Microelectric field generation device for osteogenesis

Abstract

The present invention relates to an electrical stimulation device for promoting osteogenesis, which applies electrical stimulation to a bone defect part by using an induced current generated in vivo, and a method for promoting osteogenesis using same. The electrical stimulation device for promoting osteogenesis applies electrical stimulation to bone tissue, thereby helping the movement or proliferation of bone cells, promoting osteogenesis, and having high biocompatibility and safety by minimizing an invasive site in vivo. Furthermore, the electrical stimulation device for promoting osteogenesis can be implanted into a defect part of the gum bone, which is easily damaged by periodontal diseases, to reconstruct the bone, thereby effectively treating related diseases.

Description

Microelectric field generating device for bone formation

[0001] The present invention relates to an electrical stimulation device for promoting bone formation.

[0002] To restore lost bone tissue and bone defects after tumor treatment, various bone regeneration methods are utilized in fields such as dentistry, orthopedics, and plastic surgery. Representative methods include autologous and allograft bone grafting, and bone tissue regeneration-induced using barrier membranes. However, biomaterials such as bone grafts and barrier membranes are merely osteoconductive mediators and do not possess the osteoinductive properties necessary for initial bone formation. This results in slow bone formation after surgery, and thus requires a long treatment period.

[0003] To enhance the performance of bone grafts, bioactive substances with chemotaxis, such as extracellular matrix proteins, tissue growth factors, and bone morphogenetic proteins, have been utilized in vitro to provide rapid bone formation. However, when applied in vivo, these proteins are exposed to systemic circulation, making it difficult to maintain effective local concentrations. Furthermore, high doses are required to maintain effective concentrations in the body, and these high doses can lead to adverse effects, necessitating a technique to overcome these challenges. Furthermore, these proteins are expensive compared to commonly used grafts, and their short half-lives in vivo hinder their ability to continuously stimulate bone formation.

[0004] While conventional research has shown that electrical stimulation induces osteoblast proliferation, the effects on cells of varying current strengths, direct or alternating current, and constant or intermittent current flow have not been addressed, making it difficult to apply appropriate electrical stimulation for bone formation. Furthermore, electrical stimulation devices developed for bone formation typically require numerous electrodes and additional devices, such as power supplies, leading to safety and convenience limitations.

[0005] Accordingly, there is a need for an electrical stimulation device that can maximize the bone formation effect while minimizing the transplantation of artificial materials.

[0006] The purpose of the present invention is to provide an electrical stimulation device for promoting bone formation that applies electrical stimulation to bone tissue using an induced current generated in a living body.

[0007] In addition, the present invention aims to provide a method for promoting bone formation using the above-mentioned electrical stimulation device for promoting bone formation.

[0008] The present disclosure provides a first electrode implanted in a living body and positioned at a bone tissue site; and

[0009] A device for promoting bone formation, comprising: a second electrode electrically connected to the first electrode and extending outward from the skin;

[0010] The above electrical stimulation device may not include a power source.

[0011] The first electrode may include a conductive film.

[0012] The first electrode and the second electrode may be electrically connected by a conductive thread.

[0013] The second electrode may be positioned apart from the skin.

[0014] The second electrode may be a conductive thread and may be integrated with a conductive thread that is electrically connected to the first electrode.

[0015] The above bone tissue portion may be located in the gum bone.

[0016] The electrical stimulation device for promoting bone formation according to the present disclosure may apply electrical stimulation by increasing the potential difference between the first electrode and the second electrode as the living body performs movement.

[0017] The magnitude of the above electrical stimulation may be 1 to 15 mV / mm.

[0018] A method for promoting bone formation according to the present disclosure comprises the steps of: implanting a first electrode of an electrical stimulation device for promoting bone formation according to one embodiment of the present disclosure into a bone defect; and

[0019] The step of applying electrical stimulation to the bone defect by having the subject with the bone defect perform exercise may be included.

[0020] The above method for promoting bone formation further includes a step of transplanting a bone graft material into a bone defect area,

[0021] The first electrode of the above-mentioned electrical stimulation device for promoting bone formation may be in contact with the bone graft material.

