Artificial Gastrointestinal Tissue for Endoscopic Submucosal Dissection(ESD) Training and Method for Manufacturing the Same

Abstract

The present invention relates to an artificial digestive tract tissue for training in endoscopic submucosal dissection (ESD) and a method for manufacturing the same. Specifically, the invention relates to an artificial digestive tract tissue configured to mimic the mucosal layer, submucosal layer, and muscle layer constituting the human digestive tract tissue in a multilayer structure, such that swelling occurs upon liquid injection and a color change occurs due to changes in salt concentration, and to a casting and curing-based hydrogel molding process for manufacturing the same. According to the present invention, the problems associated with existing animal tissue-based ESD training simulators can be resolved, repeated use is possible, and training tailored to the structural characteristics of specific organs (stomach, large intestine, small intestine, etc.) is possible.

Description

Technology Field

[0001] The present invention relates to an artificial digestive tract tissue for endoscopic submucosal dissection (ESD) training, and more specifically, to an artificial digestive tract tissue for ESD training that artificially replicates the multilayer structure of the human digestive tract and can reproduce the entire surgical process, including fluid injection, incision, dissection, and hemostasis. Background Technology

[0002] Endoscopic submucosal dissection (ESD) is an endoscopic treatment used for the resection of gastrointestinal lesions, such as early gastric cancer and colorectal tumors, and the operator's proficiency significantly influences the success of the procedure.

[0003] Generally, in clinical practice, to separate a lesion from surrounding tissue, a method is used in which physiological saline, glycerol, hyaluronic acid solution, etc., are first injected into the submucosal layer surrounding the lesion to cause the lesion to swell, and then the area around the lesion is incised using a special endoscopic knife and the submucosal layer is dissected.

[0004] However, for conventional training, animal tissues such as pig stomachs or simple synthetic resin models were mainly used, but they had limitations such as low similarity to the multilayer structure of human organs, a lack of realistic swelling response when liquid was injected into the submucosal layer, the inability or limited use of electrocautery equipment, and the inability to perform tumor target training.

[0005] Accordingly, there is a need to develop a new ESD training simulator that has a structure and physical properties similar to those of an actual clinical environment, enables the use of electrocautery equipment, and allows for training in liquid injection, incision, dissection, and hemostasis. Prior art literature

[0006] Japanese Registered Patent Publication No. 6948207 (September 22, 2021) The problem to be solved

[0007] The problem that the present invention aims to solve is to provide a simulator that simulates the multilayer structure of the human digestive tract to provide an ESD training environment similar to reality, and a method for manufacturing the same. means of solving the problem

[0008] To solve the above problem, the present invention can provide an artificial digestive tract tissue for training in endoscopic submucosal dissection (ESD), wherein the tissue is composed of a multilayer artificial tissue including a mucosal layer, a submucosal layer, and a muscle layer, wherein the mucosal layer exhibits electrical conductivity through ion solution treatment, and the submucosal layer is formed as a porous hydrogel and configured to swell when a liquid is injected or to change color depending on the salt concentration of the liquid.

[0009] According to one embodiment of the present invention, the submucosal layer is characterized by being prepared by an oil-in-water emulsion technique.

[0010] In addition, the mucosal layer and muscle layer are characterized by being able to be formed through a casting and curing process.

[0011] In addition, the artificial digestive tract tissue is characterized by the insertion of a tumor mimic, which enables tumor resection training.

[0012] In addition, the artificial digestive tract tissue is characterized by having a structure corresponding to any one of the stomach, large intestine, small intestine, duodenum, or esophagus.

[0013] According to another embodiment of the present invention, an artificial organ simulator for endoscopic submucosal dissection (ESD) training in the shape of a human organ can be provided, characterized by including the artificial digestive tract tissue.

[0014] In addition, the above simulator is characterized by being capable of training in marking, incision, dissection, and hemostasis using electrocautery equipment.

[0015] According to another embodiment of the present invention, the present invention may provide a method for manufacturing an artificial digestive tract tissue for endoscopic submucosal dissection (ESD) training, comprising the steps of: (a) manufacturing a submucosal layer formed of a porous hydrogel; (b) forming a mucosal layer by coating and curing a composition for forming a mucosal layer on one side of the submucosal layer; and (c) forming a muscle layer by coating and curing a composition for forming a muscle layer on the opposite side of the submucosal layer. Effects of the invention

[0016] According to the present invention, a multilayer structure can be implemented to ensure similarity to the physical structure of actual human organs, such as the stomach or large intestine. In addition, swelling and color change occur upon liquid injection, providing a training effect similar to reality.

[0017] In addition, by using an electrically conductive hydrogel to mimic the human body structure, it is possible to use electrocautery equipment that utilizes high-frequency energy. As a result, not only is it possible to train the entire process of ESD procedures, such as liquid injection, incision, dissection, and hemostasis, but targeted resection training is also possible by incorporating tumor mimics.

