block-type ADM powder-based skin graft material that is reprocessed into a block form by crushing and freeze-drying acellular dermal matrix (ADM). The above skin graft material is a block-type ADM powder-based skin graft material, wherein the absolute value of the thickness change rate before and after compression in Equation 2 below is 60% or more. [Formula 2] Thickness change rate before and after compression (%) = [(thickness after hydration and compression with 50N (T p ) - Thickness after hydration (T h )) / Thickness after hydration (T h )] ×100 In the above equation 2, the thickness after hydration is the central thickness measured 10 seconds after the skin graft is immersed in the tertiary purified water at room temperature for 3 minutes and then terminated, and the thickness after hydration and compression with 50 N is the central thickness measured 10 seconds after the skin graft is immersed in the tertiary purified water at room temperature for 3 minutes and then terminated, and the skin graft in a hydrated state is compressed in the thickness direction at room temperature until the force pressing the skin graft reaches 50 N and then maintained in that state for 10 seconds and then terminated.

2. In claim 1, the skin graft material is a block-type ADM powder-based skin graft material having a thickness of 1 cm or more.

3. In claim 1, the skin graft material is a block-type ADM powder-based skin graft material having a density of 0.2 g / cm3 or less.

4. In claim 1, the skin graft material is a block-type ADM powder-based skin graft material, wherein the absolute value of the thickness change rate before and after compression and rehydration of the following formula 3 is 5% or less. [Formula 3] Thickness change before and after compression and rehydration (%) = [(Hydration, compression with 50 N, and thickness after rehydration (T r )- Thickness after hydration (T h )) / Thickness after hydration (T h )] ×100 In the above equation 3, the thickness after hydration is the central thickness measured 10 seconds after the skin graft is immersed in tertiary purified water at room temperature for 3 minutes and then terminated, and the thickness after hydration, compression with 50 N, and rehydration is the central thickness measured 10 seconds after the skin graft is immersed in tertiary purified water at room temperature for 3 minutes and then terminated, and the hydrated skin graft is compressed in the thickness direction at room temperature until the force pressing the skin graft reaches 50 N and is maintained in that state for 10 seconds and then terminated, and the skin graft in the compressed state is immersed in tertiary purified water at room temperature for 30 seconds and then terminated.

5. In claim 1, the skin graft material is a block-type ADM powder-based skin graft material, wherein the absolute value of the thickness change rate before and after hydration of the following formula 1 is 1 to 20%. [Formula 1] Change in thickness before and after hydration (%) = [(Thickness after hydration (T h )- Thickness before hydration (T d )) / Thickness before hydration (T d )] ×100 In the above equation 1, the thickness before hydration is the central thickness of the skin graft measured at room temperature, and the thickness after hydration is the central thickness measured 10 seconds after the skin graft is immersed in tertiary purified water at room temperature for 3 minutes.

6. In claim 1, the skin graft material is a block-type ADM powder-based skin graft material containing 1 to 5 wt% of moisture, prepared by dispensing and freeze-drying an acellular dermal matrix powder solution into a mold.

7. A block-type ADM powder-based skin graft material according to claim 6, wherein the acellular dermal matrix powder is obtained by crushing a freeze-dried sheet-type acellular dermal matrix.

8. A block-type ADM powder-based skin graft material according to claim 7, wherein the freeze-dried sheet-type acellular dermal matrix has a moisture content of 3 to 10 wt%.

9. A block-type ADM powder-based skin graft material according to claim 6, wherein the acellular dermal matrix powder solution has a concentration of 5 to 9% (w / w).

10. A block-type ADM powder-based skin graft material according to claim 1, wherein the acellular dermal matrix powder has a particle size of 2,000 um or less.

11. A block-type ADM powder-based skin graft material according to claim 1, wherein the acellular dermal matrix is ​​of homologous or xenogeneic origin.

12. A block-type ADM powder-based skin graft material according to claim 1, wherein the skin graft material is sterilized by irradiating with electron beams.

13. A block-type ADM powder-based skin graft material according to claim 6, wherein the acellular dermal matrix powder solution further comprises a physiologically active substance, drug, or additive.

14. In claim 1, the skin graft material is a block-type ADM powder-based skin graft material in which stem cells are cultured.

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