[0022] The above bone defect may be the gum bone.

[0023] The implant method according to the present disclosure comprises the steps of generating gum bone using the bone formation promotion method according to one embodiment of the present disclosure; and

[0024] A step of implanting an implant into the gum bone may be included.

[0025] The electrical stimulation device for promoting bone formation according to the present invention can apply electrical stimulation to bone tissue to help bone cells move or proliferate and promote bone formation.

[0026] The electrical stimulation device for promoting bone formation according to the present invention is highly convenient to use and has high biocompatibility and safety by minimizing the area of ​​invasion in the body.

[0027] The electrical stimulation device for promoting bone formation according to the present invention can be implanted into a defective part of the gum bone that is easily damaged by periodontal disease to reconstruct the bone and effectively treat the related disease.

[0028] Figure 1 shows the appearance of a bone defect measured using an X-ray computed tomography device (Micro-CT).

[0029] Figure 2 shows the appearance of a bone defect immunostained with an alkaline phosphatase (ALP) marker measured using an optical microscope.

[0030] Figure 3 shows the appearance of a bone defect immunostained with the OCN (Osteocalcin) marker measured using an optical microscope.

[0031] Figure 4 shows the appearance of a bone defect immunostained with the OPN (Osteopontin) marker measured using an optical microscope.

[0032] The present invention will be described in detail below. Terms used herein, unless specifically defined, should be interpreted as generally understood by those skilled in the art. The drawings and examples in this specification are intended to facilitate the understanding and practice of the present invention by those skilled in the art. Content that may obscure the gist of the invention may be omitted from the drawings and examples, and the present invention is not limited to the drawings and examples.

[0033] The singular forms used in this specification are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0034] Additionally, the numerical range used in the present invention includes lower and upper limits and all values ​​within that range, increments logically derived from the shape and width of the defined range, all doubly defined values, and all possible combinations of upper and lower limits of numerical ranges defined in different shapes. Unless otherwise specifically defined in the specification of the present invention, values ​​outside the numerical range that may arise due to experimental error or rounding of values ​​are also included in the defined numerical range.

[0035] In this specification, terms such as “include,” “have,” and “equip” mean that a feature or component described in the specification exists, and unless specifically limited, do not exclude in advance the possibility that one or more other features or components may be added.

[0036] As used herein, “promoting osteogenesis” means promoting the migration or proliferation of bone cells to a bone site that is defective or in need of repair.

[0037] The present disclosure provides an electrical stimulation device for promoting bone formation that can promote differentiation of osteoblasts and maximize tissue regeneration by applying electrical stimulation optimized for bone formation.

[0038] An electrical stimulation device for promoting bone formation according to the present disclosure may include a first electrode implanted in a living body and positioned at a bone tissue site; and a second electrode electrically connected to the first electrode and extending outward from the skin.

[0039] The electrical stimulation device for promoting bone formation according to the present disclosure is advantageous in that it applies electrical stimulation to the bone tissue area through an electric field generated by the potential difference between the first electrode and the second electrode, and the potential difference between the electrodes changes due to the movement of the living body, thereby providing an optimal size of electrical stimulation to the bone tissue area.

[0040] Specifically, since the human body is composed of 70 to 80 percent water, which is a polar molecule, a dielectric phenomenon occurs, and the alternating current generated whenever the human body moves is transmitted to other parts of the body in the form of an alternating electric field by the water in the body. The propagating alternating electric field reaches the first electrode located at the bone tissue area, and an alternating electric field is input to the first electrode, and charge transfer occurs to the second electrode in a direction that cancels it out, and a potential difference is formed in the form of an alternating current between the first and second electrodes, so that the first electrode applies an electrical stimulus to the bone tissue area.

[0041] The electrical stimulation device for promoting bone formation according to the present disclosure may not include a power source, and can apply electrical stimulation suitable for bone formation with only the configuration of the first electrode and the second electrode, so it is excellent in economic efficiency and ease of use.