[0018] In particular, the multilayer tissue mimic of the present invention effectively implements different mechanical heterogeneity by layer, thereby providing tactile-based feedback that allows for stepwise learning of the risk of superficial incision, submucosal dissection, and muscle layer perforation during ESD procedure training. Brief explanation of the drawing

[0019] Figure 1 is a cross-sectional view of the three-layer structure of an artificial digestive tract tissue for ESD training according to the present invention. Figure 2 shows (a) a photograph of the color change due to solution absorption after blue saline solution is injected, and (b) a cross-sectional view of a tumor model in which the submucosal layer is swollen. FIG. 3 is a diagram showing the practice of (a) marking, (b) solution injection, and (c) electrocautery using an artificial tissue according to one embodiment of the present invention. FIG. 4 is a flowchart illustrating a method for manufacturing artificial tissue according to one embodiment of the present invention. Figure 5 is a graph showing the results of measuring the physical properties of an artificial tissue according to one embodiment of the present invention. Specific details for implementing the invention

[0020] Hereinafter, embodiments are described in detail with reference to the attached drawings. However, various modifications may be made to the embodiments, and thus the scope of the patent application is not limited or restricted by these embodiments. It should be understood that all modifications, equivalents, and substitutions to the embodiments are included within the scope of the rights.

[0021] The terms used in the embodiments are for illustrative purposes only and should not be interpreted as intended to be limiting. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as "comprising" or "having" are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0022] Hereinafter, a multilayered artificial digestive tract tissue included in an artificial organ simulator for ESD training according to one embodiment of the present invention will be described in detail.

[0023] FIG. 1 is a cross-sectional view of an artificial digestive tract tissue with a multilayer structure according to the present invention, which is composed of a mucosa, a submucosa, and a muscular layer (or muscle) similar to the wall of an actual digestive tract.

[0024] The above mucosal layer, submucosal layer, and muscle layer can be manufactured through a lamination and curing process using their respective compositions, and we will begin by describing the composition used to manufacture the submucosal layer, which is the first to be produced in the manufacturing sequence of the artificial digestive tract tissue.

[0026] <Submucosal layer composition>

[0027] The artificial submucosal layer (200) that is peeled off together with the mucosal layer during ESD training is located between the mucosal layer (100) and the muscle layer (300) as in FIG. 1 and is made of a porous hydrogel suitable for expressing lesions.

[0028] In the present invention, the composition for preparing the submucosal layer comprises a main component, a curing agent, and a catalyst. The main component is a mixture of acrylamide monomer (AM), alginate, mineral oil, the surfactant Tween 80, and distilled water. The curing agent is a mixture of ammonium persulfate (APS), N,N'-methylenebisacrylamide (MBA), and distilled water. The catalyst used to promote the reaction is tetramethylethylenediamine (TEMED).

[0029] The acrylamide monomer constituting the subject is included in an amount of 8 to 15 weight% relative to 100 weight% of the submucosal layer composition. If the acrylamide is included in an amount less than 8 weight%, it is undesirable because it has a soft texture due to a Young's modulus lower than that of the actual submucosal layer, and if it is included in an amount exceeding 15 weight%, it is also undesirable because it has a hard texture due to a Young's modulus becoming too high.

[0030] The above alginate is included in an amount of 0.3 to 0.7 weight% relative to 100 weight% of the submucosal layer composition. If the above alginate is included in an amount of less than 0.3 weight%, the mechanical strength of the submucosal layer is weakened and the tissue density becomes non-uniform, and if it exceeds 0.7 weight%, the viscosity of the submucosal layer composition becomes too high, resulting in poor processability, and the Young's modulus of the submucosal layer increases, causing the tissue to become excessively hard, which is undesirable.

[0031] The above mineral oil is included in an amount of 35 to 45 weight% relative to 100 weight% of the submucosal layer composition. Mineral oil is a non-polar oil component used in cosmetics, pharmaceutical formulations, tissue engineering gels, emulsions, etc., and in the present invention, it functions to form the oil phase of an oil-in-water emulsion after the main component, curing agent, and catalyst component are all mixed.

[0032] The above Tween-80 is a nonionic surfactant with an HLB value of 15.0, included in an amount of 0.9 to 1.6 weight% relative to 100 weight% of the submucosal layer composition, and serves to stabilize the oil-in-water emulsion.

[0033] The above APS is included in an amount of 0.1 to 0.3 weight% relative to 100 weight% of the submucosal layer composition and can be used to initiate polymerization by forming radicals through thermal energy.

[0034] The above MBA is included in an amount of 0.01 to 0.03 weight% relative to 100 weight% of the submucosal layer composition and can be used to form a three-dimensional network structure by covalently connecting polymerizable monomers such as acrylamide or alginate. If the amount of the MBA exceeds 0.03 weight%, the toughness of the tissue is lowered, causing it to tear easily, and consequently, suturing becomes impossible, which is undesirable.

