KR102528666B1 - Patch for nerve suture with self-healing and manufacturing method thereof - Google Patents

Abstract

It relates to a nerve suture patch having self-healing ability and a method for manufacturing the same according to an embodiment of the present invention, and more particularly, to a self-healing nerve suture patch containing a self-healing polymer and a hydrogel and a method for manufacturing the same. . In the nerve suture patch, the patch is quickly attached to the nerve sheath due to the adhesiveness of the hydrogel, so that the damaged nerve can be easily sutured.

Description

Patch for nerve suture with self-healing ability and manufacturing method thereof

The present invention relates to a patch for nerve suture having self-healing ability and a method for manufacturing the same, and more particularly, to a patch for nerve suture having self-healing ability capable of chemical bonding with the nerve sheath and a method for manufacturing the same.

Peripheral nerve damage causes serious impairment in social life. Peripheral nerve injury patients occur in 2.8% of trauma patients. For example, in the United States, 360,000 severely paralyzed patients occur each year, 8,648,000 of whom end up with limitations in daily life, 4,916,000 of whom are bedridden, and peripheral nerve procedures are very common, and in Europe, 300,000 per year 200,000 people in the United States perform the procedure each year.

A peripheral nerve conduit is a connector that connects severed peripheral nerves or central nerves and guides them to be regenerated. It is difficult to connect the nerves of a limb severed due to an accident or surgery unless the severed area is carefully sutured.

However, direct suturing is impossible if the cut edges are more than 5 mm apart, and in this case, there is no other way than autologous nerve transplantation. However, autologous transplantation has disadvantages such as the need to use one's own nerve and limitations on the nerves that can be harvested. do.

Since the severed nerve has a property of growing at a rate of about 1 mm per day in the peripheral region, it is possible to regenerate the severed nerve by introducing a tube-shaped nerve conduit into the severed region using this characteristic.

A nerve conduit serves as a pathway for connecting damaged nerve tissue and regenerating nerve fibers. When using a nerve conduit, connect both ends of the severed nerve to this conduit, and nerve fibers grow from one side of the nerve within the conduit. It uses the principle of being reproduced.

The use of a nerve conduit was first successful in 1990 by Lundborg using a silicone tube. However, due to the nature of silicone, it is difficult to decompose, so there was a hassle in that the tube had to be removed through reoperation after the nerve was completely restored. In addition, since non-absorbable silicone conduits do not have porosity around the conduits, nutrients cannot pass through, making it difficult to regenerate nerves, and even if regenerated, the speed is slow.

Meanwhile, in Japan, the same biodegradable polymer is used as a basic material for the purpose of applying to longer defects, the inner side is filled with a collagen sponge with excellent tissue compatibility, and the outer side is filled with a collagen solution several times. A applied type of nerve conduit was developed, and as a result of animal experiments, it was confirmed that complete restoration was achieved in the peripheral nerve area with a loss of about 8 cm, and it has been applied clinically since 2002.

However, in the case of these nerve conduits, PLA, which is used as a basic material, lacks flexibility, so unless a reinforcing material is used to strengthen the physical properties, it will remain intact until complete nerve tissue restoration due to frequent muscle movements after implantation in the body. It is difficult to secure the inner diameter and maintain the shape, and at the same time, there is a problem of crumbling even when suturing the severed nerve.

On the other hand, a conventional nerve conduit is obtained by injecting a conduit-forming material into a conduit mold having a certain shape, or manufacturing a conduit by smearing the conduit-forming material around the conduit mold, and then inserting fibers into the conduit. Since this conventional manufacturing method uses a conduit mold, the manufacturing process of the conduit mold must be performed, the size of the nerve conduit cannot be manufactured below a certain level according to the conduit mold, and the conduit mold must be removed. has

In addition, since the conventional nerve conduit is different from the modulus of the peripheral nerve, nerve compression may act very severely. In this case, a problem of causing nerve necrosis may occur due to lack of oxygen supply through blood vessels in the peripheral nerve.