[0042] The above first electrode means an electrode that is implanted into a bone tissue area while maintaining a solid form and provides a contact surface with the bone tissue area, and specifically, the bone tissue area may be a bone defect area.

[0043] The first electrode may include a conductive membrane. Specifically, the conductive membrane does not produce harmful substances after being implanted into the bone tissue area, and any membrane used in the art can be used without limitation as long as it is a conductive membrane. The conductive membrane may be a conductive polymer or a conductive metal, and specifically, may be a membrane composed of at least one selected from the group consisting of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), polyethylenedioxythiophene, polyaniline, polypyrrole, polythiophene, polyp-phenylene, polyp-phenylenevinylene, polyacetylene, polydiacetylene, polythiophenevinylene, polyfullerene, polyvinyl alcohol, silver, copper, gold, and aluminum, and specifically, may be polyvinyl alcohol, but is not limited thereto. The conductive membrane is advantageous in that charges can move between the first electrode and the second electrode without loss, and electrical stimulation can be effectively applied to the bone tissue area.

[0044] In the past, bone formation methods used a shielding membrane, specifically, an absorbable shielding membrane made of a polymer of type I collagen, oxidized cellulose, polylactic acid, or polyglycolic acid, or a non-absorbable shielding membrane made of polytetrafluoroethylene (PTFE) were used, and the size of the electrical stimulation that could be applied to the bone defect was insufficient with the conventional membrane. In the present invention, a conductive membrane is used as a first electrode and electrically connected to a second electrode, thereby applying an electrical stimulation that is maximized compared to the size of the AC current in the body to the bone defect, thereby promoting bone formation.

[0045] According to one embodiment, the conductive film may further include an absorbable shielding film or a non-absorbable shielding film on one side, thereby enabling application of an electrical stimulus suitable for bone formation, and also enabling smooth bonding of new bone tissue through selective clustering of cells, thereby providing excellent tissue regeneration ability.

[0046] The first electrode and the second electrode may be electrically connected by a conductive thread. In one embodiment, the second electrode may be a conductive thread and may be integrated with a conductive thread that is electrically connected to the first electrode. Specifically, the conductive thread may be electrically connected to the first electrode to provide a path for charge movement with low contact resistance. The second electrode may be a conventional electrode having a plate-like structure, and may refer to a terminal portion of the conductive thread that extends out of the skin in the form of a conductive thread as described above. However, the structure of the second electrode is not limited to a specific form as long as the first electrode and the second electrode are electrically connected and the second electrode extends out of the skin.

[0047] The electrical stimulation device for promoting bone formation of the present disclosure can apply an electrical stimulation appropriate for bone formation by increasing the potential difference between the first electrode and the second electrode due to the alternating current field induced by the movement of the living body. According to one embodiment, the magnitude of the electrical stimulation that can be applied through the movement of the living body can be 1 to 15 mV / mm, specifically 3 to 10 mV / mm. In addition, the electrical stimulation generated can be in the form of an alternating current, specifically 1 to 50 Hz, but is not limited thereto. When applying an electrical stimulation with the magnitude described above, bone cells are differentiated without dying, thereby having the effect of promoting bone formation.

[0048] The bone tissue portion of the electrical stimulation device for promoting bone formation of the present disclosure may be located in the gum bone. When implant surgery is performed, if the gum bone is thin, the implant itself may not be possible, or even if the implant is placed, it may not adhere properly, limiting its long-term use. When the electrical stimulation device for promoting bone formation is inserted into the gum bone and used, it can promote the activity of osteoclasts and osteoblasts, thereby achieving a beneficial effect in gum bone reconstruction.

[0049] The method for promoting bone formation of the present disclosure may include the steps of: implanting a first electrode of an electrical stimulation device for promoting bone formation according to one embodiment of the present disclosure into a bone defect; and applying electrical stimulation to the bone defect by having a subject having the bone defect perform an exercise.

[0050] The above exercise may be a physical activity greater than low-intensity exercise, and preferably moderate-intensity exercise. The above exercise induces an alternating current within the body, increasing the potential difference between the electrodes, thereby applying electrical stimulation to the bone defect.