[0035] The above distilled water constitutes the remaining components of the submucosal layer composition, and the total amount of distilled water is divided into a certain ratio and used as a solvent for the main component mixture and the curing agent mixture to ensure good dispersion of each mixture.

[0036] In addition, the above distilled water functions to form a water phase in an oil-in-water emulsion after all the components constituting the submucosal layer composition are mixed.

[0037] The TEMED added as a catalyst can be added in a certain amount (several to several hundred μL) relative to the submucosal layer composition to significantly promote the reaction in which the APS generates radicals and to proceed with gel polymerization quickly and uniformly, and if the amount of the submucosal layer composition increases, the required amount may be increased accordingly.

[0038] As previously described, when all components of the submucosal layer composition of the present invention are mixed, an oil-in-water type emulsion is formed, and a porous hydrogel layer can be formed through a curing step.

[0039] In addition to the method of using an emulsion template as in the present invention, a porous hydrogel layer with a three-dimensional network structure can be formed using gas foaming, particulate leaching, freeze-drying, 3D bioprinting, etc., but it is more preferable to use an emulsion template capable of forming uniform micropores, especially an oil-in-water type emulsion.

[0040] In such oil-in-water emulsion systems, the ratio of the oil phase to the water phase is a key factor in determining the pore size of the porous hydrogel after curing. That is, if the proportion of the oil phase in the submucosal layer composition increases relatively, the pore size and porosity increase.

[0041] However, if the proportion of the oil phase exceeds the appropriate ratio, a phase transition occurs from the oil-in-water type to the water-on-oil type, so the mass ratio of the oil phase to the water phase preferred for obtaining the porous hydrogel layer of the present invention is 0.5 to 1.2:1.

[0042] Meanwhile, the amount of surfactant described above is also one of the key variables determining the pore size within the submucosal layer composed of a porous hydrogel layer. Surfactants not only contribute to the stabilization of oil-in-water emulsions but can also control the pore size depending on the amount added.

[0043] According to one embodiment of the present invention, as the amount of the nonionic surfactant Tween-80 increases, the emulsion becomes more stable, the pore size becomes smaller, and the submucosal layer becomes a dense structure, whereas if a small amount of Tween-80 is added, the pore size becomes relatively larger, but the emulsion becomes unstable.

[0044] The preferred amount of surfactant added is 0.9 to 1.6 weight% relative to 100 weight% of the submucosal layer composition, and after curing is complete, the average pore size of the porous hydrogel layer is in the range of 20 to 80 μm.

[0045] Another important experimental variable for controlling the pore size of the hydrogel layer is the stirring speed of the stirrer. That is, as the stirring speed increases, the shear stress increases, and as a result, oil droplets are dispersed more smallly and uniformly in the water-in-oil emulsion, which leads to a smaller pore size within the hydrogel layer after curing.

[0046] On the other hand, if the stirring speed is slow, the shear force is weak, so the oil droplets remain large and uneven, and ultimately, a pore structure with large pores and low uniformity is formed. Considering structural uniformity, swelling properties upon liquid injection, and mechanical strength, the preferred stirring speed of the present invention is 400 to 600 rpm, and after curing is completed, the average pore size of the porous hydrogel layer is in the range of 20 to 80 μm.

[0047] In the present invention, the size and shape of the pores inside the porous hydrogel layer could be controlled by optimizing the ratio of the oil phase to the water phase, the amount of surfactant, and the stirring speed, and as a result, the physical properties of the differentiated submucosal layer of the present invention could be secured.

[0048] Meanwhile, since porous hydrogel layers have low mechanical strength due to their pore-rich characteristics and are soft and easily torn, the present invention secures both strength and flexibility simultaneously through a double cross-linked structure of acrylamide and alginate as the material for the hydrogel layer.

[0049] By introducing a porous hydrogel layer as a submucosal material, the present invention enables the realization of a color change and swelling of the lesion tissue due to solution absorption when blue saline is injected during ESD surgery training, as shown in Fig. 2. In particular, by controlling the concentration of salt contained in the saline and the amount of saline, the size, rigidity, and degree of swelling of the tumor model can be formed to closely resemble reality, allowing trainees to perform tumor resection training similar to actual situations.

[0050] At this time, the preferred salt concentration of the saline solution is 0.9 to 1.5 g NaCl / 100 ml, which is equal to or slightly higher than the concentration of human body fluids, and is suitable for swelling the artificial lesion and maintaining the tumor shape when injected into the submucosal layer.