Therefore, it is necessary to develop a nerve suture technique that can solve the problems of the conventional nerve conduit.

Republic of Korea Patent No. 10-0718073

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned problems, and is to provide a nerve suture patch having excellent elasticity and a self-healing ability capable of chemically bonding with peripheral nerves and a method for manufacturing the same.

In order to achieve the above purpose,

The present invention includes a self-healing polymer and a hydrogel patch,

The hydrogel patch is alginate, polyacrylamide (PAA, poly acrylamide), polyetherimide (PEI, polyetherimide), polyethylene glycol (PEG), polyethylene oxide (PEO), polyhydroxyethyl methacrylate (PHEMA), poly Vinyl alcohol (PVA), poly(N-isopropylacrylamide) (PNIPAM), polyvinylpyrrolidone (PVP), polylactic acid (PLA), polyglycolic acid (PGA), polycaprolactone (PCL), gelatin ( gelatin), collagen, carrageenan, hydroxyalkyl cellulose, alkyl cellulose, silicone, rubber, agar, carboxyvinyl copolymer, polydioxolane, polyacrylacetate, polyvinyl chloride, fibrin, Matrigel , Gelatin methacrylate (GelMA), maleic anhydride / vinyl ether, chitosan (Chitosan), and provides a self-healing patch for nerve suture, characterized in that it comprises at least one selected from the group consisting of boronic acid.

As an embodiment of the present invention, the hydrogel patch is characterized in that it contains alginate and boronic acid.

As another embodiment of the present invention, the hydrogel patch is characterized in that it includes a conjugate polymer in which boronic acid is conjugated to alginate.

As another embodiment of the present invention, the hydrogel patch is characterized in that it further comprises a nerve growth factor.

As another embodiment of the present invention, the self-healing polymer is polydimethylsiloxane (PDMS), polyethyleneoxide (PEO), perfluoropolyether (PFPE), polybutylene (PB ), poly(ethylene-co-1-butylene), poly(butadiene), hydrogenated poly(butadiene) ), polybutylene and poly(ethylene oxide)-poly(propylene oxide) block copolymers or random copolymers, and poly(hydroxyalkanoates) A first moiety comprising a polymer backbone selected from the group consisting of (poly (hydroxyalkanoate)) and 4,4'-methylenebis (phenylurea) (4,4' (phenylurea), MPU));

It is characterized in that it contains a second moiety containing isophorone bisurea (IU).

As another embodiment of the present invention, the self-healing polymer exhibits a Young's modulus of 1 to 3000 kPa and an elongation of 1200 to 3000.

In addition, the present invention comprises the steps of preparing a self-healing polymer film by applying a self-healing polymer on a substrate and drying it (S1);

Plasma treatment on the surface of the film (S2); and

It provides a method for manufacturing a self-healing patch for nerve suture, comprising the step (S3) of laminating a hydrogel on the surface of the plasma-treated film.

The self-healing polymer has excellent stress relieving properties, so when applied to peripheral nerves, there is little nerve compression, and the hydrogel applied together has a mechanical modulus similar to that of peripheral nerves, so that shear force and compression are minimized. It can be.

1 is a diagram schematically showing when a hydrogel patch and a self-healing polymer film in the present invention are applied to a peripheral nerve.
Figure 2 shows the results of confirming the adhesive force and physical properties of the nerve suture patch having self-healing ability according to an embodiment of the present invention.
3 is a view showing the result of confirming that the nerve is sutured by introducing a nerve suture patch having self-healing ability according to an embodiment of the present invention into a severed nerve.

Since the present invention can make various changes and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description.

However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the present invention, if it is determined that a detailed description of related known technologies may obscure the gist of the present invention, the detailed description will be omitted.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

In the present invention, terms such as “comprise” or “have” are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that it does not preclude in advance the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

The present invention relates to a nerve sealing patch having a self-healing ability, and more particularly, to a nerve sealing patch having a self-healing ability capable of chemical bonding with a nerve sheath.