[0051] A method for promoting bone formation according to one embodiment of the present disclosure further includes a step of transplanting a bone graft material into a bone defect, and a first electrode of the electrical stimulation device for promoting bone formation may be in contact with the bone graft material.

[0052] The above bone graft material is a bone substitute, and when transplanted into a bone defect, it acts as a scaffold to help the growth of bone cells, thereby increasing the initial bone volume. According to the present disclosure, when electrical stimulation is applied to the bone secured with the bone graft material through the electrical stimulation device for promoting bone formation, a faster and more effective bone formation effect can be obtained. According to one embodiment, the bone graft material may be autologous bone, allogeneic bone, xenogeneic bone, synthetic bone, or a graft material, and specifically, may be a synthetic bone graft material such as hydroxyapatite (HA) or beta-tricalcium phosphate (β-TCP), and more specifically, may be hydroxyapatite. The synthetic bone graft material is biocompatible, has excellent bioabsorbability and structural stability, has a low possibility of immune rejection and cross-infection, and can reduce cytotoxicity and improve bone conductivity.

[0053] In a method for promoting bone formation according to one embodiment of the present disclosure, the bone defect may be gum bone.

[0054] The implant method of the present disclosure may include a step of generating gum bone using a method for promoting bone formation according to one embodiment of the present disclosure; and a step of implanting an implant into the gum bone.

[0055] The electrical stimulation device for promoting bone formation according to the present disclosure can be implanted into a defective part of the gum bone that is easily damaged by periodontal disease to reconstruct the bone and effectively treat the related disease.

[0056] Hereinafter, the electrical stimulation device for promoting bone formation according to the present invention will be described in detail through specific examples. However, the following examples are merely references for further explanation of the present invention and are not intended to limit the present invention, which may be implemented in various forms. Furthermore, the terminology used in the description of the present invention is merely intended to effectively describe specific embodiments and is not intended to limit the present invention.

[0057]

[0058] [Manufacturing Example 1] Manufacturing of an electrical stimulation device for promoting bone formation

[0059] The electrical stimulation device for promoting bone formation of the present disclosure comprises a conductive membrane measuring 10 mm × 10 mm in size, which is made of a salt-containing cross-linked polyvinyl alcohol hydrogel, and a conductive thread 6 / 0 Monosyn® electrically connected to the hydrogel. The conductive membrane is implanted into a bone defect and fixed with pins, and the conductive thread extends outwardly of the skin to a length of about 15 cm.

[0060] [Example 1]

[0061] surgical treatment

[0062] Rabbits (New Zealand white male rabbits), aged 9 to 20 months and weighing 3.0 to 3.5 kg, were induced under general anesthesia with ketamine hydrochloride (Ketalar®, Yuhan, Co., Seoul, Korea) and xylazine (Rumpun®, Bayer Korea Ltd., Seoul, Korea). The cranial surgical site was shaved, disinfected with povidone iodine, and infiltrated with 2% lidocaine (LidocaineHCl, Huons, Seoul, Korea). An incision was made along the central portion of the frontal bone from the anterior to the posterior portion, and the flap was elevated to the periosteum to expose the skull. Two circular defects, each 10 mm in diameter, were created using a 10-mm outer diameter trephine bur. Experimental materials were applied randomly to the formed left and right defects as follows, and the periosteum was sutured with 5-0 Vicryl® (Ethicon, Somerville, NJ, USA), and the scalp was sutured with 4-0 Monosyn® (B-Braun, Melsungen, Germany). The antibiotic gentamicin (5 mg / kg) was injected intramuscularly for 1 week after surgery, and 4 weeks after surgery, the experimental animals were sacrificed by intravenous injection of phenobarbital (100 mg / kg), and tissues were collected.

[0063] Right defect

[0064] In the above surgical procedure, 0.25 g of hydroxyapatite (HA) was inserted as a bone graft material into the right defect, and a conductive membrane of an electrical stimulation device for promoting bone formation according to Manufacturing Example 1 was placed thereon and fixed with four pins. A conductive thread of approximately 15 cm was connected to the conductive membrane, and the conductive thread was positioned so as to be exposed outside the rabbit's head and separated from the skin.