[0051] Meanwhile, although one embodiment of the present invention was described as a method of injecting a liquid such as saline into a porous hydrogel layer to induce a tumor or artificial lesion, trainees may also perform tumor removal training by separately fabricating a tumor-shaped layer or module and placing it on the mucosal layer or between the mucosal layer and the submucosal layer. In this case, the tumor shape can be realized in its actual size and shape using data obtained from the patient's CT, MRI, ultrasound, 3D scan, etc., thereby allowing trainees to practice in advance before actual surgery, and the tumor module may be manufactured to be replaceable.

[0053] <Mucosal layer composition>

[0054] The artificial mucosal layer (100) that can be observed with an endoscope during ESD training is the innermost layer of the actual digestive tract and must have the following characteristics.

[0055] In other words, friction must not be excessive so that the endoscope can move smoothly within the mucosal layer, and it must possess appropriate wettability. Furthermore, since air is injected to secure the lumen in actual endoscopy, it must be able to return to its original state due to elasticity after expansion when air or carbon dioxide is injected. In addition, the mucosal layer must be able to provide texture, elasticity, and physical properties similar to those of the actual mucosa during incision and dissection according to ESD surgical training.

[0056] In the present invention, the composition for manufacturing the mucosal layer comprises a main component, a curing agent, and a catalyst. The main component is a mixture of acrylamide monomer, alginate, agarose, and distilled water, and the curing agent is a mixture of APS, MBA, and distilled water. Additionally, TEMED, which is a catalyst that promotes the reaction, and an ionic material are added to enable electrical conductivity.

[0057] The acrylamide monomer constituting the subject is included in an amount of 20 to 25 weight% relative to 100 weight% of the mucosal layer composition. If the acrylamide is included in an amount of less than 20 weight%, it is undesirable because it has a soft texture due to a Young's modulus lower than that of an actual organ, and if it is included in an amount exceeding 25 weight%, it is also undesirable because it has a hard texture due to a Young's modulus becoming too high.

[0058] The above alginate is included in an amount of 0.1 to 0.4 weight% relative to 100 weight% of the mucosal layer composition. If the above alginate is included in an amount of less than 0.1 weight%, the mechanical strength of the mucosal layer is weakened and the tissue density becomes uneven, and if it exceeds 0.4 weight%, the viscosity of the mucosal layer composition becomes too high, resulting in reduced processability, and the Young's modulus of the mucosal layer increases, causing the tissue to become excessively hard, which is undesirable.

[0059] The agarose above is included in an amount of 0.5 to 4 weight percent relative to 100 weight percent of the mucosal layer composition, and the stiffness, which is a mechanical property of the artificial organ tissue, varies depending on the amount of agarose added.

[0060] In particular, if agarose is included in an amount exceeding 4 weight%, the Young's modulus of the mucosal layer becomes too high, which differs from the physical properties of actual human organs and makes it impossible to inject a solvent beneath the mucosal layer, which is undesirable. In addition, if the agarose content is less than 0.5 weight%, the hydrogel may not cure sufficiently or the electrocautery function may be weakened.

[0061] The above APS constituting the curing agent is included in an amount of 0.1 to 0.4 weight% relative to 100 weight% of the mucosal layer composition and can be used to initiate polymerization by forming radicals through thermal energy.

[0062] The above MBA is included in an amount of 0.01 to 0.03 weight% relative to 100 weight% of the mucosal layer composition and can be used to form a three-dimensional network structure by covalently connecting polymerizable monomers such as acrylamide or alginate. Meanwhile, if the amount of the MBA exceeds 0.03 weight%, the toughness of the tissue is lowered, causing it to tear easily, which makes suturing impossible and is therefore undesirable.

[0063] The above distilled water constitutes the remaining component of the mucosal layer composition, and the total amount of distilled water is divided into a certain ratio and used as a solvent for the main component mixture and the curing agent mixture to ensure good dispersion of each mixture.

[0064] The TEMED added as a catalyst can be added in a small amount (several to several hundred μL) relative to the total composition of the mucosal layer to significantly promote the reaction in which APS generates radicals and to proceed with gel polymerization quickly and uniformly, and the amount added can be increased proportionally as the amount of the mucosal layer composition increases.

[0065] Meanwhile, since the surgical tools used for ESD surgery training are generally two types of electrosurgical tools—monopolar and bipolar—that use high-frequency currents (e.g., ESD knives), the mucosal layer must be electrically conductive to respond to them.

[0066] In one embodiment of the present invention, the mucosal layer composition may further include one or more ionic substances selected from the group consisting of CaCl2, NaCl, FeCl3, and ZrOCl2 so that the mucosal layer has electrical conductivity, but is not limited thereto.

[0067] The above ionic substance can be added to the mucosal layer composition, or treated in a manner in which the ionic substance penetrates the mucosal layer by immersing the hardened mucosal layer in a solution containing the ionic substance for a certain period of time.