In one embodiment of the present invention,

Including self-healing polymers and hydrogel patches,

The hydrogel patch is alginate, polyacrylamide (PAA, poly acrylamide), polyetherimide (PEI, polyetherimide), polyethylene glycol (PEG), polyethylene oxide (PEO), polyhydroxyethyl methacrylate (PHEMA), poly Vinyl alcohol (PVA), poly(N-isopropylacrylamide) (PNIPAM), polyvinylpyrrolidone (PVP), polylactic acid (PLA), polyglycolic acid (PGA), polycaprolactone (PCL), gelatin ( gelatin), collagen, carrageenan, hydroxyalkyl cellulose, alkyl cellulose, silicone, rubber, agar, carboxyvinyl copolymer, polydioxolane, polyacrylacetate, polyvinyl chloride, fibrin, Matrigel , Gelatin methacrylate (GelMA), maleic anhydride / vinyl ether, chitosan (Chitosan), and provides a self-healing patch for nerve suture, characterized in that it comprises at least one selected from the group consisting of boronic acid. The self-healing patch for nerve suture will be described in more detail below.

Prior to description, among the terms used in the present invention, "self-healing polymer" may refer to a polymer that recognizes a damaged or scratched part by itself and restores it to a previous state. In particular, in one embodiment of the present invention, the combination of the dynamic stress relaxation characteristics of the self-healing polymer and the low modulus of the hydrogel has advantages in preventing nerve necrosis due to nerve compression and facilitating nerve regeneration.

1 is a schematic diagram showing a process of introducing the self-healing patch for nerve suture of the present invention into a peripheral nerve.

Referring to FIG. 1 , a self-healing patch for nerve suture according to an embodiment of the present invention includes a self-healing polymer and a hydrogel patch. Specifically, a hydrogel patch may be included on one side of the self-healing polymer film, and when the self-healing patch for nerve suture is applied to the nerve sheath, the hydrogel patch may be attached to the nerve sheath.

In a specific embodiment, the hydrogel patch, the hydrogel patch is alginate, polyacrylamide (PAA, poly acrylamide), polyetherimide (PEI, polyetherimide), polyethylene glycol (PEG), polyethylene oxide (PEO), polyhydric Oxyethyl methacrylate (PHEMA), polyvinyl alcohol (PVA), poly(N-isopropylacrylamide) (PNIPAM), polyvinylpyrrolidone (PVP), polylactic acid (PLA), polyglycolic acid (PGA) , polycaprolactone (PCL), gelatin, collagen, carrageenan, hydroxyalkyl cellulose, alkyl cellulose, silicone, rubber, agar, carboxyvinyl copolymer, polydioxolane, polyacrylacetate, polyvinyl chloride , fibrin, Matrigel, gelatin methacrylate (GelMA), maleic anhydride/vinyl ether, chitosan, and boronic acid. For example, the hydrogel patch includes alginate and boronic acid, and may include a conjugate polymer in which boronic acid is conjugated to alginate.

In addition, the hydrogel patch according to an embodiment of the present invention may further include a neurotrophic factor (NGF), and the nerve growth factor may facilitate nerve regeneration during nerve suture.

The hydrogel patch is prepared by combining a gel forming agent and a crosslinking agent, and by designing a transdermally absorbable preparation having a patch form, problems of conventional skin irritation, toxicity problems due to residual solvents and/or unreacted monomers, The long-term crosslinking problem can be fundamentally solved.

Furthermore, self-healing polymers include polydimethylsiloxane (PDMS) polyethyleneoxide (PEO), perfluoropolyether (PFPE), polybutylene (PB), poly(ethylene-co-1-butylene), poly(butadiene), hydrogenated poly(butadiene), polybutylene and polybutylene. A first moiety comprising a polymer backbone selected from the group consisting of (ethylene oxide)-poly(propylene oxide) block copolymers or random copolymers, and poly(hydroxyalkanoate), and 4,4′ (phenylurea) (MPU) and a second moiety including isophorone bisurea (IU), wherein the self-healing polymer exhibits a Young's modulus of 1 to 3000 kPa and an elongation of 1200% to 3000%. The self-healing polymer of the present invention has a modulus similar to the modulus of a peripheral nerve by having the above Young's modulus and elongation, and through this, when wrapped in contact with a damaged nerve, shear force and compression can be minimized. there is.

