JP2003246851A - Biodegradable material having elastic property and artificial blood vessel formed therefrom - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To develop and provide an elastic material capable of recovery to its original form after expansion and capable of molding in an elastic specific form, particularly an artificial blood vessel, and a technique for molding. <P>SOLUTION: A fundamental structural unit having flexibility is formed by binding two or more materials with different crystallinities with a covalent bond. The resultant fundamental structural unit having flexibility is further bonded with more firm bond to form a polymer in three dimensional form The polymer can be molded in various products of plates, blocks, sponges, threads and so forth. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a stretchable material having biodegradability that is decomposed in nature.
And an article made of such a material, particularly an artificial blood vessel.

[0002]

2. Description of the Related Art Biodegradable materials represented by polylactic acid have already been reported. Since these materials are decomposed in the soil and returned to the soil, attempts to process them into various products have been studied in recent years as environmentally friendly materials. However, the materials that have been developed so far have extremely low stretchability to the point that they have no ability to return to pulling or compressing, which makes the application range of conventional materials very limited. It was a thing.

Also in the medical field, it has already been known that materials that remain permanently in the body cause many secondary diseases such as carcinogenesis and inflammation. Many artificial organs have been designed and developed as guide substrate materials.

Further, in the medical field, it has been expected to develop a material having mechanical properties similar to those of an in-vivo organ as a biodegradable artificial organ material. That is, it has been known that when an artificial organ having a mechanical property different from that of an in-vivo organ is transplanted into the in-vivo, a chain reaction due to a difference in mechanical properties occurs in the in-vivo. For example, in the case of an artificial blood vessel, the blood vessel in a living body expands or contracts depending on the blood pressure, but since no conventional artificial blood vessel made of biodegradable material has elasticity, the artificial blood vessel and the blood vessel are It has been known that the strain generated at the anastomosis portion between the blood vessel and the blood vessel causes a secondary reaction, and development of a biodegradable material having stretchability similar to that of blood vessels has been earnestly desired. Since the same phenomenon occurs in other organs, the development of biodegradable materials having elastic properties has been expected.

[0005]

To date, no biodegradable materials have been reported that have elastic properties, which are the properties to return upon pulling or compression.
Therefore, the development of biodegradable materials that act like rubber and cushions, such as artificial blood vessels, has been left as a major problem.

[0006]

Under the circumstances as described above, the present inventors have earnestly studied biodegradable materials, and as a result, as a result, a copolymer of caprolactone and lactic acid and / or glycolic acid (block or Random copolymer)
It was found that a stretchable material can be obtained by attaching a group such as a photopolymerizable acrylate to the end of a copolymer of a biodegradable material consisting of and curing the material.

That is, the present invention provides a stretchable material made of a biodegradable material. This biodegradable material is composed of a polyester-based organic polymer, and particularly preferably a block copolymer of caprolactone and lactic acid and / or glycolic acid. Since an article made of such a material made of a stretchable biodegradable material has a property of returning to its original state when pulled or compressed, a general shaped article having a rubber-like property is produced. Is possible.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

The present invention relates to a stretchable material made of a biodegradable material. In the present invention, the "biodegradable material" refers to a material having biodegradability that is decomposed in soil and returned to the soil, and is not absorbed in the living body, and a typical example thereof is a polyester organic polymer. And, for example, caprolactone (especially ε-caprolactone) and lactic acid (especially L-
There are copolymers with lactic acid) and / or glycolic acid.

The copolymers useful in the present invention may be random or block copolymers, but block copolymers consisting of blocks derived from caprolactone and blocks derived from lactic acid and / or glycolic acid are particularly preferred. If necessary, a so-called star block copolymer having a plurality of copolymer chains of caprolactone and lactic acid and / or glycolic acid can be used,
Good results are obtained.

Furthermore, in order to bring out appropriate mechanical properties, the molecular weight of the polymer can be tailored. For example, the molecular weight of the copolymer is 500-10.
In the range of 10,000, preferably 1,000 to 50,000
It can be in the range of 0. In the case of block copolymer, the molecular weight of the block derived from caprolactone is 5
00 to 100,000 is preferable, and the molecular weight of the block derived from lactic acid and / or glycolic acid is 1,000 to 5
10,000 is preferable.

Such a copolymer may be commercially available or may be produced by a known method.
See, for example, JP-A-6-16799.

In the present invention, a photoreactive group such as an acrylate group and / or a methacrylate group is covalently bonded to the end of such a copolymer. This allows the photopolymerizable copolymer to be cured by suitable radiation, such as visible light or UV light. The introduction of this terminal group can be carried out by a method known to those skilled in the art.