[0068] The molar concentration of the above ionic substance may be 0.25 to 6 M, and if the content of the ionic substance satisfies the above range, the physical properties of the mucosal layer are improved, and electrical conductivity can be appropriately controlled. That is, when the above ionic substance is included in the mucosal layer, the mucosal layer is generally 10 -3 to 10 -1 It exhibits electrical conductivity of S / cm, and especially when NaCl or KCl is added, 10 -1 It becomes possible to display up to S / cm or more.

[0069] As a result of these improvements, the electrocautery of the mucosal layer is enhanced, making it suitable for use as an artificial organ for ESD surgery practice. For example, as shown in Fig. 3, it can be used in electrocautery tools used throughout the surgery, such as surgical site marking, pre-cut, dissection, and coagulation.

[0070] Meanwhile, the mucosal layer may be made to exhibit electrical conductivity by adding a certain amount of an ionic biopolymer to the mucosal layer composition instead of the above-mentioned ionic substance. Examples of ionic biopolymers include, but are not limited to, chitosan, lysine-L-lysine, hyaluronic acid, and gelatin.

[0071] Additionally, by adding one or more conductive polymer monomers instead of the above-mentioned ionic biopolymer, the mucosal layer may be made to respond to electrocautery. Preferred examples include Poly(acrylic acid), Poly(vinyl alcohol), Poly(2-acrylamido-2-methylpropane sulfonic acid), Poly(styrene sulfonate), Sodium alginate, etc., which may be used alone or in a mixture of one or more, but are not limited thereto.

[0072] The above ionic material, ionic biopolymer, and conductive polymer can be included in the submucosal layer and muscle layer, respectively, in addition to the mucosal layer, as needed, so that all layers can exhibit electrical conductivity.

[0074] <Muscle layer composition>

[0075] The artificial muscle layer possesses relatively high strength and serves to support the entire digestive tract tissue, helping trainees recognize the incision depth when incising the submucosal layer containing the lesion during ESD surgery training.

[0076] Therefore, in actual surgery, perforation may occur if the endoscopic knife reaches the muscle layer, so it must be made harder than the submucosal layer so that the trainee can feel this difference through touch, and the color or texture must be different from the submucosal layer as shown in Figure 2 (b) so that the boundary of the layer can be clearly identified by endoscopy or the naked eye after incision or dissection of the lesion site.

[0077] In the present invention, the composition for manufacturing the muscle layer comprises a main component, a curing agent, and a catalyst similar to the mucosal layer composition, wherein a mixture of acrylamide monomer, alginate, agarose, and distilled water is used as the main component, a mixture of APS, MBA, and distilled water is used as the curing agent, and a small amount of TEMED is used as a catalyst to promote the reaction.

[0078] The acrylamide monomer constituting the subject is included in an amount of 15 to 22 weight% relative to 100 weight% of the muscle layer composition. If the acrylamide is included in an amount of less than 15 weight%, it is undesirable because it has a soft texture due to a Young's modulus lower than that of an actual organ, and if it is included in an amount exceeding 22 weight%, it is also undesirable because it has a hard texture due to a Young's modulus becoming too high.

[0079] The above alginate is included in an amount of 0.1 to 0.4 weight% relative to 100 weight% of the muscle layer composition. If the above alginate is included in an amount of less than 0.1 weight%, the mechanical strength of the muscle layer is weakened and the tissue density becomes uneven, and if it exceeds 0.4 weight%, the viscosity of the muscle layer composition becomes too high, resulting in reduced processability, and the Young's modulus of the muscle layer increases, causing the tissue to become excessively hard, which is undesirable.

[0080] The agarose above is included in an amount of 0.5 to 5 weight percent relative to 100 weight percent of the muscle layer composition, and the stiffness, which is a mechanical property of the artificial organ tissue, varies depending on the amount of agarose added.

[0081] In particular, if agarose is included in an amount exceeding 5 weight%, the Young's modulus of the muscle layer becomes too large, which is undesirable as it results in physical properties different from those of actual human organs. Additionally, if the agarose content is less than 0.5 weight%, the hydrogel may not be sufficiently cured.

[0082] The above APS constituting the curing agent is included in an amount of 0.1 to 0.4 weight% relative to 100 weight% of the muscle layer composition and can be used to initiate polymerization by forming radicals through thermal energy.

[0083] The above MBA is included in an amount of 0.01 to 0.03 weight% relative to 100 weight% of the muscle layer composition and can be used to form a three-dimensional network structure by connecting polymerizable monomers through covalent bonds.

[0084] The above distilled water constitutes the remaining components of the muscle layer composition, and the total amount of distilled water is divided into a certain ratio and used as a solvent for the main component mixture and the hardener mixture to ensure good dispersion of each mixture.

[0085] The TEMED added as a catalyst can be added in a small amount (several to several hundred μL) relative to the total composition of the mucosal layer to significantly promote the reaction in which APS generates radicals and to proceed with gel polymerization quickly and uniformly, and the amount added can be increased proportionally as the amount of the muscle layer composition increases.