More specifically, the self-healing polymer may be a PDMS-MPU _x -IU _1-x polymer represented by Formula 1 below. Meanwhile, x may range from 0.3 to 0.6.

[Formula 1]

Furthermore, a self-healing patch for nerve suture is prepared by applying an alginate-boronic acid conjugate polymer to the polymer film produced with the self-healing polymer. 10% of the entire polymer chain of the alginate can be substituted with boronic acid, and through this, it can be easily attached to the nerve with adhesiveness.

As described above, the nerve suture patch includes a self-healing polymer and an adhesive polymer film, and the adhesive polymer film includes a polysaccharide material such as alginate.

As such, a patch in which the self-healing polymer is thinly coated with the polysaccharide material may be applied to the nerve. Through this, the patch of the present invention can easily suture the severed nerve.

In addition, the nerve suture patch may further include nerve growth factor (NGF) in the alginate-boronic acid conjugate polymer.

As described above, the present invention relieves nerve compression by using a patch containing a self-healing polymer with excellent stress relaxation properties, unlike conventional nerve conduits that generate nerve compression by having a modulus different from that of peripheral nerves. And, by grafting a hydrogel having a mechanical modulus of 10 to 99 kPa to the self-healing polymer, nerve compression can be removed by providing a nerve suture patch kit similar to peripheral nerve modulus.

Therefore, the present invention can provide a nerve splicing method using the above-described nerve suture kit, and the nerve splicing surgical method may include the following steps:

(1) wrapping and contacting both cut parts of the severed nerve with the self-healing patch for nerve suture;

(2) leaving the contact after the contact; and

(3) removing the nerve suture patch.

In addition, the present invention provides a self-healing polymer film by applying a self-healing polymer on a substrate and then drying the step (S1);

Plasma treatment on the surface of the film (S2); and

It is possible to provide a method for manufacturing a self-healing patch for nerve suture, including laminating a hydrogel on the surface of the plasma-treated film (S3).

The plasma treatment is an oxygen plasma treatment, which hydrophilically modifies the surface of the self-healing polymer so that the hydrogel can be easily laminated.

Hereinafter, the present invention will be described through the following examples. However, the examples are for explaining the present invention in detail, and the scope of the present invention is not limited to the following examples.

<Example>

Example 1. Preparation of nerve suture patch having self-healing ability

1-1. Manufacture of polymer film

A self-healing polymer film was prepared using a polymer of PDMS-MPU _x -IU _1-x of Formula 1 below.

[Formula 1]

A PDMS-MPU _0.4 -IU _0.6 film was prepared. Specifically, ₄ g of PDMS-MPU _0.4 -IU in CHCl ₃ was stirred at 50 °C for 3 hours and then cooled at room temperature. Then, the solution was poured onto an OTS-treated silicon substrate (eg, 4 inches), dried at room temperature for 6 hours, and then dried at about 80° C. under reduced pressure (about 100 torr) for 3 hours.

Accordingly, a self-healing polymer film was prepared. The polymer film had a thickness of 0.5 mm. Then, the film was cut into 1 cm × 1 cm size.

The self-healing polymer film surface was treated with oxygen plasma to modify the surface of the self-healing polymer film to be hydrophilic. Then, an adhesive polymer for laminating on the surface of the self-healing polymer film was synthesized.

1-2. Alginate-boronic acid manufacturing method

1 g of alginate polymer was dissolved in 250 mL of 0.1M MES buffer (pH 4.5). 700 mg of 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 100 mg of N-hydroxysuccinimide were dissolved in 10 mL of tertiary distilled water and added to the alginate solution. Then, 3-Aminophenylboronic acid hydrochloride (300 mg) was dissolved in 10 mL of tertiary distilled water and added to the above solution. After the reaction for 12 hours, dialysis was performed for 3 days, and a dried polymer was obtained through lyophilization. In addition, nerve growth factor was added to the solution and mixed.