The reason why a stretchable material can be obtained by the present invention has not been completely clarified. For example, in the case of the materials shown in Examples below, two or more polymer blocks having different crystallinity are covalently bonded. By forming a flexible constitutional unit, which is the minimum unit, by connecting with a stronger bond, a star-shaped copolymer can be obtained.
It can be considered that when the material is molded into a three-dimensional shape, a material and a molded product having the property of returning to their original state by pulling or compressing are produced.

The material of the present invention made of such a biodegradable material and the article made from the material can have various shapes such as a plate shape, a block shape, a sponge shape, and a thread shape, and from a hard material to a soft molding. The object can be a biodegradable shaped article having an elastic property of returning to the original shape. For example, medical materials and medical products, electrical appliances, general shaped objects represented by furniture, plastic bottles, containers related to the general food and beverage industry represented by prepared food containers, elastic strings, packings, and cushions. It is useful as a general household item such as. In addition, such an article is useful for artificial organs, particularly artificial blood vessels, medical fields including therapeutic instruments, and the like.

[0016]

EXAMPLES The present invention will now be described in detail by way of examples, but the present invention is not limited to these examples in any sense.

Example 1 Copolymer of L-lactic acid and ε-caprolactone having different crystallinities (molecular weight: 10,000; molar ratio of L-lactic acid and ε-caprolactone charged: 50:50, catalyst: tin 2-ethylhexanoate) Polymerized at 90 ° C) with pentaerythritol 40
The reaction was carried out at 0 ° C to covalently bond to the tip of pentaerythritol. A star-shaped polymer having four copolymer chains composed of a poly (L-lactic acid) block and a poly (ε-caprolactone) block was obtained. Attaching a photopolymerizable acrylate group to the tip of the L-lactic acid / caprolactone copolymer chain,
A photopolymerizable polymer was completed. Its molecular weight was 10,000 according to gel chromatography.

Then, the liquid material was put into a plate-shaped mold, and UV light was irradiated for 10 minutes to finally form the plate-shaped material (50 mm × 50 mm × 1.0 m).
m). This plate-shaped material is cut into strips (1.0 mm x
(20 mm × 1.0 mm), after adding tension corresponding to 20%, it was found that when the tension was removed, the length returned almost completely to the original length.

Example 2 A liquid polymer was obtained in the same manner as in Example 1. afterwards,
After mixing ammonium hydrogen carbonate completely and uniformly, a liquid material was put into a cylindrical mold, and UV light was irradiated for 10 minutes to finally form a cylindrical artificial blood vessel.
Then, ammonium hydrogencarbonate was eluted with hot water at 90 ° C. for 10 minutes. After drying, the SEM photograph confirmed that the artificial blood vessel was an elastic porous three-dimensional carrier.

[0020]

As described above, according to the present invention, a biodegradable material having a property of returning to a tensile or compressive state can be obtained. Using this material, the development of general shaped objects with rubber-like properties, sponge-like biodegradable moldings, biodegradable threads, and even implantable artificial organs such as artificial blood vessels. Is possible.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Fusae Miyata             7-3 Hongo 7-3 Hongo, Bunkyo-ku, Tokyo             Graduate School of Engineering, Chemical System Engineering             Within the major (72) Inventor Takashi Ushida             1-1-1 Higashi 1-1-1 Tsukuba City, Ibaraki Prefecture             National Institute of Advanced Industrial Science and Technology Tsukuba Center (72) Inventor Tetsuya Tateishi             1-1-1 Higashi 1-1-1 Tsukuba City, Ibaraki Prefecture             National Institute of Advanced Industrial Science and Technology Tsukuba Center F-term (reference) 4C081 AB13 CA171 CC02 CC08                 4C097 AA15 BB01 DD01 EE08 FF02                 4J027 AB10 AB19 AB28 AJ01 AJ06                       CB10 CC05 CD01 CD07                 4J029 AA02 AB01 AB02 AB07 AC03                       AD01 AE06 EA03 EA05 EG09                       FC08 GA42 GA43 HA01 HB01                       HE02 JB171 JF371

Claims (10)

[Claims] 1. A stretchable material made of a polyester biodegradable material. 2. The material according to claim 1, wherein the biodegradable material is a copolymer of caprolactone and lactic acid and / or glycolic acid. 3. The material according to claim 2, wherein the copolymer is a star block copolymer. 4. The biodegradable material is an acrylate group and / or
Alternatively, the material according to claim 1, which contains a methacrylate group. 5. The copolymer has a molecular weight of 500 to 10
The material according to any one of claims 2 to 4, which is 50,000. 6. A molecular weight 1 having an acrylate end group.
A stretchable, biodegradable material consisting of 10,000 caprolactone / lactic acid star block copolymers. 7. An article obtained by curing the material according to claim 1. 8. The article according to claim 7, which is an artificial blood vessel. 9. The artificial blood vessel according to claim 8, which has a porous structure. 10. Molecular weight 1 having acrylate end groups
A porous artificial blood vessel made by curing 50,000 caprolactone / lactic acid star block copolymers.