[0087] Multilayered artificial digestive tract tissue

[0088] An artificial digestive tract tissue having 3 layers can be manufactured by laminating and curing the above mucosal layer, submucosal layer, and muscle layer compositions according to the manufacturing sequence of artificial digestive tract tissues (stomach, small intestine, large intestine) (e.g., Fig. 4).

[0089] Reflecting the fact that the average thickness of the actual stomach wall, small intestine wall, large intestine wall, etc., is different, the thickness of the mucosal layer, submucosal layer, and muscle layer of the artificial stomach according to one embodiment of the present invention can be manufactured in the ranges of 0.5~1.0mm, 1.0~2.5mm, and 1.5~3.0mm, respectively, and it is preferable that they be manufactured to be thicker than the small intestine wall and large intestine wall.

[0090] In addition, in the case of the artificial small intestine, the thickness of the mucosal layer, submucosa, and muscle layer can be manufactured in the ranges of 0.2–1.0 mm, 0.3–1.5 mm, and 1.0–2.0 mm, respectively.

[0091] Finally, the thicknesses of the mucosal layer, submucosa, and muscle layer of the artificial large intestine can be manufactured in the ranges of 0.2–1.0 mm, 0.5–1.0 mm, and 0.8–1.5 mm, respectively.

[0092] As such, the thickness ranges of the mucosal layer, submucosal layer, and muscle layer for each artificial organ have been set to be similar to those of actual organs, but ESD training can be conducted by changing the thickness of the mucosal layer, submucosal layer, and muscle layer as needed, and in particular, for artificial tissues that reflect the swelling phenomenon of the lesion tissue, the thickness of each layer can be changed to be thicker to facilitate surgical training such as incision and dissection.

[0094] <Example 1: Preparation of Artificial Digestive Tissue>

[0095] 1) Preparation of the submucosal layer

[0096] In one embodiment of the present invention, for the preparation of a submucosal layer, 200g of distilled water, 67g of acrylamide monomer, and 3g of alginate were first weighed and placed in a beaker, and then uniformly stirred at 300 rpm for 5 minutes using a mechanical stirrer. 7.5g of Tween-80, a surfactant, was added to the mixture, and stirred for an additional 5 minutes under the same stirring conditions (300 rpm). Subsequently, 240g of mineral oil was added, the stirring speed was increased to 500 rpm, and the mixture was stirred for 5 minutes to prepare a main mixture in which an oil-in-water emulsion was formed.

[0097] Next, a curing agent mixture made by stirring 60g of distilled water, 0.936g of ammonium persulfate (APS), and 0.11g of MBA at room temperature at 300 rpm for 5 minutes was added to the previously prepared main mixture and then stirred at 500 rpm for 5 minutes.

[0098] The submucosal layer composition was completed by finally adding 200 µl of TEMED, a catalyst, to a mixture of the main component and the curing agent, and stirring at a speed of 500 rpm for 10 minutes.

[0099] The above submucosal layer composition is injected into an acrylic mold without generating bubbles, and then cured in an oven at 70°C for 20 minutes. At this time, fine bubbles inside the composition may be removed by using a vacuum oven.

[0100] After removing the cured submucosal sheet from the mold, wash and store it. The final submucosal sheet is preferably 1 to 3 mm thick for ESD surgery training, but the thickness of the submucosal sheet can be increased or decreased as needed.

[0101] 2) Preparation of the mucosal layer

[0102] In one embodiment of the present invention, a mucosal layer was prepared by first weighing 80g of distilled water, 30g of acrylamide monomer, 0.2g of alginate, and 2g of agarose, placing them in a beaker, and then uniformly stirring them at 300 rpm for 5 minutes using a mechanical stirrer to prepare a main component mixture. Next, a curing agent mixture prepared by stirring 20g of distilled water, 0.2448g of ammonium persulfate (APS), and 0.0192g of MBA at room temperature at 300 rpm for 5 minutes was added to the previously prepared main component mixture and then stirred at 500 rpm for 5 minutes.

[0103] A mucosal layer composition was prepared by finally adding 84 μl of TEMED, a catalyst, to a mixture in which a main component mixture and a curing agent mixture were mixed in a weight ratio of 6:1, and stirring at a speed of 500 rpm for 10 minutes.

[0104] The submucosal layer sheet previously manufactured by the casting technique is cut to fit the size of an acrylic mold and then precisely positioned within the mold. Next, the mucosal layer composition is evenly applied to the upper surface of the submucosal layer sheet within the mold.

[0105] The above mold is maintained in an oven at 70°C for 10 minutes to perform a first curing, then a PET film is attached to the upper exposed surface of the cured mold, and a second curing is performed at 70°C for 5 minutes to complete a sheet with a 2-layer (multilayer) structure consisting of a mucosal layer and a submucosa layer.