1-3. Manufacture of nerve suture patch

The alginate-boronic acid conjugate was thinly coated on the self-healing polymer film prepared above in the same manner.

Example 2. Adhesion and physical properties of the nerve suture patch

2-1. Adhesion measurement of nerve suture patch

In the case of nerves, elasticity and elasticity are strong, and stress is generated through physical activity, so a modulus that disperses the force burdened on the surgical site is required. In the case of the self-healing polymer of the present nerve suture patch, due to its flexible properties similar to nerve tissue, it can show an effect of improving adhesion by dispersing the stress applied to the tissue and the attached part. In order to prove the contents, a self-healing polymer-based nerve suture patch and a general silicone (PDMS)-based suture patch were made the same as in Example 1 through a universal test machine and prepared in a size of 0.5 cm in width and 1 cm in length. did After attaching a polyethylene terephthalate (PET) film (backing film) to the back side and tissue without adhesive polymer of the film, attaching the tissue and adhesive patch, and using a 10 N load cell, the sample was stretched upward at a rate of 20 mm per minute and measured. All experiments were measured three times or more, and the adhesive strength of the self-healing polymer patch was improved more than 10 times as shown in FIG. 2 (a) than the silicone-based suture patch.

2-2. Measurement of physical properties of nerve suture patch

This nerve suture patch is in the form of helping nerve regeneration by wrapping around nerves. Therefore, elasticity of the patch generated from nerve contraction and tension is required, and additional pressure should not adversely affect nerve regeneration. Conventional polymers such as PDMS have the potential to cause nerve damage due to these characteristics, but the self-healing polymer used in this patch dramatically reduces this pressure over time. In order to measure the physical properties, the self-healing polymer, which is the polymer of this patch, was installed in a universal test machine with a width of 5 mm and a length of 10 mm, and was stretched at a rate of 20 mm/min. As the polymer increased, the force applied to the equipment increased, and when the force reached 0.3 N, the polymer tension was stopped and the polymer stress over time was analyzed. As shown in Figure 2b, it was confirmed that the stress of the polymer appeared to be 7 kPa.

The stress relaxation effect of the polymer over time was confirmed by dividing the stress over time by the stress applied to the initial polymer (0.3N). As shown in FIG. 2(c), it was confirmed that the force applied to the initial polymer was reduced to half of the initial value within 1 minute, and continued to decrease thereafter. These properties minimize nerve pressure when applied to nerves to prevent nerve necrosis and help regeneration.

<Experimental example>

Experimental Example 1. Animal preparation and implantation of nerve suture patch

All animal experiments were conducted and handled in accordance with the regulations of the Institutional Animal Care and Use Committee of the Korea Institute of Science and Technology (Approval No. 2018-067). Experimental procedures were performed in accordance with the Guide for the Care and Use of Laboratory Animals. For implantation of the nerve suture patch, Sprague-Dawley rats (male, 300 g) were anesthetized using Zoletil and Xylize cocktail (3:1 mg/kg) by intraperitoneal injection. After a deep level of anesthesia was achieved, a skin incision was extended to the dorsal side of the foot to expose the hindlimb muscles. The femoro-biceps and semitendinosus muscles were identified, and the sciatic nerve was exposed from the muscle and then the nerve was cut (Fig. 3(a)).

As shown in Figures 3 (b) and 3 (c), the nerve suture patch prepared in Example 1 was placed in the middle of the film on both sides of the cut nerve, and then the patch was wound and operated. Comparing the time required at this time, as shown in FIG. 3(f), it was about 70 seconds, and it was possible to save more than 10 times compared to the operation time using the existing suture.

As shown in FIGS. 3(d) and 3(e), when the patch was opened 10 days after nerve surgery, it was observed that fibrosis did not progress around the nerve and the severed nerve was recovered. To determine the degree of recovery after surgery, the sciatic functional index (SFI) evaluation method and the myelin thickness (g-ratio, axon diameter/total fiber diameter, normal range: 0.6-0.8) measurement method were used. .