[0065] Left defect

[0066] The left defect was treated in the same way as the right defect, except that no bone graft was inserted.

[0067]

[0068] [Example 2]

[0069] The rabbit of Example 1 exercised for 30 minutes each in the morning and afternoon, and an average of 10 Hz alternating current electrical stimulation was applied due to the exercise.

[0070]

[0071] [Comparative Example 1]

[0072] The rabbit of Example 1 was placed in an iron cage, and an alternating current electric stimulus of 20 Hz was applied to the rabbit using a vibrator electrically connected to the iron cage.

[0073]

[0074] [Comparative Example 2]

[0075] The same procedure as in Example 1 was followed, except that a PTFE membrane (polytetrafluoroethylene) was fixed instead of the conductive membrane in the electrical stimulation device for promoting bone formation in Example 1.

[0076]

[0077] [Evaluation Example 1] Bone formation evaluation (1) - Micro CT observation

[0078] Tissue samples obtained from the above examples and comparative examples were observed and analyzed for bone formation findings using micro CT (SkyScan 1072, SkyScan, Aartselaar, Belgium).

[0079] As shown in Fig. 1, in the left and right defect areas, the density of the radiopaque phase of Examples 1 and 2 is higher than that of Comparative Examples 1 and 2. In particular, Example 2, which applied 10 Hz of electrical stimulation to the bone defect area through exercise, had a higher density of the radiopaque phase in the bone defect area than Example 1, which did not exercise, and Comparative Example 1, which applied 20 Hz of electrical stimulation, and thus it was confirmed that bone formation was promoted. In addition, it was confirmed that when a bone graft material was transplanted to the bone defect area in both Examples and Comparative Examples, the density of the radiopaque phase greatly increased, and bone formation occurred more smoothly.

[0080] Automatic image analysis program

[0081] Using an automatic image analysis program (Image-Pro Plus, Media Cybernetics, Silver Spring, Maryland, USA), the following items were calculated and measured for the above-taken Micro CT images. The results are shown in Table 1.

[0082] 1) New bone area (New bone, mm) 2 ): The area of ​​newly formed bone in the defect area.

[0083] 2) Residual particle (mm) 2 ): Area of ​​bone graft remaining in the defect area

[0084] New bone area (mm) 2 ) Residual bone graft material (mm) 2 ) Left Right Left Right Example 120.1351.07-41.58 Example 225.6852.9133.41 Comparative Example 111.4335.5928.42 Comparative Example 215.8745.6333.49

[0085] According to Table 1, the new bone area and tissue augmentation ratio of the example are superior to those of the comparative example, and it can be seen that the bone formation promotion effect is maximized in the right defect area where the bone graft material was transplanted in both the example and the comparative example.

[0086] [Evaluation Example 2] Bone formation evaluation (2) - Histological observation

[0087] Tissue samples collected from rabbits of the examples and comparative examples were fixed in 10% neutral formalin for 10 days, decalcified in 5% nitric acid for 5 days, and embedded in paraffin. The specimens were sectioned in the coronal midline at 5 μm thickness, and MT staining (Masson's. Trichrome collagen staining) and immunohistochemistry (IHC) targeting alkaline phosphatase (ALP), osteocalcin (OCN), and osteopontin (OPN), which are bone differentiation-related markers, were performed. The tissue slides of the specimens were observed under a light microscope (Olympus BX50, Olympus Optical Co., Tokyo, Japan).

[0088] The results are shown in Figures 2 to 4, and each Figure represents a) Example 1, b) Example 2, c) Comparative Example 1, and d) Comparative Example 2.

[0089] MT staining

[0090] In Figure 1, blue indicates areas where bone is formed, and red indicates areas where an inflammatory response occurs. As shown in Figure 1, in Example 2, the areas reacting in blue are the most numerous, indicating that bone formation is clearly promoted, while in Comparative Example 2, the areas reacting in red are widely formed, indicating that an inflammatory response occurs.