[0106] 3) Preparation of the muscle layer

[0107] In one embodiment of the present invention, the preparation of a muscle layer was first prepared by weighing 80g of distilled water, 24g of acrylamide monomer, 0.2g of alginate, and 2g of agarose, placing them in a beaker, and then uniformly stirring them at 300 rpm for 5 minutes using a mechanical stirrer to prepare a main component mixture. Next, a curing agent mixture prepared by stirring 20g of distilled water, 0.2448g of ammonium persulfate (APS), and 0.0192g of MBA at room temperature at 300 rpm for 5 minutes was added to the previously prepared main component mixture and then stirred at 500 rpm for 5 minutes.

[0108] A muscle layer composition was prepared by finally adding 46 μl of TEMED, a catalyst, to a mixture in which a main component mixture and a curing agent mixture were mixed in a weight ratio of 6:1, and stirring at a speed of 500 rpm for 10 minutes.

[0109] The multilayer sheet of mucosal layer and submucosal layer, previously manufactured by the casting technique, is cut to fit the size of an acrylic mold and placed inside the mold such that the submucosal layer is positioned on top and the mucosal layer is positioned on the bottom. Next, the muscle layer composition is evenly applied to the upper surface of the submucosal layer sheet inside the mold.

[0110] After the above mold is first cured in an oven at 70°C for 10 minutes, a PET film is attached to the upper exposed surface, and then a second curing is performed at 70°C for 5 minutes to complete the production of a 3-layer multilayer structure sheet consisting of a mucosal layer, a submucosal layer, and a muscle layer.

[0111] The above-described multilayer structure sheet is cut using an ultrasonic cutter for use in ESD surgery training. Additionally, the above-described multilayer tissue sheet can be used to manufacture an artificial digestive tract simulator by placing it into a mold to form the shape of the stomach, small intestine, large intestine, etc.

[0112] As can be seen from this manufacturing method, since the present invention creates a multilayer tissue sheet using a casting technique, interlayer delamination is not easy, which is advantageous for ensuring long-term durability and can ensure stability against changes in heat and humidity or mechanical stress.

[0113] In addition, by adopting such a casting process, it is possible to realize a multi-layered structure of the organ, and by adjusting the thickness of each layer according to the type of digestive tract (stomach, small intestine, large intestine, etc.), it is possible to produce an artificial organ simulator that is similar in shape and physical properties to actual human organs.

[0114] As previously explained, the artificial organ simulator is manufactured by including artificial digestive tract tissue with excellent durability and stability, allowing for repeated washing and reuse, making it suitable for ESD training.

[0116] <Experimental Example 1: Evaluation of Physical Properties of Artificial Tissue>

[0117] For the multilayer tissue mimic of the present invention, the mucosal layer, submucosal layer, and muscle layer were separated and prepared, respectively, and their mechanical properties were evaluated through penetration tests and tensile tests. As a result of the evaluation, the material property data for each layer are shown in Fig. 5.

[0118] As a result of measuring the puncture stress of each layer, the submucosal layer showed a puncture stress of approximately 9.35 kPa, the muscular layer approximately 94.83 kPa, and the mucosal layer approximately 52.94 kPa.

[0119] Based on these results, the submucosal layer has low penetration resistance, making it easy for surgical instruments to enter, whereas the muscle layer exhibits the highest penetration resistance, indicating its suitability as a warning layer for immediately recognizing the risk of perforation during training. The mucosal layer has an intermediate level of penetration resistance between these two, allowing for tactile feedback similar to actual tissue when surgical instruments enter the surface layer (mucosa).

[0120] Next, looking at the results of the tensile toughness measurement, which is a value related to injection and peeling stability, the submucosal layer was measured to be approximately 111.75 kJ / m³, the mucosal layer to be approximately 63.97 kJ / m³, and the muscular layer to be approximately 155.93 kJ / m³.

[0121] Based on these measurement results, it can be seen that the submucosal layer exhibits high energy absorption characteristics despite relatively low penetration resistance, which implies that it can reproduce viscoelastic dissection behavior in which it stretches and resists during the injection and dissection processes of ESD procedures.

[0122] Therefore, the submucosal layer of the present invention mimics the characteristics of a stable peeling layer in actual clinical practice, and it can be seen that this supports, in terms of mechanical properties, the reason why the submucosal layer is utilized as the primary working space during ESD procedures.

[0123] Finally, looking at the tensile modulus measurement results, which are values ​​related to basic tactile sensation and stiffness, the submucosal layer was measured to be approximately 0.77 kPa, the mucosal layer to be approximately 33.45 kPa, and the muscular layer to be approximately 30.94 kPa.