Figure 3 (g) shows the experimental design for measuring the sciatic nerve index. After dyeing the front and back paws of the rat with black ink, it is lured into a black box, and the sciatic nerve index level is measured based on the footprints taken at this time. In the case of the sciatic nerve index, the total plantar length (PL), the distance between the first toe and the fifth toe (TS), and the distance between the second and fourth toes and the middle toe (IT) can be obtained by substituting into the formula, Expresses from -100 with no neurological function to 0 with normal function. As shown in FIG. 3 (h), it was confirmed that the functional recovery of the nerve was further improved in the nerve suture patch compared to the suture. In addition, the recovery rate according to nerve conduction can be measured by obtaining the ratio of the total outer diameter to the inner diameter of the axon through the thickness of the myelin (G-ratio) during nerve recovery. As shown in FIG. 3(i), the normal range was 0.6-0.8, and after 12 weeks, the same recovery rate as the suture was observed.

Through the above results, it was confirmed that the nerve suture patch of the present invention has an excellent recovery effect of severed nerves.

Having described specific parts of the present invention in detail above, it will be clear to those skilled in the art that these specific descriptions are only preferred embodiments, and the scope of the present invention is not limited thereby. will be. Accordingly, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (11)

A self-healing patch for nerve suture containing a self-healing polymer and a hydrogel patch,
The self-healing polymer is polydimethylsiloxane, polyethylene oxide, perfluoropolyether, polybutylene, poly(ethylene-co-1-butylene), poly(butadiene), hydrogenated poly(butadiene), polybutylene And a polymer backbone selected from the group consisting of poly(ethylene oxide)-poly(propylene oxide) block copolymers or random copolymers, and poly(hydroxyalkanoate), and 4,4'-methylenebis(phenylurea) A first moiety comprising a and
a second moiety comprising isophorone bisurea;
Characterized in that the hydrogel patch comprises a conjugate polymer in which boronic acid is conjugated to alginate,
Self-healing patch for nerve suture. delete delete According to claim 1,
The hydrogel patch is a self-healing patch for nerve suture, characterized in that it further comprises a nerve growth factor. delete According to claim 1,
The self-healing polymer exhibits a Young's modulus of 1 to 3000 kPa and an elongation of 1200% to 3000%. Preparing a self-healing polymer film by applying a self-healing polymer on a substrate and then drying it (S1);
Plasma treatment on the surface of the film (S2); and
A method for manufacturing a self-healing patch for nerve suture, comprising the step (S3) of laminating a hydrogel on the surface of the plasma-treated film,
The self-healing polymer is a polymer backbone including a first moiety containing methylenebis(phenylurea) and a second moiety containing isophorone bisurea,
The polymer backbone is polydimethylsiloxane, polyethylene oxide, perfluoropolyether, polybutylene, poly(ethylene-co-1-butylene), poly(butadiene), hydrogenated poly(butadiene), polybutylene and It is selected from the group consisting of poly(ethylene oxide)-poly(propylene oxide) block copolymers or random copolymers, and poly(hydroxyalkanoates);
The method of claim 1, wherein the hydrogel comprises a conjugated polymer in which boronic acid is conjugated to alginate. delete delete According to claim 7,
In the manufacturing method, the hydrogel further comprises a nerve growth factor, a method for producing a self-healing patch for nerve suture. According to claim 7,
The self-healing polymer,
Polydimethylsiloxane, polyethyleneoxide, perfluoropolyether, polybutylene, poly(ethylene-co-1-butylene), poly(butadiene), hydrogenated poly(butadiene), polybutylene and poly(ethylene oxide) ) -Poly (propylene oxide) block copolymer or random copolymer, and a polymer backbone selected from the group consisting of poly (hydroxyalkanoate), and a first comprising 4,4'-methylenebis (phenylurea) moiety and
A method of manufacturing a self-healing patch for nerve suture, characterized in that it comprises a second moiety containing isophorone bisurea.

Images