[0091] Tissue immunostaining

[0092] When ALP, OCN, and OPN, markers related to the promotion of bone differentiation, were stained in FIGS. 2 to 4, it can be seen that Examples 1 and 2 each reacted in brown over a wide area, indicating an increase in the expression of markers promoting bone differentiation. Meanwhile, the reason why Comparative Examples 1 and 2 also reacted to some markers is because the responses of all markers increased abnormally due to a high inflammatory response.

[0093]

[0094] In comprehensive consideration of the above results, in the cases of Examples 1 and 2 in which a constant electrical stimulation was applied to a bone defect using the electrical stimulation device for promoting osteogenesis of the present disclosure, osteogenesis was effectively promoted, and in particular, in the case of Example 2 in which an electrical stimulation of approximately 20 Hz was applied through an induced current generated by exercise, a high bone tissue increase ratio was observed, showing an excellent osteogenesis effect. In addition, the osteogenesis promotion effect was further enhanced when a bone graft material was transplanted to the bone defect.

[0095] On the other hand, in the case of Comparative Example 1, which applied an electrical stimulus of about 20 Hz, bone formation was rather reduced, and even when a PTFE membrane instead of a conductive membrane was used, bone formation did not occur smoothly and an inflammatory reaction occurred.

[0096] Through this, the electrical stimulation device for promoting bone formation of the present disclosure can apply an electrical stimulation of an appropriate size for bone formation, and has an excellent bone formation promotion effect, so it can be easily used industrially.

[0097] As described above, the present invention has been described through specific matters and limited examples and comparative examples, but these are provided only to help a more general understanding of the present invention, and the present invention is not limited to the above examples, and those skilled in the art to which the present invention pertains can make various modifications and variations based on this description.

[0098] Therefore, the idea of ​​the present invention should not be limited to the described embodiments, and all things that are equivalent or equivalent to the claims described below as well as the claims are considered to fall within the scope of the idea of ​​the present invention.

Claims

1. A first electrode implanted in a living body and positioned in a bone tissue area; and An electrical stimulation device for promoting bone formation, comprising a second electrode electrically connected to the first electrode and extending outward from the skin.

2. In paragraph 1, The above electrical stimulation device is an electrical stimulation device for promoting bone formation, which does not include a power source.

3. In paragraph 1, An electrical stimulation device for promoting bone formation, wherein the first electrode includes a conductive film.

4. In paragraph 1, An electrical stimulation device for promoting bone formation, wherein the first electrode and the second electrode are electrically connected by a conductive thread.

5. In paragraph 1, An electrical stimulation device for promoting bone formation, wherein the second electrode is positioned apart from the skin.

6. In paragraph 4, An electrical stimulation device for promoting bone formation, wherein the second electrode is a conductive thread and is integrated with a conductive thread electrically connected to the first electrode.

7. In paragraph 1, An electrical stimulation device for promoting bone formation, which applies electrical stimulation by increasing the potential difference between the first electrode and the second electrode as the above-mentioned living body performs movement.

8. In paragraph 7, An electrical stimulation device for promoting bone formation, wherein the magnitude of the electrical stimulation is 1 to 15 mV / mm.

9. In paragraph 1, The above bone tissue part is an electrical stimulation device for promoting bone formation, located in the gum bone.

10. A step of implanting a first electrode of an electrical stimulation device for promoting bone formation selected from any one of claims 1 to 9 into a bone defect; and A method for promoting bone formation, comprising: a step of applying electrical stimulation to a bone defect by causing a subject having the bone defect to perform exercise; 11. In paragraph 10, It further includes a step of transplanting bone graft material into the bone defect area, A method for promoting bone formation, wherein the first electrode of the electrical stimulation device for promoting bone formation is in contact with the bone graft material.

12. In paragraph 10, A method for promoting bone formation, wherein the above bone defect is the gum bone.

13. A step of creating gum bone using any one of the bone formation promotion methods selected from Articles 11 and 12; and An implant method, comprising: a step of implanting an implant into the gum bone;

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