[0124] Based on these measurement results, the submucosal layer exhibits very low stiffness, displaying the typical characteristics of soft tissue that is easily deformed when pressed by hand or contacted by an instrument. On the other hand, the mucosal and muscular layers exhibit relatively high stiffness, allowing for a clear distinction in tactile sensation between the layers. This enables the operator to perceive changes in the layers through mechanical feedback alone, without the aid of visual observation.

[0125] Thus, the multilayer tissue mimic according to one embodiment of the present invention can effectively reproduce the mechanical heterogeneity that appears in the mucosal layer-submucosal layer-muscle layer structure of actual human stomach tissue by differentially implementing unique puncture stress, tensile toughness, and tensile modulus for each layer.

[0126] The embodiments of the present invention described above can be implemented by various substitutions, modifications, and changes within the scope of the technical concept of the present invention, and such implementation can be easily realized by a person skilled in the art to which the present invention belongs based on the description of the embodiments described above. Explanation of the symbols

[0127] 10: Artificial digestive tract tissue 100: Mucosal layer tissue 200: Submucosal tissue 300: Muscle layer tissue 400: Lesion tissue

Claims

Claim 1 An artificial digestive tract tissue for training endoscopic submucosal dissection (ESD), wherein the tissue is composed of a multilayer artificial tissue including a mucosal layer, a submucosal layer, and a muscle layer, wherein the mucosal layer exhibits electrical conductivity through ion solution treatment, and the submucosal layer is formed of a porous hydrogel and configured to swell upon liquid injection or change color according to the salt concentration of the liquid. Claim 2 The artificial digestive tract tissue according to claim 1, characterized in that the submucosal layer is prepared by an oil-in-water emulsion technique. Claim 3 The artificial digestive tract tissue according to claim 1, characterized in that the average pore size of the submucosal layer is 20 to 80 μm. Claim 4 An artificial digestive tract tissue according to claim 2, characterized in that the mass ratio of the oil phase to the aqueous phase of the emulsion is 0.5 to 1.2:

1. Claim 5 The artificial digestive tract tissue according to claim 2, characterized in that the emulsion is formed at a stirring speed of 400 to 600 rpm. Claim 6 An artificial digestive tract tissue according to claim 1, characterized in that the electrical conductivity of the mucosal layer is imparted by either (i) a method of incorporating an ionic substance into the mucosal layer composition, or (ii) a method of immersing the hardened mucosal layer in a solution containing an ionic substance to impregnate the ionic substance. Claim 7 The artificial digestive tract tissue according to claim 1, characterized in that the ionic substance is one or more selected from the group consisting of CaCl₂, NaCl, FeCl₃, and ZrOCl₂. Claim 8 In claim 1, the electrical conductivity of the mucosal layer is 10 -3 to 10 -1 Artificial digestive tract tissue characterized by being S / cm. Claim 9 The artificial digestive tract tissue according to claim 1, characterized in that the mucosal layer and the muscle layer can be formed through a casting and curing process. Claim 10 The artificial digestive tract tissue according to claim 1, characterized in that the artificial digestive tract tissue further comprises (a) a tumor-mimicking swelling portion formed by liquid injection into the submucosal layer, or (b) a tumor-mimicking module that can be disposed on the mucosal layer or between the mucosal layer and the submucosal layer. Claim 11 The artificial digestive tract tissue according to claim 1, characterized in that the artificial digestive tract tissue has a structure corresponding to any one of the stomach, large intestine, small intestine, duodenum, or esophagus. Claim 12 The artificial digestive tract tissue according to claim 1, characterized in that the tissue reproduces mechanical heterogeneity of the mucosal layer, submucosal layer, and muscle layer by implementing different puncture stress and tensile properties for each layer. Claim 13 An artificial organ simulator for endoscopic submucosal dissection training in the shape of a human organ, characterized by including any one of the artificial digestive tract tissues selected from claims 1 to 12. Claim 14 In claim 13, the above-mentioned simulator is an artificial organ simulator for endoscopic submucosal dissection training, characterized by being capable of training marking, incision, dissection, and hemostasis using an electrocautery device. Claim 15 A method for manufacturing an artificial digestive tract tissue for endoscopic submucosal dissection (ESD) training, comprising: (a) a step of manufacturing a submucosal layer formed of a porous hydrogel; (b) a step of forming a mucosal layer by coating and curing a composition for forming a mucosal layer on one side of the submucosal layer; and (c) a step of forming a muscle layer by coating and curing a composition for forming a muscle layer on the opposite side of the submucosal layer. Claim 16 A method for manufacturing artificial digestive tract tissue for endoscopic submucosal dissection (ESD) training, characterized in that, in step (a) above, an oil-in-water emulsion is formed and then hardened to produce a submucosal layer. Claim 17 A method for manufacturing artificial digestive tract tissue for endoscopic submucosal dissection (ESD) training, characterized in that, in claim 15 or 16, steps (b) and (c) include casting and curing processes.

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